Enhanced biological phosphorus removal from wastewater by biomass with different phosphorus contents, Part I: Experimental results and comparison with metabolic models.

Enhanced biological phosphorus removal (EBPR) in waste-water treatment involves at least two types of bacterial metabolism: a polyphosphate-accumulating metabolism (PAM) and a glycogen-accumulating metabolism (GAM). Laboratory-scale sequencing batch reactors operated in an anaerobic-aerobic cycle confirmed that low influent phosphorus/chemical oxygen demand (COD) ratio feed favored a GAM-dominated culture and high influent phosphorus/COD ratio feed favored a PAM-dominated culture, as indicated by changes in phosphorus, acetate, glycogen, and polyhydroxyalkanoate (PHA) concentrations during the anaerobic phase. Differential PAM and GAM dominance may explain variance in anaerobic phosphorus release, glycogen degradation, and PHA synthesis per acetate uptake ratios previously reported in EBPR systems and proposed metabolic models. The measurement of the ratios of anaerobic phosphorus release to acetate uptake and glycogen degradation to acetate uptake is suggested as an assay to estimate the relative dominance of PAM and GAM, respectively, in EBPR cultures.