Fairfield-Suisun Sewer District

2003 NPDES Permit Renewal

Infeasibility Analyses

June 17, 2003

Introduction

These infeasibility analyses and resulting requests for compliance schedule and interim limits are 

submitted to the Regional Water Quality Control Board (RWQCB) by Fairfield-Suisun Sewer 

District to demonstrate the District’s inability to comply with the proposed water-quality based 

effluent limits for copper, mercury, cyanide, dichorobromomethane, bis(2-ethylhexyl) phthalate, 

4,4’-DDE, and dieldrin. 

Background

The Policy for Implementation of Toxics Standards for Inland Surface Waters, Enclosed Bays 

and Estuaries of California (known as the State Implementation Policy (SIP), March, 2000) 

establishes statewide policy for NPDES permitting. The SIP provides for the situation where an 

existing NPDES discharger cannot immediately comply with an effluent limitation derived from 

a California Toxics Rule (CTR) or Basin Plan criterion. The SIP allows for the adoption of 

interim effluent limits and a schedule to come into compliance with the final limit in such cases. 

To qualify for interim limits and a compliance schedule, the SIP requires that an existing 

discharger demonstrate that it is infeasible to achieve immediate compliance with the CTR- or 

Basin Plan-based limit. 

The term “infeasible” is defined in the SIP as “not capable of being accomplished in a successful 

manner within a reasonable period of time, taking into account economic, environmental, legal, 

social and technological factors.” 

The SIP requires that the following information be submitted to the Regional Board to support a 

finding of infeasibility:

(a) documentation that diligent efforts have been made to quantify pollutant levels in the 

discharge and sources of the pollutant in the waste stream, including the results of 

those efforts;

(b) documentation of source control and/or pollution minimization efforts currently under 

way or completed;

(c) a proposed schedule for additional or future source control measures, pollutant 

minimization or waste treatment; and

(d) a demonstration that the proposed schedule is as short as practicable.
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Pollutants to be Evaluated 

The pollutants for which interim limits are needed for the District are as follows:

 copper 

 mercury

 cyanide

 dichlorobromomethane

 bis(2-ethylhexyl) phthalate

 4,4’-DDE

 Dieldrin

Effluent Limit Attainability

The proposed final and interim effluent limits contained in the draft tentative order for copper, 

mercury, cyanide, dichlorobromomethane, bis (2 ethylhexyl)phthalate, 4,4’-DDE, and dieldrin 

are compared to the maximum observed effluent concentrations for these constituents in Table 1. 

Table 1. Proposed Effluent Limits for Fairfield-Suisun Sewer District

Pollutant

Water Quality Based 

Effluent Limits

PerformanceBased Interim 

Effluent Limits 

FairfieldSuisun 

Effluent 

Quality

AMEL1 MDEL2 Daily 

Max.

Monthly 

Avg. MEC3

Copper 4.7 7.5 12.3 10

Mercury 0.021 0.040 0.023 0.021

Cyanide 0.4 1.0 32 28

Dichlorobromomethane 46 88 75 55

Bis(2-ethylhexyl) phthalate 5.9 11.8 13 13

4,4’-DDE 0.00059 0.00118 0.05 <0.001

Dieldrin 0.00014 0.00028 0.01 <0.002

All values in μg/L.

1AMEL: average monthly effluent limit

2MDEL: maximum daily effluent limit

3MEC: maximum effluent concentration

The final effluent limits shown above are calculated using procedures described in Section 1.4 of 

the SIP. Background values are based on Regional Monitoring Program (RMP) data collected at 

the Sacramento River Station. Dilution was taken as zero and the receiving water was classified 

as estuarine (i.e., lowest of freshwater and saltwater criteria is used for effluent limit calculation). 

Hardness, where applicable, was assumed to be 268 mg/L. Other variables in the effluent limit 

calculation included coefficients of variation for different pollutants in different effluents.
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Maximum observed effluent concentrations are based on recent plant effluent quality data (2000-

2002). As shown in the table above, the District will not be able to immediately comply with 

proposed effluent limits for copper, mercury, cyanide, dichlorobromomethane, Bis(2-

ethylhexyl)phthalate, 4,4’-DDE, and dieldrin. The feasibility analyses for these constituents are 

discussed below.

