Abstract
Microorganisms that get dominant in the anaerobic-aerobic activated sludge process are known to take up organic substrates under anaerobic conditions. Two types of microoganisms are known to have this ability; one of them utilizes polyphosphate as the energy source under the anaerobic conditions, and another utilizes glycogen instead of polyphosphate. We conducted batch experiments on the anaerobic substrate by two types of anaerobic-aerobic activated sludges, one of them dominated by the polyphosphate dependent microorganisms, and another by the glycogen dependent microorganisms. The anaerobic uptake of acetate, propionate, lactate, pyruvate, malate, succinate, and glucose were examined. And the redox balance and the material balance in the anaerobic substrate uptake were calculated, based on a biochemical model which includes the glycolytic pathway, succinate fermentation pathway, and PHA synthetic pathway. The result showed that both the polyphosphate dependent and glycogen dependent microorganisms take up organic compounds basically in the same way, except for the source of energy for the anaerobic substrate uptake. In order to control the enhanced biological phosphorus process with the anaerobic-aerobic operation, intensive study is needed to understand the interaction between the polyphosphate dependent and glycogen dependent microorganisms.
