Design Criteria for Aerobic Aerated Lagoons

Laboratory-model studies of nine completely mixed (aerobic) aerated lagoons handling domestic wastewater indicate that the traditionally accepted (linear) first-order BOD removal concept is applicable, provided that the following modification is introduced. The first-order BOD removal coefficient, K, should be corrected to take into account the fact that as detention time increases (or organic load decreases), the value of K decreases, exhibiting a retardant effect. However, there is an alternative design approach characterized by nth order (nonlinear) BOD removal kinetics, where n=1.1. The nonlinear BOD removal coefficient does not display the retardant effect. Engineers may employ any one of the two design methods and, thereby, rationally design completely mixed (aerobic) aerated lagoons.