title: The effect of COD loading on the granule-based enhanced biological phosphorus removal system and the recoverability.
abstract: In this study, the effect of varied COD loading (200, 400, 500, 600 and 800 mg L(-1)) on stability and recoverability of granule-based enhanced biological phosphorus removal (EBPR) system was investigated during continuously 53-d operation. Results showed that COD loading higher than 500 mg L(-1) could obviously deteriorate the granular EBPR system and result in sludge bulking with filamentous bacteria. High COD loading also changed the transformation patterns of poly-β-hydroxyalkanoates (PHAs) and glycogen in metabolism process of polyphosphate-accumulating organisms (PAOs) and inhibited the EPS secretion, which completely destroyed the stability and integrality of granules. Results of FISH indicated that glycogen-accumulating organisms (GAOs) and other microorganisms had a competitive advantage over PAOs with higher COD loading. The community composition and EBPR performance were recovered irreversibly in long time operation when COD loading was higher than 500 mg L(-1).
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
authors.forename: Shenjing
authors.initials: S
authors.lastname: Yu
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China. Electronic address: pdsun@126.com.
authors.forename: Peide
authors.initials: P
authors.lastname: Sun
authors.affiliation: Zhejiang Provincial Key Laboratory of Water Science and Technology, Yangtze Delta Region Institute of Tsinghua University, Zhejiang, Jiaxing 314016, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.affiliation: School of Environment, Tsinghua University, Beijing 100084, China.
authors.forename: Lujun
authors.initials: L
authors.lastname: Chen
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
authors.forename: Xiongliu
authors.initials: X
authors.lastname: Zheng
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
authors.forename: Jingyi
authors.initials: J
authors.lastname: Han
authors.affiliation: School of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou 310012, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Yan
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D057919:Biological Oxygen Demand Analysis; D017404:In Situ Hybridization, Fluorescence; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D010758:Phosphorus / Q000302:isolation & purification*; D011122:Polyphosphates / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D011122:Polyphosphates; D010758:Phosphorus
keywords: COD loading; Extracellular polymeric substances; Granule-based EBPR system; Metabolism process of PAOs; Recoverability