Source Control and Pollution Prevention Efforts 

In addition to its pretreatment program which regulates 11 industries and 3 groundwater 

remediation sites, the District has an active pollution prevention program that has been in place 

since 1992. Currently, the District considers mercury, organophosphate pesticides, 

perchloroethylene, copper, nickel, lead and zinc to be pollutants of concern. Mercury has the 

highest priority (A) while pesticides and perchloroethylene are assigned a B priority and the 

metals are priority C. The District has implemented a variety of activities targeting these 

pollutants over the years. Some of these activities are highlighted in Table 2.

Table 2. Fairfield-Suisun Pollution Prevention Program Activities

Pollutant of Concern Source Control Activities

Mercury Thermometer exchanges, Dental outreach

Organophosphate pesticides Restaurant IPM inspections, school outreach, theatre slides, 

public events, PCO workshops

Perchloroethylene Dry cleaner inspections

Copper, nickel, lead, zinc Inspections/ BMPs for vehicles service facilities, metal 

fabricators, and industry; surface cleaner workshops

Several of the activities listed above have been conducted in cooperation with other local 

agencies in Vacaville, Vallejo, Fairfield and Suisun City. The District is also an active 

participant and supporter of several regional groups and programs, including:

 Bay Area Pollution Prevention Group (BAPPG)

 Bay Area Clean Water Agencies (BACWA)

 Bay Area Stormwater Management Agencies Association (BASMAA)

 North Bay Source Control Group

 Napa/ Solano Regional Environmental Public Education Group

 Solano County Environmental Management Local Task Force

 Napa/Solano Air Resource Team 

Additional information on pollution prevention activities targeting each constituent requiring 

interim effluent limits is discussed below.
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Copper

The maximum observed effluent concentration for copper is 10 μg/L (measured in June 2000) 

which would exceed a final MDEL of 7.5. The maximum average monthly copper value of 8.5 

(measured January 2001) exceeds the proposed final AMEL of 4.7. In addition, 3 of 78 samples 

taken between January 2000 and December 2002 have copper concentrations that would exceed 

7.5 (the proposed final MDEL) and 14 of 36 calculated monthly average values would exceed 4.7

(the proposed final AMEL). The District will not be able to immediately comply with the 

proposed final limits.

The District has identified copper as a priority C pollutant of concern and has conducted 

pollution prevention targeting copper sources including corrosion of copper plumbing, root 

control products, vehicle service facilities, mobile surface cleaners, and metal fabricators. 

Pollution prevention activities have contributed to a 34% reduction in copper influent levels 

between 1992 (59 μg/L) and 2000 (39 μg/L). The District has conducted source control for most 

of the common copper sources so it is not clear how much more reduction may be achieved. The 

District will review its current copper pollution prevention activities and modify as needed.

Mercury

The maximum observed effluent concentration for mercury is 0.021 μg/L (measured in October 

2002) which is equal to the proposed final AMEL of 0.021 μg/L. The maximum average 

monthly mercury value of 0.015 μg/L (measured in October 2002) does not exceed the final 

AMEL of 0.021. The District will have difficulty consistently complying with the proposed 

effluent limits.

Mercury is a 303(d)-listed parameter and is the subject of a TMDL currently nearing completion. 

Final effluent limits for this pollutant will be derived from the wasteload allocation established 

under the TMDL. The final effluent limit listed above for this pollutant is projected to change 

based on the results of the TMDL and wasteload allocation. Available information indicates that 

mercury is a legacy pollutant in San Francisco Bay resulting from past activities and that ongoing 

loadings from POTWs are not a significant source of this pollutant. As a result, costly measures 

for either advanced treatment or zero discharge to control mercury loading from POTWs are not 

expected to be required.

