SITE INFORMATION AND CORRESPONDENCE_CASE 2

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INFORMATION SHEET low 4 ORDER NO. R5-2007- CITY OF TRACY AND LEPRINO FOODS COMPANY LAND DISCHARGE UNITS OF THE TRACY WASTEWATER TREATMENT PLANT SAN JOAQUIN COUNTY B. Antidegradation Policy. State Water Board Resolution No. 68-16 (Resolution 68-16) requires the Regional Water Board, in regulating discharge of waste, to maintain high quality waters of the State until it is demonstrated that any change in quality will be consistent with maximum benefit to the people of the State, will not unreasonably affect beneficial uses, and will not result in water quality less than that described in the Regional Water Board's policies. Resolution 68-16 requires the discharge be regulated to meet best practicable treatment or control to assure that pollution or nuisance will not occur and the highest water quality consistent with the maximum benefit to the people of the State be maintained. As discussed in Section II.A., the Facility utilizes separate facilities for pretreatment of industrial wastewater, which includes 60 acres of unlined ponds. The wastewater contained in the unlined industrial ponds is predominantly industrial food processing wastewater from Leprino. The industrial wastewater contains constituents such as TDS, EC, BOD, and TSS. The industrial wastewater flows in series through the unlined oxidation ponds and is returned to the primary sedimentation basins of the main plant. Attachment F, Figure F-3, shows the layout of the unlined treatment ponds, direction of flow, and locations of groundwater monitoring wells. The shallow groundwater in the vicinity of the Facility is high in salinity and exceeds water quality objectives. The Basin Plan at page IV-15.00 states that, "Controllable water quality factors are not allowed to cause further degradation of water quality in instances where other factors have already resulted in water quality objectives being exceeded." EC concentrations in the treatment ponds and underlying groundwater exceed background groundwater concentrations, which indicates groundwater degradation may have occurred, as shown in Attachment F, Figure F-1. The record indicates that Regional Water Board staff have been concerned about possible degradation of groundwater caused by the unlined ponds for many years. In August 1989, Regional Water Board staff requested the Discharger submit a proposal and time schedule for installing groundwater monitoring wells to assess the potential impact the industrial holding ponds may be having on salinity in the shallow groundwater. Four groundwater monitoring wells were installed, MW-1 through MW-4 (see Attachment F, Figure F-3). MW-1 was constructed on the southeast corner of the ponds to allow upgradient or background sampling. Samples were collected from the ponds in February and October 1990. Analyses included TDS, pH, sulfate, chloride, fluoride, alkalinity, specific conductance, nitrate, and general metals. In October 1990, water quality samples were collected from the monitoring wells and analyzed for the same parameters as the ponds. The study concluded that wastewater in the holding ponds did not currently appear to be affecting salinity levels in the local groundwater. Even though the ponds contained wastewater with TDS levels exceeding secondary drinking water standards, groundwater samples indicated the shallow groundwater is naturally high in the area.