SITE INFORMATION AND CORRESPONDENCE CASE 2

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WASTE DISCHARGE REQUIREMENTS ORDER NO.R5-2002-0071 -6- CALIFORNIA NATURAL PRODUCTS WASTEWATER TREATMENT FACILITY SAN JOAQUIN COUNTY 34. Based on the anticipated wastewater quality and volume discharged from the treatment facility when operated properly, discharge of the wastewater should comply with the BOD effluent limitations presented in Section C. Compliance with the effluent limits, combined with careful management of the wastewater application areas, should control objectionable odors. 35. Wastewater application in the land application areas and landscaped areas will be rotated to provide soil drying time and to prevent odors. If odors are detected, the irrigated areas will be allowed to dry out thoroughly. Regular discing activities will be performed between crop activities. 36. Soil borings were drilled in the 17.6 acre 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. 37. In April 2001,on-site infiltration tests were conducted at the existing 17.6 acre land application site and at the proposed 16.0 acre land application area. Six double ring infiltrometer tests were performed, using wastewater from the CNP facility. Results ranged from 0.19 to 2.25 in/hr,and averaged 0.80 and 1.09 in/hr at the 17.6 acre site and 16.0 acre site respectively. Based on this information,infiltration rates for the land application area were characterized as moderate. 38. Based on a monthly average application rate of 290,000 gpd and 100-year precipitation data, it is anticipated that 1.5 percent of the available infiltration capacity of the application area soil will be utilized during the 100-year precipitation peak month. OTHER WASTE STREAMS 39. Stormwater collected at paved areas and loading docks is piped to the wastewater treatment system. Stormwater that falls on buildings is discharged to stormwater retention basins. 40. Employee showers and the newer restrooms are piped to the domestic wastewater lift station where it is pumped to the City of Lathrop's wastewater collection system. Some of the older restrooms are connected to septic tanks. Domestic wastewater is not commingled with the process water that is land applied. GROUNDWATER CONDITIONS 41. Three groundwater monitoring wells were installed at the 17.6 acre land application site in July 1988. The locations of the monitoring wells are shown on Attachment B. The Discharger has monitored groundwater levels since June 1994. However,the historic data quality is poor and therefore the data are not reliable. In the year 2001, the existing monitoring wells were resurveyed and Well W-4 was installed at the 17.6 acre land application area. Wells L-1, L-2, and L-3 were installed in the 16.0 acre land application area. Monthly monitoring of all these wells was conducted from May 2001 to February 2002.