EES 3040 Wastewater Treatment Systems
Lecture 1
Overview + Collection Systems and Design Considerations
August 18, 2021
EES 3040 Wastewater Treatment Systems
• B.S., Chemical Engineering, 2006
• Ph.D., Chemical and
Environmental Engineering, 2010
• Assistant Professor at Clemson
since Fall 2016
• Teaching EES 3040 and 3050 for
the sixth time
Research focus:
Energy and resource recovery from
wastewater
• Anaerobic biological wastewater
treatment
• Electrochemical processes for
water infrastructure
Microbial fuel cells
Electrochemical
production/treatment
Anaerobic bioreactors
Interested in research?
Email me
spopat@clemson.edu
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Attendance in Times of COVID-19
Attendance to all classes is expected.
Although no roll call will be taken,
lack of attendance will affect your
overall performance in exams and
homework.
For those unable to attend class due
to a positive COVID-19 test, all
lectures will be recorded on Zoom,
and will be shared with those absent
on request.
Important Notes from the Syllabus
TEXTBOOK
Water and Wastewater Engineering
Mackenzie L. Davis, 2011, McGraw-Hill, New York, NY
ISBN-13: 978-0-07-339786-3 or 978-0-07-171384-9
Note: Two versions of the textbook are available, an academic
version and a longer “professional” version. Either is acceptable.
The professional version has more chapters but may be less
expensive. The chapters covered in this course are included in both
versions.
All chapter numbers in the syllabus and slides will be from the professional version,
but chapter numbers for the academic version provided in parentheses
Important Notes from the Syllabus
HOMEWORK
Homework assignments will be posted on Canvas through the semester. There will be a
total of five homework assignments.
Assignments must be submitted on Canvas by the beginning of class on the day they
are due. There will be no late submissions, but the lowest grade from all of the five
homework submissions will be dropped. The assignments must be scanned and turned
in via Canvas. Make sure to box all answers for problems. Put your name on every
page, and make sure all problems are in the correct order.
Adobe Scan
To receive credit for a problem, you must show your work. No credit will be given when
only the answer is listed. If you used Excel for your work, include the Excel spreadsheet
when you upload the homework.
When in doubt, state your assumptions. And most importantly, if you think that your
answer is not correct because it does not make sense, but you are stuck and cannot
find what seems like a more sensible solution, say so. A major part of your career
development involves knowing when a solution does or does not make “sense.” For
example, if you are asked to determine the size of a trickling filter needed to treat the
wastewater from a community with 1 million people, and your solution is a 0.5 ft
diameter tank, something is very wrong; make sure you make it clear that you know
this.
MS Office Lens
Important Notes from the Syllabus
GRADING
Exam #1
Exam #2
Final Exam
Homework
Total
25%
25%
25%
25%
100%
Final grades will be assigned per the scale given below. However, Dr. Popat reserves
the right to adjust the scale or curve the grades. In no case, changes will be done if it
results in a lower letter grade for any student.
A: 90 – 100%
B: 80 – 89.9%
C: 70 – 79.9%
D: 60 – 69.9%
F: below 60%
Important Notes from the Syllabus
DATE
CLASS
TOPIC
08/18
1
Introduction
08/23
2
Collection Systems and Design Considerations
08/25#
3
Headworks and Preliminary Treatment
08/30
4
Headworks and Preliminary Treatment
09/01
5
Headworks and Preliminary Treatment
09/06*
6
Primary Treatment
09/08
7
Primary Treatment
CH
18
(12)
20
(13)
21
(14)
09/13
8
Primary Treatment
09/15*
9
Biological Secondary Treatment, Microbiology
09/20
10
Biological Secondary Treatment, Microbiology
22
(15)
09/22
N/A
Exam #1 (covering lectures 1 through 9)
N/A
09/27
11
Biological Secondary Treatment, Suspended Growth
09/29
12
Biological Secondary Treatment, Suspended Growth
10/04
13
Biological Secondary Treatment, Suspended Growth
10/06
14
Biological Secondary Treatment, Suspended Growth
10/13*
15
Biological Secondary Treatment, Suspended Growth
10/18
16
Biological Secondary Treatment, Suspended Growth
10/20#
17
Biological Secondary Treatment, Suspended Growth
10/25
18
Biological Secondary Treatment, Suspended Growth
10/27*
19
Biological Secondary Treatment, Suspended Growth
11/01
N/A
11/03
20
Secondary Settling
11/08
21
Secondary Settling
11/10
22
Secondary Settling
11/15
23
Biological Secondary Treatment, Attached Growth
11/17
24
Biological Secondary Treatment, Attached Growth
11/22
25
Biological Secondary Treatment, Attached Growth
11/29
26
Disinfection
12/01*
27
Sludge Treatment
12/06
N/A
Exam #2 (covering lectures 10 through 18)
Final Exam (two-part comprehensive exam)
23
(16)
N/A
25 (18)
24
(17)
25
(28)
27 (20)
N/A
* indicates a class when HW is due.
