Wyoming Clean Water Plant
Biosolids Management Final Report
Team 7: Blackwards
Eyosias Ashenafi
Rachel Gaide
Andrew Mitchell
Katherine Vogel
May 2014.
Copyright © 2014 Team 7 and Calvin College.
All rights reserved.
Blackwards
Executive Summary
This project focuses on designing a progressive biosolids management system for City of
Wyoming Clean Water Plant (CWP). Landfills contribute 35% of all methane emissions in the US,
and methane gas is 25 times more harmful to the environment than carbon dioxide.
Figure A: Schematic of Proposed Sludge Management Process
The team selected anaerobic digestion for sludge stabilization. The choice was made over
chemical treatment and aerobic digestion on the basis of monetary and non-monetary factors.
The primary design specifications of the client were:
-
Class A biosolids product
Progressive technology
Nutrient recovery options
Anaerobic digestion is a relatively newer technology that enables treatment plant to
produce Class A product. The team selected temperature-phase operating condition where three
smaller cylindrical tanks operating at thermophillic (65°C) conditions precede two much larger
egg shaped digesters operating at mesophillic conditions (35°C).
The tank size for each
thermophillic tank is 60,000 gallons and hydraulic residence time is 22 hours. The mesophilic
tanks have a volume of 1.5 million gallons each and have a hydraulic residence time of 15 days.
Proposed digestion system is shown in Figure B.
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Figure B: Two- stage Anaerobic Digestion system (CB&I)
Thickening was then explored in order to decrease sludge volume and therefore decrease
digester costs. Thickening options reviewed include centrifuges, rotary drums and belt presses.
Centrifuges were determined to be the best alternative because there are currently two units in
use that can be utilized in the proposed new process. The new centrifuge can be installed for
$588,800 and will be utilized to get the percent solids in waste activated sludge from 0.7% to 4%.
Once anaerobic digestion was selected as the stabilization option, the need for
dewatering was evaluated. It was decided that for ease of transportation, a dewatering step was
necessary. The methods for dewatering were the same as those for thickening, without the
benefit of having two on site. Despite this, centrifuges still proved to be the best option for the
plant. A building will also need to be put on site for these centrifuges. A 50 x 50 foot steel building
is proposed for this purpose and will cost approximately $40,000.
The team built a bench scale digester in the spring semester. The system was fed with
sludge samples from Wyoming and Grandville CWP. Total and volatile solids test was performed
on samples collected daily. The latter test indicates level of biodegradation that occurs during
digestion. Figure C below shows results from the final run. Experimental period was 18-days long.
Over this period, daily sludge samples were collected, stored at 4 C° and burned weekly. Decrease
of volatile solids can be observed in Figure C which imply volatile solids destruction and methane
production.
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Figure C: Bench Scale Results
The team designed a site plan for the proposed biosolids management system which
addresses all of the space constraints for the digesters and additional thickening and dewatering
units. The site plan also provides details on the constraints of operation throughout the year.
Post treatment storage must be able to store all of the biosolids that cannot be land applied due
to seasonal constraint.
Table A: Project Cost Breakdown
Project Cost
Digester System
Holding Tanks
Thickening
Dewatering
Storage Tanks
Cogeneration
Biogas Conditioning
Gas Storage
Contingency
Total
$15 M
$1 M
$600 K
$1.2 M
$3.1 M
$1.5 M
$507 K
$300 K
$2.1 M
$22.9 M
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Table of Contents
Executive Summary .......................................................................................................................... i
Table of Contents .............................................................................................................................v
Table of Figures ............................................................................................................................. viii
Report Tables .................................................................................................................................. ix
Abbreviations ...................................................................................................................................x
1. Introduction .............................................................................................................................. 11
1.1 Purpose Statement.............................................................................................................. 11
1.2 The Project .......................................................................................................................... 11
1.3 Overview of Wastewater Treatment .................................................................................. 11
1.4 Overview of Biosolids Classification .................................................................................... 13
2. The Client .................................................................................................................................. 14
2.1 City of Wyoming .................................................................................................................. 14
2.2 Wyoming Clean Water Plant ............................................................................................... 14
2.2.1 Overview ....................................................................................................................... 14
2.2.2 Current Wastewater Treatment Practice ..................................................................... 15
2.2.3 Current Biosolids Management .................................................................................... 16
3. Sludge Thickening Design.......................................................................................................... 18
3.1 Introduction......................................................................................................................... 18
3.2 Evaluation of Thickening Alternatives ................................................................................. 19
3.3 Recommendation ................................................................................................................ 21
3.4 Total Solids Composition for Digestion ............................................................................... 21
3.5 Thickening and Holding Tank Configuration Decision ........................................................ 22
3.6 Cost Information ................................................................................................................. 25
4. Pre-Digestion System: Thermal Hydrolysis ............................................................................... 26
5. Sludge Holding Tank Design ...................................................................................................... 28
5.1 Existing system .................................................................................................................... 28
5.2 Proposed Addition ............................................................................................................... 28
5.3 Mixing Method .................................................................................................................... 29
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5.4 Material of Construction ..................................................................................................... 30
5.5 Gas Elimination .................................................................................................................... 30
5.6 Cost Information ................................................................................................................. 31
6.1 Introduction......................................................................................................................... 32
6.2 Evaluation of Stabilization Alternatives .............................................................................. 32
6.3 Recommendation ................................................................................................................ 34
6.4 Anaerobic Digestion Process Chemistry.............................................................................. 35
6.5 Class A Biosolids Requirement ............................................................................................ 36
6.6 Digestion Temperature ....................................................................................................... 39
6.7 Digester Configuration ........................................................................................................ 41
6.7.1 Tank Design................................................................................................................... 41
6.7.2 Digester Shape .............................................................................................................. 41
7. Digester Biogas Production ....................................................................................................... 46
7.1 Introduction......................................................................................................................... 46
7.2 Potential Methane Production at Wyoming CWP .............................................................. 48
7.3 Operation and Maintenance ............................................................................................... 52
7.4 Case Studies......................................................................................................................... 53
8. Cogeneration ............................................................................................................................. 55
8.1 Cogeneration Implementation ............................................................................................ 55
8.2 Cost Savings ......................................................................................................................... 55
8.3 Biogas Conditioning ............................................................................................................. 57
8.4 Cost Information ................................................................................................................. 58
9. Post-Digestion Dewatering ....................................................................................................... 59
9.1 Dewatering Introduction ..................................................................................................... 59
9.2 Proposed Percent Dewatering ............................................................................................ 59
9.3 Method of Dewatering ........................................................................................................ 60
10. Biosolids Storage Tanks........................................................................................................... 61
10.1 Design Considerations ....................................................................................................... 61
10.2 Current Biosolids Storage Facilities ................................................................................... 61
10.3 Required Biosolids Storage Capital ................................................................................... 62
11. Pumping Station Design .......................................................................................................... 64
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11.1 Introduction....................................................................................................................... 64
11.2 Pipe Selection .................................................................................................................... 64
11.3 Pipe Diameters .................................................................................................................. 66
11.4 Cleaning Pipes ................................................................................................................... 67
11.5 Cleaning Methods ............................................................................................................. 67
12. Nutrient Removal/Recovery ................................................................................................... 68
13. Site Layout............................................................................................................................... 69
14. Bench Scale Experiments ........................................................................................................ 70
14.1 Digester Construction........................................................................................................ 70
14.2 Operation and Testing ....................................................................................................... 71
14.3 Results and Discussion ...................................................................................................... 72
14.4 Safety ................................................................................................................................. 73
15. Total Cost of Proposed System ............................................................................................... 74
16. Future Work ............................................................................................................................ 74
Acknowledgements....................................................................................................................... 75
References .................................................................................................................................... 76
Appendix I: Team Management ................................................................................................... 79
Appendix II: Mathcad Calculations ............................................................................................... 83
Appendix III: Hydraulic Profile .................................................................................................... 105
Appendix IV: Manual of Laboratory Tests .................................................................................. 107
Appendix V: Formatted Selections from Clean Water Act Part 503 ........................................... 113
Appendix VI: Equipment Info ...................................................................................................... 123
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Table of Figures
Figure 1: Layout of a Conventional Wastewater Treatment System ........................................... 12
Figure 2: Projected Biosolids Use and Disposal in the United States (EPA, 1999) ....................... 13
Figure 3: Aerial View of Wyoming CWP ........................................................................................ 15
Figure 4: Current Wastewater Treatment at Wyoming CWP ....................................................... 16
Figure 5: Current Biosolids Management at Wyoming CWP ........................................................ 17
Figure 6: Thickening Room with Andritz Bird Centrifuges ............................................................ 18
Figure 7: Schematic of a typical centrifuge system (EPA, 2000)................................................... 21
Figure 8: Centrifuge Placement Alternatives ................................................................................ 22
Figure 9: Centrisys Model CS26-4 Decanter Centrifuge ............................................................... 25
Figure 10: Sludge Stabilization with CAMBI THP System .............................................................. 27
Figure 11: Sludge Holding Tanks at Wyoming CWP ...................................................................... 28
Figure 12: Jet Mixing System ........................................................................................................ 29
Figure 13: Exponential Cost Curve for Digester Construction ...................................................... 30
Figure 14: Stages of Anaerobic Digestion ..................................................................................... 35
Figure 15: Treatment Processes that achieve Class A Biosolids ................................................... 38
Figure 16: Comparison of Coliform Destruction (Kade, 2004) ..................................................... 40
Figure 17: Two Stage, High-rate Anaerobic Digester .................................................................... 41
Figure 18: Egg Shaped Digester Configuration ............................................................................. 42
Figure 19: Single-stage Cylindrical Digesters ................................................................................ 43
Figure 20: Two- stage Anaerobic Digestion system (CB&I) .......................................................... 45
Figure 21: Effect of Sludge Retention Time (SRT) on VSS Reduction for High-rate System ......... 46
Figure 22: Potential Sources of Biogas for an AD system ............................................................. 48
Figure 23 : Methane Production Prediction for Thermophilic System ......................................... 49
Figure 24 : Methane Production Prediction for TPAD System ..................................................... 50
Figure 25 : Methane Production as a Function of Influent Flow to Plant .................................... 51
Figure 26: Egg-shaped Digester at Grandville CWP ...................................................................... 53
Figure 27: Comparison of Sludge Flow and Associated Gas Production ...................................... 54
Figure 28: Uses for Energy produced from Digestion ................................................................... 56
Figure 29: Hydrogen Sulfide.......................................................................................................... 58
Figure 30: Siloxane Removal System ............................................................................................ 58
Figure 31: Injection Biosolids Land Application Equipment ......................................................... 59
Figure 32: Biosoilds Storage Tanks in the rear .............................................................................. 61
Figure 33: Seasonal Variations in Biosolids Storage in 2013 ........................................................ 62
Figure 34: Pumping Head Needed as a Function of Pipe Diameter ............................................. 66
Figure 35: Suggested Location of Digestion Facility ..................................................................... 69
Figure 36: Bench Scale Anaerobic Digester .................................................................................. 70
Figure 37: Trial Run Spill ............................................................................................................... 71
Figure 38: Results from Trial Run .................................................................................................. 72
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Figure 39: Results from Final Digestion Run ................................................................................. 73
Figure 40: Team Photo .................................................................................................................. 79
Figure 41: Spectronic 20D+ equipment ...................................................................................... 109
Report Tables
Table 1: Average Sludge Composition .......................................................................................... 17
Table 2: Thickening Design Matrix ................................................................................................ 20
Table 3 : Comparison of Thickening Placement Alternatives ....................................................... 24
Table 4: Description of Proposed Centrifuge ................................................................................ 25
Table 5: Capital Cost of Holding Tanks.......................................................................................... 31
Table 6: Design Matrix for Sludge Stabilization ............................................................................ 34
Table 7: EPA CWA Pollutant Limits ............................................................................................... 37
Table 8: Digester Operating Temperature Characteristics ........................................................... 40
Table 9: Comparison of cylindrical and egg-shaped digesters ..................................................... 42
Table 10: Configuration of Cylindrical Digesters for Wyoming CWP ............................................ 44
Table 11: Summary of ESD facility plan from CB&I....................................................................... 45
Table 12: Typical Characteristic of Primary and Secondary Solids ............................................... 47
Table 13: Estimated Biogas Production ........................................................................................ 47
Table 14: Information about Wyoming Waste Flow .................................................................... 48
Table 15: VSR Assumption for AD systems ................................................................................... 49
Table 16: Digester Monitoring (WEF, 2007) ................................................................................. 52
Table 17: Digester Gas Composition (by volume)......................................................................... 57
Table 18: Cost Information for Biogas Conditioning .................................................................... 58
Table 19: Comparison of Final Biosolids Percent Solids Composition .......................................... 60
Table 20: Advantages and Disadvantages of Progressive Cavity Pump ....................................... 65
Table 21: Length of New Pipe Needed for Each Section of Route ............................................... 65
Table 22: Comparison of Nutrient Recovery Technologies .......................................................... 68
Table 23: Work Breakdown Structure (Fall 2013) ........................................................................ 80
Table 24: Work Breakdown Structure (Spring 2014) .................................................................... 81
Table 25: Solids Measurement Datasheet .................................................................................. 108
Table 26: COD experiment Datasheet ........................................................................................ 110
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Abbreviations
AD
BOD
°C
CHP
COD
CWA
CWP
DAF
EPA
EQ
gpm
GVRBA
HRT
kg
lb/day
m3/day
mg
mgd
MPN
NPDES
ppb
ppm
PS
SCFAs
SRT
THP
TPAD
TS
TSS
tWAS
UV
VAR
VS
VSR
WAS
WW
WWTP
WWTPs
Anaerobic Digestion
Biological Oxygen Demand
degrees Celsius
Combined Heat and Power
Chemical Oxygen Demand
Clean Water Act
Clean Water Plant
Dissolved Air Floatation
Environmental Protection Agency
Exceptional Quality
gallons per minute
Grand Valley Regional Biosolids Authority
Hydraulic Residence Time
kilogram
pounds mass per day
cubic meters per day
milligram
million gallons per day
Most Probable Number
National Pollutant Discharge Elimination System
Parts per billion
Parts per million
Primary Sludge
Short-Chained Fatty Acids
Sludge Retention Time
Thermal Hydrolysis Process
Temperature Phase Anaerobic Digestion
Total Solids
Total Suspended Solids
Thickened Waste Activated Sludge
Ultraviolet
Vector Attraction Reduction
Volatile Solids
Volatile Solids Reduction
Waste Activated Sludge
Wastewater
Wastewater Treatment Plant
Wastewater Treatment Plants
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1. Introduction
1.1 Purpose Statement
The purpose of this project is to design a modern, efficient and environmentally friendly
biosolids management system for the City of Wyoming Clean Water Plant (CWP). This document
will elaborate on the design process and future work that need to be completed.
1.2 The Project
Calvin College’s Engineering Program includes a year-long senior design project. The
design team formed for this class pursued appropriate project alternatives considering the
previous educational experience of the team members. Dr. David Wunder, the team’s faculty
advisor, suggested that the team approach the City of Wyoming CWP for potential design
projects. The City of Wyoming Clean Water Plant was built to handle waste water from Wyoming,
Byron Center and surrounding cities. The team met with Myron Erickson, superintendent of the
CWP, and with Aaron Vis, Project Manager of GVRBA (Grand Valley Regional Biosolids Authority).
During the meeting, the team was informed that GVRBA was currently collecting bids from
consulting firms for stabilization alternatives to current practice. Upon further consulting with
Myron Erickson, the team decided to design an anaerobic digester for biosolids management for
the City of Wyoming CWP.
1.3 Overview of Wastewater Treatment
In general, municipal wastewater is collected from residential areas, businesses and
industries, and pumped to wastewater treatment plants (WWTPs). Conventional wastewater
treatment consists of four major stages (Figure 1).
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Figure 1: Layout of a Conventional Wastewater Treatment System
I)
Preliminary Treatment is the first step in wastewater treatment. Rags and floatables
present in influent stream are physically removed using bar screens by size. This stage
increases downstream load capacity while preventing damage to pumping
equipment.
II)
Primary Treatment is the second stage which removes sediments by a gravity settling
and skimmers. Sludge is allowed to settle inside a primary clarifier. Skimmers remove
suspended solids and grease material on the top surface.
III)
Secondary Treatment is a biological treatment with an aeration and settling stage. It
is commonly referred to as activated sludge. During aeration, microbes feed on
organic matter inside a tank fitted with air diffusers. After a certain period of time,
the waste stream is sent to a secondary clarifier. Sludge settles inside the clarifier.
Some portion of the sludge produced is recycled back to the aeration tank to maintain
microbial growth while the remaining is sent for further treatment. Management of
solids produced from primary and secondary clarifiers is the focus of this project.
IV)
Tertiary Treatment (Disinfection) is the final step in wastewater treatment before
supernatant or treated effluent is sent to water bodies. Common disinfection schemes
include chlorination, ozonation, and ultraviolet (UV) radiation.
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Several variables are considered in the design and construction of WWTPs including operating
capacity and regulations. Population growth and industrial expansion is accounted for in
determination of design capacity. Treatment facilities and government agencies assess the
quality of supernatant water and by-product sludge to ensure it meets Environmental Protection
Agency (EPA) and National Pollutant Discharge Elimination System (NPDES) standards.
1.4 Overview of Biosolids Classification
Biosolids are treated residual solids left over after waste water treatment process.
Treated biosolids can be classified as either Class A or Class B. Class A Biosolids can also be
categorized as “exceptional quality” (EQ) if they satisfy pollutant concentration limits. Biosolids
can be applied to land, placed on a surface disposal site, or fired in a sewage sludge incinerator.
Figure 2: Projected Biosolids Use and Disposal in the United States (EPA, 1999) shows current
biosolids disposal methods in the United States. In land application, treated biosolids are used
to moisturize the soil and as fertilizers. “Surface disposal site” is another name for a landfill.
From an environmental perspective, land application is the preferred option for final disposal
place of treated biosolids.
60%
50%
40%
30%
20%
10%
0%
1998
2000
2005
Land Application
Advanced Treatment
Other Benficial Use
Surface Disposal/ Landfill
Incineration
Other disposal
2010
Figure 2: Projected Biosolids Use and Disposal in the United States (EPA, 1999)
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The end location of the biosolids determines what regulations are applicable from Part
503 of the Clean Water Act (CWA). There are three parts to achieving Class A designation for
biosolids. First, the pathogenic content of the sludge must be reduced sufficiently. Second, there
must be sufficient Vector Attraction Reduction (VAR). Third, inorganic pollutants must be below
certain maximum values. These issues are explained in context more in “Section 6.5 Class A
Biosolids Requirement.”
Class A Biosolids, with appropriate pollutant loads, can be land applied to agricultural and
non-agricultural land, public contact sites, a reclamation site, lawns and/or home gardens. Class
A Biosolids can be given away to local farms or it can be sold for its nutrients. Class B Biosolids
are restricted as to where and when land application can occur.
2. The Client
2.1 City of Wyoming
The city of Wyoming lies within the Grand Rapids Metro area in western Michigan. It
occupies an area of 24.9 square miles and serves a population of 73,000 people. The area also
includes several major industries including Gordon Food Services, Michigan Turkey Producers and
Country Fresh.
2.2 Wyoming Clean Water Plant
2.2.1 Overview
Wyoming’s CWP is located on Ivanrest Avenue on the southwestern edge of Wyoming
(see Figure 3: Aerial View of Wyoming CWP). The plant treats wastewater from the City of
Wyoming, the City of Kentwood, Gaines Township, and Byron Township, and has a design
capacity of 24 million gallons per day (mgd). Current average daily flow through the plant is
14.7mgd, 12% of which originates from local industries. Treated water from the plant is
discharged into the Grand River.
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Figure 3: Aerial View of Wyoming CWP
2.2.2 Current Wastewater Treatment Practice
Raw wastewater from the City of Wyoming, the City of Kentwood, Byron Township, and
Gaines Township is collected at Wyoming CWP. Bar screens remove large sediments and
materials present in incoming wastewater. The flow proceeds to primary clarifiers where large
granular molecules are removed by gravity sedimentation. Currently, there are four primary
clarifiers with removal rate of 10-40% biological oxygen demand (BOD) and 50-60% total
suspended solids (TSS). Clarified effluent from primary treatment proceeds to one of three
aeration basins. The basins are equipped with fine bubble diffusers to aerate and provide a
conducive environment for microbial growth. Mixed liquor is sent to secondary clarifiers.
Flocculated and dense, suspended solids in mixed liquor settle inside the clarifiers. In 2008, a
biological phosphorus removal process (anoxic/anaerobic zone) was incorporated into secondary
treatment. Waste activated sludge (WAS) is recycled to the aeration basins. Clear low-BOD, lowTSS clarified effluent is chlorinated and de-chlorinated for disinfection before being discharged
to the Grand River. An overview of the treatment process is shown in Figure 4.
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Figure 4: Current Wastewater Treatment at Wyoming CWP
2.2.3 Current Biosolids Management
Biosolids produced by Wyoming and Grand Rapids WWTPs are currently managed by the
GVRBA. GVRBA was formed in 2003 to address strict regulatory requirements and manage
regionally-produced biosolids efficiently.
Sources of biosolids at Wyoming CWP are primary and secondary clarifiers (Figure 5).
Based on dry ton basis, approximately 55% thickened waste activated sludge (tWAS) and 45%
primary sludge (PS) pumped to sludge holding tanks. Certain volume of WAS from secondary
clarifiers is thickened using centrifuges. Thickened WAS is stored in one of three wet wells before
it is sent to GVRBA pumping station or storage tanks. Characteristics of PS, un-thickened and
thickened WAS are given in Table 1: Average Sludge Composition. To prevent phosphorus
release, WAS is thickened to maximum of 2% total solids (TS), and the wet wells are aerated and
treated with ferric chloride.
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Table 1: Average Sludge Composition1
Parameter
Total Solids, %TS
Volatile Solids, %VS
pH
Alkalinity (mg/L)
Primary
Sludge
4.26
3.72
5.52
922
Un-thickened
WAS
0.96
0.8
6.98
216
Thickened
WAS
3.53
2.95
6.53
444
Approximately 75% of the year biosolids from Wyoming CWP are stored in three tanks
with a combined capacity of 6 million gallons. The biosolids are then lime stabilized and then used
for land application. This process is shown in Figure 5. The remaining 25% is pumped to GVRBA
storage tanks in Grand Rapids WWTP through two 3-miles long pipelines. Incoming flow is
combined with biosolids from the City of Grand Rapids WWTP. The resulting flow is dewatered
by centrifuges and stored in a landfill.
Figure 5: Current Biosolids Management at Wyoming CWP
The team sought out to design a new biosolids management process, focusing on energy
and nutrient capture, environmental concerns and government regulations.
1
Data from 12/11/13 to 02/15/14
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3. Sludge Thickening Design
3.1 Introduction
Thickening is a mechanical process of altering the solid content of an influent stream. By
removing fluid portion of the entering stream, it is used to increase the concentration of solids in
sludge. Primarily, a thickening step increases tank detention time, reduces operation costs and
lowers tankage capacity downstream in biosolids processing and storage.
Currently, thickening at Wyoming CWP is performed with two Andritz Bird centrifuges
with a unit capacity of 265 gallons per minute (gpm). The existing thickening system is shown in
Figure 6. The centrifuges thicken WAS from 0.5-1%TS on average to 4-5%TS. Mannich and
emulsion polymers are added enhance solids capture. The centrate is the clarified supernatant
produced from the process and is sent to the head works of the plant. Existing centrifuge units
were considered as thickening alternative. Both centrifuges are 24 years old; however one was
rebuilt in 2012, and the other was rebuilt in 2013. The plant expects another 10 years of operation
from both centrifuges. A rehabilitation of the thickening system is under consideration by the
Wyoming CWP.
Figure 6: Thickening Room with Andritz Bird Centrifuges
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3.2 Evaluation of Thickening Alternatives
Three sludge thickening technologies were considered in the design process. Score of 0%
to 100% was assigned on the basis of performance of each alternative under each category. High
score corresponds to attractive feature or good performance in the respective category. This
leads to values that seem in conflict with categories that describe weaknesses rather than
strengths. Decision matrix of thickening alternatives is presented on Table 2.
Category Considerations:
1. Sustainability: How much energy is required to operate this technology? What form of
energy is used and how is it produced? How much equipment is already owned by the
client and can be reused for this project? Does this technology require nonrenewable
resources in order to function? How efficient is the technology at completing the required
process?
2. Effluent Quality: Does this technology thicken solids adequately? Is it possible to get a
uniform solids concentration in effluent consistently?
3. Progressive Technology: Would the novelty of this technology improve public image of
the facility?
4. Capital Costs: How much does the equipment cost to obtain? How much will it cost to
install? How much time will it take employees to train on using the new equipment?
5. Operating Costs: How much does the technology cost to operate each month?
6. Safety: Is the technology difficult to operate or does the technology utilize conditions that
could cause employee injury during machine malfunction?
7. Expandability: Assuming that the future will require increased production can this
technology be expanded easily?
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Table 2: Thickening Design Matrix
Thickening Alternatives
Gravity Belt
Centrifuge
Rotary Drum
Press
1
0.6
0.7
0.7
0.7
0.7
Category
Weight
Sustainability
Effluent Quality
13
16
Progressive Technology
10
0.7
0.7
0.
Capital Costs
Operating Cost
Safety
Expandability
Total Points
19
22
12
8
100
1
0.8
0.9
0.7
84.2
0.7
0.8
0.9
0.7
73.3
0.7
0.6
0.8
0.7
67
Description of Evaluation
I. Centrifuge: The centrifuge yields a higher score in capital costs and sustainability because there
are already two centrifuges on site that could be used for this project. The centrifuge does not
make Class A designation more likely nor does it make it automatically achievable. It does allow
for some expansion as the addition of another centrifuge would be possible with the provided
space, though it does have higher maintenance and energy costs.
II. Rotary Drum: Evaluation of using rotary drums for thickening was very similar to evaluation of
centrifuges with one major difference: there are not rotary drums on site currently. There are no
rotary drums currently on the site and thus this would make the capital cost for the drum much
higher than that of the centrifuge.
III. Gravity Belt Press: The operation prices for the belt press are slightly more than that of the
centrifuge or the rotary drum. Belt presses have been used in industry for over a century, thus
the low score in progressive technology. Other than these slight difference, a belt press also
requires more space than the rotary drum or the centrifuges.
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3.3 Recommendation
Based on the results from the decision matrix, centrifuges are recommended for
thickening purposes. Centrifuges separate solid and fluid content of a sludge via application of
centrifugal force. Configuration of a conventional centrifuge is shown in Figure 7. Slurry or
influent sludge enters the unit on the right. The bowl drive located at the entrance and bowl
rotation provides centrifugal force that will separate the solids and liquid components of influent
sludge. The scroll drive provides horizontal rotation to the screw conveyor which moves solids
towards the right or the conical section for discharge. Liquid discharge or centrate leaves the unit
on the opposite end. Geometry of system components and drive specification determine the
efficiency and flow range a unit can handle.
Figure 7: Schematic of a typical centrifuge system (EPA, 2000)
3.4 Total Solids Composition for Digestion
To achieve optimal feed composition for digestion, the feed could be thickened to 6%.
This is not ideal for design however because at that level of solids content, the fluid is approaching
a non-Newtonian flow. This would make operation and pumping extremely difficult. To avoid
these issues, the team chose to thicken to only 4%2.
2
http://www.lawpca.org/Anaerobic%20Digestion/Conceptual%20Design%20Report.pdf
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3.5 Thickening and Holding Tank Configuration Decision
Thickening the solids will decrease the size requirements of system components
downstream. The team decided to thicken secondary solids from 0.7% solids to 4% solids.
Primary solids is composed of 3.5% percent solids, and therefore could be put into the digester
without thickening. However, the team, in acknowledgement that they cannot anticipate all
future operating decisions, chose to build the system such that primary solids could be thickened
prior to digestion. From this point, the team faced a decision of whether to put thickening
upstream or downstream of mixing.
The Wyoming CWP already has two centrifuges on site and the team decided that they
would like to use these centrifuges for thickening rather than replace them. This resulted in a
need to determine the optimal location of thickening within the process between
primary/secondary settling and digestion. The team identified three potential alternatives, which
are pictorially described in Figure 8. In this figure, blue represents structures that already exist,
red represents structures that will need to be built, and green annotations refer to potential
expansions or space constraints that are ambiguous. The number under the label “Centrifuges”
refer to the number of units currently in place or that would need to be installed. The holding
tanks must have mixing mechanisms in order to provide a more consistent feed to the digesters.
Figure 8: Centrifuge Placement Alternatives
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Alternative 1 involves leaving the current system in place and untouched upstream of the
holding tank. The holding tank must be enlarged and a centrifuge building must be installed
between the holding tank and digestion. Two centrifuges will be needed.
Alternative 2 involves rerouting the flow from secondary settling to the mixing tank and
then rerouting flow from the mixing tank to the thickening building. This alternative requires a
much larger mixing tank and one new centrifuge with a potential future expansion requiring
another new centrifuge.
Alternative 3 involves rerouting flow from primary settling to the thickening building and
increasing the size of the mixing tank. This alternative needs one new centrifuge with a possible
future expansion that would require another new centrifuge.
A cost analysis of each alternative was completed and is shown in Table 3 : Comparison
of Thickening Placement Alternatives. The holding tank expansion was cost estimated using the
assumption that concrete would be the building material and that three days of storage would
be needed (see Section 5 for more information on holding/mixing tanks). Piping distances were
estimated using satellite imagery in reference to the size of a car parking spot.
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Table 3 : Comparison of Thickening Placement Alternatives
Major Pipe Rerouting
Alternative
1
2
3
Alternative
1
2
3
Pumping Changes
Description
Cost
Description
Additional Pipe from Mixing to Second Thickening
Building
$ 23,800
2 new pumps from Holding to Centrifuge
