title: Floatation of flocculent and granular sludge in a high-loaded anammox reactor.
abstract: The floatation of flocculent and granular sludge was investigated in this study. An anaerobic ammonium oxidation (anammox) upflow anaerobic sludge blanket (UASB) reactor was operated for 665 days. During this time, the maximum nitrogen removal rate was 52.6 kg Nm(-3) d(-1). Floccule floatation occurred between days 100 and 140, which potentially resulted from the sudden increase in gas yield and the poor settling ability of the floccules. Increasing the shear rate from 0.084 to 0.135 s(-1) was effective at eliminating floccule floatation. In addition, granule floatation occurred between days 572 and 665, which likely resulted from the formation of hollows within the granules. Floatation may be effectively prevented by maintaining a shear rate of more than 0.778 s(-1). Furthermore, the mechanisms of granule floatation and the floatation processes were proposed. Overall, controlling the shear force may effectively overcome sludge floatation.
authors: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors: Hui
authors: H
authors: Chen
authors: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors: Chun
authors: C
authors: Ma
authors: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China.
authors: Guang-Feng
authors: GF
authors: Yang
authors: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
authors: Hui-Zhong
authors: HZ
authors: Wang
authors: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China.
authors: Zhi-Ming
authors: ZM
authors: Yu
authors: College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China; Key Laboratory of Hangzhou City for Ecosystem Protection and Restoration, Hangzhou Normal University, Hangzhou 310036, China. Electronic address: jrczju@yahoo.com.cn.
authors: Ren-Cun
authors: RC
authors: Jin
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D000693:Anaerobiosis; D001704:Biopolymers / Q000032:analysis; D019149:Bioreactors; D005110:Extracellular Space / Q000737:chemistry; D005427:Flocculation; D057446:Hydrodynamics; D009584:Nitrogen / Q000302:isolation & purification; D010084:Oxidation-Reduction; D010316:Particle Size; D012722:Sewage / Q000737:chemistry*
chemical_list: D064751:Ammonium Compounds; D001704:Biopolymers; D012722:Sewage; D009584:Nitrogen
keywords: Anammox; High-loaded reactor; Shear rate; Sludge floatation; Upflow anaerobic sludge blanket