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The fust two parameters (oxygen requirement and alkalinity destruction) are important in the design detention of the hybrid, NOTES heterotrophic/autotrophic treatment system. Oxygen is essential for the growth of nitriFers, and alkalinity con- sumption 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 popula- tion dynamics. The low cell production frequently causes washout of nitrifiers in combined carbon-nitrogen oxidation systems without high sludge age. The AquaClear batch process assures that washout is less likely to occur than in a conventional flowthrough system or process due to the design of the hydraulic control. Compared to heterotrophic oxidation of carbonaceous waste mate- rial, nitrification generates relatively little biomass. Therefore, addi- tional solids capacity for nitrogenous processing beyond those alloca- tions given for the heterotrophic process is not r.;quired. The secondary process of the AquaClear batch system removes an average 94.8 percent of ammonia nitrogen. NOTE: By increasing detention time to 16 hours, the process begins to run out the right side of the growth curve This additional deten- tion time utilizes Oz demand for further conversion of NH, to NO3. Samples of MISS are pulled from the ML entering the clarifier. Formula: Influent BOD Ib/day 6 F:M = Solids in aeration Ib/day ( ) Example: Calculate the F:M. Assumptions: Q = 0.075 MGD Aeration tank volume, V = 0.050 MGD BODS = 125 mg/1 MLVSS = 1600 mg/I F = Influent BOD5 = (BODS) (Q, MGD) (8.34 lb/gal) = (125) (0.075) (834) = 78.18 lb/day M = Solids inventory in aeration tank = (MLVDD mg/1) (V,MGD) (8.34 lb/gal) = (1600) (0.50) (8.34) = 6672 lbs F:M = 78.18 BOD,/day 6672 lbs MLVSS = 0.01 lb BODS/day/lb MLVSS 15