john jay l. swift, p.e
TRANSCRIPT
Pete Tjemsland, Water and Sewer Utilities ManagerAl Chrisman, Water Reclamation Facility SupervisorJim McBride, Water Reclamation Facility OperatorTyler White, Water Reclamation Facility OperatorNathan Gaul, Water Reclamation Facility OperatorHank Arnold, Water Reclamation Facility Operator
Presentation Outline
Introduction/Project LocationExisting WRFProject HistoryProject ObjectivesExpansion Plan OptionsDescription of WRF Expansion ImprovementsExpanded WRF PerformanceThoughts and Observations
SecondaryClarifiers
Anoxic Zones
(zero D.O.)Aeration BasinSelector
Zone
Screened
Influent AIR
Return Activated Sludge (RAS)
Secondary
Effluent
Recycle
Original Water Reclamation Facility Schematic
EXISTINGOXIDATION DITCH
EXISTING PEAKFLOW
EQUALIZATION BASIN
SECONDARYCLARIFIERS
(2)
SELECTOR/DIVERSION
BOX ANTHRFILTER
UV EFFLUENTCHANNEL
LIFTSTATION
HEADWORKS/SCREENINGS
REUSELIFT
STATION
VOL = 0.70 MG
VOL = 0.70 MG
50‐FT DIA
Design Flow = 0.8 MGD Max Month Average
Equalized Peak Hour Flow = 1.8 MGD
Water Reclamation Facility Expansion Project History
April 2003
Wastewater Comprehensive Plan issued. Annual growth rate of 1.4% used.
2004‐2005
City attempted to line up regional partners as WRF load approached design capacity.
May 2005 NPDES Permit with new effluent nitrogen limits
issued by Department of Ecology.
2006
Lack of commitment among some of the regional partners and increasing growth in the
City leads to decision to upgrade 0.8 mgd WRF without regional partners.
Water Reclamation Facility Expansion Project History (continued)
January 2006 City indicated that new City Comprehensive
Plan will use annual growth rate of 6.5%.
May 2006
WRF Expansion Study started. Annual growth rate of 6.5% for 2006‐2011 and 5% for
2012‐2025 used.
December 2006
WRF Expansion Study issued, including conceptual plan for expansion of WRF and
reuse sites.
March 2007 WRF expansion design started.
Water Reclamation Facility Expansion Project History (continued)
April 2008
Final plans and specifications for Phase 1 WRF expansion project are advertised for bid.
May 2008
Bids for WRF expansion project opened.
July‐October 2008
Construction of WRF expansion project started.
March‐June 2010
Construction of WRF expansion project completed/startup.
Water Reclamation Facility Expansion Project Objectives
Meet regulatory requirements for nitrogen removal.
Provide capacity for existing population and growth.
Accommodate WRF layout for long‐term growth.
Meet Water Reclamation and Reuse Standards/satisfy Departments of Ecology and Health design requirements for Class A WRF.
Water Reclamation Facility Expansion Project Objectives (Continued)
Remain on the existing WRF site.
Provide cost‐effective design (limited budget).
Allow construction phasing for future expansion.
Incorporate flow equalization.
Expand existing Class A biosolids treatment system.
Projected WRF Influent Maximum Month Flows (2006 WRF Expansion Study)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
2000 2005 2010 2015 2020 2025 2030
Flow
(mgd)
Year
NPDES Permit Criteria for Maximum Month
Projected Sequim WRF Maximum Month Flow @ 1.4% Growth Rate, 2% Annexation Rate (Used in 2003 Sewer Comp Plan)
Projected Sequim WRF Maximum Month Flows @ 6.5% Growth Rate for 5 years, 5% Growth Rate for Remainder, Complete Annexation of UGA within 20 years
WRF at Capacity Phase 1A Const.
Phase 1B Construction
Phase 2 Construction
Flows and Loadings (2006 WRF Expansion Study)
0.00
0.50
1.00
1.50
2.00
2.50
3.00
2005 2010 2015 2020 2025
Flow
(mgd)
Year
Maximum Month Flow
Peak Hour (Equalized) Flow
Two Secondary Clarifiers Exceed CapacityPhase 1A Exceeds Capacity
Filters ExceedCapacity
Existing Oxidation Ditch Exceeds Capacity(NPDES Permitted Design Flow 0.8 mgd)
Existing UV System Exceeds Capacity per NWRI Standards
Converted Activated Sludge Basin Exceeds Capacity Phase 1B Exceeds Capacity
Phase 1A Construction
Phase 1B Construction
Phase 2 Construction
Design Year
Construction Schedule and Design Flows
Existing Phase 1A Phase 1B Phase 2
Construction Start Year 1995 2008 2012* 2019‐2020
Year Capacity Will Be Reached 2008 2013 2020 2025
Design Average Flow Capacity
(mgd)
0.8 1.10 1.67 2.23
Eq. Peak Hr Flow Capacity (mgd) 1.80 1.80 2.46** 3.16
Notes: *Phases 1A and 1B started construction in 2008.
