SITE INFORMATION AND CORRESPONDENCE_CASE 2

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CENTRAL VALLEY WATER BOF � RESPONSE {SWRCB/OCC File A-1646 -2- PETITIONS FOR REVIEW OF W)m*TE DISCHARGE REQUIREMENTS ORDER NO. R5-2007-0036 (NPDES NO. CA0079154) AND TIME SCHEDULE ORDER NO. R5-2007-0037 CITY OF TRACY, WASTEWATER TREATMENT PLANT biofiltration, conventional activated sludge, and secondary sedimentation. The Facility has been recently upgraded to provide nitrification/denitrification in the activated sludge process and tertiary filtration. The tertiary effluent is disinfected by chlorination and dechlorinated prior to discharge. Biosolids are thickened by dissolved air flotation, anaerobically digested, and dewatered in unlined sand drying beds. The dried biosolids are hauled off-site for land application or disposed in a landfill. The Discharger's industrial facility consists of four unlined industrial ponds (approximately 52 acres). In addition, Leprino, a local cheese manufacturer, leases two lined aerated lagoons and one 8-acre unlined oxidation pond from the Discharger for preliminary treatment of its industrial food processing wastewater and discharges to the Facility under an industrial pretreatment permit issued by the Discharger. Leprino's industrial pretreatment program permit allows for a discharge of up to 850,000 gallons per day of industrial food-processing wastewater. RESPONSES TO CONTENTIONS The following are the Central Valley Water Board's responses to discrete contentions raised in the Discharger's petition. For convenience, the responses are correlated to the issues as they appear in the petition. CONTENTION A: The Central Valley Water Board improperly imposed daily maximum effluent limitations without federally mandated impracticability analysis for BODS, TSS, Aluminum, Total Residual Chlorine, Ammonia, Dissolved Oxygen, Copper, Dichlorobromomethane, Chlorodibromomethane, Iron, pH, Turbidity, and Total Coliform. BODS and TSS. The California Department of Public Health (DPH) has developed reclamation criteria in Title 22, which prescribes treatment processes and indicator parameters to produce a treated wastewater that is essentially pathogen free and acceptable for direct body contact use. There is little to no dilution of the effluent in the receiving water, which may result in public contact with undiluted effluent through contact recreation or through the irrigation of agricultural land with Old River water. Therefore, a pathogen free effluent [Title 22 (or equivalent) tertiary treatment] is necessary. The final effluent limitations for 5-day biochemical oxygen demand (BODS) and total suspended solids (TSS) are based on the technical capability of the tertiary process. BODS is a measure of the amount of oxygen used in the biochemical oxidation of organic matter. The secondary and tertiary treatment standards for BODS and TSS are indicators of the effectiveness of the treatment processes. The principal design parameter for wastewater treatment plants is the daily BODS and TSS loading rates and the corresponding removal rate of the system. In applying 40 CFR Part 133 for weekly and monthly average BODS and TSS limitations, the application of tertiary treatment processes results in the ability to achieve lower levels for BODS and TSS than the secondary standards. Therefore, the 30- day average BODS and TSS limitations were based on the capability of a tertiary system.