$ 114,000
~ Replace 6 pumps from Secondary to Holding?
~ Add pumps to handle extra flow from holding
to centrifuge
~ Move/replace pumps from (thickening to
holding) to (holding to thickening)
$ 68,900
~ Add pumps to handle flow from thickening to
holding
2 lines from Secondary To Holding Tank
From Holding Tank to Thickening Building
From Primary to Holding Tank
Holding Tank Expansion
Description
Yes
Yes
Largest Volume Needed
Yes
Smallest Volume
Needed
New Centrifuge Units
Cost
Description
Cost
$ 314,900
2
$ 1,176,000
$ 1,117,000
13
$ 588,000
$ 284,600
14
$ 588,000
New Buildings
Description
New Thickening
Building
Cost
Cost
Negligible
compared
to other
costs
Negligible
compared
to other
costs
Negligible
compared
to other
costs
Total Cost
$ 40,000
$ 1,554,700
No New Buildings
$0
$ 1,819,000
No New Buildings
$0
$ 941,500
3
If the population served by the City of Wyoming Clean Water Plant continues to expand, then an additional unit will be needed. This would require an expansion to the
thickening building, as two new units cannot fit into the existing structure
4 Same as 3
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3.6 Cost Information
One additional centrifuge is required to meet redundancy needs for future WAS flow
condition in the proposed sludge management system. It will be located in Thickening room next
to the existing Bird centrifuges. Primary sludge produced at Wyoming CWP has high %TS and
does not require thickening. Centrisys decanter centrifuge shown in Figure 9: Centrisys Model
CS26-4 Decanter Centrifuge was selected for thickening WAS sludge. The unit’s dimension are
8.25 ft. high by 15.75 ft. wide. Basic technical and cost information of Centrisys decanter
centrifuges used in design are summarized in Table 4: Description of Proposed Centrifuge. Gforce in the table represents the horizontal acceleration that the units imparts on feed slurry in
comparison to gravitational acceleration.
Figure 9: Centrisys Model CS26-4 Decanter Centrifuge5
Table 4: Description of Proposed Centrifuge6
Centrifuge Brand
Model
Flow Rate (gpm)
G-force
Motor Horsepower
Product Price*
Number of Units
Total Price
Centrisys
CS26-4
200-400
3000
125
$588,000
1
$588,000
5
http://centrisys.us/products/decanter-centrifuges/CS26-4/
Cost includes centrifuge, hydraulic backdrive, control panel, stand w/out walkway, hoppers (to collect cake and centrate),
piping into plant systems, spare parts kit, service for setup, and shipping.
6
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4. Pre-Digestion System: Thermal Hydrolysis
Cambi THP is a thermal hydrolysis process (THP) that solubilizes or disintegrates
extracellular substances present in sludge before digestion at high temperature and pressure.
Feed sludge is heated at 165°C for 20-30 minutes. Solids content of the feed sludge should be 1617%TS, and thus a prior dewatering stage is required. Advantages of Cambi THP include low
digester volume requirement, pathogen reduction, high dewater-ability of biosolids and high
biogas generation. Foaming and odor problems are minimized, and the system can enhance
stabilization levels post digestion. High quality biosolids can be produced that can be land
applied. Schematic of sludge management system with Cambi THP is shown in Figure 10.
Cambi THP is an emerging technology from Europe that’s gaining popularity in North
America. East Bay Municipal Utility District WWTP in San Francisco and Blue Plains Advanced
WWTP in Washington D.C. are two treatment plants in the US that have successfully integrated
Cambi THP in their sludge management program. Both plants are designated as Class A solids
processing facilities and use cogeneration system to generate heat and electricity from methane
production. Cambi THP is an expensive technology to implement and maintain at small or
medium scale WWTPs. It requires dewatering equipment. Energy costs associated with
dewatering and heating during THP are relatively higher compared to conventional digestion
systems. The team considered CAMBI as a pretreatment step. It was not selected in the final
design due to high capital and operating cost requirements.
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Figure 10: Sludge Stabilization with CAMBI THP System
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5. Sludge Holding Tank Design
5.1 Existing system
Two 150,000 gallons tanks are presently used in Wyoming CWP to store the blend of
primary sludge and thickened WAS (Figure 11). They are located next to the main administration
building. These tanks mix the two streams in order to provide a uniform feed to the digester.
They minimize fluctuations in feed sludge composition and loading rate. They serve as
equalization basins of thickened primary and secondary sludge before stabilization during normal
and higher flow conditions (max month flow). They are also referred to as sludge mixing tanks.
Figure 11: Sludge Holding Tanks at Wyoming CWP
5.2 Proposed Addition
Based on 2025 projected flow, two additional holding tanks with a combined volume of
300,000 gallons will be required. Three day storage at maximum month sludge production rate
was used for determining holding size. More days of storage will lead to sludge quality
deterioration. For emergency situations, it is recommended that the CWP either increase
thickening to no more than 5%TS (to minimize pumping problems) or direct excess flow to Grand
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Rapids WWTP using existing GVRBA facilities. Both holding tanks will be lined with coal tar epoxy
and will be located adjacent to existing tanks.
5.3 Mixing Method
For the holding tank there were several options of mixing, the most common in industry
being the jet mixing system and the other being mechanical agitation. Mechanical agitation
consists of propellers attached to a shaft driven by a motor. Mechanical agitation has a capital
cost of $15,000 per tank. This system tends to collect rags and other debris on the agitator. The
Jet mixing system, as displayed in Figure 12, consists of a chopper pump, several nozzles, and
piping. The Jet mixer, $25,000 per tank, has two key advantage over the mechanical agitation.
This mixer can be turned on and off as needed which is ideal for the times that the sludge is not
being used.
Figure 12: Jet Mixing System
For a 300,000 to 500,000 gallon tank this system can suspend up to 10% TS in under three
hours. This saves municipal plants 30% of the expected operation energy costs7. Secondly, the jet
mixers can be turned onto the walls and clean the tank when needed and the maintenance for
the jet mixers is minimal. For these reasons the Jet mixer system was implemented.
7
http://www.osti.gov/scitech/servlets/purl/768043
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5.4 Material of Construction
Cost curves were constructed using cost data found online for determining appropriate
construction material (Figure 13). Steel tank is the cheapest option amongst the different
alternatives. For all materials, construction price decreases with increase in tank volume. In other
words, it is cost effective to construct a single or few large tanks than several small tanks. The
figure also indicates that price difference between the material alternatives narrows down with
increase in tankage. Concrete is a conventional and preferred material for tank construction due
to its durability, low corrosion property, low maintenance cost and high thermal resistance.
$1.60
$1.40
y = 0.65*Cost-0.454
Cost per gallon
$1.20
$1.00
y = 0.7*Cost-0.474
$0.80
$0.60
$0.40
y = 0.5*Cost-0.351
$0.20
$0
0.2
0.4
0.6
0.8
1
1.2
Tank Volume (million gallons)
Steel
Glass lined steel
Concrete
Figure 13: Exponential Cost Curve for Digester Construction
5.5 Gas Elimination
In the event that the sludge holding / mixing tanks must be used in an emergency
situation, it is possible that the sludge will naturally produce biogas. A major component of
biogas is methane. As biogas is produced, the pressure inside the tank would build up. Both the
pressure build up and the composition of the biogas contribute to an explosion risk.
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For this reason, a flare will be installed that will automatically bleed gas pressure. The
biogas will be burned rather than being simply released because methane is a worse greenhouse
gas than carbon dioxide. The flare will cost $21,000 dollars.8
5.6 Cost Information
Table 5: Capital Cost of Holding Tanks
8
Item
Cost
Holding tanks (2)
Jet Mixers (2)
Flare
Total
$33,000
$25,000
$21,000
$1,181,000
http://www.epa.gov/gasstar/documents/installflares.pdf
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6. Sludge Stabilization Design
6.1 Introduction
Waste solid, commonly referred to as sludge in industry is produced from the physical
separation that occurs in primary treatment and biological activity in activated sludge process.
Stabilization is the process of decomposing organics and destroying pathogens present in primary
and secondary sludge. In most treatment systems, sludge stabilization is incorporated in the
treatment scheme to reduce pathogenic content, to control odor problems and to enhance
sludge dewatering.
6.2 Evaluation of Stabilization Alternatives
Conventional stabilization methods considered during the initial stages were alkaline
stabilization, aerobic and anaerobic digestion.
I. Alkaline Stabilization: is a conventional sludge stabilization method which uses alkaline
substance mainly lime for the destruction of pathogens in sludge. Lime is corrosive in nature
which leads to a shorter design compared to other stabilization options. It also presents safety
hazards. It is a caustic chemical with severe health risks when in direct contact of the skin. End
result of the process has a higher volume due to lime addition. Class A product would not be
achieved without operational modifications including increased dosage and contact time. It is
difficult to accurately represent on a cost scale as it cost varies depending on location of lime
suppliers and seasonal availability. At present, lime stabilization is used at Wyoming CWP. The
lime is currently supplied for no cost since it is a byproduct of acetylene production from a local
company.
II. Aerobic Digestion: is the decomposition of biomass using aerobic bacteria in oxygen-rich
environment. About 75% of cell biomass can be oxidized in a series of chemical reactions to
produce carbon dioxide, water and nitrogen. Compared to anaerobic digesters, it requires less
maintenance and control. Project cost is relatively low, except energy cost associated with
oxygen supply. Heating requirements are limited. Satisfactory volatile solids reduction and BOD
removal can be obtained with proper design and operation. Effluent stream has low solids
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content and consequently higher volume which necessitates frequent trucking and disposal. The
process does not recover methane in sludge for energy generation. Sludge retention time for
Class B product is 40-60 days and depends upon the digester temperature. This process does not
allow for Class A product.
III. Anaerobic Digestion (AD): is the biological degradation of organic materials with
microorganisms in an oxygen-free environment. Volatile solids in sludge are destructed in sealed
tanks, resulting in the production of simple compounds. It is a progressive and proven technology
in the municipal waste management industry. It is sustainable system because methane that
would otherwise get released to the environment from a land fill site is captured on-site resulting
in energy sustainability and reduction of greenhouse gas emissions. Anaerobic digestion can yield
Class A biosolids on a uniform basis with proper design and operation. In comparison to other
stabilization options, the capital cost of anaerobic systems is high due to tank construction,
thickening and dewatering equipment installation and cogeneration system cost. Operational
costs are high due to sludge heating and energy requirements for thickening and dewatering
equipment.
Based on system performance of the different methods, a decision matrix for sludge
stabilization was constructed (Table 6). Three of the stabilization alternatives were weighed on a
scale of 0% to 100%, with 0% corresponding to poor performance and 100% corresponding to
superior performance. Categories in the matrix were given appropriate weight based on client’s
needs, adaptability to existing system and future implications. Description of each category is
presented below.
Category Considerations
1. Capital Costs: How much does the equipment cost to obtain? How much will it cost to
install? How much time will it take employees to train on using the new equipment?
2. Operational Costs: How much does the technology cost to operate each month?
3. Progressive Technology: Would the novelty of this technology improve public image of
the facility?
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4. Sustainability: How much energy is required to operate this technology? What form of
energy is used and how is it produced? How much equipment is already owned by the
client and can be reused for this project? Does this technology require nonrenewable
energy sources?
5. Reliability: Does this technology depend on operator input for changes in feed flow? Does
this technology produce a product that is consistent over time?
6. Design life: How often will this technology need to be replaced?
7. Biosolids Quality: Does this technology make achieving Class A easier or possible?
8. Effect on Plant: If the effluent water is recycled into the plant, will the composition of the
stream cause the water treatment process to be less effective?
9. Potential Energy Production: Will this technology result in methane production
Table 6: Design Matrix for Sludge Stabilization
14
Alkaline
Stabilization
0.9
Anaerobic
Digestion
0.8
Aerobic
Digestion
0.7
Operational Cost
1
0.7
0.3
0.7
Progressive Technology
9
0.2
0.8
0.6
Sustainability
9
0.2
1
0.7
Reliability
9
0.7
0.8
0.8
Design Life
11
0.6
0.8
0.8
Biosolids Quality
18
0
1
0.2
Effect on Plant
3
1
0.4
1
Potential Energy Production
16
0
1
0
Total Points
100
36.8
60.5
48.8
Category
Weight
Capital Cost
6.3 Recommendation
Based on the design matrix above, anaerobic digestion is the ideal stabilization alternative
at Wyoming CWP. The process meets design objectives and regulations. Design objectives of this
project include attainment of Class A product and energy recovery. High rate reactors with mixing
and uniform loading are recommended.
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6.4 Anaerobic Digestion Process Chemistry
Different microorganisms are involved in the decomposition of organic material in
anaerobic digestion process. Cellulose, proteins and other organic compounds in sludge are
solubilized into fatty acids, alcohol and carbon dioxide by extracellular enzymes. The soluble
compounds are further broken down to short-chained fatty acids (SCFAs) such as acetic acid and
hydrogen by acidogenic bacteria. The final stage is the formation of biogas from acetate
decarboxylation and conversion of carbon dioxide and hydrogen by methanogenic bacteria. The
final product, biogas consists of 60% methane and 40% carbon dioxide. Byproducts include
hydrogen sulfide, siloxane and ammonia.
The activation of different microorganisms depends on the operating temperature of
digester, pH and sludge retention time (SRT). Methanogenic bacteria are important
microorganisms in the digestion process that regulate the rate of methane formation. Stages of
anaerobic digestion are presented in Figure 14.
Figure 14: Stages of Anaerobic Digestion
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6.5 Class A Biosolids Requirement
In order to obtain Class A designation for the end product of the anaerobic digester, three
requirements must be met. First, the biosolids must have satisfactory pathogen content
reduction. There are six alternatives for reducing the pathogenic content to below detectable
levels. The proposed anaerobic digestion system for Wyoming CWP meets Alternative 1
(Thermally Treated Biosolids).
Two basic requirements must be met to achieve Class A status. First, either the biosolids
must have a fecal coliform level less than 1000 Most Probable Number (MPN) per gram of total
solids or the biosolids must have a salmonella level less than three MPN per four grams of total
solids. Research has shown that this level can be achieved using a thermophilic anaerobic
digester. Second, the time and temperature of the stabilization must meet one of four options.
Influent total solids levels of 4% means that this design will meet option D. The Clean Water Act
classifies the sludge by percent solid, temperature, and residence time. The equation shown
below describes the relationship between temperature and minimum residence time according
to Part 503 of EPA regulation.
D=
50,070,000
100.14∗T
In this equation, T stands for temperature in degrees Celsius (C) and D is residence time
in days. Since a thermophilic digester operates at a temperature of 55°C, this equation shows
that our residence time must be at least one day.
The residence time chosen was 10 days;
therefore this constraint will be met.
The second requirement for Class A designation is Vector Attraction Reduction (VAR). In
layman’s terms, this means that the biosolids must not have enough energy to support large
populations of new microbes. There are 8 alternatives for meeting vector attraction reduction.
This design meets option 1, which reads as follows:
The mass of volatile solids in the sewage sludge shall be reduced by a minimum of 38
percent. (see calculation procedures in “Environmental Regulations and Technology—
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Control of Pathogens and Vector Attraction in Sewage Sludge”, EPA–625/R–92/013, 1992,
U.S. Environmental Protection Agency, Cincinnati, Ohio 45268).
Research has shown that actual VSS reduction for thermophilic anaerobic digesters is
usually between 40 and 60% which meets this requirement.
The third requirement for Class A designation is meeting pollutant restrictions. For this
requirement, the end location of the biosolids determines what regulation applies.
All land
applied biosolids must be at or below the values shown in column 1 of Table 7. In addition, any
biosolids applied to agricultural land, forest, public contact sites, or reclamation sites must either
have a cumulative pollutant loading rate less than column 2 or must have a point concentration
less than column 3. Any biosolids sold or given away in a bag or another container for land
application must either have concentrations less than the third column or must have a total
annual loading rate less than column 4. The four most common treatment configurations that
produce Class A biosolids are presented on Figure 15. In this project, option 2 and 4 were
investigated.
Table 7: EPA CWA Pollutant Limits
Pollutant
Ceiling
Concentration
(mg/kg)
Arsenic
Cadmium
Copper
Lead
Mercury
Molybdenum
Nickel
Selenium
Zinc
75
85
4300
840
57
75
420
100
7500
Cumulative
Pollutant
Loading Rate
(kg / hectare)
41
39
1500
300
17
420
100
2800
Monthly Average
Concentration
(mg/kg)
41
39
1500
300
173
420
100
2800
Annual Pollutant
Loading Rate
(kg / hectare / 365
day)
2
1.9
75
15
0.85
21
5
140
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Figure 15: Treatment Processes that achieve Class A Biosolids9
9
Willis and Schafer, 2006
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6.6 Digestion Temperature
Anaerobic digestion can occur at different temperatures. Mesophilic and thermophilic
operation correspond to digestion at 35°C and 55°C respectively. Both processes have their own
strengths and weaknesses. Important benefits of mesophilic operation include operational
simplicity and good pathogen reduction. The mesophilic range does not require nearly as much
attention to operating details as the thermophilic range. As a result, most WWTP digestion
systems in the US operate at mesophilic temperature. However, volume requirement of
mesophilic digesters is almost twice than volume required in thermophilic digesters since average
mesophilic HRT is 20 days, approximately twice that of thermophilic HRT. The hydraulic retention
time is longer because it takes a long time for the microbes to mature and digest substrate in
sludge. The heating costs for mesophilic is not as high as thermophilic due to lower heating
temperatures but construction costs are much higher. It is practically not possible to reach Class
A pathogen level at mesophilic temperature without additional treatment.
The second mode of anaerobic digestion is operation at thermophilic or 55°C. The high
temperature requirement is associated with high heating costs. However, the tank volume is
nearly half of that required for mesophilic digestion which lowers construction costs
considerably. Reaching the thermophilic temperature range also allows the biosolids to reach
Class A pathogen level with pre-digestion pasteurization or thermal hydrolysis system. Semibatch operation at thermophilic temperature can achieve Class A status if short-circuiting is
avoided. Thermophilic digesters are commonly buried to minimize heat loss from digester walls
to the atmosphere.
Temperature-phased anaerobic digestion (TPAD) is the thermophilic and mesophilic
anaerobic digestion in sequence. Solid residence times (SRT) are varied across two tanks to find
appropriate loading rate. TPAD systems have been proven to have better performance in volatile
solids (VS) reduction and gas production than single-stage mesophilic or thermophilic digestion
(Bolzonella et al). Other benefits include good odor control and no short-circuiting or reinfection
which makes Class A designation possible. Previous research work has shown that TPAD system
produces fecal coliform less than the regulatory level of 1000MPN or 3-log per gram of total solids
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(Figure 16: Comparison of Coliform Destruction (Kade, 2004). A summary of the different
digestion temperatures is presented on Table 8.
Figure 16: Comparison of Coliform Destruction (Kade, 2004)
Table 8: Digester Operating Temperature Characteristics
Category
Operating Temperature
Energy Costs
Residence Time
Class
Mesophilic
35°C
Lowest
Highest
B
Thermophilic
55°C
Highest
Lowest
A or B
TPAD
Both
Middle
Middle
A
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6.7 Digester Configuration
6.7.1 Tank Design
The team considered thermophilic digestion and TPAD. First, anaerobic digestion system
operating at thermophilic temperature was studied. In particular, sizing requirements and
potential gas production were determined for a high rate, single stage thermophilic digesters.
Since there is no recycle stream, the solids retention time (SRT) is equal to the hydraulic retention
time (HRT). Second, temperature-phased anaerobic digestion (TPAD) system for Wyoming CWP
was investigated. Schematic of a two-stage digestion system is shown Figure 17.
Figure 17: Two Stage, High-rate Anaerobic Digester10
6.7.2 Digester Shape
Commonly used digestion tanks are cylindrical and egg-shaped. Advantages and
disadvantages of both configurations are outlined in Table 9. Cylindrical shaped digesters are
conventionally used in many WWTP digestion facilities and farming communities for treating
animal manure. Common construction material for cylindrical digesters is concrete. A
modification of cylindrical tanks, German digesters have cylindrical shape with truncated, conical
top and bottom surfaces for efficient mixing and hydraulics. Cylindrical digesters were chosen for
the design of thermophilic digestion system.
10
Source: http://water.me.vccs.edu/courses/env108/anaerobic.htm
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Table 9: Comparison of cylindrical and egg-shaped digesters11
Cylindrical Digesters
Advantage
Disadvantage
High gas storage
Poor mixing
Possible use
Grit and scum
of floating covers
accumulation
Conventional
construction methods
Egg-shaped Digesters
Advantage
Disadvantage
Better mixing
Complex design (digester,
(hydraulic efficiency)
foundation and seismic)
Low grit accumulation and
High construction cost
foaming
Smaller footprint
Limited gas storage capacity
Low O&M costs
Egg-shaped digesters are gaining popularity in the United States due to their high
hydraulic performance. Major benefits include simple operation control, smaller footprint and
good mixing. Common construction material is steel due to ease of construction. A local waste
water (WW) treatment facility, Grandville Clean Water Plant has an egg-shaped digester.
Minimum foaming occurs due to the narrowing near the top. Proposed TPAD system for
Wyoming CWP has egg-shaped, mesophilic digesters. Enough land space is available for
construction with capacity for future expansion.
Figure 18: Egg Shaped Digester Configuration12
11
12
Adapted from Metcalf and Eddy, 2003
Source: http://www.gec.jp/jsim_data/water/water_4/html/doc_282_1.html
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6.7.2.1 Cylindrical, Thermophilic Digesters
The anaerobic digestion tank design integrated two key parameters volume and
redundancy. After researching common practice, it was decided that the projected 2025 averageannual sludge flow should be shared between two digesters of equal size. There will be a total
of three digester of equal size including a redundant digester for max month loads (Figure 19).
Figure 19: Single-stage Cylindrical Digesters
For peak days, the storage tanks preceding the digesters will contain the exceeding flows
so the digesters will not have to continually turn on and off. Also, when the digesters are running
at relatively constant volumetric flow rates, the digester offline can be maintained if required. In
order to find volume of digestion tanks, appropriate design loads for average month condition as
well as hydraulic residence time was designated. The radius and height are equal due to ideal
heating conditions as well as ease of burial. All calculations can be found in Appendix II: Mathcad
Calculations. Table 10: Configuration of Cylindrical Digesters for Wyoming CWP provides a
summary of the results.
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Table 10: Configuration of Cylindrical Digesters for Wyoming CWP
Parameter
Digester volume (per unit)
Number of units
Material of construction
Diameter and height
above ground
Mixing mechanism
Burial
Value
1,000,000 gallons13
3
Reinforced concrete
35ft.
Typically mechanical agitation or
recirculation
Fully above ground (water table
located 12-15 ft. below ground)
Batch or semi batch operation of single- stage thermophilic digestion is required to meet
Class A requirements. Continuously fed systems re-infect the digested sludge. Other operational
issues include volatile solids (VS) fluctuation, foaming and odor problems. Methane production
and cost analysis of this option were performed for comparison with TPAD system and presented
in this report. Foam and odor control for this configuration were not investigated.
6.7.2.2 TPAD system with Egg-Shaped Digestion (ESDTM)
Temperature-phase anaerobic digestion (TPAD) system is a digestion alternative
developed by Richard Dague and co-workers at Iowa State University. The US patent number of
the process is 5,746,919 and was given on May 5, 1998. It consists of a short thermophilic
digestion followed by a long mesophilic digestion system (Figure 20). Major benefits include good
hydrolysis, high volatile solids destruction, significant gas production, odor control and ability to
meet Class A requirements. Significant pathogen destruction occurs in the acid/thermophilic
stage while high volume of methane is produced from the mesophilic stage. Limited number of
WWTPs use TPAD system for sludge stabilization.
13
Grit accumulation, mixing equipment space requirement and gas storage volume included in calculation.
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Figure 20: Two- stage Anaerobic Digestion system (CB&I)
TPAD system for Wyoming CWP will consist of three thermophilic (acid) reactors followed
by two egg-shaped mesophilic digesters. Cleaning of the egg-shaped digesters is minimal since
there is only minor scum accumulation in egg-shaped digesters. Summary of proposed system
based on 2025 design conditions is presented on Table 11.
Table 11: Summary of ESD facility plan from CB&I
Parameters
Unit volume
Number of units
Tank shape
Height above ground
Major diameter
Digestion time
Mixing system
Thermophilic
(Acid) Reactors
60,000 gallons
Three
Cylindrical
76ft.
12ft.
22hr
External recirculation pump
and integral foam
Suppression
Mesophilic
1,500,000 gallons
Two
Sphere- egg shaped
96ft.
72ft.
15 days
Jet mix draft tube and integral
foam Suppression
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7. Digester Biogas Production
7.1 Introduction
The anaerobic biodegradation of organic waste produces biogas and other gaseous
compounds such as hydrogen sulfide and siloxane. In particular, biogas production is associated
with volatile solids (VS) destruction. Several relationships exist that describe the effect of
different parameters on VS reduction. Based on Equation 14-14 from Metcalf & Eddy, VS
reduction rate (in percent) as a function of sludge retention time (SRT) is graphed and presented
on Figure 21. Higher destruction occurs at long retention times, high temperatures and neutral
pH conditions.
70%
65%
VSS Reduction %
60%
y = 0.137ln(x) + 0.189
55%
50%
45%
40%
35%
30%
25%
20%
0
5
10
15
20
25
30
35
SRT (in days)
Figure 21: Effect of Sludge Retention Time (SRT) on VSS Reduction for High-rate System
The biological and chemical property of the influent sludge as well as loading rate are
important variables that determine the maximum level of gas production possible. Table 12
summarizes the properties of the primary and secondary sludge from wastewater treatment
process. Primary and thickened WAS will be digested in proposed system. Pre-digestion storage
provides a uniform, homogenous feed to the digester tanks and potentially a stable operation.
Parameters such as phosphorous and nitrogen levels in secondary sludge are largely determined
by the efficiency of biological treatment. Typically, primary sludge removed from primary
46 | P a g e
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clarifiers contains high percentage of substrate (BOD) and TSS and has high energy production
potential via digestion. Furthermore, the configuration of digester and efficiency of mixing
mechanism affect the conversion of volatile solids to biogas.
Table 12: Typical Characteristic of Primary and Secondary Solids 14
Parameters
Total Solids
Volatile Solids (% of TS)
Grease (% of TS)
Phosphorus (% of TS)
Nitrogen (% of TS)
pH
Concentration
(dry-weight basis)
Primary Sludge Secondary Sludge
2-8
0.4-1.2
60-80
60-85
5-8
5-12
0.8-2.8
1.5-3
1.5-4
2.4-7
5-8
6.5-8
Based on past research and actual operation of AD systems, different mathematical
models have been formulated on methane yield. Two widely-used approaches to estimate
volume of biogas production are volatile solids reduction and conversion of soluble BOD in
sludge. Observed values of biogas volume per mass for both approaches is tabulated in
Table 13. Biogas can be produced at different parts of an AD system and can be used to
generate heat and electricity (see Figure 22: Potential Sources of Biogas for an AD system). The
majority of biogas is produced in the digesters, and biogas from the other sources is normally
flared due to its limited amount.
Table 13: Estimated Biogas Production15
Parameter
Volatile solids reduction
Soluble BOD conversion
14
15
Value
0.8-1.1
13-18
0.35
5.61
Unit
m3/kg
ft3/lb.
m3/kg
ft3/lb.
WEF Task Force, 2010
WEF Task Force, 2010
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Sludge
Holding
Tank
Biosolids
Storage
Tanks
Biogas
Digesters
CHP
Figure 22: Potential Sources of Biogas for an AD system
7.2 Potential Methane Production at Wyoming CWP
Volatile solids reduction (VSR) approach was used to calculate methane production under
different flow conditions. The loads of the influent stream were found and documented on Table
14: Information about Wyoming. Potential VSR using the two AD configurations was computed
based on SRT (Table 15). These loads were used in an anaerobic biomass equation to find the
pounds of biomass (in terms of TSS and VSS) produced per day. Based on 15 ft3 volume biogas
production per lb. VSS destroyed, estimated biogas generation during average annual and
maximum month flow conditions were determined. Finally, methane generation was found with
the assumption that 60% of biogas by volume is methane. Detailed calculations can be found in
the Appendix II: Mathcad Calculations.
Table 14: Information about Wyoming Waste Flow
Parameter
2014
Annual average flow (mgd)
14.7
TSS loading- annual
29056
average (lb./day)
TSS loading- maximum
31630
month (lb./day)
VS Loading rate
0.084-0.09
3
(lb./ft /day)
16
2025
2416
47438
51641
0.137-0.149
Represents the plant’s design capacity and expected flow
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Table 15: VSR Assumption for AD systems
AD Configuration
VSR (%)
Single-stage, thermophilic
Two-stage, TPAD system
51%
57%
Methane production is dependent on TSS loading which is proportional to wastewater
flow into the plant. It can vary with changes in the number of residential homes and industries
that are served by the treatment plant. Furthermore, higher gas generation than theoretical
findings may occur with operation of CB&I’s TPAD system due to its high mixing efficiency.
Theoretical methane production with thermophilic and TPAD system at Wyoming CWP is
presented below in Figure 23 : Methane Production Prediction for Thermophilic System and
Figure 24 : Methane Production Prediction for TPAD System respectively.
Methane Production (ft3/day)
181000
Thermo
166,000
200000
111000
150000
102000
100000
Max. month
50000
Average annual
0
2014
2025
Figure 23 : Methane Production Prediction for Thermophilic System
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Methane Production (ft3/day)
204000
250000
187,000
125000
200000
150000
TPAD
115000
100000
Max. month
50000
Average annual
0
2014
2025
Figure 24 : Methane Production Prediction for TPAD System
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Methane Generation Vs. Flow
1,000,000
y = 11535x0.8963
R² = 0.8812
Methane Production (ft3/day)
100,000
10,000
y = 10669x1.0545
R² = 0.8628
1,000
100
10
Wyoming
CWP
(2014)
1
0.1
1
10
Wyoming
CWP
(2025)
14.7
24
100
Current Flow to WWTPs in WI (mgd)
Figure 25 : Methane Production as a Function of Influent Flow to Plant
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7.3 Operation and Maintenance
Several physical and chemical properties of sludge in digester tanks should be monitored
frequently for process control. Products of acidogenesis process lower digester pH while
methanogenesis products raise pH. Neutral pH is considered the ideal digester pH to support the
different stages of digestion process. Fluctuations in pH can have detrimental effect on volatile
solids reduction and gas production. Digester parameters that should be monitored daily are
presented in Table 16. Alkalinity and volatile acids determine the health of an AD system. Higher
alkalinity values are associated with system stability in terms of ability to sustain increased
organic loading. Ratio of Volatile acids (VA) and alkalinity give an early indication of pH changes.
Table 16: Digester Monitoring (WEF, 2007)
Parameter
Units
Temperature
°C
pH
Alkalinity (mg/L)
VA/Alkalinity ratio
Total Solids (TS)
Volatile Solids (VS)
Flow
mg/L
mg/L
%
%
gal/day
ft3/ lb. VS
destroyed
Gas Production
Gas Composition
%
Target
65- Thermo.
35- Meso.
6.8-7.2
2000-5000
0.1-0.2
(record)
(record)
(record)
Test Method
Meter
AWWA 2320
Ratio calculation
2540B
2540E
Meter
12-16
Meter
Low CO2, H2S
and NH3
Gas Analyzer/
chromatography
Meter
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7.4 Case Studies
Digestion systems at three WWTPs were evaluated in light of assessing methane
production and benefits from its utilization. A comparison of the plants’ design capacity and gas
production is presented on Error! Reference source not found.. Expected gas production at
Wyoming CWP is also included.
I. Grandville CWP (Grandville, MI)
In fall 2012, construction of an egg-shaped anaerobic digester was completed at
Grandville CWP (Figure 26). It was the first of its kind in Michigan. The digester has one million
gallon volume and operates at mesophilic temperature. Primary sludge is the only feed stream
of the system since WAS is co-settled in primary clarifiers. Biosolids produced from the plant has
Class B quality and is land applied locally. The plant utilizes methane produced from digestion
process using a cogeneration system to meet 90% of its heating and electricity demands.
Estimated energy savings is $142,000 per year, and the expected payback period for the digestion
system is 8 years.
Figure 26: Egg-shaped Digester at Grandville CWP
II. Blue Plains Advanced WWTP (Washington D.C.)
Blue Plains is one of the largest WW treatment facilities in the world. The plant is located
in Washington D.C., and it serves more than 2 million people. Lime stabilization is currently being
used to treat waste sludge. A new digestion process train will be completed in 2015 at a cost of
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$400 million. A CAMBI THP system, four cylindrical digesters (3.8 million gallon units) and a
cogeneration system will be installed. The biosolids from the plant will have Class A quality and
can be land applied without space and time limitations. The plants will meet about 30% of its
energy needs from methane generated.
III. Western Lake Superior Sanitary District (Duluth, MN)
The treatment facility serves City of Duluth, Hermantown and neighboring townships in
Minnesota. The solids management consists of a dissolved air floatation and two-stage,
temperature phased anaerobic digestion (TPAD) system. It was the first, full-scale TPAD system
in North America. Prior to 2001, sludge co-incineration with solid waste was used. Sludge is
treated in a sealed, cylindrical tank at thermophilic temperature for 5 days in the first stage,
followed by mesophilic treatment in three separate, 1.05 million gallon tanks for 15 additional
days. Treated biosolids is land applied after dewatering with centrifuges.
600,000
500,000
Sludge Fow (gal./day)
400,000
350,000
400,000
300,000
300,000
250,000
200,000
200,000
150,000
100,000
100,000
Gas Production (ft3/day)
450,000
500,000
50,000
0
0
Grandville CWP
Wyoming CWP
(Current Capacity)
Sludge Flow
Wyoming CWP
(Design Capacity)
Western Lake
Superior
Gas Production
Figure 27: Comparison of Sludge Flow and Associated Gas Production
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8. Cogeneration
Digester gas is typically composed of 60% methane and 40% carbon dioxide. Unlike
natural gas, digester gas does not contain ethane, propane, butane or other combustible gases,
which results in its relatively low heating value. A combined Heat and Power (CHP) system is
required to capture the energy in digester gas. Heating sludge pre-digestion will be the primary
use of energy from methane production.
8.1 Cogeneration Implementation
The cogeneration system that the team recommends for implementation is a CHP system.
This system generates energy in the form of both stem for the sludge and the remaining portion
as electricity for the rest of the plant. The CHP system uses combustion and steam turbines that
use the biogas and create mechanical energy which powers a generator that produces electricity
for use. This system will cost $1.5 million dollars according to HESCO.
8.2 Cost Savings
Gas production increases with the increase in flow, and thus there is more potential
energy produced in 2025 than for the current flow conditions. It was determined the cost to heat
the sludge prior to digestion in 2025 will be 10.9MMBTU/year and that the energy produced from
digestion will be 15MMBTU/year. The energy used for heating will account for approximately
80% of the energy produced as seen in Figure 28. The remaining energy will be used on site as a
subsidiary electricity source. Annual cost savings from this additional energy is estimated at
$95,000.
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100%
80%
60%
40%
20%
0%
Energy Produced 2014
Energy Produced 2025
Energy for Sludge Heating
Remaining
Figure 28: Uses for Energy produced from Digestion
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8.3 Biogas Conditioning
Digester gas contains trace amounts (<5%) of hydrogen sulfide, siloxane and other gases
which cause problems in gas piping and cogeneration system. Several technologies are available
in the market to remove these harmful gases. Hydrogen sulfide can be removed or controlled by
application of activated carbon, ferric chloride or scrubbing with liquid media. High pH in the
digester tanks reduces the rate of hydrogen sulfide formation. Piloting of TPAD system and gas
chromatographic tests provide valuable information regarding concentration of this contaminant
gases based on system changes such as loading rate and mixing rate.
The system provider is Unison Solutions, Inc. A special media, SulfaTreat media is used to
remove hydrogen sulfide, inside a vertical vessel. Typical and design maximum concentration for
hydrogen sulfide and siloxane are presented on Table 17: Digester Gas Composition (by volume).
Rated removal efficiency for particulates above 3 microns is 99%. Recommended removal
systems for both gases are shown in Error! Reference source not found. and Error! Reference
source not found..The two systems are pivotal for smooth operation and maintaining the design
life of cogeneration units.
Table 17: Digester Gas Composition (by volume)
Parameter
Hydrogen Sulfide
Siloxane
17
Typical Range in
Digester Gas17
200-3500ppm
100-4000ppb
Max. Discharge
Conc. (Unison)
10ppm
100ppb
WEF Task Force, 2010
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Figure 29: Hydrogen Sulfide
Removal System
Figure 30: Siloxane Removal System
8.4 Cost Information
The cost of the biogas conditioning systems is outlined in Table 18: Cost Information for
Biogas Conditioning. The values are before tax and installation. Cost information was found from
Unison Solutions, Inc.
Table 18: Cost Information for Biogas Conditioning
Removal System
Hydrogen Sulfide
Siloxane
Gas Compression/
Moisture
Shipping
Commissioning
Total
Capital Cost
$135,000
$85,000
$270,000
$8500
$8500
$507,000
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9. Post-Digestion Dewatering
9.1 Dewatering Introduction
Dewatering is an optional mechanical process in biosolids management that increases
total solids (TS) concentration in post treatment flow. Major benefits of dewatering include:



