Transcript Slide 1
Anne Arundel County
Department of Public Works
Mayo Water Reclamation
Facility
Presented to West Rhodes 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, $/gallon
Cox Creek
5,796,000
11.327
0.51
Annapolis
4,753,000
8.561
0.56
Broadneck
3,088,500
5.131
0.60
Patuxent
3,347,500
5.317
0.63
Broadwater
1,139,200
1.078
1.06
Maryland City
1,307,800
1.054
1.24
Mayo
1,091,300
0.560
1.95
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 Alternatives 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