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TABLE 2 PERCOLATION TEST RESULTS WITH CORRESPONDING SOIL TYPE, PERCOLATION RATE AND APPLICATION RATE IN GALLONS / FT2 / DAY PERC TEST #1: 36" DEEP - SANDY LOAM 35.7 min/inch / 0.467 gallons/ft/day PERC TEST #2: 4.2 FT DEEP - SILT LOAM 8.3 min/inch / 0.800 gallons/ft2/day PERC TEST #3: 7.5 FT DEEP SILT LOAM 83.3 min/inch / 0.123 gallons/112/day GROUNDWATER' INFORMATION The 1983 and 1999 Lines of Equal Depth indicate the depth to groundwater was approximately 10 ft below grade. These two years are considered years of the heaviest rainfall. Consequently, the EHD utilizes this information when groundwater levels were considered to be at their highest recorded levels. From the Lines of Equal Elevation maps published by the County, the groundwater appears to flow in an easterly direction. ONSITE WASTEWATER TREATMENT SYSTEM (OWTS): DESIGN AND OPERATIONAL PARAMETERS It is my professional engineering opinion that the MicroSepTec treatment system can operate successfully with the proposed upgrades, and treat the wastewater emanating from the Chevron Service Station Complex to acceptable levels as promulgated by the State Water Resources Control Board. The effluent limitations for OWTSs include 90 ppm (mg/L) for Biochemical Oxidation Demand (BOD) and 90 ppm for Total Suspended Solids (TSS), and 10 ppm for Total Nitrogen (TN). Wastewater flow volume from the Complex is approximately 2,775 gpd (Appendix B). The attached onsite wastewater treatment system Design Plans illustrate the complete system upgrades. By substantially increasing the trash/surge (T/S) tank to 10k gallon size, this will allow much greater retention of primarily trash and organic matter. Effluent from the second compartment of this tank will gravity to a 1.2k gallon, two compartment pump chamber tank. The front compartment of this tank will provide additional particulate matter separation before flowing into the second compartment. The second compartment will house an Orenco BioTube Pump Vault with a high-head duplex pump system, contributing even further particulate filtration before the effluent is distributed equally through an Orenco Automatic Distributing Valve among the three MicroSepTec EnviroServers. Effluent from the three compartment grease interceptor tank will gravity to the inlet of the 10k gallon T/S tank. From visual inspection, it was evident that the interceptor tank had not been serviced for an extended period of time. The grease interceptor is operating as intended, but there must be periodic pump-out service. Pa e - Chesney Consulting