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rthe . SEPTIC SYSTEM OPERATIONAL PARAMETERS AND COMPONENTS SS 7 The design of the future pressurized filter bed septic system for the facility are based upon f s of efficient operation, disposal field longevity, and environmental protection. An overview f the septic system eration is as follows: Influent wastes from all 22 res will come into two separate 2,000 gallon, single compartment, lift stations. The west liffstationhandle influent from the 10 restrooms located in Building"D." The east lift station will handle the�l-�i�gstrooms from Building"C" and two restrooms located in existing Building`B," for a total of 12 Mtrooms. Each left station will contain a duplex pump system enclosed in a filter vault that will pump the effluent to the first of three- 2,000 gallon septic tanks adjacent to the south of the filter bed disposal area. The first septic tank receiving pumped effluent from the lift stations will be a dual compartment, 2,000 gallon tank with the front compartment taking the energy out of the pumped effluent. Effluent will then gravity flow to a second, single compartment, 2,000 gallon tank. The effluent will continue to gravity to the third 2,000 gallon, dual compartment tank. The second compartment of this tank will be the pump chamber used to pressurize the effluent for disposal to a two filter be These three tanks will provide significant quiescent travel distance of approximately the-of - 2,000 gallon tanks for additional treatment to occur. Pressurization of the effluent will be accomplished through a _- duplex pump system that will alternate pumping between the two filter beds. The filter bed arrangement will consist of Infiltrator® Chambers with the pressure lateral secured at the tops of the chambers. Effluent will spray to the top of the Chambers and trickle down the sidewalls to the soil- effluent interface. Six-inch louvers are located on each side of the Chambers to allow oxygen diffusion and potential effluent uptake by root structures that may extend to this depth. SEPTIC TANKS Septic tanks store the accumulated sludge, scum and effluent(clear zone) volumes,which in turn affect treatment of nitrogen within the tanks. Typically,the volumetric capacity of septic tanks serving commercial facilities should be equal to approximately 5 rimes the average daily flow (ADF or QAvE). In the following calculation, the pump-out interval factor times the QAVE time the peaking factor(PF) correlate the pump-out time interval in years with the recommended tank capacity. The peaking factor value for this project is estimated to be 2.5. Septic Tank Capacity Based on Pump-out Interval of One Year: Recommended tank capacity for a potential pump-out interval of one year after complete build-out: 1.6(pump-out interval factor)(QAVE)x Peaking Factor(PF=2.5) = 1.6 (2,108 gals/day) x 2.5 = 8,400 gals. Total septic tank capacity= five- 2,000 gallon tanks= 10,000 gallons. Detention Time: Detention Time= 10,000 gal total tank capacity x 0.70 (30%volume lost to sludge/scum accumulation) 2.5 (Peaking factor)x 2,108 gals/day(ADF) Detention Time = 1.3 days. The minimum acceptable detention time is 1.0 day. 15 Chesney Consulting