A kinetic study of a combined anaerobic-aerobic system for treatment of domestic sewage

Monod, zero and first order kinetic models have been used to represent the biodegradation of domestic sewage in a combined treatment system. This cons isted of one UASB reactor, 750 1 working volume, followed by two serial RBC reactors, each having a working volume of 551. First order model is the on ly one that adequately represents biodegradation in both aerobic and anaero bic parts of the system. In anaerobic unit the first order kinetic constant is 0.31 h(-1) in summer temperatures (around 19 degrees C) and 0.20 h(-1) in winter temperatures (around 12.5 degrees C). In aerobic units the values are higher (around 2.0 h(-1)), using, in all these cases, BOD units for su bstrate concentration (C) 1999 Elsevier Science Ltd. All rights reserved.