Activated sludge systems operated for enhanced biological phosphorus removal (EBPR) are particularly sensitive to dynamic loading conditions. Increases in effluent phosphorus are often reported immediately after low loading conditions, such as weekends or rain events. Mathematical models
for EBPR can be used to predict a system's response to low loading conditions. However, it is not clear to what extent do existing EBPR models represent the endogenous processes that dominate during low loading and/or starvation conditions. The purpose of this study is to evaluate
the endogenous processes during aerobic starvation and determine whether current EBPR models are able to predict the response of an EBPR system to aerobic starvation. Activated sludge from a laboratory EBPR system was used to perform batch experiments. Phosphorus release and storage product
utilization were monitored during aerobic starvation. Based on the observed results, we hypothesized that PAO preferentially use polyhydroxyalkanoates, then glycogen, and then polyphosphate during starvation. The Activated Sludge Model No. 2 and EAWAG models over predicted phosphorus release
during aerobic starvation. Modifications to the EAWAG model were proposed to accurately describe the observed transformations of polyphosphate and glycogen. The modified model was in close agreement with the phosphorus release and glycogen oxidation observed during starvation. It is expected
that the modified model can better predict the performance of systems exposed to low loading conditions, but further research is needed to further validate the proposed model modifications.
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.