Reduction in biosolids volume for disposal.
No seasonal dependence on disposal method.
Wide range of applications for Class A product.
Because digestion causes the biodegradation of solids, the post digestion percent solids is
expected to be reduced to 2.5%. The calculations used to produce this value can be found in
Appendix II: Mathcad Calculations.
9.2 Proposed Percent Dewatering
The team considered two potential final biosolids levels: 4% solids and 18-20% solids.
Currently, the Wyoming CWP has equipment on site for injection of 3-8% biosolids and an
example can be seen in Figure 31. The equipment is managed by a separate company but stored
and maintained on site. Currently the Wyoming CWP land applies biosolids at approximately 6%
solids.
Figure 31: Injection Biosolids Land Application Equipment
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The ideal percent solids for pumping is 4% solids because flow is reduced while flow
characteristics remain similar to water. A composition at 4% solids would not require the
purchase of any additional land application equipment.
If total solids of post dewatered sludge is between 18-20%, then the effluent of the
process is termed as cake solids. Cake solids do not behave like a fluid and cannot be pumped or
injected. An example of cake solids is Milorganite, a commercial fertilizer manufactured by the
Milwaukee Metropolitan Sewage District. There is currently little to no market demand for
bagged cake biosolids in the Grand Rapids metropolitan area. A comparison of the two options
for thickening is summarized in Table 19. After consulting Wyoming CWP, the team decided only
to dewater to 4% solids with the option to dewater to a higher percentage during atypical
operation.
Table 19: Comparison of Final Biosolids Percent Solids Composition
Dewatering
Final Percent
Solids
4%
18-20%
Can be Bagged for
Residential
Application
No
Yes
Hydraulic
Capital Needed for
Properties of
Land Application
Water
Already Exists on Site
Yes
Yes
No
No
Volume to be
Stored in
Winter
Large
Small
9.3 Method of Dewatering
Because dewatering is the same mechanical process as thickening, the options for
dewatering are similar. The team looked into three methods for dewatering including
centrifuges, rotary drums and gravity thickening equipment. Each of these options could
concentrate the solids to 4%. The team selected centrifuged because it was the most effective
and versatile method. With centrifuges, the option to increase the amount of dewatering to up
to 10% can be done with no additional equipment. This condition provides the CWP with
flexibility in the future and also allows for conserving storage during unusual long winters.
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10. Biosolids Storage Tanks
10.1 Design Considerations
For the purpose of this project, the system was designed for typical use without GVRBA
facilities. For this reason, the Wyoming CWP must be able to store biosolids for approximately 3
months during the year when biosolids cannot be land applied via injection due to frozen ground.
10.2 Current Biosolids Storage Facilities
Currently, the Wyoming CWP has two 1.9-million gallon tanks and one 2.1 million gallon
tank on site. These tanks handle current biosolids treatment operations such as an equalization
basin during upsurges, system shutdown and other emergency situations. These tanks are shown
in the distance in Figure 32.
Figure 32: Biosoilds Storage Tanks in the rear
Based on 2013 GVRBA sludge data, a graph of biosolids entering, leaving and remaining
in the storage tanks was created (Figure 33: Seasonal Variations in Biosolids Storage in 2013). The
remaining biosolids volume at end-of-month (EOM) is the differential of the flow in and out of
the tank plus initial volume in tank from previous month. The dark line represents the total
capacity of the existing biosolids storage tanks. According to the graph, approximately half of the
tank volume is unused. Also, the values for land application show that the majority of biosolids
are stored during summer months.
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7,000,000
Biosolids Volume
(gal.)
6,000,000
5,000,000
4,000,000
3,000,000
2,000,000
1,000,000
0
Storage Capacity
Sludge in tanks @EOM
Addition to storage tanks
Land Applied
Figure 33: Seasonal Variations in Biosolids Storage in 2013
10.3 Required Biosolids Storage Capital
Calculations of the volume of biosolids produced during the winter were completed and
can be found in Appendix II: Mathcad Calculations. An additional two cylindrical tanks with
volumes of 2 million gallons will be needed for holding typical biosolids production in the winter
of 2025. A cost estimate for each was calculated based on an assumed cost per volume for a
concrete tank construction. Each tank costs approximately $1.5 million. In the event of a longer
winter period than typical, several contingencies for operation exist. First, the biosolids can be
dewatered to higher than 4% total solids. Second, biosolids storage at GVRBA could be utilized.
However, since the volumetric flow rates used in this calculation are from the year 2025, neither
of these options should be needed for some time.
While being stored over the winter, the biosolids are at risk of gravity thickening which
would make removing the biosolids for land application difficult. For this reason, the tanks need
an agitation or mixing system to keep solids suspended. The jet pump mixing system described
for the holding tanks was again utilized here. This system is used mainly because the system can
be shut off when not needed which is ideal for when the sludge is not needed, but when restarted
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can agitate the contents of the tank in under 3 hours. This mixing system will cost $25,000 per
tank.
During atypical operation, biogas could build up in the biosolids storage tanks. Increasing
pressure and gas composition causes a risk for explosion. For this reason a flare will be installed
into the facility to relieve pressures. This flare will cost $21,000 to purchase and install.18
Biosolids quantity (dry metric tons) = Sludge Volume (gal. ) ∗ %TS ∗ 8.34
18
lb
1 ton
∗
gal 2000lb
(1)
http://www.epa.gov/gasstar/documents/installflares.pdf
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11. Pumping Station Design
11.1 Introduction
Pumping sludge, a non-Newtonian fluid, presents a unique challenge. The complexity
arises from variations in physical and chemical quality of sludge on a seasonal basis. Some factors
affecting sludge pumping include viscosity, temperature and flow velocity. Frictional head loss
varies with changes in viscosity of sludge at different %TS and temperature. This phenomenon
should be considered in sizing pumps and pipes. Worst case operation and maximum viscosity of
wastewater strength material should be researched and used as a basis for design. In addition,
empirical findings in sludge pumping from previous work should be studied.
11.2 Pipe Selection
Redundancy is required in piping and pumps. On the other hand, system components
must be regularly cleaned and maintained for extended use (at or above design life) and for good
hydraulic performance. As a result, flanges or couplings must be placed at appropriate locations
(at bends, before and after a pump etc…) for easy maintenance. In addition, pipe bends should
be minimized.
In regards to pump selection, information regarding suitable sludge pumps is presented
in Table 20: Advantages and Disadvantages of Progressive Cavity Pump. Progressive cavity pumps
can be used to transport primary, secondary, thickened and digester sludge. It is a positive
displacement pump. Darcy-Weisbach equation was used to calculate head loss in sludge
transport. Each component of the system was drawn into the site plan shown in Section 13. Site
Layout. Then pipes were drawn into the site plant between each component and the lengths of
each section of pipe were combined for each route. Assumed cost of 8 inch inner diameter steel
pipe is $4.7 per linear foot.
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Table 20: Advantages and Disadvantages of Progressive Cavity Pump
Pump Type
Description
Progressive
Cavity
Positive
Displacement
pump
Chopper/
grinder
Rotary Lobe
Centrifugal
pump
Positive
Displacement
pump
Advantages
Accuracy of flow
Small turbulence
Ideal for fluid with
varying viscosity
Lower suction head
Minimum clogging
Reliable at large TS conc.
Compact
Higher flow rate and
efficiency
Disadvantages
Fixed flow rate
Regular stator replacement
Large footprint
Higher energy cost
Not precise
No particulates
Table 21: Length of New Pipe Needed for Each Section of Route
Pipe Route
Primary Settling to Thickening
Building
Secondary Settling to
Thickening Building
Thickening Building to Sludge
Holding Tanks
Sludge Holding Tanks to Top of
Thermophilic Digesters
Bottom of Mesophilic Digesters
to Dewatering Building
Dewatering Building to
Biosolids Storage
Total
Pipe Length
(feet)
420
0
280
770
640
370
Cost
$2000
$0
$1350
$3600
$3000
$1750
$11,700
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11.3 Pipe Diameters
For each flow route, the head needed from a pump was calculated (See Appendix II:
Mathcad Calculations). This included minor frictional losses, major frictional losses, and elevation
change. Then all variables were kept constant except pipe diameter and the results graphed in
Figure 34: Pumping Head Needed as a Function of Pipe Diameter.
In Figure 34: Pumping Head Needed as a Function of Pipe Diameter, Pump 1 Head refers
to the head needed from a pump to convey flow from the bottom of the holding/mixing tanks to
the top of the thermophilic digesters. Pump 2 Head refers to the head needed from a pump to
convey flow from the bottom of the mesophilic digesters to the dewatering building. Pump 3
Head refers to the head needed from a pump to convey flow from the dewatering building to the
top of a biosolids storage facility.
80
Pump Head Needed (ft.)
70
60
50
40
Pump 1 Head
30
Pump 3 Head
20
Pump 2 Head
10
0
0
5
10
15
Pipe Diameter (in.)
Figure 34: Pumping Head Needed as a Function of Pipe Diameter
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11.4 Cleaning Pipes
Transport of solids from primary settling and secondary settling have a few associated
problems. These materials are high in grease and tend to adhere to surfaces. As sludge is
pumped through pipes, a film coating forms on the inner surface of the pipe. This film increases
frictional losses which means the pumps must operate at a higher head in order to send the
sludge through the pipe. One method of reducing the work needed from the pump is to
periodically clean off this film.
11.5 Cleaning Methods
In today’s water and sewage management pigging is a type of plug that is pumped
through a water or sewer main to clean out the sludge, slime, or corrosion. The more commonly
used type of pigging today is foam pigging which is very effective but has its limitations. The first
limitation is the possibility of getting stuck in the pipe which then leads to digging out the main
which is highly energy intensive. This system also would need to include pig docking stations
where the pig can be added and removed from the piping system. The overall process is quite
slow and labor intensive. Another option for pigging is a new and much easier system called ice
pigging. This system involves a truck with a slurry of salty ice that will act as a semi-solid mixture
that will clean the sides of the pipe as it is passed down. The major perks of a system like this are
efficiency, ease of operation, and effectiveness. The efficiency is much better with this system
because instead of pigging docks used with the foam pigs, the ice just needs a standard valve that
can pass ice through. Another benefit of choosing the ice method is there is no possibility of the
ice getting stuck. If the ice ever does get bound up it will quickly melt. Additionally the ice is far
more effective in the removal of biofilm and sediment. The current practice is to increase the
pressure which is not cleaning the piping system very well. If the ice system is implemented in
the pipes it could raise pumping efficiency considerably. The icing option is very clear and it is
our recommendation to the city of Wyoming CWP because of many factors but mainly the cost,
ease of use, and effectiveness.
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12. Nutrient Removal/Recovery
Nutrient removal from wastewater discharges is an increasing challenge for water
authorities, as regulatory authorities tighten discharge standards to avoid eutrophication
problems in receiving waters. Significant costs are associated with the extra treatment processes
required to meet these new discharge standards. The most widely used technologies for nutrient
removal include biological nitrification/denitrification for nitrogen removal and polymer
flocculation for phosphorus removal. Both approaches result in the nutrient being made
unrecoverable for possible use as a fertilizer. An alternative to these conventional technologies
which can provide for recovery of the nutrient as a commercial fertilizer could be the production
of struvite. Below are listed all of the options currently available for nutrient recovery with the
associated benefits and detriments for the overall system.
Table 22: Comparison of Nutrient Recovery Technologies
Method
Phosphorus
Recovery
Poor
High
High
Nitrogen
Recovery
None
None
None
Throughput
Dewatering
Chemical
Addition
None
None
High
Multiple Screens
High
Poor
Decanting Centrifuge
High
Good
Polymer Flocculation
High
Good
Nitrification /
None
High
Low
Poor
none
De-nitrification
Traditional Ammonia
None
High
Low
Poor
High
Stripping
DVO Approach
Some
Some
High
Poor
Some
Struvite
High
High
High
Average
High
From the preliminary research into these options, the team would suggest the
implementation of the Struvite system in a few years. The system was successful on the pilot
plant scale and is starting to be implemented in different waste water treatment plants in
conjunction with an anaerobic digester. For the plant that would be similar to CWP with a two
stage digestion and 25mgd was estimated at 13 million dollars. In addition to the removal and
recovery of Phosphorus and Nitrogen, ammonia is also removed from the system. The team
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would suggest waiting until the digester is fully operational and nutrient potential can be
analyzed in detail before proceeding with any of the above options 19.
13. Site Layout
Figure 35: Suggested Location of Digestion Facility
19
http://www.epa.gov/agstar/documents/conf12/10b_Dvorak-Frear.pdf
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14. Bench Scale Experiments
14.1 Digester Construction
The team constructed a bench scale anaerobic digester for experimental purposes. The
batch process was used for modeling since the proposed continuous flow method would be too
difficult to maintain due to high cost, time, and space requirements. The digester was modeled
using a 4.5-gal pressure cooker. The digester was fitted with a motor and two radial impellers
that rotate at 5 rpm. To simulate thermophilic conditions, the digester was placed in a water bath
at 50°C. A plastic tube directs biogas produced from digestion to an inverted, graduated cylinder.
Seed for the digester was obtained from egg-shaped anaerobic digester at Grandville CWP. Raw
and thickened WAS were collected from Wyoming CWP.
Figure 36: Bench Scale Anaerobic Digester
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14.2 Operation and Testing
Once the digester was fed with seed and feed sludge samples, the first test run was
commenced on Thursday, February 25, 2014. The team discovered on the second day that almost
all of the water has evaporated, and the sludge was cooked inside the digester and eventually
spilled. The gas tube was plugged with sludge (see Figure 37: Trial Run Spill). To solve the
problem, about two gallons of sludge was removed, and the gas tube was connected near the
cover. The team performed COD, total solids and volatile solids experiments to measure system
performance based on changes in organic content. COD experiment was not successful because
the digester has high solids content. Result of the first experimental run is shown on Error!
Reference source not found.. No general trend of TS and VS was observed over the test period.
Figure 37: Trial Run Spill
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6%
35%
30%
25%
4%
20%
3%
15%
2%
10%
Total Solids
1%
5%
Total Volatile Solids
0%
24-Feb
% Volatile Solids (avg.)
% Total Solids (avg.)
5%
0%
25-Feb
26-Feb
27-Feb
28-Feb
1-Mar
2-Mar
3-Mar
4-Mar
Sampling Dates
Figure 38: Results from Trial Run
For future experiments, the team decided on taking small samples every day, storing in
refrigerator and performing solids test weekly. High-range COD vials were purchased for COD
tests. The head motor was replaced with a 6rpm motor to solve mixing problems. To standardize
sampling method, one team member was assigned to take all remaining daily samples. For the
final run, the digester was operated for a total of 18 days. Over this period of time, a daily sample
was collected, stored at 4 C° and burned weekly.
14.3 Results and Discussion
For the final run, the digester was in operation for a total of 18 days. Over this period of
time, sludge samples were collected daily, stored at 4°C and burned weekly. In Figure 39: Results
from Final Digestion Run, it is clear that the volatile solids show a general downward progression
which imply that solids degradation occurred and methane was produced. The total solids show
a similar trend overall but the trend is not as apparent. The team believes that this is the result
of the testing method. By burning weekly, the sample had time to degrade slightly in the
refrigerator, thus the trend is increasing for some sampling periods, but there is an observable
overall decreasing trend.
72 | P a g e
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Figure 39: Results from Final Digestion Run
14.4 Safety
To ensure safety of the team and other students working in the lab room, all experiments
(except solids testing) were conducted inside a fume hood. Upon entering the lab, safety glasses
and goggles were worn. Furthermore, all items in contact with test sludge and in the vicinity were
thoroughly washed and disinfected.
73 | P a g e
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15. Total Cost of Proposed System
Project Cost
Digester System
Holding Tanks
Thickening
Dewatering
Storage Tanks
Cogeneration
Biogas Conditioning
Gas Storage
Contingency
Total
$15 M
$1 M
$600 K
$1.2 M
$3.1 M
$1.5 M
$507 K
$300 K
$2.1 M
$22.9 M
16. Future Work
Final design of a full-scale digestion system would include further analysis. The team
proposes the following items should be researched:
-
Piloting (gas production, pollutant concentration in biosolids)
-
Instrumentation (SCADA system)
-
HVAC and Plumbing
-
Architectural and Structural Design
-
Geotechnical Analysis
-
Effective Nutrient Recovery
74 | P a g e
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Acknowledgements
The team would like to thank Dr. David B. Wunder (Ph.D., P.E.) for serving as the team’s
advisor and providing valuable information throughout the semester. Myron Erickson (P.E.),
superintendent at City of Wyoming CWP and Aaron Vis, Project Manager of GRVBA have been
active participants in our work. The team appreciates their timely response to team requests and
showing guidance. Phil Jasperse, manager of Calvin’s metal shop was instrumental in the
construction and operation of our bench scale digester. Brain Vu from Grandville CWP has
supplemented our bench scale efforts by supplying feed samples from the plant’s egg-shaped
digester, and the team appreciates his assistance. Finally, the team is grateful for Jim Flamming
(P.E.) and David Filipiak (CHMM) from Fishbeck, Thomson, Carr and Huber, Inc. (FTC&H) for
serving us our industrial consultants in the design process and evaluating the team’s decisions.
75 | P a g e
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References
"Opportunities for Combined Heat and Power at Wastewater Treatment Facilities: Market
Analysis and Lessons from the Field." U.S. Environmental Protection Agency: Combined
Heat
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2013.
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Abbasi, Tasneem, and Tauseef Abbasi. "Anaerobic Digestion for Global Warming Control and
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Arnett, Clifford, Joseph Farrell, Daniel Hull, Steven Krugel, Billy Turner, Warren Uhte, and John
Willis. Biosolids Flow-Through Thermiphilic Treatment Process. Columbus Water Works,
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Sludge Discharge to Wastewater Treatment Works." Water Environment Research 82.5
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Badger Laboratories and Engineering. 2008. Quality Assurance Manual.
Bolzonella, David, Francesco Fatone, Silvia Di Fabio, and Franco Cecchi. "Mesophilic, Thermophilic
and Temperature Phased Anaerobic Digestion Of Waste Activated Sludge." The Italian
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Camp Dresser & McKee Inc. Charting the Future of Biosolids Management: Final Report. Rep.
N.p.: Water Environment Research, 2011. Print.
Clean Water Act, Part 503, section (a)(3)(ii)(D), page 20
D, Parry, and Loomis P. "DC Water Biosolids and Energy Process: Blue Plains Advanced
Wastewater Treatment Plant." 18th European Biosolids & Organic Resources Conference
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Day, Doug. "A Good Egg" TPO- Treatment Plant Operator Dec. 2013: 28-33. Web. 13 Apr. 2014.
Digestion Systems for Livestock Manures. USDA.
Eastern Research Group, Inc. Protocol for Quantifying and Reporting the Performance of
Anaerobic Digestion Systems for Livestock Manures. Rep. Lexington: n.p., 2011. U.S.
Environmental Protection Agency, 2011. Web.
Environmental Research Information Center. Technology Transfer. Sludge Treatment and
Disposal. Cincinnati, OH: Environmental Protection Agency, Environmental Research
Information Center, Technology Transfer, 1978. Print.
EPA "Opportunities for Combined Heat and Power at Wastewater Treatment Facilities: Market
Analysis and Lessons from the Field." U.S. Environmental Protection Agency: Combined
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Dec.
2013.
<http://www.epa.gov/chp/documents/wwtf_opportunities.pdf>.
EPA “Biosolids Generation, Use, and Disposal in the United States.” N.p.: United States
Environmental
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<http://www.epa.gov/compost/pubs/biosolid.pdf >.
Erickson, Ryan J. "Concrete Water Storage Tanks." Sunrise Engineering, n.d. Web. 1 Apr. 2014.
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Goldstein, Jerome. "Around the World with Anaerobic Digestion." Biocycle Energy 44.4 (2003):
78-81. Print.
Greer, Diane. "Funding Anaerobic Digestion Facilities." BioCycle Energy 52.3 (2011): 70-73. Print.
Greer, Diane. "Vermont Builds Anaerobic Digestion Capacity." BioCycle Energy 52.10 (2011): 3841. Print.
Informa Economics. National Market Value of Anaerobic Digestor Products. Rep. Innovation
Center for US Dairy, Feb. 2013. Web.
Kade, Farid. "Enhancing Solids Destruction from Anaerobic Municipal Digesters." M.S. thesis,
Marquette University (2004). Web.
Khalid, Azeem, Muhammad Arshad, Muzammil Anjum, Tariq Mahmood, and Lorna Dawson. "The
Anaerobic Digestion of Solid Organic Waste." Waste Management 31.8 (2011): 1737-744.
Print.
Kleiven, Harald. Cambi; Recycling Energy. Norway: n.p., 2010. Print.
Kopp, Ewert. "New Processes for the Improvement of Sludge Digestion and Sludge
Dewatering." Influence of Surface Charge and Exopolysaccharides on the Conditioning
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pag. Print.
Mancl, Karen. Wastewater Treatment Principles and Regulations. Ohio State University, n.d.
Web. 13 Nov. 2013. <http://ohioline.osu.edu/aex-fact/0768.html>
Martin, J. 2007. A Protocol for Quantifying and Reporting the Performance of Anaerobic
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2013: 27-30. Web. 14 Dec. 2013. <http://www.mml.org/thereview/reviewjanfeb2013/offline/download.pdf>.
Metcalf & Eddy., George Tchobanoglous, Franklin L. 1927- Burton, and H. David Stensel.
Wastewater Engineering: Treatment and Reuse. 4th ed. Boston: McGraw-Hill, 2003.
Panter, Keith, and David Auty. "Thermal Hydrolysis, Anaerobic Digestion and Dewatering of
Sewage Sludge as a Best First Step in Sludge Strategy: Full Scale Examples in Large Projects
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<http://depts.washington.edu/cpac/Activities/Meetings/Satellite/2010/Thursday/Paule
y%20Biomass%20Gasification%20presentation.pdf>.
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Development. Chemical Oxygen Demand: [test] Method 410.4. By James O'Dell.
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ds_method_410_4.pdf>.
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ds_method_biological_1684-bio.pdf>.
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United States. Water Environment Federation. Laboratory Evaluation of Thermophilic-Anaerobic
Digestion to Produce Class A Biosolids. By Michael Aitken, Glenn Walters, Phillip Crunk,
John Willis, Joseph Farrell, Perry Schafer, Cliff Arnett, and Billy Turner. 7th ed. Vol. 77.
Stockholm: Water Environment Research, 2005. Print.
United States. Water Environment Federation. Laboratory Evaluation of Thermophilic-Anaerobic
Digestion to Produce Class A Biosolids. By Michael Aitken, Glenn Walters, Phillip Crunk,
John Willis, Joseph Farrell, Perry Schafer, Cliff Arnett, and Billy Turner. 7th ed. Vol. 77.
Stockholm: Water Environment Research, 2005. Print.
US
EPA
"Alkaline
Stabilization
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Biosolids
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Apr. 2014.
US EPA "Centrifuge Thickening and Dewatering." Biosolids Technology Fact
Sheet (2000).http://water.epa.gov/scitech/wastetech/upload/2002_06_28_mtb_centrif
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Force. Design of municipal wastewater treatment plants. Volume 3: Solids Processing and
Management. 5th ed. Alexandria, VA: Water Environment Federation Press, 2010. Print.
WEF Manual of Practice No. 11, Operation of Municipal Wastewater Treatment Plants.
Alexandria, VA: Water Environment Federation, 2007. Web. 2 May 2014.
Wilkinson, Kevin. "Development of On-Farm Anaerobic Digestion." BioCycle Global Jan. 2011: 4950. BioCycle Global. Web.
Willis, John, and Perry Schafer. Advances in Thermophilic Anaerobic Digestion. Rep. no. 1114.
Rancho Cordova: Brown and Caldwell, n.d. Print.
78 | P a g e
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Appendix I: Team Management
Eyosias Ashenafi
Eyosias is a senior civil and environmental
engineering student from Addis Ababa, Ethiopia.
He enjoys playing soccer and studying maps in
his free time. He also volunteers regularly with
local organizations including Comprenew. He
has worked on an environmental research
project at Calvin. Two summers ago, he worked
with middle school students in Detroit, teaching
math and science. His roles in the project
included
project
management
and
communication.
Rachel Gaide
Rachel is a senior chemical engineering student
from Pueblo, CO. She enjoys baking, playing
volleyball and softball, and reading historical
fiction in her free time. She has interned at Xcel
Energy for a summer and been an engineering
Figure 40: Team Photo
research assist for a summer. She volunteers as
a Sunday school teacher and librarian for Trinity Lutheran Church and school. She is currently
seeking full time employment following graduation in May 2014.
Andrew Mitchell
Andrew is senior civil and environmental engineering student from Iron Mountain, MI. He likes
skiing or snowboarding, kayaking, and multiple motorsports. Andrew is captain of the Calvin
men’s swim team and enjoys the athletic competition. He spent the last summer in Kenya Africa
working with Bridging the Gap Africa building suspended bridges.
Katherine Vogel
Katherine Vogel grew up in Littleton, CO and is receiving a BSE with a concentration in Civil and
Environmental engineering. She volunteers at Madison Square Church as a Sunday school small
group leader and as a student representative for two governance committees at Calvin College.
Katherine enjoys yoga, watching educational YouTube, reading science fiction, and baking in her
free time. She has completed two summers of internship at Knight Piésold Consulting and is
currently looking for full time employment in the Denver Metro Area.
79 | P a g e
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Table 23: Work Breakdown Structure (Fall 2013)
Task
Define Scope and Objectives
Background of Project (Introduction)
Flows and Loads Tech Memo
Determine Operating Capacity
Responsible
Person
Thu 9/26/13 Thu 10/3/13 Thu 10/3/13
Team
Thu 9/26/13 Thu 10/17/13 Thu 10/17/13
AM
Thu 10/10/13 Fri 11/8/13
Fri 11/8/13
KV
Mon
Thu 11/7/13 Thu 11/7/13
KV
10/14/13
Fri 10/11/13 Fri 11/29/13 Fri 11/29/13
RG
Start
Finish
Actual Finish
Analytical Methods Tech Memo
Solids Management Alternatives Tech
Thu 9/26/13 Mon 12/2/13 Thu 12/19/13
Memo
Stabilization
Thu 10/3/13 Mon 12/2/13 Thu 12/19/13
Chemical
Thu 10/3/13 Fri 10/11/13 Thu 12/19/13
Wet Chemical
Thu 10/3/13 Thu 12/19/13 Thu 12/19/13
Lime Stabilization
Thu 10/3/13 Thu 12/19/13 Thu 12/19/13
Time and Temp
Thu 10/3/13 Thu 10/17/13 Thu 10/17/13
Biological
Thu 10/3/13 Thu 10/24/13 Thu 10/24/13
Aerobic Digestion
Thu 10/3/13 Fri 10/11/13 Fri 10/11/13
Anaerobic
Thu 10/3/13 Thu 10/24/13 Thu 10/24/13
Wed
TPAD
Thu 10/3/13 Wed 10/16/13
10/16/13
Wed
Thermophilic
Thu 10/3/13 Wed 10/16/13
10/16/13
Wed
Mesophilic
Thu 10/3/13 Wed 10/16/13
10/16/13
Dewatering
Thu 9/26/13 Thu 10/17/13 Thu 10/17/13
Thickening
Thu 10/3/13 Thu 10/31/13 Thu 10/31/13
Government Regulations
Mon 11/4/13 Mon 12/9/13 Mon 12/9/13
Major Components of Digester
Thu 10/17/13 Thu 11/14/13 Thu 11/14/13
Wed
Mixing method
Thu 10/17/13 Wed 10/23/13
10/23/13
Reactor Type
Thu 10/17/13 Thu 11/7/13 Thu 11/7/13
Heating Method
Thu 10/24/13 Thu 10/31/13 Thu 10/31/13
Complete Process Flow Diagram
Thu 10/10/13 Fri 11/29/13 Fri 11/29/13
Optimization of Biodigester Design
Fri 11/1/13
Tue 12/3/13 Tue 12/3/13
PPFS 1st Draft
Thu 9/26/13 Thu 11/28/13 Thu 11/28/13
PPFS Editing
Fri 11/22/13 Sat 12/14/13 Sat 12/14/13
EA
AM
KV
RG
AM
Team
Team
AM
EA, AM
EA, AM
EA, AM
RG
EA
KV
Team
Team
Team
Team
EA
RG
Team
Team
80 | P a g e
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Table 24: Work Breakdown Structure (Spring 2014)
Task
Due
Date
Bench Scale Experiments
Sampling
Testing
Every
Sat.
Data Input & Analysis
Every
Sat.
Final Design
Mathcad calculations
Final Report UPDATE
-2015 &2025
Comparison
- Cost analysis
- Thickening edit on
PPFS
-Dewatering edit on
PPFS
Regulations edit
Edit PPFS
Research TS coming
out of a digester
Digester shape and
material
Mixing for Digester
Heat Exchanger
Pumping Design
Nutrient Recovery
P&ID
Site Layout
Review Project Brief
Odor Control
Instrumentation
Effects to Head Stream
Cogeneration
Excavation/digester
design
Team Photo
10Mar
EA,
AM
EA,
AM
17- 24Mar Mar
KV,
RG
KV,
RG
31Mar
Week of
7- 14- 21- 285Apr Apr Apr Apr May
ALL-daily
KV, RG EA, KV,
AM RG
KV, RG EA, KV,
AM RG
EA,
AM
EA,
AM
EA,
AM
EA,
AM
KV,
RG
KV,
RG
EA,
AM
EA,
AM
EA
ALL
EA
EA, KV
EA
RG
KV
AM
AM
EA
RG
RG
EA, KV
RG
KV
EA
EA
KV,AM
KV,RG
RG
EA
AM
Assigned Tasks
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KV,
RG
KV,
RG
Blackwards
Engineering Fridays at
Calvin
Industrial Consultant
Meeting
Website Update
Executive Summary for
CEAC
Senior Banquet &
Projects Night
Draft Design Report
Final Design Report
14Mar
ALL
ALL
2Apr
11Apr
10May
25Apr
15May
AM/RG
ALL
ALL
ALL
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Appendix II: Mathcad Calculations
Part A: Sizing of System Components
Anaerobic Digestion Calculation for Wyoming CWP
Wyoming, MI
WWTP Location
Design Information
- Projected 2025 values for biosolids parameters were used for sizing digester, determining heating
requirements and evaluating gas production.
Annual Average Flow
Maximum Month Flow
Primary Sludge (PS)
gal
QPS.ave  104516
day
gal
QPS.max 124218
day
%Total Solids PS
%TSPS.ave  3.5%
%TSPS.max 3.5%
Waste Activated Sludge (WAS)
gal
QWAS.ave  422902
day
gal
QWAS.max 498356
day
%Total Solids WAS
%TSWAS.ave  0.7%
%TSWAS.max 0.7%
gal
QPS.ave  72.581
min
gal
QPS.max 86.263
min
gal
QWAS.ave  293.682
min
gal
QWAS.max 346.081
min
Combined Sludge Production
gal
Qcombined.ave  QPS.ave  QWAS.ave  366.263
min
Average Annual Flow
Maximum Month Flow
gal
Qcombined.max QPS.max QWAS.max 432.343
min
Thickening with Centrifuges
Existing System
Currently, there are two Andritz Bird centrifuges in the Sludge Thickening Building.
Centrifuge capacity per unit
gal
5 gal
Birdcapacity  265
 3.816 10 
min
day
Number of units
Birdnumber  2
Proposed Addition (for thickening primary sludge)
Number of centrifuge unit
Capacity of added centrifuge
%Thickening
Centrifuge add  1
Centrifuge cap  265gpm
%TScentri  4%
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Addition of a third centrifuge and a rehab of existing centrifuges is planned to occur in the next 10
years.
Qthick.PSave 
QPS.ave %TSPS.ave
Qthick.WAS .ave 
%TScentri
 63.508
QWAS.ave %TSWAS.ave
Qthick.PS.maxmonth
%TScentri
QPS.max %TSPS.max
gal
min
 51.394
 75.48
gal
min
gal
%TScentri
min
QWAS.max %TSWAS.max
gal
Qthick.WAS.maxmonth
 60.564
%TScentri
min
Combined Flow to Sludge Holding Tanks
- Based on Annual Average flow condition (2025 projected)
QPS.ave %TSPS.ave QWAS.ave %TSWAS.ave
Qholding.ave 

