title: Influence of hydraulic retention time on partial nitrification of continuous-flow aerobic granular-sludge reactor.
abstract: This study investigated the effects of hydraulic retention time (HRT) at 12 h, 7.2 h and 2.4 h on partial nitrification efficiency of continuous-flow aerobic granular reactors (CFAGRs) with mature aerobic granules (500 +/- 20mg l-1). At HRT 12 h and 7.2h, the removal efficiency of both ammonia-nitrogen (NH4+ - N) and nitrite accumulation rate were exceeding 90%. At HRT 2.4 h, NH4+ - N removal efficiency was reduced but most of the conversion efficiency to nitrite was only slightly reduced. At HRT < 2.4 h, washout of aerobic granules occurred. In all tests conducted herein, the chemical oxygen demand removal efficiencies exceeded 90%. The clone library results noted the presence of ammonia-oxidizing bacteria belonged to beta-Proteobacteria subclass, including 94% of Nitrosomonas europaea and 6% of Nitrosomonas sp. The polymerase chain reaction and denaturing gradient gel electrophoresis results suggested that Alpha proteobacterium, Pseudoxanthomonas mexicana strain, Sphaerotilus natans and Uncultured gamma proteobacterium were responsible for the aerobic granular stability and processing performance. The present CFAGR successfully implemented continuous partial nitrification using aerobic granules at low HRT.
authors: Chunli
authors: C
authors: Wan
authors: Xue
authors: X
authors: Yang
authors: Duu-Jong
authors: DJ
authors: Lee
authors: Supu
authors: S
authors: Sun
authors: Xiang
authors: X
authors: Liu
authors: Peng
authors: P
authors: Zhang
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D058645:Denaturing Gradient Gel Electrophoresis; D006863:Hydrogen-Ion Concentration; D059013:Microbial Consortia; D058465:Nitrification; D016133:Polymerase Chain Reaction; D013997:Time Factors; D018505:Waste Management
chemical_list: D064751:Ammonium Compounds