Given that POTWs are not a significant source of mercury in the Bay, in addition to the District’s 

existing high quality effluent, residential service area, and favorable discharge location, it is not 

immediately evident the extent to which additional pollution prevention efforts would be 

effective or have any detectable beneficial impact on the receiving water. Certainly, the highest 

value measured by the District is below the water quality objective. Reasonable potential was 

only triggered by background ambient data.

However, the District has a identified mercury as a pollutant of concern and has conducted 

pollution prevention activities for mercury sources including thermometer exchange programs in 

cooperation with other local agencies, and outreach to dentists in the District’s service area. In 

addition, the District conducted a study of the impact of its effluent on methyl mercury levels in 

Suisun Marsh. The District will continue its efforts targeting mercury sources. Specifically, the 
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District has surveyed local dentists regarding their amalgam waste management practices and 

will develop future outreach based on the results of the survey.

Cyanide

The maximum observed effluent concentration for cyanide is 28 μg/L (measured in June 2001) 

which would exceed a final MDEL of 1.0 μg/L. The maximum average monthly cyanide value 

of 17 (measured June 2001) exceeds the proposed final AMEL of 0.4 μg/L.. In addition, 32 of 

74 samples taken between January 2000 and December 2002 have cyanide concentrations that 

would exceed 1.0 (the proposed final MDEL), one sample has a cyanide concentration of 1 μg/L,

and the remaining 41 samples have cyanide concentrations below the detection limit of 3 μg/L. 

All the calculated monthly average values would exceed 0.4 μg/L (the proposed final AMEL). 

The District will not be able to immediately comply with the proposed final limits and will have 

difficulty consistently complying with the proposed interim limits.

Cyanide has been detected occasionally (i.e., 6 of 30 samples from January 2000 – December 

2002) but not consistently in the District’s influent. Typically, cyanide is not present in 

wastewater influent but is generated in the treatment plant disinfection process. For example, 

based on a review of the literature1(including a study being conducted by water Environment 

Research Foundation (WERF)), effluent cyanide levels may be due to chlorination processes or 

may be the result of analytical interferences. 

The District has not previously identified cyanide as a pollutant of concern and, therefore, has not 

conducted source investigations for this constituent. In addition, as noted above, it is unlikely

that these investigations would be fruitful based on the influent data. A special study is being 

conducted under a region-wide effort to develop a site-specific objective for cyanide which is 

expected to more closely represent actual water quality conditions than current water quality

objectives. The District is participating in this study. In addition, in accordance with the 

requirements of its NPDES permit, the District conducted a Cyanide Reduction Study focusing 

on determining if cyanide was being generated in the treatment process. The study determined 

that it was likely that cyanide levels in the effluent were an artifact of the 

chlorination/dechlorination process. This study was submitted to the Regional Board in 

February 2000.

Dichlorobromomethane

The maximum observed effluent concentration for dichlorobromomethane is 55 μg/L (measured 

in September 2002) which would exceed the proposed final AMEL of 46 μg/L.. Of the 6 

samples taken between January 2000 and December 2002, two have dichlorobromomethane

concentrations that would exceed 46 μg/L (the proposed final AMEL). The District will not be 

able to immediately comply with the proposed final limits.

Dichlorobromomethane is generated as a byproduct of chlorination of water and wastewater and 

does not typically have influent sources. The District has not previously identified 

dichlorobromomethane as a pollutant of concern and, therefore, has not conducted pollution 

prevention activities for this constituent. Influent levels of dichlorobromomethane average less 

than 1 μg/L and have not exceeded 2.1 μg/L. Therefore, it is unlikely that there are significant 
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sources of dichlorobromomethane in the influent, making source investigations and source 

control activities unlikely to be fruitful. With only six influent and effluent samples in 3 years, 

there is not enough information to completely assess the District’s ability to comply with the 

proposed interim or final limits. Should reductions be necessary, the District will evaluate its 

treatment plant processes to determine if there are opportunities to optimize its processes to 

reduce generation of dichlorobromomethane. 