 0.165mgd

%TScentri
%TScentri
- Based on maximum month condition (2025 projected)
QPS.max %TSPS.max QWAS.max %TSWAS.max
Qholding.max 

 0.2 mgd
%TScentri
%TScentri
Sludge Storage at Holding Tanks
There are two sludge holding tanks at Wyoming CWP with mixing.
Sludge holding tank volume per unit
Number of sludge holding tanks at present
Calculation for required storage
Volhold.present  150000gal
Numberhold.present  2
Storagereq  3day  Qholding.max
5
Storage req  5.877 10  gal
Difference between required tankage and current capacity
Vdiff  Storagereq  Volhold.present Numberhold.present
5
Proposed addition(s)
Sludge holding tank volume per unit
Number of sludge holding to be added
Vdiff  3  10  gal
5
Volhold.new  1.5 10 gal
Numberhold.new  2
During emergency flow conditions, GVRBA facilities i.e. flow routing to Grand Rapids WWTP can be
utilized.
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Design I: Sizing of Cylindrical Digesters
Thermophilic Design (55 degrees Celsius)
Digestion System Properties
-Thermophilic operation (high VS and pathogen destruction)
- No recycle stream (HRT=MCRT)
- Single-stage, high-rate digester (short HRT)
- Steady state operation
- Complete mix reactors
Operational Temperature
Tthermo  55°C
HRT  10day
Hydraulic Retention Time
Feed to digester
Qfeed  Qholding.ave
6
Total digester volume required
Voldigesters.max  Qholding.ave HR T  1.65  10  gal
Allowance for grit accumulation on top, mixing equipment, gas collection etc...
6
FinalVoldigesters  1.2Voldigesters.max  2  10  gal
There will be a total of three digester tanks including a redundant tank of equal size.
Numberdigester  2
Number of operational digesters
Digester volume per tank
FinalVoldigesters
UnitVolumedigester 
Numberdigester
UnitVolumedigester  992756.10
gal
Designed digester is cylindrical with equal radius and height.
1
Radius/height
 UnitVolumedigester 
rdigester  




