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VFW INFORMATION SHEET ORDER NO. R5-2003-0099 NEWPORT PACIFIC CAPITAL COMPANY ARBOR MOBILE HOME PARK WASTEWATER TREATMENT FACILTY SAN JOAQUIN COUNTY Introduction Arbor Mobile Home Park(MHP)is at 19690 N. Highway 99 Acampo. Wastewater originates from residential sources consisting of 173 mobile homes, the nearby Arbor Storage Complex, and a clubhouse. The MHP is completely occupied, therefore wastewater flow rates are anticipated to remain stable in the future. The present discharge flow rate is approximately 45,000 gallons per day. Wastewater System Raw sewage is collected in the collection system and conveyed by gravity to the wastewater treatment plant. The Arbor MHP wastewater treatment plant is an activated sludge package plant. Wastewater is discharged from the package plant to polishing tanks then is disposed of in seepage pits or gravelless leachfields. There are a total of 60 seepage pits and one gravelless leachfield area. Seepage pits and the leachfield are rotated between resting and in-service on a regular basis. Wasted sludge is discharged to the sludge storage tank where it is aerobically digested. The digested sludge is hauled to the City of Lodi regional wastewater treatment system as needed. The seepage pits are 60-inches in diameter and 25-feet deep with a perforated PVC pipe positioned in the center of each well. The pipe is positioned in the center of each well with crushed rock packed around the pipe and on the bottom of the well. The unsaturated zone between the bottom of each well and the shallowest reported groundwater level is approximately 25 feet. The Discharger has experienced failure in the disposal area due to high concentrations of suspended solids in the effluent, which resulted in reduced permeability and reduced infiltration. In response to the failure, the Discharger has improved operation of the system to reduce the concentration of suspended solids in the effluent. This Order requires the Discharger to prepare an Operation and Maintenance Plan, an Effluent Collection System Plan, a Groundwater Well Installation Workplan, a Groundwater Well Installation Report, and a Groundwater Quality Study Report. Effluent Limitations Effluent limitations are included in the WDRs. The limits address total dissolved solids (TDS), total suspended solids (TSS), and biochemical oxygen demand (BOD). The limits were included to allow the Discharger to continue operation of the wastewater treatment system while groundwater quality data is collected. The effluent limits were selected based on the treated wastewater concentrations. Total Dissolved Solids The TDS limitation is based on TDS concentrations in the water supply and treated wastewater. The use of the water by residents results in a TDS concentration increase of approximately 125 mg/L. The limit was set at 400 mg/L (monthly average) and 600 mg/L (daily maximum)based on two sample