Determination of ultimate carbonaceous BOD and the specific rate constant (K1)

Ultimate carbonaceous biochemical oxygen demand (BODu) and the specific rate constant (K1) at which the demand is exerted are important parameters in designing biological wastewater treatment plants and in assessing the impact of wastewater on receiving streams. An analytical method is presented which uses time-series concentrations of BOD, defined as the calculated sum of dissolved oxygen (DO) losses at each time of measurement, for determining BODu and K1. Time-series DO measurements are obtained from a water sample that is incubated in darkness at 20 degrees Celsius in the presence of nitrapyrin, a chemical nitrification inhibitor. Time-series concentrations of BOD that approximate first order kinetics can be analyzed graphically or mathematically to compute BODu and K1.