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Values and Assumptions I= 1,126 gals/wk x 52 wks/yr=58,552 gals=total WW/yr= 7,828 cu ft = 0.70 in. 3.09 Ac x 43,560 sq ft/Ac x(1 ft/12 in.) Nw = mg N/L=60.1 TKN. d = Assume 15%due to the sandy loam nature of the native soil and therefore medium denitrification potential. R = 11 in/yr. Nb= Assumed to be 0.1 ppm NO3-N. 0.70 in/yr(60.1 me.N/L)_G - .15)+(11 in/yr x 0.1 m /g_L) Nr = (0.70 in/yr+ 11 in/yr) Nr = 3.1 ppm as nitrate-nitrogen(NO3 N)or 13.9 ppm as nitrate(NO,) The maximum calculated nitrate loading concentration in the recharge effluent from the Church is determined to be slightly less than one-third of the Maximum Contaminant Level(MCL)for nitrate. IV. SEPTIC SYSTEM DESIGN CRITERIA SSS§3.7. The design of the filter bed disposal system for this project is based upon criteria for efficient operation, disposal field longevity, and environmental protection. An overview of the system operation is as follows: Influent waste from the new Church Building will gravity through a four-inch tightline into a new, two compartment 3,500 gallon septic .-As- ferenced below,the filter bed system is to be 65 ft east-west and 32 ft north-south, for a total are of 2,080 sqI A. SEPTIC TANK Septic tanks store the accumulated sludge, scum and effluent(clear zone)volumes, which in turn affect the treatment of nitrogen within the tanks. There are different methods to size septic tank capacity based on pump-out intervals and average daily or weekly flows,which will be used for this project. Septic Tank Sizing Verification for the proposed 3,500 Gallon Tank to Serve the Church: For a pump out interval of every 3 years,tank volume V=2.8 Q.x Peaking Factor. The peaking factor is typically taken to be 1.5 for commercial projects based on a"peak day" since it is assumed the majority of flow will occur on Sundays. Septic Tank Capacity Based on Potential Pump-out Interval: V=2.8(pump-out interval factor for 3 yrs.)x 826 gals(Sunday QAVE)x Peaking Factor(PF=1.5)=3,469 gals. Therefore, a 3,500 gal tank is sufficient based upon this calculation. Detention Time: =3,500 gal total tank capacity x 0.7(30%volume lost to sludge/scum accumulation) 1.5 (Peaking factor)x 826 gals/day(Max Flow on Sundays) =2.0 days. The minimum acceptable detention time is 1.0 day. Again,the 3,500 gal tank is sufficient. 9