Anne Arundel County
Department of Public Works
Mayo Water Reclamation
Facility
Presented to West/Rhode River Keepers
March 23, 2012
Agenda


Project – Purpose and Need Statement
Plant Service Area



Treatment Facilities






Design of Conventional Plant
Negotiations with MDE and FDA
Expansion Alternatives
Ongoing Plant Improvements


Unit Processes
Performance
Plant Outfall
Operating Costs
Refurbish Existing Units
Plant Expansion Efforts




Septic Tank Effluent Pump (STEP) System
Flows
Phase 1 Improvements
Current Options Being Considered
Project Purpose and Need
•Expand Capacity – Lift Moratorium
•Current Permitted Capacity – 0.615 mgd
•Current Allocated Flow – 0.579 mgd
•Ultimate Projected Flow – 1.14 mgd
•Upgrade Treatment – Enhanced Nutrient Removal
(ENR)
•Current Total Nitrogen – 18.6 mg/l
•Current Total Phosphorous – 0.76 mg/l
•ENR-Total Nitrogen – 3 mg/l
•ENR – Total Phosphorous – 0.3 mg/l
Service
Area

Need service area
figure from George


Septic tank
effluent flows to
pumping
stations
Flow pumped
to treatment
plant
Solids Handling
Service Area
continued
 Flows
 Current
 Average Daily Flow
(ADF) = 0.56 mgd
 Peak Flow = 2.18 mgd
 Currently 3,615 EDUs
 Projected
 Build-out ADF = 1.14
mgd (uses 225 gallons
per day per EDU)
 Build-out Peak = 3.58
mgd (uses MD peaking
curve)
 Essentially Un-changed
since Mayo inception
Build-out Equivalent Dwelling
Units (EDUs)
Treatment Facilities
 Treatment Train
 STEP – solids settle
 Influent Pumping
 Recirculating Sand Filters
 Reduces solids (TSS), ammonia-N
(NH3), Biological Oxygen Demand (BOD)
 Small degree of pathogen reduction
 Emergent Wetlands
 Subsurface flow lined gravel beds
supporting growth of bulrushes and
cattails
 Further reduces solids, (TSS), ammoniaN (NH3), Biological Oxygen Demand
(BOD)
 Small degree of pathogen reduction
 Phosphorus Clarifier
 Lime added to precipitate phosphorus
Treatment Facilities
 Treatment Train, continued
 Peat Wetlands
 Drained, lined beds, with alternating
layers of sand and peat with a
grassy vegetative cover over which
wastewater is sprayed
 Effluent polishing (TSS removal)
 Some pathogen reduction
 UV Disinfection
 Primary source of pathogen
reduction
 UV radiation penetrates pathogen
DNA and precludes them from
reproducing
 Effluent Pumping
Existing Mayo WRF
FILTER
PS
DISTRIBUTION
BOX A
INFLUENT
PEAT WETLAND
UV DISINFECTION
RECIRCULATING
SAND FILTERS
RAPID
MIX
CHEMICAL
CLARIFIERS
2 HOUR
EMERGENCY
SHELLFISH STORAGE
FILTER
PS
INFLUENT
MAIN INFLUENT
PS
EMERGENT
WETLANDS
SLUDGE
STORAGE
EFFLUENT
UV DISINFECTION
PEAT WETLAND
PS
EFFLUENT
PUMPING
STATION
PEAT WETLANDS
OFFSHORE
WETLANDS
24 HOUR EMERGENCY
SHELLFISH STORAGE /
FLOW EQUALIZATION
TANKS
RHODE
RIVER
Operating Performance
Annual Averages: 2011






Total Suspended Solids 2.0 mg/l
Total Nitrogen
18.6 mg/l
Total Phosphorus
0.76 mg/l
Fecal Coliform
<2.0 MPN/100ML
BOD
1.0 mg/l
Permitted Operating levels are higher than other
plants
Example Monitoring Report
Plant Outfall

Camp
Wabanna


Discharges to
a Shellfish
Harvesting
Area
Limited
Capacity
Approved
without
Shellfish
Closure Zone
Operating Costs
Water
Reclamation
Facility

2012 Annual
Operating
Budget, $
Current Plant
Flow, million
gallons per day
Unit Cost, $/1,000
gallons
Cox Creek
5,796,000
11.327
1.40
Annapolis
4,753,000
8.561
1.52
Broadneck
3,088,500
5.131
1.65
Patuxent
3,347,500
5.317
1.72
Broadwater
1,139,200
1.078
2.90
Maryland City
1,307,800
1.054
3.40
Mayo
1,091,300
0.560
5.34
Does not include CIP costs
 Refurbish existing units when treatment effectiveness decreases (sand filters,
emergent wetlands)
Plant Expansion Efforts

Planning started 1998

Design nearly complete 2002

Change in treatment process dictates changes to outfall

Negotiations with MDE and FDA required to determine if
existing outfall could be used – Risk Analysis

Possible outfall modifications

New outfall location (abandon existing)

Establish shellfish harvesting closure zone around existing outfall

MDE requires new outfall location – no new closure zones

Growth moratorium in place until plant can be expanded
Initial Expansion Alternatives
 Seven Expansion Alternatives developed for
discussions with MDE
 MDE Criteria
 Change in treatment process requires shellfish harvesting
closure zone –or- new outfall location
 State policy prohibits establishing new shellfish harvesting
closure zones
 ENR treatment requires change in treatment process
 No choice: new outfall location
 County Selection Criteria
 No Shellfish Closure Zone
 Includes Enhanced Nutrient Removal (ENR)
Conceptual Aternatives Considered

Alt 1: ENR Upgrade at Mayo – Existing Ouftall

Alt 2: ENR Upgrade at Mayo – New Deep Water Outfall

Alt 3: Pump Mayo Wastewater to Annapolis WRF (ENR treatment)