# Dr. Popat is away at for a conference,
and lecture will be delivered online as
a video recording.
EES 3040
EES 3030
The Urban Water Cycle
Why is It Necessary to Treat WW?
1. Reduce oxygen demand
2. Reduce nutrients that promote eutrophication (N and P)
3. Reduce pathogens (viruses, bacteria, protozoa)
4. Reduce hazardous chemicals (industrial waste,
PPCP – pharmaceuticals and personal care products)
Protect receiving water for recreation
and/or as a source of drinking water
How is WW Treatment Accomplished?
Bar Racks/
Screens
Collection
System
1° Clarifier
Grit
Chamber
Flow
Measurement
Emergency
Grit to
Bypass, CSOs
Landfill
2° Clarifier
Filter
(optional)
Activated
Sludge
air
Cl2
RAS
PFR
WAS
Headworks
Thiosulfate,
air
Thickening
Discharge
Anaerobic
Digester
Thickening/
Dewatering
= liquid flow
= sludge flow
Solids Disposal:
Agriculture; Landfill; Combustion, etc.
A typical
Wastewater
Treatment
Plant (WWTP)
consists of a
mix of physical,
chemical and
biological
processes
How is WW Treatment Accomplished?
Stickney
WWTP,
Chicago, IL
677 MGD
Basic Design Considerations
1. Flow rates
• Vary within a day, within a season, year-to-year and type of collection system
2. WW characteristics
• Municipal, industrial or mixture
3. Regulations
• Applies to both liquid and sludge effluents
4. Location of the WWTP and its layout
Chapter 18 (12)
General Wastewater Collection
and Treatment Design Considerations
1. WW Sources and Flow Rates
1. Domestic, also called sanitary
• WW from homes, businesses, institutions etc.
• ~380 liters/person-day
• 60-90% of potable water ends up in WW - large range due to differences in locations
2. Industrial
• Varies largely based on the type of business
(for e.g. food packaging vs. steel mill)
3. Infiltration
• Large sections of sewer systems consist of concrete pipes that are leaky – rainwater can
enter through joints
Concrete Sewer Pipes
1. WW Sources and Flow Rates
3. Infiltration (contd.)
• Infiltration can be as high as 1 m3/day-mm diameter-km length
(or 129,600 gpd/ft diameter-mi length)
• For a 4’ pipe, this is 520,000 gpd/mi-length
• Causes large increase in flow rate + significant dilution (not necessarily a good thing)
• During dry weather, can have an issue of exfiltration (which leads to groundwater
contamination)
4. Inflow
• Different from infiltration
• E.g. include roof downspouts, yard drainage etc.
• Is a function of wet weather
Inflow and Infiltration
Inflow & Infiltration - Inflow-Infiltration.pdf
8/19/19, 11'12 AM
1. WW Sources and Flow Rates
5. Stormwater
• Most old sewer systems are “combined” sanitary + stormwater
• Positive: “first flush” (30 min) is high in pollutants that should be treated (oil and grease,
brake linings, heavy metals, feces)
• Negative: combined sewer outflows (CSO); when wet weather flows exceed the capacity
of the WWTP, excess is discharged without any treatment
• Even dilute flows can depress dissolved oxygen, which leads to death of obligate aerobic
heterotrophs, increases in pathogens, and odors
Combined Sewer Outflows
Combined Sewer Outflows
• CSO-related issues, with examples to be posted on Canvas
• Solutions to combined sewer overflows:
• Storage, then treatment (Chicago Tunnel and Reservoir Plan)
• High-rate treatment (e.g. vortex clarifiers)
• Separation of sanitary and stormwater
1. WW Sources and Flow Rates
• Flow variability
• Critical design parameter: peak hourly flow (Qp)
• Why? à Flooding or bypass if the flow cannot be handled
Variations in WWTP Flow Rates
Ratio of extreme flows to
average daily flow
• Flow variability
• Ratio of peak to average decreases as population increases
• Why? à more miles of sewer provide a dampening effect on peak flow
• Also concerned about minimum flows because some design considerations are based on
minimum flow as shown in table 18-2 (12-2)