The influence of anaerobic reaction time on the fraction of denitrifying phosphate accumulating organism in BNR precesses

This study investigated the influence of anaerobic reaction time on the fra ction of denitrifying phosphate accumulating organisms (DNPAO) to total pho sphate accumulating organisms (PAOs) using a series of batch experiments. T he results showed that the DNPAO increased as the anaerobic reaction time i ncreased. This implied that the PHA (poly hydroxyalkanoates) accumulating r ate of DNPAO was lower than that of non-denitrifying phosphate accumulating organisms (nonDNPAO). Thus, the DNPAO required a longer anaerobic reaction time to reach the saturated intracellular PHA level. Furthermore, more tha n two hours of anaerobic hydraulic retention time is necessary when designi ng an enhanced DNPAO process.