Effect of Alternating Aerobic and Anaerobic Conditions on the Economics of the Activated Sludge System

Results of our trials demonstrate that the alternating aerobic/anaerobic activated sludge (AAA-CMAS) system is capable of producing effluent of high quality in either fully-loaded or under-loaded conditions. The aeration energy saving and the sludge reduction of the AAA-CMAS system was shown to be of the order of 30% and 15% respectively. Because denitrification process is taking place within the reactor under controlled conditions and not in the sedimentation tank where degree of denitrification cannot be controlled, effluent of the AAA-CMAS system was found to contain much less suspended solids and E. coli counts than that of the conventional system, resulting in further cost saving in chlorination and in back-washing of the filter.