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B. SEPTIC TANK <br /> Septic tanks store accumulated sludge, scum and effluent(clear zone)volumes, which in turn <br /> affect treatment of nitrogen within the tanks. Detention time calculations demonstrate that when <br /> I <br /> an average ADF of 100 gpd is applied to the 2,000 gallon tank,there remains ample detention <br /> time. A 2,000 gallon P&L Concrete, traffic-rated septic tank is proposed instead of a 1,200 gallon <br /> tank to mitigate nitrate loading potential. <br /> Detention Time Calculation: <br /> Detention Time=2,000 gal tank capacity x 0.70 (30%volume lost to sludge/scum accumulation) <br /> 1.5 (Peaking Factor)x 100 gals/day(ADF) <br /> Detention Time=9.3 days. The minimum acceptable detention time is 1.0 day. . <br /> C. OPERATIONS AND MAINTENANCE PLAN <br /> Under Section 1.12.1 of the SJC OWTS Standards, an engineered OWTS "shall be operated and <br /> maintained pursuant to an Operations and Maintenance Plan(OMP) compiled by the OWTS <br /> engineer." <br /> Due to the unique configuration of the effluent disposal structure, Section 7.1 of the SJC OWTS <br /> Standards applies, which states: Engineered systems are non-standard systems uniquely designed <br /> for a specific location by a Registered Civil Engineer based on site specific information. <br /> Therefore, the proposed OWTS can be considered an engineered system. <br /> Beginning with the septic tank,the tank should be inspected after two years by a qualified <br /> professional. The tank should be pumped, if needed. After three or four years of operation,the <br /> tank should be pumped. <br /> The leachlines are designed with observations ports at the west ends of the.east leachlines. These <br /> ports can act as clean-outs and to observe if effluent is flowing into the west leachline. The entire <br /> length of each leachline (primary and replacement) can be jetted if cleaning is required, since the <br /> pressure jet can reach 300 ft and the leachlines are 255 ft(including the tightline under the <br /> concrete slab). <br /> The bull run valves installed near the tightline exit of the septic tank and at the west end of the <br /> leachlines, can initially be set to leachline 1 (primary), and upon failure switched to leachline 2 <br /> (replacement). Eventually, it may be that this valve is periodically switched back and forth <br /> between the two leachlines. <br /> i <br /> Page -9- <br /> Chesney Consulting <br />