title: Altered carbon flow by polyphosphate-accumulating organisms during enhanced biological phosphorus removal.
abstract: The effect of carbon source availability during enhanced biological phosphorus removal (EBPR) was evaluated. To assess the EBPR activity of polyphosphate-accumulating organisms (PAOs), PAO-enriched sludge from a laboratory-scale sequencing batch reactor and activated sludge from a full-scale municipal wastewater treatment plant were used, and their EBRP performances were compared. Spiking with acetate (1000 mg/L chemical oxygen demand) during the aerobic phase disrupted the EBPR performance of both types of sludge; however, when the carbon source was removed, still in the aerobic phase, the EBPR performance of both types of sludge was restored. The PAO-enriched sludge showed 3 to 5 times greater glycogen restoration activity per biomass than the full-scale activated sludge. During high acetate loading in the anaerobic phase, PAOs are supposed to deplete internally stored polyphosphate, causing a "poly-phosphate limited condition". Under such a condition, unlike the full-scale activated sludge, the PAO-enriched sludge produced a higher fraction of poly-hydroxylvalerate. It was proposed that PAOs can use the glyoxylate pathway and the methymalonyl-CoA pathway through a full or partial tricarboxylic acid cycle under the anaerobic condition.
authors.affiliation: Department of Civil and Environmental Engineering, University of Wisconsin, Madison, Wisconsin 53706-1691, USA.
authors.forename: Chang Hoon
authors.initials: CH
authors.lastname: Ahn
authors.forename: Jae Kwang
authors.initials: JK
authors.lastname: Park
authors.forename: Liang-Ming
authors.initials: LM
authors.lastname: Whang