combined sewer overflow (cso) treatment technology evaluation · primary treatment hydraulics...
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Combined Sewer Overflow (CSO) Treatment Technology Evaluation
Bob BucherKing County DNRP-WTDTechnology Assessment Program
Fall Science Seminar
October 27, 2009
Project Background
King County CSO Program Planning
Recommendations from CSO Control Plan Review
• Conventional Primary stillremains first choice for treatment
• Pilot High Rate Sedimentation processes
Sluice Gate
Control Room &Odor Control
OverflowWeir
CSO Influent
Primary Treatment Hydraulics
Surface Overflow Rate (SOR)Volume of wastewater treated per square foot of treatment liquid surface area (gallons per day per square foot, or gpd/sf)
Treatment Process Performance
• CSO Treatment Standards– TSS– Fecal Coliform– Settleable Solids
• Water Quality-Based Permit Limits– Metals– Ammonia– Chlorine
• Sediment-Based Permit Limits
Pilot Testing of CSO Treatment Alternatives(Previous King County Experience)
Densadeg – 2001 Actiflo – 2001
Pilot Testing of CSO Treatment Alternatives(Current Test Program – West Point)
Pilot Testing of CSO Treatment Alternatives(Current Test Program – West Point)
Conventional Overflow Weir
Lamella Plates
Chemical Enhanced – addition of coagulant (PAX 18) and polymer (anionic)
Pilot Testing of CSO Treatment Alternatives(What are Lamella Plates?)
Lamella plates increase a basin’s effective settling area. Each lamella plate settler provides an effective settling area equal to that of its horizontal projection.
Source: http://www.meurerresearch.com/plate_theory.html
West Point Pilot - Test Trialso Dye Testing
o West Point Primary Comparison
o Chemical Optimization
o Capacity Testing
o Dilution Testing
o Performance Testing
o Hydrograph Testing
Chemical Optimization Test TrialTrial 13D
0
20
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0 4 8 12 16 20 24PAX 18 dose (mg/L)
% re
mov
al
Conv TSS Plate TSS Conv Turbidity Plate Turbidity
Dilution Test Trial
0%
20%
40%
60%
80%
100%
0 20 40 60 80 100 120Influent TSS (mg/L)
% R
emov
al
CEPCCE-LamellaPCLamella
SOR: PC: 1900 gpd/sq Lamella: 19000 gpd/sfDosing: PAX-18: 16 mg/L Nalco: 1mg/L
Capacity Test Trial
≈ 3,700 gpd/sf≈ 3,700 gpd/sf
≈ 23,000 gpd/sf≈ 23,000 gpd/sf
PAX 18 coagulant = 12 mg/LAnionic polymer = 1.5 mg/L
Performance Test TrialTrial 33
0
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10/14/2009 11:45 10/14/2009 12:15 10/14/2009 12:45 10/14/2009 13:15 10/14/2009 13:45 10/14/2009 14:15
Time
Turb
idity
(FN
U)
Influent Conv Effluent Plate Effluent
PAX18 = 12 mg/LNalclear 7768 = 1.5 mg/L
Conv SOR = 6,800 gpd/sfPlate SOR = 23,000 gpd/sf
start influent sampling
start effluent sampling
Additional Sampling for metals, nutrients, and trace organics.
Hydrograph Test TrialPeak Run Hydrograph
0
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0:00 0:28 0:57 1:26 1:55 2:24 2:52 3:21
Time from RunStart
Flow
, gpm
Testing Schedule and Final Report
Performance / Hydrograph testing through early November.Final Report in January 2010.
Acknowledgementso King County
o CSO Program
o West Point Process Group
o West Point Process Laboratory
o West Point Maintenance Staff
o Environmental Laboratory
o CDM
Combined Sewer Overflow (CSO) Treatment Technology Evaluation
Bob BucherKing County DNRP-WTDTechnology Assessment Program
Fall Science Seminar
October 27, 2009
Pilot Testing of CSO Treatment Alternatives(Current Test Program – West Point)
INLET OUTLET
OUTLET
Flocculation Zone Sedimentation Zone