Boundary Area of Digester
Lateral Surface Area
Top/bottom Area of Digester
3
 34.8ft

A lateral  2  rdigester
2
 7.62  10  ft
3
2
A top   rdigester
2
 3.81  10  ft
3
2
The digesters will be constructed entirely above ground since the water table is located 12-15ft below
ground surface.
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Part B: Methane Production
Volatile Solids Reduction (VSR) Approach
Design Information
Design VSS/TSS ratio of treatment plant is 0.8
Influent TSS concentration
Average annual
mg
TSScave.annual  237
L
Maximum month
mg
TSScmax.month 258
L
TSS removal rate
%TSSremo.pri  49%
%TSSremo.sec  93%
Primary Clarifiers
Secondary Clarifiers (assumed)
I. Present Condition (2014)
Average annual wastewater flow
Qann.2014  14.7mgd
TSS loading (lb./day)
Average annual
4 lb
TSSave.2014  Qann.2014 TSScave.annual  2.907 10 
day
Maximum month
4 lb
TSSmax.2014 Qann.2014 TSScmax.month  3.165 10 
day
Volatile Solids entering digesters
Average annual condition




VSstart.ave.2014  0.8TSSave.2014%TSSremo.pri  1  %TSSremo.pri TSSave.2014%TSSremo.sec


4 lb
VSstart.ave.2014  2.243 10 
day
Maximum month condition
VSstart.max.2014 0.8TSSmax.2014
%TSSremo.pri  1  %TSSremo.pri TSSmax.2014
%TSSremo.sec


4 lb
VSstart.max.2014 2.442 10 
day
Loading rate
VSstart.ave.2014
lb
loading ave 
 0.084
2000000gal
3
ft  day
loading max 
VSstart.max.2014
2000000gal
lb
 0.091
Normal loading range= 0.05-0.2
3
ft  day
lb
3
ft  day
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% Volatile solids destruction (Empirical formula from Metcalf and Eddy, Page 1513)
Design I: Thermophilic digestion (cylindrical)
SRTI  10
%VSdes.I  13.7ln
 SRTI  18.9 %  50.45%

Sludge retention time

% Volatile solids destruction



Higher destruction requires longer SRT and subsequently bigger digester tanks. Since there is enough
capacity in sludge holding, the SRT can be varied to increase volatile solids destruction. Based on
diminishing returns, a 10-day digestion period gives an optimum VSS reduction.
Design II: TPAD digestion (egg shaped mesophilic reactor)
SRTII  16
%VSdes.II  13.7ln
 SRTII  18.9 %  56.88%

Sludge retention time

% Volatile solids destruction



lbm
biogas  0.062
3
ft
Density of digester gas
Biogas production
Design I: Thermophilic digestion (cylindrical)
4 lb
Mass biogas.ave.I.2014  %VSdes.I  VSstart.ave.2014  1.131 10 
day
4 lb
Mass biogas.max.I.2014 %VSdes.I  VSstart.max.2014 1.232 10 
day
Design I: TPAD digestion (egg shaped mesophilic reactor)
4 lb
Mass biogas.ave.II.2014  %VSdes.II  VSstart.ave.2014  1.276 10 
day
4 lb
Mass biogas.max.II.2014 %VSdes.II  VSstart.max.2014 1.389 10 
vol biogas.ave.14 
Mass biogas.ave.II.2014
biogas
5 ft
 2.058 10 
day
3
day
Biogas production (ft3/lb VSS destroyed)
biogasVSS  15
ft
3
lb
Methane Production
Assume 60% of biogas (digester gas) is methane.
Design I: Thermophilic digestion (cylindrical)
3
5 ft
VCH4.ave.I.2014 0.6Mass biogas.ave.I.2014 biogasVSS  1.02 10 
day
3
5 ft
VCH4.max.I.2014
 0.6Mass biogas.max.I.2014
 biogasVSS  1.11 10 
day
Design II: TPAD digestion (egg shaped mesophilic reactor)
5 ft
3
VCH4.ave.II.2014 0.6Mass biogas.ave.II.2014 biogasVSS  1.15 10 
day
3
5 ft
VCH4.max.II.2014
 0.6Mass biogas.max.II.2014
 biogasVSS  1.25 10 
day
87 | P a g e
Blackwards
II. 2025 Design Condition
Qann.2025  24mgd
Average annual wastewater flow
TSS loading (lb/day)
Average annual
4 lb
TSSave.2025  Qann.2025 TSScave.annual  4.747 10 
day
Maximum month
4 lb
TSSmax.2025 Qann.2025 TSScmax.month  5.167 10 
day
Volatile Solids entering digesters
Average annual condition




VSstart.ave.2025  0.8TSSave.2025%TSSremo.pri  1  %TSSremo.pri TSSave.2025%TSSremo.sec


4 lb
VSstart.ave.2025  3.662 10 
day
Maximum month condition
VSstart.max.2025 0.8TSSmax.2025
%TSSremo.pri  1  %TSSremo.pri TSSmax.2025
%TSSremo.sec


lb
4
VSstart.max.2025 3.986 10 
day
Loading rate
VSstart.ave.2025
lb
loading ave.2025 
 0.137
2000000gal
3
ft  day
loading max.2025
Normal range= 0.05-0.2
VSstart.max.2025
2000000gal
 0.149
lb
3
ft  day
lb
3
ft  day
Biogas production
Design I: Thermophilic digestion (cylindrical)
4 lb
Mass biogas.ave.I.2025  %VSdes.I  VSstart.ave.2025  1.847 10 
day
4 lb
Mass biogas.max.I.2025 %VSdes.I  VSstart.max.2025 2.011 10 
day
Design II: TPAD digestion (egg shaped mesophilic reactor)
4 lb
Mass biogas.ave.II.2025  %VSdes.II  VSstart.ave.2025  2.083 10 
day
4 lb
Mass biogas.max.II.2025 %VSdes.II  VSstart.max.2025 2.268 10 
volbiogas.ave.25 
Mass biogas.ave.II.2025
biogas
5 ft
 3.36  10 
day
3
day
88 | P a g e
Blackwards
Methane Production
Assume 60% of biogas (digester gas) is methane.
Design I: Thermophilic digestion (cylindrical)
3
5 ft
VCH4.ave.I.2025 0.6Mass biogas.ave.I.2025 biogasVSS  1.66 10 
day
5 ft
3
VCH4.max.I.2025
 0.6Mass biogas.max.I.2025
 biogasVSS  1.81 10 
day
Design II: TPAD digestion (egg shaped mesophilic reactor)
3
5 ft
VCH4.ave.II.2025 0.6Mass biogas.ave.II.2025 biogasVSS  1.87 10 
day
3
5 ft
VCH4.max.II.2025
 0.6Mass biogas.max.II.2025
 biogasVSS  2.04 10 
day
Energy Production from Methane
EnergyCH4  650
Energy content of methane gas
BT U
ft
Electric efficiency
%effec  38.92%
Availability in a year
avail  98%
3
*Since it costs more to buy natural gas than sell on a volume basis, it is imperative to utilize
biogas produce on-site for heating purposes.
Power Generation
2014 Average Flow conditions
Design I: Thermophilic digestion (cylindrical)
Average annual
Powerave.I.2014  %effec EnergyCH4VCH4.ave.I.2014
avail
7 BT U
Powerave.I.2014  2.52 10 
day
Design II: TPAD system
Average annual
Powerave.II.2014  %effec EnergyCH4VCH4.ave.II.2014
avail
7 BT U
Powerave.II.2014  2.85 10 
day
89 | P a g e
Blackwards
2025 Average Flow conditions
Design I: Thermophilic digestion (cylindrical)
rated
Average annual
electrical
power of 380kW per unit.
There will be a total of two G8-380 model Tech 3
Solutions Turbo Charged
cogeneration systems with a
Powerave.I.2025  %effec EnergyCH4VCH4.ave.I.2025
avail
7 BT U
Powerave.I.2025  4.12 10 
day
Design II: TPAD system
Average annual
Powerave.II.2025  %effec EnergyCH4VCH4.ave.II.2025
avail
7 BT U
Powerave.II.2025  4.65 10 
day
Cogeneration System Capacity
TPAD system was selected for design after comparing biosolids quality and energy generation potential.
The team used maximum methane gas production rate to size cogeneration system.
Cogen  %effec EnergyCH4VCH4.max.II.2025
5
Cogen  6.305 10  W
90 | P a g e
Blackwards
Calculation of Storage Space Needed
Assuming a month is 31 days
month  31day
Assuming that we need 3 and a half months storage to get through winter
StorageNeeded  3month  93day
Flow Rate of sludge leaving the holding/mixing tank for average conditions
Qholding  0.16546mgd
Percent Total Solids leaving the holding tank
TSholding  0.04
Mass fraction
Flow Rate of Solids entering digester
Assume that density of solids = density of water
3 gal
Solidsholding  Qholding TSholding  6.618 10 
day
Percent Total Volatile Solids of Total Solids for flow entering Digester
TVS 0.80
Flow Rate of Volatile Solids entering digester
Assume that density of volatile solids = density of solids
3 gal
VolatileSolidsholding  Qholding TSholding TVS  5.295 10 
day
Flow Rate of Fixed Solids Entering digester
3 gal
FixedSolidsholding  Qholding TSholding ( 1  TVS)  1.324 10 
day
Flow Rate of Water Entering Digester


5 gal
Water holding  Qholding 1  TSholding  1.588 10 
day
Reduction in Volatile Solids within Digester
Reduction  0.5
Flow Rate of Volatile Solids leaving Digester and Entering Dewatering
3 gal
VolatileSolidspostDigestion  Reduction VolatileSolidsholding  2.647 10 
day
Flow Rate of Total Solids Percentage leaving digester and entering dewatering
3 gal
SolidspostDigestion  VolatileSolidspostDigestion  FixedSolidsholding  3.971 10 
day
Flow Rate of Sludge Poste Digestion
5 gal
QpostDigestion  Water holding  SolidspostDigestion  1.628 10 
day
91 | P a g e
Blackwards
Percent Total Solids leaving digester and entering dewatering
TSpostDigestion 
SolidspostDigestion
QpostDigestion
 0.024
Percent Total Solids leaving dewatering
TSpostDewatering  0.04
Flow Rate of Sludge leaving
QpostDewatering 
QpostDigestion  TSpostDigestion 
TSpostDewatering
4 gal
 9.928 10 
day
Current Storage on Site
Storagecurrent  6000000gal
How Long Current Storage can handle normal flow
Storagecurrent
TimeCurrentStorage 
 60.438day

QpostDewatering
Storage Needed for Winter in No Dewatering Scenario
7
Storagenodewatering  QpostDigestion  StorageNeeded  1.514 10  gal
Ntanks newNoDewatering 
Storagenodewatering
 Storagecurrent

2000000gal
 4.571
Storage Needed for Winter in Dewatering Scenario
6
Storagedewatering  QpostDewatering  StorageNeeded  9.233 10  gal
NewtanksDewatering 
Storagedewatering  Storagecurrent 
2000000gal
 1.616
Cost of Tanks
VolumeoneTank  2000000gal
0.65
UnitCost 
gal
6
Cost oneTank  VolumeoneTank  UnitCost  1.3  10
6
Cost total  2 Cost oneTank  2.6  10
92 | P a g e
Blackwards
Pumping Station Design
Head Needed for Pump that Takes Sludge from Mixing/Holding Tanks to Digestion Tanks
Q1  115gpm
Average Flow Rate
D1  8in
Diameter of Pipe
Lpipe1  770ft
Length of Pipe
Actual distance between buildings is 660 ft.
Assume an extra 25 ft of pipe inside each
2
 D1
building to handle flow between units
2
A cross1 
 0.349ft
 Cross Sectional Area of Pipe
4
v 1 
Q1
A cross1
 0.734
ft
s
Flow Velocity
Major Headloss Due to Friction with Pipe
Use Figure 19-4 from Chapter 19 of System Design for Sludge Pumping by Carl N. Anderson
and David J. Hanna
This figure can be used to get frictional losses within a pipe flowing with sludge from
the frictional losses within a pipe flowing with water, the TS percentage, and the
velocity within the pipe
93 | P a g e
Blackwards
factor 1  80
Factor relates headloss for water to headloss for sludge
Use Darcy Weisbach formula for head calculation of water flowing within pipe
Kinematic Viscosity
Use coldest temperature for viscosity (10 deg Celsius) which will be worst case
Viscosity Value taken from engineeringtoolbox.com
2
6m
H20  1.30710

s
v 1 D1
4
ReH201 
 3.478 10
H20
Calculating Reynold's Number
Assume laminar flow
64
3
f1 
 1.84 10
ReH201
Calculating friction factor
2
h LfH201  f1 
Lpipe1 v 1
D1 2g
 0.018ft

hLf1  hLfH201factor 1  1.424ft

Calculating Frictional head loss
Relate headloss for water to headloss for sludge
Friction Losses due to bends in pipe
nbend1  11
Kbend  0.75
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a branch flow through a cross fitting or
Tee fitting
KbendTot1  nbend1 Kbend  8.25
Friction Losses due to in line valves
nvalve1  22
Kvalve  2
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-7, pg. 899 for a Rubber flapper check valve with a
flow velocity less than 6ft/s
KvalveTot1  nvalve1Kvalve  44
Frictional losses due to transition from tank to pipe
nentrance1  1
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a rounded entrance flush with side of
tank
Kentrance  0.25
KentranceTot1  nentrance1 Kentrance  0.25
94 | P a g e
Blackwards
Frictional losses due to transition from pipe to tank
nexit1  1
Kexit  1
K value taken from Pumping Station Design edited by Robert L. Sanks
Table B-6, pg. 898
KexitTot1 nexit1Kexit  1
Total Energy Loss Coefficients
KSum1  KbendTot1  KvalveTot1  KentranceTot1  KexitTot1  53.5
Total Minor Headloos
2
h Lminor1 
KSum1 v 1
2g
 0.448ft

Use energy equation
Relating surface of fluid in mixing/holding tanks to surface of fluid in digester
System Description
Assume constant pipe diameter (Ai=Af) therefore vi=vf because Qi = Qf
vi1  v1
vf1  v1
Althought system is not explosed to atmosphere, the system is not pressured relative to
outside system. Therefore pressure at surface level is 1 atmosphere.
Pi1  1atm
Pf1  1atm
Z i refers to the water surface heght within the mixing / holding tank. Conseratively this
number was chosen for a tank half full.
zi1  640ft
Z f refers to the sludge surface height inside digester above sea level.
zf1  685ft
Fluid Properties
  999.7
kg
Specific Gravity of water
3
m
 v 2 v 2   P
Pi1 
f1
i1
f1
h p1  



   zf1  zi1  h Lf1  h Lminor1  46.871ft


2g    g
 g 
 2g
95 | P a g e
Blackwards
Head Needed for Pump that Takes Sludge from Digestion to Dewatering
Q2  115gpm
Average Flow Rate
D2  8in
Diameter of Pipe
Lpipe2  640ft
Length of Pipe
2
A cross2 
v 2 
 D2
Q2
A cross2
4
 0.349ft

 0.734
ft
s
2
Actual distance between buildings is 660 ft.
Assume an extra 25 ft of pipe inside each
building to handle flow between units
Cross Sectional Area of Pipe
Flow Velocity
Major Headloss Due to Friction with Pipe
Use Figure 19-4 from Chapter 19 of System Design for Sludge Pumping by Carl N. Anderson
and David J. Hanna
This figure can be used to get frictional losses within a pipe flowing with sludge from
the frictional losses within a pipe flowing with water, the TS percentage, and the
velocity within the pipe
96 | P a g e
Blackwards
factor 2  80
Factor relates headloss for water to headloss for sludge
Use Darcy Weisbach formula for head calculation of water flowing within pipe
Kinematic Viscosity
Use coldest temperature for viscosity (10 deg Celsius) which will be worst case
Viscosity Value taken from engineeringtoolbox.com
2
6m
H20  1.30710

s
v 2 D2
4
ReH202 
 3.478 10
H20
Calculating Reynold's Number
Assume laminar flow
64
3
f2 
 1.84 10
ReH202
Calculating friction factor
2
h LfH202  f2 
Lpipe2 v 2
D2 2g
 0.015ft

hLf2  hLfH202factor 2  1.183ft

Calculating Frictional head loss
Relate headloss for water to headloss for sludge
Friction Losses due to bends in pipe
nbend2  6
Kbend  0.75
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a branch flow through a cross fitting or
Tee fitting
KbendTot2  nbend2 Kbend  4.5
Friction Losses due to in line valves
nvalve2  12
Kvalve  2
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-7, pg. 899 for a Rubber flapper check valve with a
flow velocity less than 6ft/s
KvalveTot2  nvalve2Kvalve  24
Frictional losses due to transition from tank to pipe
nentrance2  1
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a rounded entrance flush with side of
tank
Kentrance  0.25
KentranceTot2  nentrance2 Kentrance  0.25
97 | P a g e
Blackwards
Frictional losses due to transition from pipe to tank
nexit2  0
Kexit  1
K value taken from Pumping Station Design edited by Robert L. Sanks
Table B-6, pg. 898
KexitTot2 nexit2Kexit  0
Total Energy Loss Coefficients
KSum2  KbendTot2  KvalveTot2  KentranceTot2  KexitTot2  28.75
Total Minor Headloos
2
h Lminor2 
KSum2 v 2
2g
 0.241ft

Use energy equation
Relating surface of fluid in mixing/holding tanks to surface of fluid in digester
System Description
Assume constant pipe diameter (A1=A2) therefore v1=v2 because Q1 = Q2
vi2  v2
vf2  v2
Althought system is not explosed to atmosphere, the system is not pressured relative to
outside system. Therefore pressure at surface level is 1 atmosphere.
Pi2  1atm
Pf2  1atm
Z 1 refers to the sludge surface heght in the digesters. Conseratively this number was
chosen for a tank half full.
zi2  590ft
Z 2 refers to the height of the dewatering centrifuges above sea level.
zf2  600ft
Fluid Properties
  999.7
kg
Specific Gravity of water
3
m
 v 2 v 2   P
Pi2 
f2
i2
f2
h p2  



   zf2  zi2  h Lf2  h Lminor2  11.424ft


2g    g
 g 
 2g
98 | P a g e
Blackwards
Head Needed for Pump that Takes Sludge from Dewatering to Storage Tanks
Q3  115gpm
Average Flow Rate
D3  8in
Diameter of Pipe
Lpipe3  370ft
Length of Pipe
2
A cross3 
v 3 
 D3
Q3
A cross3
4
 0.349ft

 0.734
ft
s
2
Actual distance between buildings is 660 ft.
Assume an extra 25 ft of pipe inside each
building to handle flow between units
Cross Sectional Area of Pipe
Flow Velocity
Major Headloss Due to Friction with Pipe
Use Figure 19-4 from Chapter 19 of System Design for Sludge Pumping by Carl N. Anderson
and David J. Hanna
This figure can be used to get frictional losses within a pipe flowing with sludge from
the frictional losses within a pipe flowing with water, the TS percentage, and the
velocity within the pipe
99 | P a g e
Blackwards
factor 3  80
Factor relates headloss for water to headloss for sludge
Use Darcy Weisbach formula for head calculation of water flowing within pipe
Kinematic Viscosity
Use coldest temperature for viscosity (10 deg Celsius) which will be worst case
Viscosity Value taken from engineeringtoolbox.com
2
6m
H20  1.30710

s
v 3 D3
4
ReH203 
 3.478 10
H20
Calculating Reynold's Number
Assume laminar flow
64
3
f3 
 1.84 10
ReH203
Calculating friction factor
2
h LfH203  f3 
Lpipe3 v 3
D3 2g
3
 8.55  10
hLf3  hLfH203factor 3  0.684ft

 ft
Calculating Frictional head loss
Relate headloss for water to headloss for sludge
Friction Losses due to bends in pipe
nbend3  2
Kbend  0.75
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a branch flow through a cross fitting
or Tee fitting
KbendTot3  nbend3 Kbend  1.5
Friction Losses due to in line valves
nvalve3  9
Kvalve  2
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-7, pg. 899 for a Rubber flapper check valve with a
flow velocity less than 6ft/s
KvalveTot3  nvalve3Kvalve  18
Frictional losses due to transition from tank to pipe
nentrance3  0
K value taken from Pumping Station Design edited by Robert L.
Sanks Table B-6, pg. 898 for a rounded entrance flush with side of
tank
Kentrance  0.25
KentranceTot3  nentrance3 Kentrance  0
100 | P a g e
Blackwards
Frictional losses due to transition from pipe to tank
nexit3  1
Kexit  1
K value taken from Pumping Station Design edited by Robert L. Sanks
Table B-6, pg. 898
KexitTot3 nexit3Kexit  1
Total Energy Loss Coefficients
KSum3  KbendTot3  KvalveTot3  KentranceTot3  KexitTot3  20.5
Total Minor Headloos
2
h Lminor3 
KSum3 v 3
2g
 0.172ft

Use energy equation
Relating surface of fluid in mixing/holding tanks to surface of fluid in digester
System Description
Assume constant pipe diameter (A1=A2) therefore v1=v2 because Q1 = Q2
vf3  v3
vi3  v3
Althought system is not explosed to atmosphere, the system is not pressured relative to
outside system. Therefore pressure at surface level is 1 atmosphere.
Pf3  1atm
Pi3  1atm
Z 1 refers to the sludge surface heght in the digesters. Conseratively this number was
chosen for a tank half full.
zi3  600ft
Z 2 refers to the height of the dewatering centrifuges above sea level.
zf3  640ft
Fluid Properties
  999.7
kg
Specific Gravity of water
3
m
 v 2 v 2   P
Pi3 
f3
i3
f3
h p  



