SITE INFORMATION AND CORRESPONDENCE CASE 2

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WASTE DISCHARGE REQUIREMENTS ORDER NO. S PAT MITCHELL AND CALIFORNIA NATURAL PRODUCTS WASTEWATER TREATMENT AND DISPOSAL FACILITY SAN JOAQUIN COUNTY 27. Soil borings were drilled in the land application area in July 1988. The soil was described as silt, sand, and clay mixtures. According to the San Joaquin County Soil Survey, the soils underlying the land application site consist of a loamy coarse sand and a fine sandy loam, with rapid and moderately rapid permeabilities,respectively. The sandy loam soils contain a weakly cemented to a strongly cemented hardpan layer at a depth of four to six feet. Several years ago,the Discharger deep- ripped through this hardpan layer to improve percolation. 28. Three shallow groundwater monitoring wells were installed at the application site in July 1988. The locations of Wells MW-2 and MW-3 are shown in Attachment B. The portion of the previous application area that contained Well MW-1 was developed as a warehouse facility. Groundwater levels have been monitored by the Discharger since June 1994. However, many of the elevation data are of poor quality and may not be reliable. The depth to groundwater is approximately 10 to 15 feet below ground surface (bgs). 29. The City of Lathrop operates three drinking water supply wells which are located between Lathrop Road, Louise Avenue,McKinley Avenue, and the Western Pacific rail line. The closest of the municipal wells is approximately 1,600 feet east of the application area. 30. The average analytical results for groundwater samples collected since 1994 from Wells MW 1,MW2, and MW3 are presented below. Also presented is the average concentration of analytes in samples collected from monitoring wells located at the processing facility(Wells A,B,and C)where land application has not occurred. Regular quarterly sampling was not initiated until May 1998;prior to that time samples were collected infrequently dating back to 1988. The data averaged below consist of between four to nine sample events. The facility data is averaged from one sampling event performed on 24 July 2000. A summary of the average analytical results is presented below: Land Application Area Facility Area Analytes Units MWl MW2 MW3 Average A-C BOD mg/1 136 4.3 4.4 6.3 TDS mg/1 1,255 1,467 1,355 1,633 Fixed TDS mg/1 1,204 964 1,040 1,317 NO3 as Nitrate mg/1 154 168 135 203 Chloride mg/1 92 152 252 116 Potassium mg/1 3.4 3.4 4.8 7.3 Sodium mg/1 248 221 194 267 Elec. Cond. µmhos/cm 2,249 2,392 2,304 2,467 31. These WDRs further require evaluation of shallow groundwater conditions, including background water quality and direction of groundwater movement throughout the year. 32. Employee showers and newer restrooms are piped to the domestic wastewater lift station where it is pumped to the City of Lathrop's collection system. Domestic wastewater is not co-mingled with the process water that is land applied. Some of the older restrooms are connected to septic tanks. �wq..rua..ex v..n.wmr.xvaun.im.