SITE INFORMATION AND CORRESPONDENCE CASE 2

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1 • WASTE DISCHARGE REQUIREMENTS ORDER NO.R5-2003-0141 -7- CALIFORNIA NATURAL PRODUCTS WASTEWATER TREATMENT FACILITY SAN JOAQUIN COUNTY 17.6 Acre Area 16.0 Acre Area Anal es Units Average (W-1 through W-5) Average(L-1 through L-3) TDS mg/l 1,380 428 NO3 as N mg/l 30 16 Ammonia mg/1 1.3 0.2 TKN mg/l 0.8 0.7 TDS denotes Total Dissolved Solids. NO3 as N denotes Nitrate as Nitrogen. TKN denotes Total Kjeldahl Nitrogen. 41. As indicated in the table above,the average TDS and nitrate as nitrogen concentrations in the groundwater below the 17.6 acre land application area are significantly higher than the groundwater below the 16.0 acre land application area, which has been used for land application only since February 2003. The data indicates that groundwater below the 17.6 acre land application area may be impacted by the discharge of wastewater from the facility. It is noted that Well W-5, installed in January 2003 as the upgradient well for the 17.6 acre land application area, is questionable as to whether or not it is upgradient and out of the influence of wastewater discharge to the land application area. However, a limited number of samples collected from Well W-5 have had lower concentrations of TDS and nitrate as nitrogen(1,050 mg/L and 12.4 mg/L respectively) than the average concentrations reported in the table presented above. 42. These WDRs require monitoring of shallow groundwater conditions, including background water quality and direction of groundwater movement throughout the year. 43. The Discharger has substituted certain chemicals in the processing facility with more environmentally acceptable alternatives (i.e. potassium hydroxide for sodium hydroxide, and nitric/phosphoric acid for CIP solutions)resulting in wastewater with more plant nutrients. This approach should result in lower TDS-,percolate concentrations when applied to cropped land application areas. In addition, the Discharger began growing crops on the 17.6 acre land application area in the year 2001;both actions should lead to a reduction in TDS and nitrate concentrations beneath the 17.6 acre land application area. If reductions are not observed, the Discharger will have to reduce the groundwater impacts through other alternatives. SITE SPECIFIC CONDITIONS 44. Local land use consists of industrial,residential, and agricultural operations. The topography of the surrounding area is level. 45. The land application areas are located outside the 100-year flood zone. 46. 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. 47. The average annual total precipitation for this area of San Joaquin County is 13.12 inches. The 100-year annual total precipitation for this area is 21.83 inches. The peak monthly 100-year precipitation of 5.08 inches occurs in January.