1990 Volume 36 Issue 2 Pages 153-157
In order to make no biochemical oxygen demand (BOD) loading influent was changed from synthetic wastewater to tap water, and the activated sludge was cultured for 18 d. The relationship between the state of activated sludge and the time course pattern of nitrite nitrogen contents in anaerobically treated activated sludge (NO2-N pattern) was investigated. Concentration of activated sludge decreased with culture time. Effluent chemical oxygen demand (COD) increased gradually. Effluent BOD increased later than effluent COD. At the 14-18th day, sludge volume index, BOD and COD showed high levels, and the state of activated sludge was confirmed to be abnormal. The NO2-N patterns were type A at the 0-10th day, and patterns of type A changed according to the changes of the state of activated sludge. At the 14-18th day, when the state became abnormal, the NO2-N patterns changed to like type D. Thus, under no BOD loading, it also appears that the NO2-N pattern could be a useful index for the evaluation of the state of activated sludge.
