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rT7henitlrate loading calculated above using a realistic wastewater flow volume reflects a more accurate nitrate loading potential than the calculated loading above based on. 150 gallons per toilet. In addition to this calculated reduction in nitrate-nitrogen loading, it is expected that nitrate loading will be further decreased from disposal area landscaping grass. Uptake by plants will be based on the concentration calculated above. Most plants utilize only two forms of nitrogen: nitrate and ammonium (NH4). Approximately 75% of conventionally treated septic effluent is ammonium. For six months out of each year(April-September), it is theorized the landscape grass planted over the new filter bed will utilize 50% of available ammonium molecules from the septic effluent (the remaining 50% is lost to nitrification/denitrification, immobilization and leaching). The colder months of the year, the plants may synthesize 20% available nitrate. Consequently, an additional 35% (50% + 20%'—. 2 = 35%) reduction in nitrate concentrations may occur, above the anticipated wastewater treatment: 8.9 ppm nitrate-nitrogen - 35% = 5.8 ppm NO3- N or 25.8 ppm NO3 potentially entering groundwater. C. SEPTIC SYSTEM OPERATIONAL PARAMETERS AND COMPONENTS The design of a future septic system for the facility is based upon the factors of operation, longevity, and environmental protection. The San Joaquin County Environmental Health Department (EHD) has stipulated design requirements for environmental protection. This includes the following: Due to the nitrate concentration determined in the water table underlying the existing western leachfield, EHD will require that the existing, separate septic system (tank and leachfield)north of the north building (ADS Delivery) also be connected to the proposed new pressurized filter bed system. This will require that a duplex pump system be installed in this existing tank to pump the effluent over to the pump chamber (1,200 gallon tank) that is to be - installed. The inlet line must come into the pump chamber submerged in the effluent so as to not create an aeration effect. A duplex pump filter vault must be installed in this pump chamber to pressurize the new filter bed. SEPTIC TANKS Septic tanks affect the sludge, scum and effluent 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 times the average daily flow (ADF or QAVE), which will be based on 345 gals ADF calculated above for the nitrate loading . In the following equations, the numerical value times the QAvE the peaking factor(PF) correlate with the pump-out time interval in yrs. The peaking value is normally taken to be 1.5 for commercial projects: SEPTIC TANK CAPACITY.EXAMPLE: Recommended tank capacity for a pump out interval of two yrs: 2.4(QAVE) x Peaking Factor(PF) _ 2.4(1050 gals/day) x 1.5 = 3,780 gal septic tank capacity: One - 2,000 gallon tank and one 1,200 pump chamber(single compartment 1,200 gal septic tank) shall suffice. 13 _ Chesney Consulting