   zf3  zi3  h Lf3  h Lminor3  40.856ft


2g    g
 g 
 2g
101 | P a g e
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Cost Analysis of Holding Tank / Centrifuge Configuration
Assume Concrete as Tank Material
Costtank  0.65
1
gal
Taken from page 6 of "Concrete Water Storage Tanks" by Ryan J. Erickson
Assume 3 days of storage (Hydralic Residence Time [HRT]) needed in holding tank
HRT  3day
Assume max month flow conditions
gal
QOriginalPrimary 86.3
min
TSOriginalPrimary 0.035
gal
QOriginalSecondary  346.1
min
TSOriginalSecondary  0.007
Assume centrifuge thicken to 4%
TSThick  0.04
Volume of holding tanks on site
Volexisting  150000gal
Calculate New Flow Rates
QThickPrimary QOriginalPrimary
TSOriginalPrimary
TSThick
QThickSecondary  QOriginalSecondary 
 75.513
TSOriginalSecondary
TSThick
gal
min
 60.568
gal
min
Calculate Flow into Holding Tank for Each Alternative
gal
Qalt1  QOriginalPrimary QThickSecondary  146.868
min
gal
Qalt2  QOriginalPrimary QOriginalSecondary  432.4
min
gal
Qalt3  QThickPrimary QThickSecondary  136.08
min
Calculate Volume of Holding Tank Necessary for Each Alternative
5
Volalt1  HRT Qalt1  6.345 10  gal
6
Volalt2  HR T Qalt2  1.868 10  gal
5
Volalt3  HR T Qalt3  5.879 10  gal
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Calculate Volume Still Needed for Each Holding Tank for Each Alternative
5
VolneededAlt1  Volalt1  Volexisting  4.845 10  gal
6
VolneededAlt2  Volalt2  Volexisting  1.718 10  gal
5
VolneededAlt3  Volalt3  Volexisting  4.379 10  gal
Calculate Cost of New tanks
5
Cost alt1  VolneededAlt1  Cost tank  3.149 10
6
Cost alt2  VolneededAlt2  Cost tank  1.117 10
5
Cost alt3  VolneededAlt3 Cost tank  2.846 10
Piping
Piping distances have been estimated using a satellite photo and using a car parking spot
as a reference point.
Typical Car Spot is 7.5 ft to 9 ft wide by 16 ft to 20 ft long
We'll say a spot is 18 ft long
Lengthcar  18ft
Cost of piping
Assume cast iron, 6" diameter. Number taken from RSMeans Building
Construction Cost Data,2009
Costpipe 
44
ft
Parking lengths between primary settling and thickening
PrimaryToThickening 35
LPrimaryToThickening Lengthcar PrimaryToThickening 630ft
Parking lengths between secondary settling and thickening
SecondaryToThickening  34
LSecondaryToThickening  Lengthcar SecondaryToThickening  612ft
Parking lengths between primary settling and mixing
PrimaryToMixing 27
LPrimaryToMixing Lengthcar PrimaryToMixing 486ft
Parking lengths between secondary settling and mixing
SecondaryToMixing  55
LSecondaryToMixing  Lengthcar SecondaryToMixing  990ft
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Parking lengths between mixing and second thickening building
MixingToThickening2 15
Parking lengths between mixing and second thickening building
ThickeningToMixing 17
LThickeningToMixing Lengthcar ThickeningToMixing 306ft
Length of Pipe Needed for Each Alternative
Pipealt1  Lengthcar (2MixingToThickening2
)  540ft
3
Pipealt2  Length car  ( 2SecondaryToMixing  2ThickeningT oM ixing)  2.592 10  ft
3
Pipealt3  Length car  ( 2PrimaryToThickening ThickeningT oM ixing)  1.566 10  ft
Cost of Pipe Needed for Each Alternative
4
Cost pipeAlt1  Cost pipe Pipealt1  2.376 10
5
Cost pipeAlt2  Cost pipe Pipealt2  1.14  10
4
Cost pipeAlt3  Cost pipe Pipealt3  6.89  10
MixingToDigestion 37
LMixingToDigestion Lengthcar MixingToDigestion 666ft
DigestionToDewatering  37
LDigestionToDewatering  Lengthcar DigestionToDewatering  666ft
DewateringToStorage  20
LDewateringToStorage  Lengthcar DewateringToStorage  360ft
DigestionToCogen  11
LDigestionToCogen  Lengthcar DigestionToCogen  198ft
HoldingToCogen  51
LHoldingToCogen  Lengthcar HoldingToCogen  918ft
StorageToCogen  44
LStorageToCogen  Lengthcar StorageToCogen  792ft
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Appendix III: Hydraulic Profile
A Hydraulic Profile was created of the proposed system from information given by the
Wyoming CWP. Where information was not available, a conservative estimate was chosen. In
the drawing, the Primary and Secondary settling tanks are not shown to scale. Pipe lengths were
chosen using the drawing of the site layout in AutoCAD 2012.
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106 | P a g e
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Appendix IV: Manual of Laboratory Tests
Solid Concentration Test
Purpose
The purpose of this experiment is determine the solid concentration present in a sludge sample.
Physical and thermal treatment methods are applied to measure suspended and dissolved solids
(TSS and TDS) in addition to volatile and fixed solids present in each grouping. Treatment facilities
perform solids test for quality control. Since we will not use filters to determine TDS and TSS,
total solids can be found by following equation:
%𝐓𝐨𝐭𝐚𝐥 𝐒𝐨𝐥𝐢𝐝𝐬 = %𝐅𝐢𝐱𝐞𝐝 𝐒𝐨𝐥𝐢𝐝𝐬 (𝐅𝐒) + %𝐕𝐨𝐥𝐚𝐭𝐢𝐥𝐞 𝐒𝐨𝐥𝐢𝐝𝐬 (𝐕𝐒)
TS and VS can be determined by exposing sludge sample to different temperatures for a duration
of time. For our purposes, we are interested in TS and VSS levels of sludge samples pre- and postdigestion. VSS is a measure of the organic matter and microbial population of a waste stream and
thus serves as an indicator of the methane production potential. In this experiment, three dishes
with sludge samples will be tested for repeatability and calculating averages in each test run.
Equipment Used
100mL aluminum dishes, muffle furnace (Lucifer), drying oven, analytical balance and
thermometer
Procedure
(Adapted from Method 2540B and 2540E of Standard Methods book, 19 th Edition)
1. Label three clean empty dishes with date.
2. Place the dishes in Lucifer furnace for 1 hour at 550°C (1022°F).
3. Put dishes in the decanter until ready for use.
4. Take out of decanter and weigh the dishes. This is the weight of empty dish.
Use table below for recording.
5. Obtain approximately 30mL of slurry sludge (V).
6. Pulverize thoroughly with mortar and pestle.
7. Weigh the dish with sludge. This is the weight of the wet dish.
8. Place samples in furnace for overnight at 103°C (217°F). Only small amount of organic
matter is lost at this temperature.
9. Remove from furnace and place in desiccator to cool.
10. Weigh this sample. This is the weight of the dry sample at 103°C.
11. Heat the furnace to 550°C (1022°F), place samples and heat for one hour.
12. Let the samples cool down inside the furnace for 20 minutes with doors open.
13. At the end of the hour, remove samples and let them cool in desiccator.
14. Weigh this sample. This is the weight of the burned sample at 550°C.
15. Perform TS and TVS calculations.
107 | P a g e
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Table 25: Solids Measurement Datasheet
Parameter
Dish 1
Weight of empty dish, Wdish (mg)
Weight of wet dish, Wwet (mg)
Weight of dry sample at 103°C, W103 (mg)
Weight of burned sample at 550°C, W550c (mg)
Calculations
𝑾
Dish 2
Dish 3
−𝑾
%𝑻𝑺 = (𝑾𝟏𝟎𝟑−𝑾𝒅𝒊𝒔𝒉 ) ∗ 𝟏𝟎𝟎
𝒘𝒆𝒕
𝑾
𝒅𝒊𝒔𝒉
−𝑾
%𝑽𝑺 = (𝑾 𝟏𝟎𝟑−𝑾 𝟓𝟓𝟎 ) ∗ 𝟏𝟎𝟎
𝟏𝟎𝟑
𝒅𝒊𝒔𝒉
*Duplicate measurements should agree within 5% of the average (AWWA’s Standard book)
108 | P a g e
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Chemical Oxygen Demand (COD) Test
Purpose
The purpose of this experiment is to determine the amount of organic matter present in a sample
that could be oxidized by a strong reducing agent such as sulfuric acid. It is normally reported in
units of mg/L. Previous research has shown that correlation between COD and 5-day BOD could
be derived. Standard potassium hydrogen phthalate (KHP) solutions will be used to create
calibration curve for COD. A 425 mg/L KHP solution has a theoretical COD value of 500mg/L.
Safety Precaution
COD vials contain high concentration of sulfuric acid and some mercury sulfate which may cause
skin burn and cancer. Thus the experiment should be performed in fume hood. MSDS for the
COD vials can be found in the lab binder and team’s folder.
Equipment/materials Used
Pierce Reacti-Therm digester block, CHEMetrics COD vials, plastic vial rack, Spectronic 20D+
spectrophotometer analytical balance, micropipette, standard KHP solutions, amber bottles and
thermometer
Procedure
(Adapted from CHEMetrics Test Procedure Manual)
1. Obtain 20mL sludge sample using amber bottles and thoroughly
mix.
2. Label vials using masking tape and organize on white rack.
3. Heat the digester block to 150°C (7.6 on the scale) inside fume
hood. To measure T°, insert thermometer at the small slot on the
block.
4. Carefully remove cap from vials avoiding physical contact and gas
inhale.
5. Using micropipette, place 2mL of sample into vials.
6. Close cap tightly and invert vials five times for mixing holding the
cap. Heat is produced from the mixture of strong acid and sample
Figure 41: Spectronic 20D+
(mostly water).
equipment
7. Use a damp towel to wipe the surface of the vial carefully.
8. Place samples in the heated digester block for 2hrs and record
start time.
9. Prepare vials for another sludge sample, deionized water (reagent blank) and standard
KHP solutions as described above, place in digester block and record time.
10. At the end of the 2hr. digestion period, turn off the block. Leave it for the next 15
minutes to cool down.
109 | P a g e
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11. With care, remove the vials holding the cap and let them cool for at least 30mins in a
dark place.
12. Follow instructions on the left to start the spectrophotometer. Select the 600-950nm
filter position.
13. Set the absorbance of the device to zero using reagent blank. Clean the outer surface of
the vial.
14. Make sure to clean and swipe.
15. Place used COD vials in fume hood. DO NOT drain down the sink. The contents should
be transferred to the bottle with labels “Hazardous Waste: COD……” Rinse vials with DI
water.
16. Bottles with KHP solutions should be refrigerated for future experiments.
17. Prepare a calibration curve using KHP standard solutions.
Experiment Time:
1. Preparation (~ 30min) - Requires supervision
2. Digestion (2hrs) - Does NOT require supervision
3. Cooling (45- 50mins) - Does NOT require supervision
4. Measurement & Data analysis (~15mins) - Requires supervision
Table 26: COD experiment Datasheet
DI water
KHP
(mg/L)
KHP
(mg/L)
KHP
(mg/L)
Sample
1
Sample 2
Start time (hr: min)*
End of digestion
Absorbance
COD**
*Start time is the actual time that the vial containing specified liquid is placed in digester block.
**Based on calibration curve.
References
1. Idris, Azni, and W.A.W.A.K.G Ghani. "Preliminary Study on Biogas Production of Biogas
from Municipal Solid Waste (MSW) Leachate." Journal of Engineering Science and
Technology 4.4 (2009): 374-80. Web. 23 Feb. 2014.
2. Standard Methods for the Examination of Water and Wastewater. 19th ed. Washington,
DC: American Public Health Association, 1995. Print.
110 | P a g e
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Day
1
2
3
4
5
6
7
Start
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
Label on
Dish
Weight of
dish (gm)
1.1
1.2
1.3
2.1
2.2
2.3
3.1
3.2
3.3
7.1
7.2
4.1
4.2
5.1
5.2
6.1
6.2
13
14
19
20
1
27
2
3
4
21
22
6
7
11
12
5
28
24
26
10
9
25
34
32
33
30
31
18
17
1.3353
1.337
1.327
1.3284
1.3218
1.3251
1.331
1.324
1.329
1.322
1.3213
1.3215
1.3235
1.319
1.3248
1.32
1.35
1.3378
1.32
1.3257
1.3367
1.3292
1.3157
1.3277
1.329
1.3275
1.3338
1.3406
1.3285
1.333
1.337
1.3315
1.353
1.3291
1.3499
1.3275
1.3252
1.3275
1.3329
1.3212
1.323
1.3308
1.3199
1.3224
1.3299
1.3427
Lab Data For Team 7 Batch Reactor
ALL Weights in GRAMS
Wet
Residue
Dry sample
sample
Weight (gm)
weight (gm)
(gm)
[Post Burn]
3.7936
1.4727
1.3537
12.9505
1.9476
1.4225
24.7171
2.5211
1.5074
6.0106
1.4429
1.3537
9.9672
1.5305
1.3679
7.9889
1.4867
1.3608
21.867
1.6831
1.4072
21.837
1.6672
1.4005
25.178
1.7277
1.4152
13.1531
1.4641
1.3729
23.0265
1.6306
1.4142
8.4604
1.5256
1.3555
9.0242
1.4995
1.3595
6.3348
1.4562
1.3495
8.8766
1.4683
1.3595
13.2671
1.4093
1.3344
13.065
1.4362
1.3661
16.5658
1.5402
1.4034
11.044
1.5246
1.3882
21.5065
2.0201
1.4128
24.5058
2.3271
1.455
16.7377
1.5968
1.3836
9.4627
1.3593
1.3267
9.0305
1.37
1.338
4.801
1.3532
1.334
3.992
1.4051
1.3443
8.4327
1.3681
1.352
6.1142
1.3689
1.3472
5.575
1.3941
1.3432
9.4711
1.3838
1.345
11.1815
1.4063
1.3541
6.2485
1.4028
1.342
7.378
1.3868
1.3599
7.7371
1.3669
1.3384
6.2136
1.3719
1.355
7.6083
1.4326
1.3559
3.2745
1.3382
1.3285
10.539
1.3502
1.3329
8.1502
1.3562
1.3562
7.5372
1.3412
1.3412
10.4089
1.3534
1.3534
10.5184
1.3599
1.3599
5.5514
1.3536
1.3536
2.7
1.3308
1.3308
14.7538
1.3952
1.3952
18.7488
1.4112
1.4112
%TS
%TVS
5.59%
5.26%
5.11%
2.45%
2.41%
2.43%
1.71%
1.67%
1.67%
1.20%
1.43%
2.86%
2.29%
2.74%
1.90%
0.75%
0.74%
1.33%
2.10%
3.44%
4.27%
1.7%
0.54%
0.5%
0.7%
2.9%
0.5%
0.6%
1.5%
0.6%
0.7%
1.5%
0.6%
0.6%
0.5%
1.7%
0.67%
0.25%
0.34%
0.32%
0.33%
0.32%
0.80%
0.61%
0.49%
0.39%
13.39%
14.00%
15.11%
22.10%
22.09%
22.09%
21.64%
22.29%
21.62%
35.82%
30.04%
16.66%
20.45%
22.23%
24.18%
16.13%
18.68%
32.41%
33.33%
12.54%
11.94%
79.7%
74.8%
75.7%
79.3%
78.4%
76.7%
77.6%
76.4%
75.3%
85.3%
79.6%
75.4%
76.8%
73.0%
74.6%
76.2%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
0.0%
AVG. of
TS
AVG. of
TVS
5.32%
14.17%
2.43%
22.09%
1.69%
21.85%
1.31%
32.93%
2.57%
18.56%
2.32%
23.21%
0.74%
17.40%
1.72%
32.87%
3.86%
12.24%
1.70%
79.67%
1.70%
75.21%
1.80%
78.84%
0.54%
76.68%
1.08%
76.98%
1.08%
80.30%
0.58%
77.49%
1.1%
74.90%
0.46%
75.41%
0.33%
0.00%
0.33%
0.00%
0.70%
0.00%
0.44%
0.00%
111 | P a g e
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Day
Label on
Dish
Weight of
dish (gm)
Wet
sample
(gm)
Dry sample
weight (gm)
Residue
Weight (gm)
[Post Burn]
%TS
%TVS
29
23
16
15
1.3172
1.3258
1.3244
1.3216
10.7777
11.8108
13.3099
6.7823
1.3594
1.4091
1.5057
1.3789
1.3286
1.3437
1.3654
1.336
0.4%
0.8%
1.5%
1.0%
73.0%
78.5%
77.4%
74.9%
8
1.3396
9.6512
1.4258
1.3597
1.0%
76.7%
1
2
1
2
3
4
5
6
7
8
9
10
14
15
16
17
18
19
21
22
23
24
25
26
20
27
28
29
30
1.3241
1.3244
1.3275
1.3254
1.3212
1.3296
1.3247
1.3283
1.3309
1.326
1.3136
1.3319
1.3285
1.3318
1.3249
1.3229
1.3299
1.3257
1.3152
1.3258
1.3247
1.3154
1.3209
1.3163
1.3235
1.3157
1.3304
1.3245
1.3179
5.476
10.9002
9.284
11.3384
12.9161
10.0404
10.2969
7.4655
11.0218
10.6328
14.8563
13.2135
10.9875
8.7546
11.1817
12.9692
10.2797
10.8992
11.1329
9.1113
12.2669
13.3836
10.0873
8.3964
10.5313
15.147
10.4603
15.3836
8.8661
1.3688
1.4392
1.4283
1.4397
1.4485
1.4633
1.442
1.3958
1.4379
1.4255
1.4476
1.4528
1.4122
1.3926
1.3734
1.4021
1.4024
1.4051
1.3999
1.4073
1.4217
1.4194
1.3965
1.3785
1.3861
1.4421
1.3758
1.4349
1.3474
1.3337
1.3515
1.3513
1.3534
1.3539
1.3607
1.3489
1.3448
1.3575
1.3512
1.1%
1.2%
1.3%
1.1%
1.1%
1.5%
1.3%
1.1%
1.1%
1.1%
1.0%
1.0%
0.9%
0.8%
78.5%
76.4%
76.4%
75.5%
74.3%
76.7%
79.4%
75.6%
75.1%
74.7%
AVG. of
TS
AVG. of
TVS
0.62%
75.75%
1.28%
76.13%
1.04%
76.68%
1.14%
77.46%
1.20%
75.95%
1.32%
75.53%
1.20%
77.46%
1.09%
74.91%
1.00%
74.61%
0.84%
73.58%
0.68%
73.40%
0.82%
71.13%
0.95%
72.70%
0.87%
72.64%
0.87%
72.62%
0.68%
0.65%
71.41%
69.00%
0.64%
67.48%
Start
Date
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
1.3626
1.3507
1.3478
1.3379
1.3438
1.3504
1.3491
1.3391
1.3473
1.3512
1.3439
1.342
1.333
1.3414
1.3677
1.3376
1.3788
1.3316
0.7%
0.8%
0.8%
0.9%
1.0%
0.9%
0.9%
0.9%
0.9%
0.7%
0.9%
0.5%
0.8%
0.4%
74.6%
73.5%
73.7%
73.2%
73.6%
71.7%
70.5%
71.8%
73.6%
72.7%
72.6%
72.1%
73.2%
71.4%
58.9%
84.1%
50.8%
53.6%
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Appendix V: Formatted Selections from Clean Water
Act Part 503
503.13 Pollutant limits.
a) Sewage sludge.
1) Bulk sewage sludge or sewage sludge sold or given away in a bag or other container
shall not be applied to the land if the concentration of any pollutant in the sewage
sludge exceeds the ceiling concentration for the pollutant in Table 1 of 503.13.
2) If bulk sewage sludge is applied to agricultural land, forest, a public contact site, or a
reclamation site, either:
i.
The cumulative loading rate for each pollutant shall not exceed the cumulative
pollutant loading rate for the pollutant in Table 2 of 503.13; or
ii.
The concentration of each pollutant in the sewage sludge shall not exceed the
concentration for the pollutant in Table 3 of 503.13.
3) If bulk sewage sludge is applied to a lawn or a home garden, the concentration of each
pollutant in the sewage sludge shall not exceed the concentration for the pollutant in
Table 3 of 503.13.
4) If sewage sludge is sold or given away in a bag or other container for application to
the land, either:
i.
The concentration of each pollutant in the sewage sludge shall not exceed the
concentration for the pollutant in Table 3 of 503.13; or
ii.
The product of the concentration of each pollutant in the sewage sludge and the
annual whole sludge application rate for the sewage sludge shall not cause the
annual pollutant loading rate for the pollutant in Table 4 of 503.13 to be exceeded.
The procedure used to determine the annual whole sludge application rate is
presented in appendix A of this part.
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b) Pollutant concentrations and loading rates—sewage sludge.
1) Ceiling concentrations.
Table 1 of §503.13 – Ceiling Concentrations
Ceiling
Concentration
(mg/kg)1
75
85
4300
840
57
75
420
100
7500
Pollutant
Arsenic
Cadmium
Copper
Lead
Mercury
Molybdenum
Nickel
Selenium
Zinc
1 Dry weight basis
2) Cumulative pollutant loading rates
Table 2 of §503.13 – Cumulative Pollutant Loading Rates
Pollutant
Arsenic
Cadmium
Copper
Lead
Mercury
Nickel
Selenium
Zinc
3) Pollutant concentrations
Cumulative pollutant
loading rate
(kg / hectare)
41
39
1500
300
17
420
100
2800
Table 3 of §503.13 – Pollutant Concentrations
Pollutant
Arsenic
Cadmium
Copper
Lead
Mercury
Nickel
Monthly average
concentration
(mg/kg)1
41
39
1500
300
173
420
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Selenium
Zinc
1
100
2800
Dry weight basis
4) Annual pollutant loading rates
Table 4 of §503.13 – Annual Pollutant Loading Rates
Annual pollutant loading rate
Pollutant
(kg / hectare / 365 day
period)
Arsenic
2
Cadmium
1.9
Copper
75
Lead
15
Mercury
0.85
Nickel
21
Selenium
5
Zinc
140
c) Domestic septage. The annual application rate for domestic septage applied to
agricultural land, forest, or a reclamation site shall not exceed the annual application rate
calculated using equation (1).
𝐍
𝐀𝐀𝐑 = 𝟎.𝟎𝟎𝟐𝟔
Eq. (1)
Where:
AAR = Annual Application rate in gallons per acre per 365 day period.
N = amount of nitrogen in pounds per acre per 365 day period needed by the crop or
vegetation grown on the land.
[58 FR 9387, Feb. 19, 1993, as amended at 58 FR 9099, Feb. 25, 1994; 60 FR 54769, Oct. 25, 1995]
503.32 Pathogens.
a) Sewage sludge—Class A.
1) The requirement in 503.32(a)(2) and the requirements in either 503.32(a)(3), (a)(4),
(a)(5), (a)(6), (a)(7), or (a)(8) shall be met for a sewage sludge to be classified Class A
with respect to pathogens.
2) The Class A pathogen requirements in 503.32 (a)(3) through (a)(8) shall be met either
prior to meeting or at the same time the vector attraction reduction requirements in
503.33, except the vector attraction reduction requirements in 503.33 (b)(6) through
(b)(8), are met.
3) Class A—Alternative 1.
i.
Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
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ii.
of Salmonella sp. bacteria in the sewage sludge shall be less than three Most
Probable Number per four grams of total solids (dry weight basis) at the time the
sewage sludge is used or disposed; at the time the sewage sludge is prepared for
sale or give away in a bag or other container for application to the land; or at the
time the sewage sludge or material derived from sewage sludge is prepared to
meet the requirements in 503.10 (b), (c), (e), or (f).
The temperature of the sewage sludge that is used or disposed shall be
maintained at a specific value for a period of time.
A. When the percent solids of the sewage sludge is seven percent or higher, the
temperature of the sewage sludge shall be 50 degrees Celsius or higher; the
time period shall be 20 minutes or longer; and the temperature and time
period shall be determined using equation (2), except when small particles of
sewage sludge are heated by either warmed gases or an immiscible liquid.
𝐃=
𝟏𝟑𝟏,𝟕𝟎𝟎,𝟎𝟎𝟎
𝟏𝟎𝟎.𝟏𝟒𝟎𝟎𝐭
Eq. (2)
Where,
D=time in days.
t=temperature in degrees Celsius.
B. When the percent solids of the sewage sludge is seven percent or higher and
small particles of sewage sludge are heated by either warmed gases or an
immiscible liquid, the temperature of the sewage sludge shall be 50 degrees
Celsius or higher; the time period shall be 15 seconds or longer; and the
temperature and time period shall be determined using equation (2).
C. When the percent solids of the sewage sludge is less than seven percent and
the time period is at least 15 seconds, but less than 30 minutes, the
temperature and time period shall be determined using equation (2).
D. When the percent solids of the sewage sludge is less than seven percent; the
temperature of the sewage sludge is 50 degrees Celsius or higher; and the time
period is 30 minutes or longer, the temperature and time period shall be
determined using equation (3).
𝐃=
𝟓𝟎,𝟎𝟕𝟎,𝟎𝟎𝟎
𝟏𝟎𝟎.𝟏𝟒𝟎𝟎𝐭
Eq. (3)
Where,
D=time in days.
t=temperature in degrees Celsius.
4) Class A—Alternative 2.
i.
Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
of Salmonella sp. bacteria in the sewage sludge shall be less than three Most
Probable Number per four grams of total solids (dry weight basis) at the time the
sewage sludge is used or disposed; at the time the sewage sludge is prepared for
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sale or give away in a bag or other container for application to the land; or at the
time the sewage sludge or material derived from sewage sludge is prepared to
meet the requirements in 503.10 (b), (c), (e), or (f).
ii.
A. The pH of the sewage sludge that is used or disposed shall be raised to above
12 and shall remain above 12 for 72 hours.
B. The temperature of the sewage sludge shall be above 52 degrees Celsius for
12 hours or longer during the period that the pH of the sewage sludge is above
12.
C. At the end of the 72 hour period during which the pH of the sewage sludge is
above 12, the sewage sludge shall be air dried to achieve a percent solids in
the sewage sludge greater than 50 percent.
5) Class A—Alternative 3.
i.
Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
of Salmonella sp. bacteria in sewage sludge shall be less than three Most Probable
Number per four grams of total solids (dry weight basis) at the time the sewage
sludge is used or disposed; at the time the sewage sludge is prepared for sale or
give away in a bag or other container for application to the land; or at the time the
sewage sludge or material derived from sewage sludge is prepared to meet the
requirements in 503.10 (b), (c), (e), or (f).
ii.
A. The sewage sludge shall be analyzed prior to pathogen treatment to
determine whether the sewage sludge contains enteric viruses.
B. When the density of enteric viruses in the sewage sludge prior to pathogen
treatment is less than one Plaque-forming Unit per four grams of total solids
(dry weight basis), the sewage sludge is Class A with respect to enteric viruses
until the next monitoring episode for the sewage sludge.
C. When the density of enteric viruses in the sewage sludge prior to pathogen
treatment is equal to or greater than one Plaque-forming Unit per four grams
of total solids (dry weight basis), the sewage sludge is Class A with respect to
enteric viruses when the density of enteric viruses in the sewage sludge after
pathogen treatment is less than one Plaque-forming Unit per four grams of
total solids (dry weight basis) and when the values or ranges of values for the
operating parameters for the pathogen treatment process that produces the
sewage sludge that meets the enteric virus density requirement are
documented.
D. After the enteric virus reduction in paragraph (a)(5)(ii)(C) of this section is
demonstrated for the pathogen treatment process, the sewage sludge
continues to be Class A with respect to enteric viruses when the values for the
pathogen treatment process operating parameters are consistent with the
values or ranges of values documented in paragraph (a)(5)(ii)(C) of this section.
iii.
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A. The sewage sludge shall be analyzed prior to pathogen treatment to
determine whether the sewage sludge contains viable helminth ova.
B. When the density of viable helminth ova in the sewage sludge prior to
pathogen treatment is less than one per four grams of total solids (dry weight
basis), the sewage sludge is Class A with respect to viable helminth ova until
the next monitoring episode for the sewage sludge.
C. When the density of viable helminth ova in the sewage sludge prior to
pathogen treatment is equal to or greater than one per four grams of total
solids (dry weight basis), the sewage sludge is Class A with respect to viable
helminth ova when the density of viable helminth ova in the sewage sludge
after pathogen treatment is less than one per four grams of total solids (dry
weight basis) and when the values or ranges of values for the operating
parameters for the pathogen treatment process that produces the sewage
sludge that meets the viable helminth ova density requirement are
documented
D. After the viable helminth ova reduction in paragraph (a)(5)(iii)(C) of this
section is demonstrated for the pathogen treatment process, the sewage
sludge continues to be Class A with respect to viable helminth ova when the
values for the pathogen treatment process operating parameters are
consistent with the values or ranges of values documented in paragraph
(a)(5)(iii)(C) of this section.
6) Class A—Alternative 4.
i.
Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
of Salmonella sp. bacteria in the sewage sludge shall be less than three Most
Probable Number per four grams of total solids (dry weight basis) at the time the
sewage sludge is used or disposed; at the time the sewage sludge is prepared for
sale or give away in a bag or other container for application to the land; or at the
time the sewage sludge or material derived from sewage sludge is prepared to
meet the requirements in 503.10 (b), (c), (e), or (f).