**4.65 mgd unequalized peak hour flow
Plant Design Flows and Loadings
Existing
Permit
Estimated
Actual Expansion
Factor
Increase
Annual Average Flow NS 1.50 mgd
Maximum Month Flow 0.80 mgd 0.68 mgd 1.67 mgd 2.5
Peak Hour Equalized Flow 1.80 mgd 2.46 mgd
Maximum Month BOD5 1,725 lb/d 1,450 lb/d 4,036 lb/d 2.8
Maximum Month TSS 1,450 lb/d 3,855 lb/d
Maximum Month TKN NS 776 lb/d
NS – Not Specified
Reclaimed Water Limitations
Parameter Average Monthly Average Weekly
BOD5 30 mg/L 45 mg/L
TSS 30 mg/L 45 mg/L
Turbidity 2 NTU 5 NTU
Total Coliform Bacteria 2.2 MPN/100 ml (7‐day median) 23 MPN/100 ml (max.)
Ammonia (as N) 3.3 mg/L 5.7 mg/L (daily max.)
Total Nitrogen (as N) 10 mg/L NA
pH ≥6 (daily min.) ≤9 (daily max.)
Dissolved Oxygen >0 mg/L
Nitrogen Removal in Oxidation Ditch Maintained Aerobic/Anoxic Zones
To SecondaryClarifier
Influent
RAS
Aerator ON
AEROBIC ZONE
ANOXIC ZONE
Aerator OFF
NEW FLOWEQUALIZATION BASIN
CONVENTIONAL ACTIVATEDSLUDGE MLE BASIN #1
(CONVERTED FROM EXISTINGOXIDATION DITCH)
CONVENTIONAL ACTIVATEDSLUDGE MLE BASIN #2
(CONVERTED FROM EXISTINGEQUALIZATION BASIN)
SECONDARYCLARIFIERS
(2)
SECONDARYCLARIFIERS
(1)
EXPANDEDSELECTOR/DIVERSION
BOX
NEW SPLITTER
BOX
ANTHRAFILTER
NEWFILTER
UV1
UV2
EXISTING
NEW
EXISTING
NEW
VOL = 0.75 MG
EXPANDED LIFT
STATION
WRF Expansion Alternative No. 1 Conventional Activated Sludge in Existing
Oxidation Ditch Tanks
VOL = 0.70 MG
VOL = 0.70 MG
NEW MEMBRANEBIOREACTOR BASIN
EXISTINGOXIDATION DITCH
EXISTING FLOWEQUALIZATION
BASIN
SECONDARYCLARIFIERS
(2)
EXPANDEDSELECTOR/DIVERSION
BOX ANTHRAFILTER
UV1
UV2
EXISTINGLIFT
STATION
NEWLIFT
STATION
NEW
EXISTING
VOL = 0.5 MG
VOL = 0.70 MG
VOL = 0.70 MG
WRF Expansion Alternative No. 2 New Membrane Bioreactor Tank
EQUALIZATION BASIN(CONVERTED FROM EXISTING
OXIDATION DITCH)
MEMBRANE BIOREACTORBASIN (CONVERTED FROM
EXISTING EQUALIZATIONBASIN)
EXPANDEDSELECTOR/DIVERSION
BOXUV1
UV2NEW
LIFTSTATION
VOL = 0.70 MG
VOL = 0.70 MG
NEW
WRF Expansion Alternative No. 3 Membrane Bioreactor in EQ Basin
EQUALIZATION BASIN(CONVERTED FROM EXISTING
OXIDATION DITCH)
CONVENTIONAL ACTIVATEDSLUDGE MLE BASIN
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -CONVERTED FROM EXISTING
EQUALIZATION BASIN
SECONDARYCLARIFIERS
(2)
SECONDARYCLARIFIERS
(1)
NEW SPLITTER
BOX
ANTHRAFILTER
NEWFILTER
UV1
UV2
EXISTING
NEW
EXISTING
NEWEXPANDED LIFT
STATION
VOL = 0.70 MG
VOL = 1.35 MG
WRF Expansion Alternative No. 4 Conventional Activated Sludge in Enlarged EQ
Basin (Selected Alternative)
Aeration Basin Design Data
Parameter Value
Qty. of Trains 2
Side Water Depth 20.75 Ft
Total Volume 1.35 Mgal
Design MLSS 4,000 mg/L
Aerobic SRT 8.1 days
Selector Zone Volume (Total) 0.06 Mgal
Anoxic Zone Volume (Total) 0.27 Mgal
Internal Recycle Flow (Total) 5,200 gpm
Design Recycle Ratio 4 : 1
Blowers 3 @ 850 scfm/ea. (75 hp)
Air Diffusers Fine bubble disc
membrane
Monthly Average Influent Flow
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
Sep‐08 Dec‐08 Mar‐09 Jul‐09 Oct‐09 Jan‐10 May‐10 Aug‐10 Nov‐10
