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OutlineMajor municipal facilities
2006 Willamette Mercury TMDL
Clean Water Services Permit
Mercury Minimization Plan
Monitoring Results
Summary
Municipal Treatment Facilities Sources of wastewater
50 major facilities in Oregon
Size of major facilities:
Sweet Home, Cottage Grove (pop. <10,000)
Portland, Clean Water Services (pop.>500,000)
Type of wastewater facilities
Designed to remove oxygen-demanding pollutants, solids and bacteria
Also very effective at removing metals, mercury and other pollutants
City of Albany Willamette River (RM 118.0) 8.7
City of Canby Willamette River (RM 33) 2.0
City of Corvallis Willamette River (RM 130.8) 9.7
City of Cottage Grove CF Willamette River (RM 21.5) 1.8
City of Dallas Rickreall Creek 2.0
MWMC - Eugene/Springfield Willamette River (RM 178.0) 49.0
City of Lebanon South Santiam (RM 17.4) 3.0
City of McMinnville S. Yamhill River (RM 1.0) 5.6
City of Newberg Willamette River (RM 49.7) 4.0
City of Portland-Tyron Creek Willamette River (RM 20.3) 8.3
City of Salem Willamette River (RM 78.1) 35.0
City of Silverton Silver Creek (RM 2.4) 2.5
City of Stayton North Santiam (RM 14.9) 1.9
City of Sweet Home South Santiam (RM 31.5) 1.4
City of Wilsonville Willamette River (RM 38.6) 2.7
City of Woodburn Pudding River (RM 21.4) 5.0
Clackamas WES - Tri-Cities Willamette River (RM 25.5) 11.9
Clackamas WES - Kellogg Creek Willamette River (RM 18.7) 10.0
Clean Water Services-Durham Tualatin River (RM 9.2) 25.7
Clean Water Services-Rock Creek Tualatin River (RM 37.7) 46.4
Clean Water Services-Forest Grove Tualatin River (RM 53.8) 6.3
Clean Water Services-Hillsboro Tualatin River (RM 43) 4.5
Oak Lodge Sanitary District Willamette River (RM 20.1) 4.0
Receiving streamMunicipal Treatment Facility
Average Dry
Weather Design
Flow (MGD)
2006 Willamette Basin Mercury TMDL TMDL findings
for mainstem Willamette River:
More than 95% of mercury from soil erosion and air deposition – local and global
Small quantity from municipal WWTFs
Abandoned mines
2006 Willamette Basin Mercury TMDL 26.4% reduction in total mercury is needed
Sector specific allocations
Point sources:
Implement mercury minimization efforts
Conduct mercury monitoring
Assess BMP approach over time as part of an adaptive management strategy; DEQ would also update the TMDL
TMDL provisions not fully implemented
Clean Water Services Permit 4 treatment facilities & municipal storm water
system in urban Washington County
Watershed-based NPDES permit
Permit includes:
Monitoring
Quarterly monitoring of influent and effluent
Parameters: mercury, dissolved mercury, methyl mercury, dissolved methyl mercury
Mercury Minimization Plan
Submitted as part of permit renewal
Incorporated into final permit
Mercury Minimization Plan Key Elements:
Survey/inspect dental offices
Audit of CWS facilities
Industry monitoring
Outreach to schools/healthcare facilities/laboratories
Commercial/residential outreach
Implementation Status
Monitoring WWTF influent, effluent and biosolids monitoring
Influent/effluent levels of total mercury
% removal
Estimated loading
Recent data (methyl mercury)
Biosolids
Ambient data
Effluent Mercury StatisticsStatistic
Rock Creek WWTF
Durham WWTF
Forest Grove WWTF
Hillsboro WWTF
Number of Samples 174 176 104 119
Geometric Mean (ng/L) 1.6 1.6 2.2 2.9
Maximum (ng/L) 5.1 5.8 14.2 18
Standard Deviation 0.93 0.83 2.0 1.7
Coefficient of Variation 0.51 0.46 0.74 0.54
Annual Average Flow (MGD) 57.4 33.9 7.1 3.9
Mass Load (kg/year) 0.13 0.08 0.02 0.01
2006 Willamette TMDL Mass Load Estimate (kg/yr)
0.69 0.51 0.06 0.10
Technology Evaluation Literature review to evaluate performance of treatment
strategies
Technologies evaluated: precipitation, filtration, ion exchange, reverse osmosis
Technologies used for industrial applications with much higher loading & effluent concentrations
Did not identify pilot or full-scale systems that would be able to achieve potential mercury limits
Summary Receive wastewater from residential/commercial/
industrial sources and treat it before release
Designed to remove conventional pollutants (solids, BOD, bacteria)
Also very effective at removing mercury (>95%)
Significant reduction in methyl mercury
Produce high quality effluent that exceeds federal standards
Mercury monitoring is very expensive; need to ensure that data being collected informs management actions
Summary (cont.) Mercury loading from municipal treatment facilities
Well below 2006 TMDL estimate
Primary source of mercury: dental facilities; actions taken to reduce mercury
Remaining mercury sources are diffuse
Municipal actions geared toward reducing mercury in the environment; doesn’t have a wastewater nexus
Technology solutions not available to reduce effluent concentrations to target levels
Mercury minimization plan is the most effective approach
What does this mean?? Municipal facilities will likely consider a variance
Clean Water Act tool when water quality based effluent limits cannot be met
Waiver would likely be based on these factors:
Naturally occurring pollutant concentrations prevent attainment of the criterion.
Human-caused conditions or pollutions sources prevent attainment of the criterion and cannot be remedied.
Controls more stringent than technology-based controls will result in substantial and widespread economic and social impact.
Minimization plan would be an element of a variance
Questions?
Contact information:Raj Kapur
Clean Water Services
Kapurr@cleanwaterservices.org
503-681-4424
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