title: [Aerobic granular sludge bulking due to the lack of nutrient and its recovery].
abstract: Under 5 m(COD)/m(N)/m(P) ratios, the shape, settle ability and organic removal performance of aerobic granules were investigated in 5 identical SBRs. The performance of aerobic granules bulking and its recovery methods were also analysed based on SVI30 value. The results indicated that when m(COD)/m(N)/m(P) was 100/5.8/1.2, the granules had integral and dense structures with the SVI30 of 15 - 30 mL x g(-1) and COD removal of above 90%. The system operated stably without any bulking. When m (COD)/m(N)/m(P) was 100/3/0.6 and 100/1.9/0.4, although the granules disintegration was observed, SVI30 was lower than 35 mLx g(-1) and the granules had no bulking, and high COD removal was keeping at above 85%. When m(COD)/m (N)/m(P) was 100/ 0.5/0.1 and 100/0/0, the SVI30 in both systems reached 150 mL x g(-1), and the granules was hard to settle due to sludge bulking in both systems. There is a significant difference of COD removal rate in two systems. The former COD removal rate stayed at 65% -80% in late experiment, while the latter COD removal was quite low during the early operation and finally reduced to about 10% until the system broke down. Aerobic granule bulking due to the lack of N and P could be recovered by adding sufficient nutrient to the systems. After 48 cycles' operation, granules settle ability and organic removal were fully recovered, however there was no obvious recovery on granules morphology except for the color.
authors.affiliation: School of Forestry, Northeast Forestry University, Harbin 150040, China.
authors.forename: Zhu
authors.initials: Z
authors.lastname: Zhang
authors.forename: Da-Wen
authors.initials: DW
authors.lastname: Gao
authors.forename: Xiang-Juan
authors.initials: XJ
authors.lastname: Yuan
authors.forename: Qian-Qian
authors.initials: QQ
authors.lastname: Gou
mesh_terms: D000332:Aerobiosis; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry; D009584:Nitrogen / Q000737:chemistry; D009930:Organic Chemicals / Q000302:isolation & purification*; D010758:Phosphorus / Q000737:chemistry; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D009930:Organic Chemicals; D012722:Sewage; D010758:Phosphorus; D002244:Carbon; D009584:Nitrogen