Influe
nt Flow
Date
Flow (mgd)
Influent Flow Permit Limit ‐ 1.67 mgd
New Aeration Basin Online
Monthly Average Influent BOD5
and TSS Flows
0
500
1000
1500
2000
2500
3000
3500
4000
4500
Sep‐08 Dec‐08 Mar‐09 Jul‐09 Oct‐09 Jan‐10 May‐10 Aug‐10 Nov‐10
Influe
nt BOD5an
d TSS
Date
BOD (lb/d)
TSS (lb/d)
BOD5 Design Load ‐ 4,038 lb/d
TSS Design Load ‐ 3,865
New Aeration Basin Online
Monthly Average Effluent BOD5
and TSS Concentrations
0
5
10
15
20
25
30
35
Sep‐08 Dec‐08 Mar‐09 Jul‐09 Oct‐09 Jan‐10 May‐10 Aug‐10 Nov‐10
Efflue
nt BOD5an
d TSS Co
ncen
tration
Date
BOD (mg/L)
TSS (mg/L)
BOD5& TSS Effluent PermitLimit ‐ 30 mg/L
New Aeration Basin Online
Monthly Average Effluent Ammonia and Nitrogen Concentrations
0
5
10
15
20
25
30
Sep‐08 Dec‐08 Mar‐09 Jul‐09 Oct‐09 Jan‐10 May‐10 Aug‐10 Nov‐10
Ammon
ia and
Total Nitrogen Co
ncen
tration
Date
Total N (mg/L)
NH3 (mg/L)
Total Nitrogen Permit Limit ‐ 10 mg/L
New Aeration Basin Online
Ammonia Effluent Permit Limit ‐ 3.3 mg/L
Daily 30‐minute MLSS Settleability
0
200
400
600
800
1000
1200
Sep‐08 Dec‐08 Mar‐09 Jul‐09 Oct‐09 Jan‐10 May‐10 Aug‐10 Nov‐10
Settled Solid
s
Date
1/2‐hour Settleability (ml)
New Aeration Basin Online
Daily Average SVI
0
50
100
150
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300
350
400
450
Sep‐08 Dec‐08 Mar‐09 Jul‐09 Oct‐09 Jan‐10 May‐10 Aug‐10 Nov‐10
SVI
Date
SVI (ml/g)
New Aeration Basin
Project Construction Cost Summary
Construction* $9,223,532
Cost per Gallon per Day $5.50
Cost per ERU $892
Cost per Pound of BOD5 $2,285* Includes change orders and sales tax.ERUs = 10,343
Thoughts and Observations
Existing tanks can be converted to new treatment process uses to conserve site areaCapacity of existing Aeration Basins can be increased by raising side water depth (though pumping may be required)Oxidation ditch tanks can be converted to plug‐flow aeration basinsInline Equalization Basins can decrease sizes of process units based on peak flowInline Equalization Basins can produce relatively constant loading on downstream processesInline Equalization Basins can be kept free of odor, floatables, and settled solids
Thoughts and Observations (continued)
Inline Equalization Basins can serve as a wet well for plant lift stationClarifiers can have walls raised to increase side water depth and capacityPackage filters can supplement existing filtration capacityHigh‐output UV disinfection systems can replace low‐output units in same channel to increase capacityBlowers in weatherproof, acoustic enclosures reduce housing area requirementsProcess studies can result in regulatory approval of capacity increases without large capital improvementsUse of existing structures for plant upgrades requires consideration of effects on construction schedule, order of work, and means and methods
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35.00 ft will trigger a pump adjustmentbased on the rate of change of elevation
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