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r Values and Assumptions:- I =308,100 izals...=.total WW/yr=41,190 cu ft=4.38 in/yr 2.59 Ac x 43,560 sq ft/Ac. x (1 ft/12 in) Nw= 31 mg NIL d = Assume 20%N'denitrifcation reduction in septic tank(Ref. 11) and assume 25% denitrification due to high fine-grained clay soil.as measured throughout soil profile (Ref. 8). R = 9.5 in/yr. Nb Assumed to be 0.1 ppm NO.-,-N 4.38 in/yr 31 m .NIL (1::-(0.20+,0.2-5))+(9.5-in/yr x -0..1_-m LL)_. Nr = (4.3 8 in/yr+9.5"in/yr) Nr 5.5 p m as-nitrate-n1trogen (NO3-N) o 24:2 pm as nitrate(NO,) IV. WASTEWATER MANAGEMENT SYSTEM - OPERATIONAL CRITERIA SSS§ 3.7. Discussions on the efficient operation of the effluent disposal method, disposal field longevity, and environmental protection are based upon the environmental parameters discussed within this report. An example of the wastewater management system to'be constructed is as follows, and is based upon discussions with EHD personnel and EHD Sewage Standards. A. SEPTIC TANK. Septic tanks store the accumulated sludge, scum and effluent (clear zone) volumes, which in turn affect treatment of Total Nitrogen (TN) within the tank. Total Nitrogen is the summation of ammonia-nitrogen (NH4) and'organic nitrogen(proteins, amino acids, enzymes). Since the septic tank is predominately anaerobic, nitrogen cannot exist in its oxidized state as nitrate within the septic effluent for any length of time. Nitrate is quickly reduced to NO or NO2. If nitrate existed in. the tank effluent,.this would also be added-to ammonium and organic nitrogen to arrive at Total Nitrogen. The following calculation illustrates that a 2,000 gallon septic tank will be applicable for sufficient hydraulic residence time (HRT) of influent within the septic tank.- This tank size will promote nitrogen decomposition due to the increased-HRT."Additionally,a septic tank effluent filter must be installed on the outlet tee of the tank. Detention Time Example: Detention Time=2,000 gal totaE tank capacity x 0.95.(5%volume lost to anticipated very low volume of sludge/scum accumulation) . 2.0(Weekly Peaking factor) x 1,035 gals/day(Highest ADF on Sundays) Detention Time= 1.0 days--.-The minimum acceptable detention time is 1.0 day. Therefore, a 2,000 gallon septic tank is suitable for-sufficient detention time and will allow for greater nitrogen decomposition. 14 Chesney Consulting