title: Integrated fixed-biofilm activated sludge reactor as a powerful tool to enrich anammox biofilm and granular sludge.
abstract: A pilot-scale activated sludge bioreactor was filled with immobile carrier to treat high ammonium wastewater. Autotrophic nitrogen elimination occurred rapidly by inoculating nitrifying activated sludge and anammox biofilm. As the ammonium loading rate increased, nitrogen removal rate of 1.2kgNm(-3)d(-1) was obtained with the removal efficiency of 80%. Activated sludge diameter distribution profiles presented two peak values, indicating simultaneous existence of flocculent and granular sludge. Red granular sludge was observed in the reactor. Furthermore, the results of morphological and molecular analysis showed that the characteristics of granular sludge were similar to that of biofilm, while much different from the flocculent sludge. It was assumed granular sludge was formed through the continuous growth and detachment of anammox biofilm. The mechanism of granular sludge formation was discussed and the procedure model was proposed. According to the experimental results, the integrated fixed-biofilm activated sludge reactor provided an alternative to nitrogen removal based on anammox.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China. Electronic address: zhangliang_1986@126.com.
authors.forename: Liang
authors.initials: L
authors.lastname: Zhang
authors.affiliation: School of Civil Engineering, Beijing JiaoTong University, Beijing 100122, China.
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Liu
authors.affiliation: Beijing Drainage Group Co. Ltd (BDG), Beijing 100022, China.
authors.forename: Shujun
authors.initials: S
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
authors.forename: Yandong
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China; Key Laboratory of Beijing Water Quality Science and Water Environment Recovery Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: pyz@bjut.edu.cn.
authors.forename: Yongzhen
authors.initials: Y
authors.lastname: Peng
mesh_terms: D064751:Ammonium Compounds / Q000032:analysis / Q000378:metabolism*; D018441:Biofilms; D019149:Bioreactors; D005427:Flocculation; D058465:Nitrification; D009584:Nitrogen; D012722:Sewage; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D064751:Ammonium Compounds; D009584:Nitrogen; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Anammox; Biofilm; Granular sludge; Nitritation; Nitrogen removal