Alt 4: ENR Upgrade at Mayo – Pump treated effluent to Annapolis
WRF Outfall

Alt 5: Pump Expanded flow (.525 mgd) to Annapolis WRF via
Woodland Beach; Retain Mayo treatment for existing flow (.615
mgd)

Alt 6: ENR Upgrade at Mayo – Re-circulate effluent thru existing
treatment process – Existing Outfall

Alt 7: Expand Mayo using existing treatment process – Existing
Outfall
Initial Expansion Alternatives, cont.
 Alternatives that maintain existing treatment
were deleted
 Alternatives that keep the existing outfall were
deleted
 Alternatives that meet criteria: 2, 3 and 4
 For feasible alternatives, Cost Analysis showed
 Alternative 2 (new outfall) is the most expensive
 Alternative 3 (pump STEP flow wastewater to
Annapolis) is the least expensive
Alternatives Comparison
ENR
Treatment
(Y/N)
Closure Zone
Required
(Y/N)
Recommendation
1: ENR @Mayo-Ex. Outfall
Y
Y
Drop
2: ENR @ Mayo – Deep Water
Outfall
Y
Y/N
Advance
3: Pump Mayo to Annapolis
ENR
Y
N
Advance
4: ENR @ Mayo – pump to
Annapolis Outfall
Y
N
Advance
5: Hybrid: Pump Mayo to
Annapolis ENR/ Retain Ex.
Mayo treatment
N
N
Drop
6. ENR @ Mayo: recirculate
thru Ex. Mayo treatment
N
N
Drop
7. Modular expansion at Mayo
– Existing treatment/outfall
N
N
Drop
Alternative
Initial Expansion Alternative 2:
Natural
Oyster Bar
(Typical)
Possible New
Closure Area
Mayo WRF
New Outfall
N
• ENR WWTP
Upgrade at Mayo
• Typical
• Pump to new outfall
Existing
Forcemain
(Reused)
Existing
Forcemain
and Outfall
(Abandoned)
New Forcemain
Initial Expansion Alternative 2:
• ENR WWTP Upgrade at Mayo
2 HOUR
EMERGENCY
SHELLFISH STORAGE
• Pump to new outfall
FLOW
DISTRIBUTION
BOX
CLARIFIERS
MAYO
INFLUENT
AERATION
BASINS
EFFLUENT
PUMPING
STATION
UV
DISINFECTION
POSTAERATION
MAIN
INFLUENT
PUMPING
STATION
DENITRIFICATION
FILTERS
ENR UPGRADE
24 HOUR EMERGENCY
SHELLFISH STORAGE /
FLOW EQUALIZATION
TANKS
DEEP WATER
OUTFALL
CHESAPEAKE BAY
Initial Expansion Alternative 3:
Annapolis WRF Outfall
N
Annapolis
WRF
Existing
Annapolis WRF
Sewer
Mayo Raw
SPS
Existing
Forcemain
and Outfall
(Abandoned)
Proposed
Forcemain
• No WWTP
Upgrade at Mayo
• Pump wastewater
to Annapolis for
treatment
Initial Expansion Alternative 3:
• No WWTP Upgrade at Mayo
2 HOUR
EMERGENCY
SHELLFISH STORAGE
PUMP TO
ANNAPOLIS
WRF
• Pump wastewater to Annapolis for
treatment
MAYO
INFLUENT
MAIN
INFLUENT
PUMPING
STATION
24 HOUR EMERGENCY
SHELLFISH STORAGE /
FLOW EQUALIZATION
TANKS
Initial Expansion Alternative 4:
Annapolis WRF Outfall
N
Annapolis
WRF
• ENR WWTP
Upgrade at Mayo
• Pump effluent to
Annapolis Outfall
Mayo WRF
Existing
Forcemain
and Outfall
(Abandoned)
Proposed
Forcemain
Initial Expansion Alternative 4:
• ENR WWTP Upgrade at Mayo
2 HOUR
EMERGENCY
SHELLFISH STORAGE
• Pump effluent to Annapolis Outfall
FLOW
DISTRIBUTION
BOX
CLARIFIERS
MAYO
INFLUENT
AERATION
BASINS
UV
DISINFECTION
POSTAERATION
MAIN
INFLUENT
PUMPING
STATION
DENITRIFICATION
FILTERS
ENR UPGRADE
PUMP TO
ANNAPOLIS
WRF OUTFALL
24 HOUR EMERGENCY
SHELLFISH STORAGE /
FLOW EQUALIZATION
TANKS
Alternatives Cost Comparison
$100,000,000
$90,000,000
$80,000,000
$70,000,000
$60,000,000
$50,000,000
$40,000,000
$30,000,000
$20,000,000
$10,000,000
$Alternative 1 Alternative 2 Alternative 3 Alternative 4 Alternative 5 Alternative 6 Alternative 7
Capital Cost
Present Worth O&M Cost
Phase 1 Improvements
 Accelerate replacement of limited operational components
given delays to Expansion/ENR Project.
 No Expansion Related Upgrades – Moratorium remains in
place
 Phase 1 Upgrade – needed for systems near the end of
useful life
 Main Pump Station – pump replacements
 Two covered flow equalization tanks
 Ultra-Violet Disinfection System replacement
 Upgrade Electrical Distribution System
 Emergency Back-up Power
 Upgrade System Controls (SCADA)
Next Steps

Pursue Phase 1 Upgrade Contract

Refine Scopes and Costs for Alternatives
2, 3 and 4

Develop and Evaluate Non-cost criteria

Re-convene Mayo CAC

Recommend and Pursue Preferred
Alternative.
Questions
&
Answers