MULTIORDER APPROACH TO BOD KINETICS

Employing a reaeration technique, oxygen uptake curves were obtained for 20 samples from 8 New Jersey, U.S.A. streams. Using a stepwise nonlinear regression approach, rate constants and ultimate BOD values were calculated for equations in which the order of the reaction was assumed to be 1, 1.5, 2, 2.5, 3, 3.5 and 4. There was a tendency for the error mean square to decrease as the reaction order increased from 1 to 4. However, the reduced error was accompanied by an approximate doubling of the ultimate BOD values in going from a first to a fourth order reaction. These ultimate BOD values calculated at the higher reaction orders are in all probability unrealistically high. © 1979.