title: Enhanced biological phosphorus removal by granular sludge: from macro- to micro-scale.
abstract: In this study, phosphorus accumulating microbial granules were successfully cultivated in a sequencing batch reactor (SBR) using synthetic wastewater. The average diameter of the granules was 0.74 mm and the diameter distribution fitted well with normal distribution with a correlation coefficient of 0.989. Good performance of biological phosphorus removal (BPR) was obtained in the granular system. The average phosphorus removal efficiency was over 94.3% and the level of phosphorus in the effluent was below 0.50mg/L during 300 days of operation. Particle analysis showed that positive charged particles were formed with the release of phosphorus in the anaerobic stage. These particles served as the cores of granules and stimulate the granulation. The maturated granules had a well-formed micro-pore structure with an average pore width between 291.5 nm and 446.5 nm. The spatial distribution of phosphorus decreased gradually from the surface to the center of the granules. Smaller granules had a higher specific area, pore width and phosphorus removal activity than bigger granules.
authors.affiliation: School of Municipal and Environmental Engineering, Harbin Institute of Technology, 73 Huanghe Road, Harbin 150090, China.
authors.forename: Chang-Yong
authors.initials: CY
authors.lastname: Wu
authors.forename: Yong-Zhen
authors.initials: YZ
authors.lastname: Peng
authors.forename: Shu-Ying
authors.initials: SY
authors.lastname: Wang
authors.forename: Yong
authors.initials: Y
authors.lastname: Ma
mesh_terms: D001673:Biodegradation, Environmental; D019149:Bioreactors; D002118:Calcium / Q000032:analysis; D002244:Carbon / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008274:Magnesium / Q000032:analysis; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen / Q000032:analysis; D010316:Particle Size; D010758:Phosphorus / Q000302:isolation & purification*; D016062:Porosity; D012722:Sewage / Q000382:microbiology*; D013499:Surface Properties; D013997:Time Factors; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D010758:Phosphorus; D002244:Carbon; D008274:Magnesium; D009584:Nitrogen; D002118:Calcium