Phosphorus removal in an enhanced biological phosphorus removal process: roles of extracellular polymeric substances.
Phosphorus-accumulating organisms are considered to be the key microorganisms in the enhanced biological phosphorus removal (EBPR) process. A large amount of phosphorus is found in the extracellular polymeric substances (EPS) matrix of these microorganisms. However, the roles of EPS in phosphorus removal have not been fully understood. In this study, the phosphorus in the EBPR sludge was fractionated and further analyzed using quantitative (31)P nuclear magnetic resonance spectroscopy. The amounts and forms of phosphorus in EPS as well as their changes in an anaerobic-aerobic process were also investigated. EPS could act as a reservoir for phosphorus in the anaerobic-aerobic process. About 5-9% of phosphorus in sludge was reserved in the EPS at the end of the aerobic phase and might further contribute to the phosphorus removal. The chain length of the intracellular long-chain polyphosphate (polyP) decreased in the anaerobic phase and then recovered under aerobic conditions. However, the polyP in the EPS had a much shorter chain length than the intracellular polyP in the whole cycle. The migration and transformation of various forms of phosphorus among microbial cells, EPS, and bulk liquid were also explored. On the basis of these results, a model with a consideration of the roles of EPS was proposed, which is beneficial to elucidate the mechanism of phosphorus removal in the EBPR system.
Department of Chemistry, University of Science and Technology of China , Hefei, Anhui 230026, People's Republic of China.
Hai-Ling
HL
Zhang
Wei
W
Fang
Yong-Peng
YP
Wang
Guo-Ping
GP
Sheng
Raymond J
RJ
Zeng
Wen-Wei
WW
Li
Han-Qing
HQ
Yu
D000332:Aerobiosis / Q000187:drug effects; D000693:Anaerobiosis / Q000187:drug effects; D001673:Biodegradation, Environmental / Q000187:drug effects; D005591:Chemical Fractionation; D005110:Extracellular Space / Q000737:chemistry*; D005232:Fatty Acids, Volatile / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D008954:Models, Biological; D010758:Phosphorus / Q000302:isolation & purification*; D011108:Polymers / Q000494:pharmacology*; D025341:Principal Component Analysis; D012722:Sewage / Q000032:analysis; D013997:Time Factors
D005232:Fatty Acids, Volatile; D011108:Polymers; D012722:Sewage; D010758:Phosphorus