ii.
The density of enteric viruses in the sewage sludge shall be less than one Plaqueforming Unit per four grams of total solids (dry weight basis) at the time the
sewage sludge is used or disposed; at the time the sewage sludge is prepared for
sale or give away in a bag or other container for application to the land; or at the
time the sewage sludge or material derived from sewage sludge is prepared to
meet the requirements in 503.10 (b), (c), (e), or (f), unless otherwise specified by
the permitting authority.
iii.
The density of viable helminth ova in the sewage sludge shall be less than one per
four grams of total solids (dry weight basis) at the time the sewage sludge is used
or disposed; at the time the sewage sludge is prepared for sale or give away in a
bag or other container for application to the land; or at the time the sewage sludge
or material derived from sewage sludge is prepared to meet the requirements in
503.10 (b), (c), (e), or (f), unless otherwise specified by the permitting authority.
7) Class A—Alternative 5.
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i.
Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
of Salmonella, sp. bacteria in the sewage sludge shall be less than three Most
Probable Number per four grams of total solids (dry weight basis) at the time the
sewage sludge is used or disposed; at the time the sewage sludge is prepared for
sale or given away in a bag or other container for application to the land; or at the
time the sewage sludge or material derived from sewage sludge is prepared to
meet the requirements in 503.10(b), (c), (e), or (f).
ii.
Sewage sludge that is used or disposed shall be treated in one of the Processes to
Further Reduce Pathogens described in appendix B of this part.
8) Class A—Alternative 6.
i.
Either the density of fecal coliform in the sewage sludge shall be less than 1000
Most Probable Number per gram of total solids (dry weight basis), or the density
of Salmonella, sp. bacteria in the sewage sludge shall be less than three Most
Probable Number per four grams of total solids (dry weight basis) at the time the
sewage sludge is used or disposed; at the time the sewage sludge is prepared for
sale or given away in a bag or other container for application to the land; or at the
time the sewage sludge or material derived from sewage sludge is prepared to
meet the requirements in 503.10(b), (c), (e), or (f).
ii.
Sewage sludge that is used or disposed shall be treated in a process that is
equivalent to a Process to Further Reduce Pathogens, as determined by the
permitting authority.
b) Sewage sludge—Class B.
1)
i.
The requirements in either 503.32(b)(2), (b)(3), or (b)(4) shall be met for a
sewage sludge to be classified Class B with respect to pathogens.
ii.
The site restrictions in 503.32(b)(5) shall be met when sewage sludge that
meets the Class B pathogen requirements in 503.32(b)(2), (b)(3), or (b)(4) is
applied to the land.
2) Class B—Alternative 1.
i.
Seven representative samples of the sewage sludge that is used or disposed shall
be collected.
ii.
The geometric mean of the density of fecal coliform in the samples collected in
paragraph (b)(2)(i) of this section shall be less than either 2,000,000 Most
Probable Number per gram of total solids (dry weight basis) or 2,000,000 Colony
Forming Units per gram of total solids (dry weight basis).
3) Class B—Alternative 2. Sewage sludge that is used or disposed shall be treated in one
of the Processes to Significantly Reduce Pathogens described in appendix B of this
part.
4) Class B—Alternative 3. Sewage sludge that is used or disposed shall be treated in a
process that is equivalent to a Process to Significantly Reduce Pathogens, as
determined by the permitting authority.
5) Site restrictions.
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i.
Food crops with harvested parts that touch the sewage sludge/soil mixture and
are totally above the land surface shall not be harvested for 14 months after
application of sewage sludge.
ii.
Food crops with harvested parts below the surface of the land shall not be
harvested for 20 months after application of sewage sludge when the sewage
sludge remains on the land surface for four months or longer prior to
incorporation into the soil.
iii.
Food crops with harvested parts below the surface of the land shall not be
harvested for 38 months after application of sewage sludge when the sewage
sludge remains on the land surface for less than four months prior to
incorporation into the soil.
iv.
Food crops, feed crops, and fiber crops shall not be harvested for 30 days after
application of sewage sludge
v. Animals shall not be grazed on the land for 30 days after application of sewage
sludge.
vi.
Turf grown on land where sewage sludge is applied shall not be harvested for one
year after application of the sewage sludge when the harvested turf is placed on
either land with a high potential for public exposure or a lawn, unless otherwise
specified by the permitting authority.
vii.
Public access to land with a high potential for public exposure shall be restricted
for one year after application of sewage sludge.
viii.
Public access to land with a low potential for public exposure shall be restricted
for 30 days after application of sewage sludge.
c) Domestic septage.
1) The site restrictions in 503.32(b)(5) shall be met when domestic septage is applied to
agricultural land, forest, or a reclamation site; or
2) The pH of domestic septage applied to agricultural land, forest, or a reclamation site
shall be raised to 12 or higher by alkali addition and, without the addition of more
alkali, shall remain at 12 or higher for 30 minutes and the site restrictions in 503.32
(b)(5)(i) through (b)(5)(iv) shall be met. [58 FR 9387, Feb. 19, 1993, as amended at 64
FR 42571, Aug. 4, 1999] 503.33 Vector attraction reduction.
503.33 Vector attraction reduction
a)
1) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(10)
shall be met when bulk sewage sludge is applied to agricultural land, forest, a public
contact site, or a reclamation site.
2) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(8)
shall be met when bulk sewage sludge is applied to a lawn or a home garden.
3) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(8)
shall be met when sewage sludge is sold or given away in a bag or other container for
application to the land.
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4) One of the vector attraction reduction requirements in 503.33 (b)(1) through (b)(11)
shall be met when sewage sludge (other than domestic septage) is placed on an active
sewage sludge unit.
5) One of the vector attraction reduction requirements in 503.33 (b)(9), (b)(10), or
(b)(12) shall be met when domestic septage is applied to agricultural land, forest, or
a reclamation site and one of the vector attraction reduction requirements in 503.33
(b)(9) through (b)(12) shall be met when domestic septage is placed on an active
sewage sludge unit.
b)
1) The mass of volatile solids in the sewage sludge shall be reduced by a minimum of 38
percent (see calculation procedures in “Environmental Regulations and Technology—
Control of Pathogens and Vector Attraction in Sewage Sludge”, EPA–625/R–92/013,
1992, U.S. Environmental Protection Agency, Cincinnati, Ohio 45268).
2) When the 38 percent volatile solids reduction requirement in 503.33(b)(1) cannot be
met for an anaerobically digested sewage sludge, vector attraction reduction can be
demonstrated by digesting a portion of the previously digested sewage sludge
anaerobically in the laboratory in a bench-scale unit for 40 additional days at a
temperature between 30 and 37 degrees Celsius. When at the end of the 40 days, the
volatile solids in the sewage sludge at the beginning of that period is reduced by less
than 17 percent, vector attraction reduction is achieved.
3) When the 38 percent volatile solids reduction requirement in 503.33(b)(1) cannot be
met for an aerobically digested sewage sludge, vector attraction reduction can be
demonstrated by digesting a portion of the previously digested sewage sludge that
has a percent solids of two percent or less aerobically in the laboratory in a benchscale unit for 30 additional days at 20 degrees Celsius. When at the end of the 30 days,
the volatile solids in the sewage sludge at the beginning of that period is reduced by
less than 15 percent, vector attraction reduction is achieved.
4) The specific oxygen uptake rate (SOUR) for sewage sludge treated in an aerobic
process shall be equal to or less than 1.5 milligrams of oxygen per hour per gram of
total solids (dry weight basis) at a temperature of20 degrees Celsius.
5) Sewage sludge shall be treated in an aerobic process for 14 days or longer. During that
time, the temperature of the sewage sludge shall be higher than 40 degrees Celsius
and the average temperature of the sewage sludge shall be higher than 45 degrees
Celsius.
6) The pH of sewage sludge shall be raised to 12 or higher by alkali addition and, without
the addition of more alkali, shall remain at 12 or higher for two hours and then at 11.5
or higher for an additional 22 hours.
7) The percent solids of sewage sludge that does not contain unstabilized solids
generated in a primary wastewater treatment process shall be equal to or greater
than 75 percent based on the moisture content and total solids prior to mixing with
other materials.
8) The percent solids of sewage sludge that contains unstabilized solids generated in a
primary wastewater treatment process shall be equal to or greater than 90 percent
based on the moisture content and total solids prior to mixing with other materials.
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9)
i.
ii.
iii.
Sewage sludge shall be injected below the surface of the land.
No significant amount of the sewage sludge shall be present on the land surface
within one hour after thesewage sludge is injected.
When the sewage sludge that is injected below the surface of the land is Class A
with respect to pathogens, the sewage sludge shall be injected below the land
surface within eight hours after being discharged from the pathogen treatment
process.
10)
i.
Sewage sludge applied to the land surface or placed on an active sewage sludge
unit shall be incorporated into the soil within six hours after application to or
placement on the land, unless otherwise specified by the permitting authority.
ii.
When sewage sludge that is incorporated into the soil is Class A with respect to
pathogens, the sewage sludge shall be applied to or placed on the land within
eight hours after being discharged from the pathogen treatment process.
11) Sewage sludge placed on an active sewage sludge unit shall be covered with soil or
other material at the end of each operating day.
12) The pH of domestic septage shall be raised to 12 or higher by alkali addition and,
without the addition of more alkali, shall remain at 12 or higher for 30 minutes.
[58 FR 9387, Feb. 19, 1993, as amended at 64 FR 42571, Aug. 4, 1999]
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Appendix VI: Equipment Info
123 | P a g e
I
Biosolids Treatment
Wastewater System Solutions
A World of Solutions
Visit www.CBI.com
Egg-shaped digestion systems
Thermophilic pretreatment systems
CB&I's Egg-Shaped Digesters (ESD'M) comb ine t he optimum
shape for anaerobic digestion with patented and prop ri etary
design improvements to maximize reliabi lity and minimize
operating and mai ntenance costs. CB&l is the leading suppl ier
of ESD systems in the Weste rn Hem isphere with a proven
track record, having supplied more than 80 stee l ESD vesse ls
and related systems since 1989.
CB&I's ATP'M 2-stage digestion system reduces pathogens to
meet U.S. EPA req uirements fo r Class A biosolids and improves
the stabilization process while reducing tota l retention withi n
the digestion process.
Gas storage
Gasholders and spheres round out CB&I's product offering
with econom ica l storage of the methane gas generated from
anaerobic digestion.
ATP 2-STAGE DIGESTION SYSTEM
Vent air
....•... :
t-
Air Aspiration
.. ··•· .. :
..
j.
Air Aspiration
Heat
~anger
~ Digested Biosolids
Heat
Pretreated Sludge
Recovery
Exchanger
Egg-Shaped Digester Facilities
CB&I focuses on delivering advanced anaerobic digestion
solutions safely, on time and with the highest quality
standards. Our advanced EPC approach includes designing
and bu ilding projects turnkey, self performing the work from
concept to com missioning and providing a lump-sum price
for the project. For any project, we can provide:
•
•
•
•
•
•
•
•
Concept definition
Design and detai l engineering
Specifications and procurement
Fabrication
Project management
Field construction
Inspection and testing
Startup and training
Egg-Shaped Digester (ESD™) Systems
Egg-shaped anaerobic digesters have been used throughout
North America and Europe for many yea rs. Their optimum
shape eliminates dead zones w ith in the vessel to maxim ize
soli ds stabilization and minimize so lid s accumulation. CB&I's
techn ica l experti se and process improvements enhance the
benefits of ESDrM techno logy.
The key to the ESD system is the blending of t he optimum egg
shape w ith effective and effic ient liquid mixing to enhance
digester performance. The double cu rvature sha pe, reduced
operating liquid level surface area and effective mixing
eliminate scum and grit bu ild-ups, dead zones and the need
to take t he egg-shaped digesters out of service for clean ing.
Th is contrasts with conventiona l digesters, wh ich, even w ith
the use of more co mpl ex and energy intensive mixing systems,
must be pe riodically clea ned.
High reliability and superior performance
•
•
•
Employs lea k-tight, all welded stee l constru ction for long
life and durability
Maintains full working volu me and consistent residence time
Accepts high solids concentrations and reduces
digester volume
•
•
•
•
•
Features outsta nding capabil ity to t reat fats, oil and grease
Appli es integrated foam supp ress ion system
t o co ntrol foaming
Uses no internal moving pa rt s w ith in the digester
App lies red und ant mechanica l syste ms for reliability
Enhances process control fl exibility and minimizes
operator atte ntion with automated contro l system
Low operating and maintenance costs
•
•
•
•
•
•
Cleani ng expenses and downtime are virtually el iminated
Simple, easy-to-operate, automated control system
permits stand-alone operation
Durable, monolithic Automatic Foamed-In-Place (AFIPTM)
in su lation system minimizes heat loss and reduces
ene rgy input
AFIP in sulation protects vessel from atmosp heri c moist ure
Patented internal disc harge syste m limits maintenance
Patented jet pump mixing system
- Eliminates all internal movin g parts
- Decreases foam generation and attendant foam
con trol problems
- Minimizes energy use and maintenance costs
Low install ion costs
•
•
•
•
JET PUMP DUAL ZONE MIXING SYSTEM
Sma ll footprint minimizes land requirements and costs
High reliablity ca n elimi nate the cost of back-up digesters
Large space underneath vessel eli minates the need
fo r a sepa rate equ ipment bu ilding
Intern al mixing system is simp le and inexpe nsive
Stee l composition all ows econom ica l, fast,
all-weather const ru ct ion
Economical AF IP in sulation is appl ied on site
UPPER DRAFT TUBE
Good neighbor
•
•
Lea k-t ight, al l-welded steel containment
significantly reduces odor em issions
Co mpact plant w ith sma ll footprint
minimizes comm unity impa ct
AF IP insu lation provides attractive appea rance
Superior safety and security
•
•
•
UPPER ZONE
MIXING
SYSTEM
Includes patented internal d ischarge syste m
Removes risk of routine gas relea ses
Eli m inates confin ed space work areas
HEAT-X
SYSTEM
ATP Class A System
The ATP thermophi li c pret reatment syste m ope rates under
nearly anoxic co ndition s resulting in acidified, hydrolyzed
and homoge nized slud ge. This thermal co nditi oning, when
co mbined w ith anaerobic digestion, provides U.S. EPA ce rtifi ed
Class A-pathogen redu ctio n.
ATP's no minal Hydraulic Residence Time (HRT) is one day,
fol lowed by 12 to 15 days of mesop hilic anaerob ic digestio n.
Th e ATP syste m has been used for more than 100 insta ll atio ns
throughout No rt h America and Europe. Representative
pathogen reduction performance data is provided be low.
U.S. 40 CFR PART 503
ATP
Salmonella
<3 MPN/4 grams
< 1 MPBN/4 gram s
Helminth Eggs
< 1/4grams
< 1/4 grams
Enterovirus
< 1PFU/4 grams
<1PFU/4 grams
Superior performance
•
•
•
•
•
•
•
Ce rtifi ed U.S. EPA Class A process
Greater so lid s destruction
Increased digester ca pacity
En hanced gas production
Improved dewaterabi lity
Minimized odor
Demonstrated Nocardia destruction
Low operating costs
•
•
•
Heat recove ry reduces heating req uirements
Digester heatin g system is eliminated
Automated co ntrol syst em supports standalone operation
High reliability
•
•
•
•
Minimal moving parts in vessel
Fu lly redunda nt mixing syst ems
Asp irated ai r injection
Atmospheric operat ion
Flexible application
•
•
•
•
•
New or existing in sta ll ations
Upg rades fo r both convent iona l and
egg-s haped d igeste r fac iliti es
Batch or co ntinuo us feed optio ns avai lable
Singl e vesse l design for small fac ilities
Multipl e vesse l design for larg er fac ilit ies
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Gas Storage
Dry seal gas storage
Whether the need is for high-p ressure or low-pressure
storage, CB&I provides a variety of gasholder so lutions to
meet any requirement.
•
High-pressure gas storage
Hortonsphere®pressure vessels provide large volumes of
product gas storage in a sma ll area. These vesse ls:
•
•
•
Holds more gas in a sma ll er footprint compared with
low-pressure storage
Al lows for variable discharge pressure for downstream usage
Provides lower capita l cost than large-volume, low-pressure gas storage
Low-pressure gas storage
•
•
Wet seal gas storage
•
•
•
•
Two types of low-pressu re gas storage are
ava il able, dry seal and wet sea l. Compared
with high-pressure storage, these systems
provide consistent gas pressure to meet the
needs of downstream usage and operate with
minimal mechanical operating equipment.
Increases gas storage
volume compared
with a wet seal design
for a given tank
volume
Reduces odor
em issions
Provides weatherprotected piston
and seal
Accepts multiple
liquids for the wet seal
All ows for sludge and gas storage within a single vessel
Operates on either constant or variable liquid level
Reduces cap ital expend iture due to size and
output requirements
DRY SEAL GAS HOLDER
WET SEAL GASHOLDER
LOW
POSITION
LOW
POSITION
. ... ...... . Open Top
•·· ··· ······Tank Shell
····· Tank Shell
······ ··· Liquid Level
• .. . Piston
HIGH
POS ITION
HIGH
POSITION
•- ······Open Top
•- - Tank Shell
..... . Piston
Liquid Level
A World of Solutions
Visit www.CBI.com
On ly employees, agents or representatives authorized under and pursuant to written agreem ent with CB&I are authorized to distribute t his brochure to an actual or potential
client of CB&I. ©Copyright 2013 by Chicag o Bridge & Iro n Company. All rights reserved. Printed in USA. 08M082013H 2-7 09.27.20 13
108.27
2750.0
224.44
5700.7
Overall Length
186.41
4734.9
Main Frame Length
38.02
965.8
32.39
822.7
Motor Mount
Length
Main Rotating Assembly Components are
Centrifugally Cast Stainless Steel Duplex
Vibration Sensor
(Optional)
125 H.P. Main Drive Motor
47.37
1203.2
Lifting Lugs Width
27.17
690.0
Rotodiff
55.37
1406.4
Main Frame Width
54.33
1380.0
Motor Mount Width
Electrical
Junction
Box
Bearing Temperature
Sensors, Typical 2 places
(Optional)
Shown with Covers Removed
4.31
109.5
26.46
672.2
177.17
4500.0
39.71
1008.7
Liquid End Chamber
Inspection & Weir Plate
Access Hatch
5.91
150.0
Rotodiff
Safety Cover
129.13
3280.0
Main Cover Length
Note:
Cover Hooks to be used for
main Cover Remoaval ONLY.
Do NOT use to lift entire unit.
4.94
125.4
17.57
446.3
Main Cover Lifting Lugs
117.32
2980.0
Main Cover & Integrated Housing
Pulley
Safety Cover
5.91
150.0
Solids End Chamber
Inspection Hatch
57.09
1450.0
Clearance needed for
Feed Pipe Removal
1.77
R45.0
4.92
125.0
Feed Pipe Offset from
Bracket
Lifting Lugs
Typical 4 Corners
of Main Frame
61.46
1561.2
Strap Down Slots
72.44
1840.0
Min. Height
Required for
Rotating
Assembly
Removal
2-1/2" NPT Feed Pipe
Connection
38.75
984.2
Approx.
33.46
850.0
37.91
962.8
5.91
150.0
Name Plate
Rotodiff & Junction
Box Chamber
Access Plate
Strap Down Slots
7.00
177.8
3.91
99.4
4.53
115.0 Typ.
Spacing
20.87
530.0
A
1.57
40.0
164.50
4178.3
5.90
149.8
Centrate Discharge
See Flange Detail
7.00
177.8
Solids Discharge
See Flange Detail
24.50
622.3
B
11.89
302.0
C
Weights:
41.73
1060.0
Rotating Assembly
8,054 lbs.
Bowl Filling w/S.G. 1.0 1,328 lbs.
Complete Centrifuge 18,100 lbs.
(with filling)
23.75
603.3
5.22
132.5 Typ. Spacing
Static Load Below each point of
complete Centrifuge:
A = 3,840 lbs.
B = 4,060 lbs.
C = 1,150 lbs.
9.84
250.0
9.06
230.0
19.69
500.0
18.11
460.0
21.65
550.0
43.31
1100.0
47.50
1206.5
Dynamic Load Below each point of
complete Centrifuge:
(additional 25% of static load)
A = 4,800 lbs.
B = 5,075 lbs.
C = 1,438 lbs.
M10x1.5
Tapped Hole
Typ. 24 Places
Discharge Flange Dimensions
Typical Centrate & Solids End
A
10.91
277.2
36.59
929.5
113.54
2884.0
14.36
364.9
B
Main Motor
Electrical
Connection
C
REVISE ON CAD ONLY
9586 58th Place
Kenosha, WI 53144
CENTRIFUGE SYSTEMS
Designed by:
Drawn by:
Chk'd by:
Date:
D.S.
Date:
Date:
02/22/08
Tel: (262) 654-6006
Fax: (262) 654-6063
3rd Angle
Projection
Date:
THIS PRINT IS PROVIDED ON A RESTRICTED BASIS AND IS NOT TO BE
USED IN ANY WAY DETRIMENTAL TO THE INTERESTS OF CENTRISYS CORP.
Title: Cs26-4.01 2-Phase Centrifuge
General Arrangement
Project:
Material(s):
NA
Estimated weight (lbs):
Approved by:
Frequency of mounting isolators:
0.83Hz @ max loading of 6,500 lbs.
Vibration Isolators
Typical 10 Places
18100
Part #:
Sht:
14715
Drawing #:
1 OF 1 Scale: 1:20
M-C14715
REV
Page 1 of 15
Leaders in Biogas Technology
BUDGET PROPOSAL
GAS CONDITIONING SYSTEM
Date: 4/25/14
Expires: 7/25/14
Glenn Hummel
HESCO
Proposal Number: PX-214-1742.1
Project Name: GVRBA (Grand Valley Regional Biosolids Authority)
Unison Solutions, Inc. is pleased to provide this BUDGET proposal for a Gas Conditioning System for the
GVRBA (Grand Valley Regional Biosolids Authority) Project. This BUDGET proposal includes all of the
system engineering, CAD design services, technician labor, fabrication and materials to construct a Gas
Conditioning System.
Thank you for giving Unison Solutions the opportunity to provide you with the enclosed proposal. If you
have questions or require additional information, please contact me at your convenience.
Sincerely,
Tony Schilling
Unison Solutions, Inc.
Phone: 563-585-0967
Cell: 563-543-6069
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 2 of 15
EQUIPMENT/SUB-SYSTEMS
HYDROGEN SULFIDE REMOVAL SYSTEM
- Hydrogen Sulfide Inlet Moisture/Particulate Filter
- Hydrogen Sulfide Removal Media Vessel
- Work Platform and Ladder
- Initial Charge of SulfaTreat Media
GAS COMPRESSION/MOISTURE REMOVAL SYSTEM
- Gas Blower Inlet Moisture/Particulate Filter
- Gas Blower
- Forced Air to Gas Heat Exchanger
- Dual Core Heat Exchanger
- Gas Recirculation
- Skid Base
GLYCOL CHILLER
- Glycol Chiller
- Initial fill of Propylene Glycol/Water Mixture
SILOXANE REMOVAL SYSTEM
- Siloxane Removal Media Vessels
- Work Platform and Ladder
- Initial charge of Siloxane Removal Media
- Siloxane Removal Final Particulate Filter
CONTROL SYSTEM
- Gas Conditioning System Control Panel
- Transformer
DESIGN CONDITIONS
SITE INFORMATION
- Minimum Ambient Temperature
- Maximum Ambient Temperature
- Site Elevation
5°F
86°F
800’ AMSL
SYSTEM REQUIREMENTS
- Gas Flow
285 scfm
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 3 of 15
ASSUMED INLET GAS CONDITIONS
- Inlet Gas Pressure
- Inlet Gas Temperature
- Relative Humidity
- Methane (CH4)
- Carbon Dioxide (CO2)
- Nitrogen (N2)
- Oxygen (O2)
- Hydrogen Sulfide (H2S)
- Siloxanes (L2, L3, L4, L5, D3, D4, D5, D6)
10”WC
100°F
100%
60%
40%
<1%
<1%
500 ppmv
1,500 ppbv
DISCHARGE GAS CONDITIONS
- Discharge Gas Pressure
- Discharge Gas Temperature
- Dew Point Temperature
- Maximum Hydrogen Sulfide
- Maximum Siloxane
- Particulate Removal
3 psig
80°F
40°F
<10 ppmv
<100 ppbv
99% removal of >3 micron
SITE REQUIREMENTS
ELECTRICAL CLASSIFICATION
- NEC Class I, Division 1 Group D Areas
- Hydrogen Sulfide Removal System
- Gas Compression/Moisture Removal System
- Siloxane Removal System
- Unclassified Electrical Areas
- Glycol Chiller
- Gas Conditioning System Control Panel
EQUIPMENT MOUNTING
- Skid Mounted
- Gas Compression/Moisture Removal System
- Standalone
- Hydrogen Sulfide Removal System
- Glycol Chiller
- Siloxane Removal System
- Gas Conditioning System Control Panel
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 4 of 15
EQUIPMENT/SUB-SYSTEM DETAILS
HYDROGEN SULFIDE REMOVAL SYSTEM
- Hydrogen Sulfide Inlet Moisture/Particulate Filter
- Mounted upstream of the Hydrogen Sulfide Removal Media Vessel
- 99% removal of 3micron and larger particulates and liquid droplets
- Materials of construction shall be 304L stainless steel
- 150# ANSI B16.5 side inlet and outlet connections
- Cleanable polypropylene structured mesh element
- Differential pressure gauge across the filter element
- Sight glass for liquid level indication
- Level switch above the condensate drain to warn of failure
- Bottom drain with strainer, float drain, manual bypass and piping
- (1) Hydrogen Sulfide Removal Media Vessel
- 12’Ø x 10’ straight side
- Rated for 5psig pressure and 1psig vacuum
- Materials of construction shall be 304L stainless steel
- 150# ANSI B16.5 side inlet and outlet connections
- Flanged and dished top and bottom heads
- Vessel shall be free-standing on four 304L stainless steel legs
- Vessel equipped with a top manway
- Vessel equipped with a side manway
- Internal supports and grating for media
- Pressure relief valves included
- Two top vents with stainless steel ball valves
- Bottom manual condensate drain with stainless steel ball valves
- Work Platform and Ladder
- Work platform shall be welded carbon steel construction with satin black
