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Fcn)tn� <br /> MOUND SYSTEM DESIGN CRITERIA. The design of the pressurized mound disposal system for the project isbased upon <br /> or efficient operation, disposal field longe ' d environmental protection. An overview <br /> ystem operation is as follows: Influent w to from e Church Building will gravity through a <br /> six-inch_. S tightline into a single compartin t 2,000 septic tank. Kitchen w from <br /> shwashing o solid food wastes) will gravity to a , 0 ga on, three compartm t grease <br /> interceptor t . Kitchen effluent from this tank it into the east side of the ngle <br /> comp ie septic tank. Effluent from this 2,000 gallon tank will then gravity into the first <br /> co ent of a two compartment, 1,200 gallon septic tank. The second compartment of this tank / <br /> will be the pump, or dose chamber. This chamber will have a Filtered Pump Vault(FPV), and an <br /> alternating duplex pump system to pump the effluent north to the mound system and pressurize the <br /> effluent through the moon m for disposal, as d on the Site Plans. As referenced below, <br /> the mound system is to b 30 ft ide north-south d 85 ft ng east-west. <br /> A. SEPTIC TANK, GREASE INTERCEPTOR TANK AND DOSING CHAMBER <br /> Septic tanks store the accumulated sludge, scum and effluent (clear zone) volumes, which in tum <br /> affect treatment of nitrogen within the tanks. Although there are differing methods to size septic <br /> tanks for a project, tank capacity based on pump-out interval and average daily flow will be used: <br /> For a pump out interval of every 5 years, tank volume V=3.65 Q„,x Peaking Factor. The peaking <br /> factor is typically taken to be 2.5 for commercial projects based on a"peak day” since it is assumed <br /> the majority of flow will occur on Sunday's and Wednesday's. Additionally, to operate as a plug <br /> flow reactor,the volumetric septic tank capacity should be approximately 5x the ADF: 5 x 375 = <br /> 1,875 gallons. Therefore, sufficient septic tank capacity exists. There must be an effluent filter <br /> (FPV) in the second compartment of the 1,200 gallon pump chamber tank. The first compartment of <br /> this 1,200 gallon tank is to trap and settle any solids that may flow from the single compartment <br /> 2,000 gallon tank. It is a possibility that all three tanks may have to have anti-flotation (straps and <br /> deadmen) attachments due to the high groundwater. When the tanks are pumped, only one-third of <br /> the tank contents should be pumped to retain ballast. <br /> Septic Tank Capacity Based on Potential Pump-out Interval of Five Years: <br /> 3.65(pump-out interval factor) (QAVE)x Peaking Factor(PF=2.5)=3.65 (375 gals/day)x 2.5 =3,500 gals. <br /> Total septic tank capacity=2,000+2,000+ 1,200 gallon tank=5,200 gallon. <br /> Detention Time: <br /> Detention Time=5,200 gal total tank capacity x 0.70 (30%volume lost to sludge/scum accumulationl <br /> 2.5 (Peaking factor)x 375 gals/day(ADF) <br /> Detention Time= 3.9 days.The minimum acceptable detention time is 1.0 day. <br /> 15 <br /> Chesney Consulting <br />