Bis(2-Ethylhexyl)Phthalate 

The maximum observed effluent concentration for bis(2-ethylhexyl)phthalate is 13 μg/L which 

exceeds the proposed final MDEL of 11.8 μg/L and the proposed final AMEL of 5.9 μg/L.. Only

7 data points are available for January 2000 through December 2002 with the two earliest 

samples having high detection limits (i.e., 25 μg/L). The District will have difficulty complying 

with the proposed interim and final limits but insufficient data are available to assess compliance 

with any certainty.

Bis(2-ethylhexyl)phthalate (Bis-2) is a plasticizer. Approximately 97% of the Bis-2 produced 

annually is used as a plasticizer for PVC and other plastics. Because of the widespread use of 

plastics in every facet of everyday life, Bis-2 is ubiquitous. Influent levels of Bis-2 average 30 

μg/L. The District has not previously identified Bis-2 as a pollutant of concern and, therefore, 

has not conducted pollution prevention activities for this constituent. With only seven effluent 

samples in 3 years and six influent samples, there is not enough information to completely assess 

the District’s ability to comply with the proposed interim or final limits. Since high levels of 

Bis-2 in POTW effluent are usually associated with sampling and/or laboratory analysis 

conditions, the District proposes to conduct a special study to determine if cleaner sampling and 

analysis techniques can reduce the amount of Bis-2 in the effluent. 

4,4’-DDE, Dieldrin

The chlorinated pesticides, 4,4’-DDE and dieldrin , have not been detected in the District’s 

effluent and have been below reporting limits of 0.01 μg/L. The reporting limits and the 

detection limits (0.001 μg/L for 4,4’-DDE and 0.002 μg/L for dieldrin) exceed the proposed final 

limits for both constituents. Therefore, there is insufficient information to determine if the 

District is able to comply with the proposed effluent limits.

4,4’-DDE is a decomposition product of DDT, which was banned in the US for most uses in 

1972 and all remaining uses in 1988. Dieldrin was banned for most uses in 1974 and all 

remaining uses in 1987. Dieldrin is also a decomposition product of Aldrin whose use was also 

discontinued in the late 1980’s. The District has not previously identified 4,4’-DDE or dieldrin 

as pollutants of concern and, therefore, has not conducted pollution prevention activities that 

directly target these constituents. However, the District has an ongoing pesticide pollution 

prevention program that includes a restaurant Integrated Pest Management (IPM) education 

program, residential outreach (theatre slides, bus boards, public events), school outreach and 

PCO workshops. As noted above, there is insufficient information to completely assess the 

District’s ability to comply with the proposed effluent limits for 4,4’-DDE and dieldrin. Since 

reasonable potential for these constituents is triggered only by background ambient conditions, 

the District will continue existing efforts for pesticides generally.
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Summary

This evaluation indicates that immediate compliance with projected final effluent limits for 

copper, mercury, cyanide, bromodichloromethane, bis(2-ethylhexyl) phthalate, 4,4’-DDE and 

dieldrin is not feasible for the District.

In accordance with the requirements of the SIP, the District requests that the Regional Board 

refrain from the adoption of final effluent limits for these constituents. In lieu of final limits, the 

NPDES permit should include the interim performance based limits with which the District can 

comply. Proposed source control actions are shown in Table 3 below.

Table 3. Proposed Source Control Actions

Constituent Proposed Action Estimated Time to 

Complete

Copper Existing outreach to municipal water 

supply agencies, plumbers, vehicle 

service facilities, metal fabricators, and 

surface cleaners

Ongoing

Mercury No additional activity since RP triggered 

by background data

N/A

Cyanide Participate in study to develop sitespecific objectiveJune, 2003

Dichlorobomomethane Conduct source identification across 

plant processes

Three years after 

permit adoption

Bis(2-Ethylhexyl)Phthalate Conduct study to evaluate clean sampling Three years after 

permit adoption

4,4’-DDE No additional activity since RP triggered 

by background data

N/A

Dieldrin No additional activity since RP triggered 

by background data

N/A