powder coat finish
- Ladder shall be galvanized steel construction
- Initial Charge of SulfaTreat Media
- The initial charge of SulfaTreat media for each Hydrogen Sulfide Removal
Media Vessel will be provided.
- SulfaTreat to be loaded into Hydrogen Sulfide Removal Vessel by
INSTALLATION CONTRACTOR
GAS COMPRESSION/MOISTURE REMOVAL SYSTEM
- Gas Blower Inlet Moisture/Particulate Filter
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 5 of 15
- Mounted upstream of the Gas Blower
- 99% removal of 3micron and larger particulates and liquid droplets
- Materials of construction shall be 304L stainless steel
- 150# ANSI B16.5 side inlet and outlet connections
- Cleanable polypropylene structured mesh element
- Differential pressure gauge across the filter element
- Sight glass for liquid level indication
- Level switches above the condensate drains to warn of failure
- Bottom drain with strainer, condensate pump, check valve, manual bypass and
piping
- Gas Blower
- One Rotary Lobe Positive Displacement Blower rated for 285scfm
- Belt driven 15Hp, 480V/3Ph/60Hz EXP electric motor
- Motor speed will be controlled by a VFD
- Cast iron casing
- Inlet and discharge flex connectors
- Discharge silencer
- Discharge check valve
- Discharge pressure safety valve
- Belt guard
- Forced Air to Gas Heat Exchanger
- Air to Gas plate/fin core
- Materials of construction shall be aluminum plate and fins
- 480V/3Ph/60Hz EXP electric motor
- Motor speed will be controlled by a VFD
- Dual Core Heat Exchanger
- Stage 1 - Gas to gas plate/fin core
- Materials of constructions shall be aluminum plate and fins
- Stage 2 - Gas to glycol fin/tube core
- Materials of construction shall be aluminum fins on 304L stainless steel tubes
- Mounted in single 304 stainless steel housing
- 150# ANSI B16.5 inlet and outlet connections
- All condensation generated during cooling will be removed inside the heat
exchanger housing
- Level switch mounted on the housing to warn of drain failure
- RTD mounted on the housing to verify the coldest temperature that the gas
reaches
- Bottom drain with strainer, float drain, manual bypass and piping
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 6 of 15
- Gas Recirculation
- Modulating V-port Ball Valve shall be provided to allow excess gas to flow from
the discharge of the system back to the inlet. This valve shall be controlled by
monitoring the delivery pressure of the system.
- V-port Ball Valve
- Type 7 explosion proof actuator
- 120V weatherproof
- Skid Base
- Welded carbon steel construction with satin black powder coat finish
- All components mounted, piped and wired on skid base
- 24V and 120V electrical components wired to one of two junction boxes on
edge of skid
- INSTALLATION CONTRACTOR to provide conduit and wiring to 480V
components
- Conduit shall be rigid aluminum
- Condensate drains piped to edge of the skid base. Drains to be routed to floor
drain by INSTALLATION CONTRACTOR.
GLYCOL CHILLER
- Glycol Chiller
- Sized for the process heat load
- Suitable for outdoor installation
- Refrigeration System
- One refrigeration circuit
- One compressor sized for 100% capacity
- Chiller capacity: 25% to 100% of rated capacity
- EC motor driven condenser fans
- Aluminum micro-channel air cooled condensers
- 316L stainless steel evaporator
- R410a refrigerant. R-410a is an HFC refrigerant with 0 ODP
- Refrigeration circuit has sealed core filter drier, liquid line solenoid
valve, liquid line shut-off valve, and sight glass/moisture indicator
- Electronic expansion valve
- Glycol Chiller shall be factory tested and shipped with complete
refrigerant charge
- Glycol Circulation
- One glycol circulation pump sized for 100% capacity
- Pump is stainless steel end suction centrifugal
- Pump motor is TEFC
- Pump isolation valves on inlet and outlet
- Pump discharge check valve
- Glycol reservoir is a 304 stainless steel closed tank
- Glycol piping is copper with anti-corrosion coating
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 7 of 15
- Armaflex insulation
- Glycol Chiller to utilize propylene glycol/water mix
- Initial fill of Propylene glycol will be provided
- Support Structure
- G90 galvanized steel member frame
- Powder-coated aluminum cover panels
- All components mounted, piped and wired on skid
- Glycol Chiller Control Panel
- UL Type 4
- UL 508A Listed Industrial Control Panel
- Painted carbon steel
- 480V/3Ph/60Hz feed will be required
- 480V disconnect
- Microprocessor based controller with full text LCD display
- 480VAC to 24VAC transformer
SILOXANE REMOVAL SYSTEM
- (2) Siloxane Removal Media Vessels
- 4’Ø x 8’ straight side
- Materials of construction shall be 304L stainless steel
- 150# ANSI B16.5 inlet and outlet connections
- Flanged and dished top and bottom heads
- Vessels shall be free-standing on four 304L stainless steel legs
- Elliptical access nozzle on top of each nozzle
- Internal septas for even gas distribution through media
- Pressure relief valves included
- Bottom manual condensate drain with stainless steel ball valves
- Test/purge ports with ball valves on the inlet and outlet of each Siloxane
Removal Media Vessel
- Lead/Lag piping and valves between Siloxane Removal Media Vessels will be
provided
- Work Platform and Ladder
- Work Platform shall be welded carbon steel construction with satin black
powder coat finish
- Ladder shall be galvanized steel construction
- Initial charge of Siloxane Removal Media
- The initial charge of siloxane removal media for each Siloxane Removal Media
Vessel will be provided.
- The media shall be specifically engineered for removal of siloxanes and similar
contaminants from landfill and digester gas sources.
- Siloxane media to be loaded into the Siloxane Removal Media Vessels by the
INSTALLATION CONTRACTOR.
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 8 of 15
- Siloxane Removal Final Particulate Filter
- Mounted downstream of the Siloxane Removal Vessels
- 99% removal of 3micron and larger particulates and liquid droplets
- Materials of construction shall be 304L stainless steel
- 150# ANSI B16.5 side inlet and outlet connections
- Cleanable polypropylene structured mesh element
- Differential pressure gauge across the filter element
- Sight glass for liquid level indication
- Level switch above the condensate drain to warn of failure
- Bottom drain on vessel with manual ball valve
CONTROL SYSTEM
- Gas Conditioning System Control Panel
- Enclosure
- UL Type 12
- UL 508A Listed Industrial Control Panel
- Painted carbon steel
- Indoor location
- Thermal Management (as necessary)
- Rated for installation in ambient temperatures from 40°F to 104°F
- Power Distribution
- Fused Disconnect
- 480V/3Ph/60Hz feed required
- 35kA Short Circuit Current Rating
- Over current and branch circuit protection via fuses
- 480VAC field wiring to terminate at the component or terminal strips
inside control panel
- Surge Suppression
- 480VAC Transient Voltage Surge Suppressor
- 120VAC Surge Filter
- Motor Control
- (1) 15Hp rated VFD for Gas Blower Motor
- (1) 1-1/2Hp rated VFD for Forced Air to Gas Heat Exchanger Motor
- (1) 1/2Hp rated Motor Starter Overload for Condensate Pump
- Programmable Logic Controller
- Allen Bradley
- Compact Logix PLC and I/O
- Native Allen Bradley Ethernet IP data network
- Human Machine Interface
- Proface PFXGP4601TAF
- TFT Color LCD Display
- 12” diagonal
- 800 x 600 pixels
- Instrument wiring to terminate at terminal strips inside Control Panel
- Transformer
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 9 of 15
- 5kVA
- 480VAC to 120VAC
- NEMA 3R; Painted carbon steel
INSTRUMENTATION
- All instrumentation provided will be designed for gas service and rated for use in a NEC
Class I, Division 1 Group D area.
- Hydrogen Sulfide Removal System Instrumentation
- Inlet Pressure Transmitter
- Inlet Resistive Temperature Detector (RTD) 3 Wire-100Ω
- Gas Compression/Moisture Removal System Instrumentation
- Level Switches at each Condensate Drain
- Level Indicators at each Condensate Drain
- RTD’s (3 Wire-100Ω) at each Temperature Change Point
- RTD (3 Wire-100Ω) to Monitor Glycol Temperature
- Bi-metal Thermometers at each Temperature Change Point
- Gas Blower Discharge Pressure Transmitter
- Siloxane Removal System Instrumentation
- Delivery Pressure Transmitter
PIPING
- Pipe will be SA-312 TP304/304L Weld Pipe, minimum Schedule 10S. Threaded pipe
shall be minimum Schedule 40S.
- Flange connections will be ANSI B16.5, SA-182 F304/304L Class 150.
- Pipe welding will follow ASME B31.3 Process Piping. Welded pipe will be visually
inspected and pressure tested.
VALVES
- Inlet Electric Actuated Butterfly Valve
- Butterfly valve will be lug style, iron body with stainless steel disc and stem and
FKM seat.
- Type 7 explosion proof actuator
- Spring return closed upon power loss
- 120V weatherproof
- Ball Valves
- Stainless steel with PTFE or RTFE seat.
- Valves will be full port.
- Butterfly Valves
- Lug style iron body with stainless steel disc and stem and FKM seat.
- Check Valves
- Will be one of 2 styles; ball or dual-door.
- Ball check valves shall be stainless steel with RTFE ball.
- Dual-door check valves shall be wafer style body, material shall be
aluminum and/or stainless steel with an FKM seat.
- Globe Valves
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 10 of 15
- Stainless steel with PTFE packing
FASTENERS
- Fasteners shall be F593 304 stainless steel
TEMPERATURE CONTROLLED ENCLOSURE (OPTIONAL)
- All electrical inside the enclosure is rated Class I Division 1
- Mounted to THE Gas Compression/Moisture Removal Skid
- Steel exterior with multiple color options for site esthetics
- 3/4” fire rated plywood construction over steel studs
- Insulated walls and ceiling
- Interior 5/8” green board (mildew resistant drywall)
- Lighted interior with two EXP incandescent light fixtures
- Thermostatically controlled heater to prevent freezing
- LEL inside enclosure for gas detection and warning
- Ventilation fan and intake louver to prevent over heating inside enclosure
- Double steel entry doors
Note: Customer will be required to power the heater, ventilation fan and lights
SUBMITTALS
- Quantity: (3) copies of 3 ring binders and (1) electronic CD copy
- Shop Drawings and Product Data will be provided in sufficient detail to confirm compliance
with the requirements for the project. Shop Drawings and Product Data will be provided in a
complete submittal package.
- Shop Drawings
- Installation drawings and specifically prepared technical data, including design
capacities will be provided.
- Specifically prepared wiring diagrams unless standard wiring diagrams are submitted
with product data will be provided.
- Written description of operation will be provided.
- Product Data
- Catalog cuts and product specifications for each product specified will be provided.
- Standard wiring diagrams unless wiring diagrams are specifically prepared and
submitted with Shop Drawings will be provided.
FACTORY TESTING
- The System will be tested on ambient air at Unison’s facility prior to shipment.
- The CUSTOMER is allowed to witness the testing and Unison will inform the customer (2)
weeks prior to anticipated testing date so customer can make travel arrangements.
OPERATION & MAINTENANCE MANUALS
- Quantity: (6) copies of 3 ring binders and (1) electronic CD copy
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 11 of 15
- After shipment the Gas Conditioning System will be provided with a specifically prepared
Operation & Maintenance Manuals. The information provided includes a system overview,
operator interface, start-up/shut down procedures, communications, alarms procedures,
maintenance overview, mechanical component spec sheets and electrical component spec
sheets.
OPERATION & MAINTENANCE
- Hydrogen Sulfide Removal System
- Clean Hydrogen Sulfide Inlet Moisture/Particulate Filter
- Replace Hydrogen Sulfide Media
- Estimated Cost = $31,460.00 every 205 days**
*Labor for change out, disposal and shipping of media not included
**No Gas Test data provided at time of proposal. Assumed 500ppmv
- Gas Compression/Moisture Removal System
- Clean Gas Compressor Inlet Moisture/Particulate Filter
- Change Blower Oil
- Clean Glycol Chiller Condenser
- Test Glycol for Freeze Point
- Estimated Cost = $1,500.00 every 365 days
- Siloxane Removal System
- Replace Siloxane Media
- Estimated Cost = $16,830.00 per change out**
*Labor for change out, disposal and shipping of media not included
**No Gas Test data provided at time of proposal
ELECTRICAL PARASITIC
- Electrical Parasitic
- Condensate Pump = 1 kW
- Gas Blower Motor = 12 kW
- Forced Air to Gas Heat Exchanger = 1 kW
- Glycol Chiller = 18 kW
- Controls & Auxiliary Equipment = 4 kW
Total = 36 kW (Full Load)
Total = 25 kW (Average Run Load)
Optional - If Temperature Controlled Enclosure is Included
- Enclosure Lighting = 2 kW
- Enclosure Heater = 17 kW
- Enclosure Ventilation Fan = 2 kW
DELIVERY SCHEDULE
- Submittals delivered 3 to 4 weeks after order acceptance
- Equipment delivery 16 to 18 weeks after submittal approval
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 12 of 15
- Delivery is subject to confirmation at the time of order placement and/or submittal approval
PRICING SUMMARY
- Price includes all labor and expenses associated with the fabrication of the system.
- Prices do not reflect any taxes that may be applicable and are valid for 90 days.
- Price is FCA; Factory, Dubuque, IA 52002, per Incoterms 2010. Shipping costs not included, see
estimate below
- Price does not include Start-up and Commissioning. Costs are shown below
BUDGET Hydrogen Sulfide Removal System ...................................................................... $135,000.00
BUDGET Gas Compression/Moisture Removal System ...................................................... $270,000.00
BUDGET Siloxane Removal System ....................................................................................... $85,000.00
Shipping ESTIMATE to Grand Rapids, MI ................................................................................ $7,000.00
Cost is an estimate and is subject to change without notice. It does not include any
special packaging or permitting that may be required and is dependent on the final
equipment dimensions and weights.
Start-up and Commissioning Services ESTIMATE ................................................................... $8,500.00
Price includes Four (4) consecutive, 8 hour days, for one Unison Technician onsite
with travel and expenses included. Additional days may be necessary to complete
start-up and commissioning, they will be billed to the Buyer/Owner/End User at
the cost of $1,200 per day, per technician, plus travel & expenses.
Temperature Controlled Enclosure (OPTIONAL) .................................................................. $70,000.00
PAYMENT SCHEDULE
- 30% upon order acceptance
- 30% at midpoint of construction
- 30% upon equipment delivery
- 10% upon site acceptance not to exceed 180 days from shipment
- Net 30 days on all payments
PROVIDED BY OTHERS
- VPN connection for remote access to Unison supplied equipment for troubleshooting and
remote assistance.
PRICE DOES NOT INCLUDE
- Shipping of equipment to jobsite
- Start-up and commissioning services
- Wind or seismic calculations for all equipment
- Any maintenance work after start-up
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 13 of 15
- Siloxane or H2S removal media after initial fill
- Performance guarantee or service/maintenance contract
- Any gas testing or analyses
- Permitting for the installation of the equipment or air permits
- Freeze protection; including insulation and/or heat trace and heat trace power
- Pipe stands for field piping
ASSUMPTIONS
VESSELS & MEDIA
- H2S and VOC’s present in the gas will foul Siloxane media, additional gas testing will be
necessary to finalize all vessel and media requirements, budget pricing is dependent on
gas data given at the time of the proposal.
- No assumption of media life has been given; additional gas testing will be required at
the Buyer/Owner/End Users expense.
- Any assumption of media life that has been given is an estimate; additional gas testing
will be required at the Buyer/Owner/End Users expense.
- Vessel sizes are estimates only, gas testing will be necessary to finalize all vessel sizing.
MECHANICAL
- Flare is supplied by OTHERS
- If an existing flare is being used, it is assumed this flare is in good working order, with
all safety and control equipment.
- Foundations and/or maintenance pads are designed by OTHERS to properly support
the equipment.
ELECTRICAL
- 480V/3Ph/60Hz is available
- The following Equipment/Sub-systems will be located in an NEC Class I, Division 1
Group D Area
- Hydrogen Sulfide Removal System
- Gas Compression/Moisture Removal System
- Siloxane Removal System
- The following Equipment/Sub-systems will be located in an Unclassified Area
- Glycol Chiller
- Gas Conditioning System Control Panel
INSTALLATION CONTRACTOR RESPONSIBILITIES
- Installation responsibilities are broken out below into three categories to outline the work;
these responsibilities by no means fall on any single contractor or individual. It is the
responsibility of the Buyer/Owner/End User to ensure all these conditions are adhered to, as
necessary. It is responsibility of the Buyer/Owner/End User to install all equipment in
compliance with local and national codes applicable to the installation site.
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 14 of 15
BUYER/OWNER/END USER RESPONSIBILITIES
- All foundations and/or maintenance pads as necessary for equipment
- Provide and seal all roof and building penetrations as necessary
- Provide all anchor bolts, temporary lift equipment, power, labor, and all other
incidentals required for proper installation of the equipment shown on the drawings
that will be provided by Unison Solutions, Inc.
- All rigging and setting of equipment at job site
- Proper storage of the equipment and media prior to installation
- Provide installation of Equipment/Sub-systems per the Unison Solutions Installation
Guide
- Load initial charge of Hydrogen Sulfide Media and Siloxane Media into the vessels
MECHANICAL CONTRACTOR RESPONSIBILITIES
- Provide all field piping between the Equipment/Sub-systems, including but not limited
to:
- Hydrogen Sulfide Removal System
- Gas Compression/Moisture Removal System
- Glycol Chiller
- Siloxane Removal System
- Provide pipe supports as necessary. Piping shall be self-supporting, and not supported
off of the Unison supplied equipment.
- Install all field located or shipped loose devices
- Provide all Heat Trace and/or Insulation as necessary to provide proper freeze
protection as defined by Unison Solutions.
ELECTRICAL CONTRACTOR RESPONSIBILITIES
- Provide 480V/3Ph/60Hz feed to the Gas Conditioning System Control Panel
- Provide all field wiring and conduits between the Equipment/Sub-systems to the Gas
Conditioning Control Panel and associated equipment. This includes but not limited to:
- Hydrogen Sulfide Removal System
- Gas Compression/Moisture Removal System
- Glycol Chiller
- Siloxane Removal System
- Gas Conditioning System Control Panel
- Provide local disconnects as necessary
- Provide all Hazardous location conduits & wiring systems per Article 500 of the NEC
- Provide conduit seals entering and/or leaving the Class I, Division 1 Electrical Area.
Conduit seals will need to be filled during Start-up and Commissioning after verification
of field wiring by Unison’s Start-up Technician. Conduit seals are to be filled prior to the
introduction of gas to the equipment.
- Provide heat trace power from local lighting panel, as necessary.
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
Page 15 of 15
WARRANTY
- Unison Solutions, Inc. will warrant all workmanship and materials in conformance with the
attached Warranty Statement. Warranty is valid for 18 months from the time the equipment is
shipped from Unison’s factory or 12 months from the date of startup, whichever occurs first.
- This proposal is for equipment only and does not include any system engineering and design
services expressed or implied.
- Unison Solutions, Inc. will not release the PLC program for this system. This is considered
proprietary and the intellectual property of Unison Solutions, Inc.
5451 Chavenelle Road, Dubuque, Iowa 52002  [O] 563.585.0967 www.unisonsolutions.com
Design and content included in this document is proprietary and remains the property of Unison Solutions, Inc.
WARRANTY STATEMENT Unison Solutions, Inc. (Unison) is committed to providing quality products and services to its customers. As a demonstration of this commitment, Unison offers the following warranty on its products. Grant of Warranty: Unison provides this warranty for its equipment under the terms and conditions which are detailed herein. This warranty is granted to the person, corporation, organization, or legal entity (Owner), which owns the equipment on date of start‐up. This warranty applies to the owner during the warranty period, and is not transferable. Warranty Coverage: Equipment that is determined by Unison to have malfunctioned during the warranty period under normal use solely as a result of defects in manufacturing workmanship or materials shall be repaired or replaced at Unison’s option. Unison’s liability under this warranty to the Owner shall be limited to Unison’s decision to repair or replace, at its factory or in the field, items deemed defective after inspection at the factory or in the field. Warranty Exclusions: All equipment, parts and work not manufactured or performed by Unison carry their own manufacturer’s warranty and are not covered by this warranty. Unison’s warranty does not override, extend, displace or limit those warranties. Unison’s only obligation regarding equipment, parts and work manufactured or performed by others shall be to assign to the Owner whatever warranty Unison receives from the original manufacturer. Unison does not warrant its products from malfunction or failure due to shipping or storage damage, deterioration due to exposure to the elements, vandalism, accidents, power disturbances, or acts of nature or God. This warranty does not cover damage due to misapplication, abuse, neglect, misuse, improper installation, or lack of proper service and/or maintenance, nor does it cover normal wear and tear. This warranty does not apply to modifications not specifically authorized in writing by Unison or to parts and labor for repairs not made by Unison or an authorized warranty service provider. This warranty does not cover incidental or consequential damages or expenses incurred by the Owner or any other party resulting from the order, and/or use of its equipment, whether arising from breach of warranty, non‐conformity to order specifications, delay in delivery, or any loss sustained by the Owner. No agent or employee of Unison has any authority to make verbal representations or warranties of any goods manufactured and sold by Unison without the written authorization signed by an authorized officer of Unison. Unison warrants the equipment designed and fabricated to perform in accordance with the specifications as stated in the proposal for the equipment and while the equipment is properly operated within the site specific design limits for that equipment. Any alterations or repair of Unison’s equipment by personnel other than those directly employed by, or authorized by Unison shall void the warranty unless otherwise stated under specific written guidelines issued by Unison to the Owner. This warranty does not cover corrosion or premature wear or failure of components resulting from the effects caused by siloxanes, hydrogen sulfide or volatile organic compounds in excess of the design limits. All media must be purchased through Unison Solutions or approved in writing by Unison Solutions dur‐
ing warranty period. Media purchased though alternate sources and not approved in writing by Unison shall void the war‐
ranty. The design limit is based on site specific gas data provided by the Owner prior to the proposal for the equipment. Owner shall be responsible for all maintenance service, including, but not limited to, lubricating and cleaning the equipment, replacing expendable parts, media, making minor adjustments and performing operating checks, all in accordance with the procedures outlined in Unison’s maintenance literature. Unison does not warrant the future availabil‐
ity of expendable maintenance items. Warranty Period: This Unison warranty is valid for 18 months from the time the equipment is shipped from Unison’s factory or 12 months from the date of startup, whichever occurs first. Repairs During Warranty Period: All warranty claim requests must be initiated with a Return Material Authorization (RMA) number for processing and tracking purposes. The RMA number shall be issued to the Owner upon claim approval and/or field inspection. When field service is deemed necessary in order to determine a warranty claim, the costs associated with travel, lodging, etc. shall be the responsibility of the Owner except under prior agreement for a field inspection. This warranty does not include reimbursement of any costs for shipping the equipment or parts to Unison or an authorized service establishment, or for labor and/or materials required for removal or reinstallation of equipment or parts in connection with a warranty repair. This warranty covers only those repairs that have been conducted by Unison or by a Unison authorized warranty service provider, or by someone specifically authorized by Unison to perform a particular repair or service activity. All component parts replaced under the terms of this warranty shall become the property of Unison. UNISON ASSUMES NO OTHER WARRANTY FOR ITS EQUIPMENT, EITHER EXPRESS OR IMPLIED, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE, OR NONINFRINGEMENT, OR LIABILITY FOR ANY INCIDENTAL OR CONSEQUENTIAL DAMAGE. 5451 Chavenelle Road, Dubuque, Iowa 52002 2013 Unison Solutions, Inc. [O] 563.585.0967 [F] 563.585.0970 www.unisonsolutions.com WARRANTY STATEMENT