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Technical Description MLVSS is a good approximation of microorganism concentrations in the MLSS. Data obtained are calculated using a moving seven-day average. Equation 4 predicts that 2.5 moles of oxygen are required to convert one mole of ammonium into 2 moles of nitrate ions for new biomass and water. This is equivalent to 4.2 mg/L of 02 per mg/L of NH4—N converted to new cells and nitrate. Therefore, 02 x Q = 0 (502 + 2N114 2NO3 +41120) (5) where 02 = 4.2 mg/L Q = NH4 o = N05 + H20 (N-3 + CO2 + NO3 + PO4+3 + SD4-2 +H4) The overall equation predicts that 1.98 moles of H are produced per mole of ammonium con- verted, or 7.14 mg of alkalinity as CA CO3 is destroyed per mg of NH4—N converted. The equa- tion also predicts that 0.17 mg of cells is produced per mg of NH4—N converted. The first two parameters (oxygen requirement and alkalinity destruction) are important in the de- sign detention of any hybrid, heterotrophic/autotrophic treatment system. Oxygen is essential for the growth of nitrifiers, and alkalinity consumption is important because nitrifying organisms are efficient only over a relatively narrow pH range. The third parameter, biomass production, is important to the understanding of microbial population dynamics. The low cell production frequently causes washout of nitrifiers in combined carbon-nitrogen oxi- dation systems without high sludge age. The Bio-Pure batch process assures that washout is less likely to occur than in a conventional flowthrough system or process due to the design of the hy- draulic control. Compared to heterotrophic oxidation of carbonaceous waste material, nitrification generates rela- tively little biomass. Therefore, additional solids capacity for nitrogenous processing beyond those allocations given for the heterotrophic process is not required. (NOTE: By increasing detention time from 14 to 16 hours, the process begins to run out the right side of the growth curve. This additional detention time utilizes 02 demand for further conversion of NH4 to NO3.) Samples of MLSS are pulled from the ML entering the clarifier. Formula: F:M = Influent BOD, lbs/day (6) Solids in aeration lbs/day Example: Calculate the F:M. Assumptions: Q = 0.075 MGD Aeration tank volume, V = 0.050 MGD BOD5 = 125 mg/L MLVSS = = Influent BOD 5 1600 mg/L 12 1./ /.