title: Characteristics of pellets with immobilized activated sludge and its performance in increasing nitrification in sequencing batch reactors at low temperatures.
abstract: Immobilized pellets obtained by means of entrapping activated sludge in waterborne polyurethane were successfully adapted in ammonium (NH4(+)-N) synthetic wastewater. Its physicochemical characteristics were determined using scanning electron microscope, pyrosequencing, and microelectrodes, and its influence on the nitrification process in sequencing batch reactors (SBRs) at low temperatures was evaluated. A large number of rod-shaped bacteria were observed on the surface of the immobilized pellet, in which Rudaea spp. (Xanthomonadaceae family) was an important bacterial component (23.44% of the total bacteria). The oxygen uptake rate of immobilized pellets reached 240.83±15.59 mgO2/(L·hr), and the oxygen was primarily consumed by the bacteria on the pellet surfaces (0-600 μm). The dosing of the pellets (30 mL/L) into an SBR significantly improved the nitrification efficiency at low temperatures of 7-11°C, achieving an average NH4(+)-N removal of 84.09%, which is higher than the removal of 67.46% observed for the control group.
authors.affiliation: College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Dong
authors.affiliation: Wenzhou Housing and Urban-Rural Development Committee, Wenzhou 325000, China.
authors.forename: Guang
authors.initials: G
authors.lastname: Lu
authors.affiliation: Wenzhou Public Utilities Investment Group Co. Ltd., Wenzhou 325000, China. Electronic address: Vangji@126.com.
authors.forename: Li
authors.initials: L
authors.lastname: Yan
authors.affiliation: Environmental Science and Engineering, Shanghai Jiaotong University, Shanghai 200240, China.
authors.forename: Zhenjia
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China.
authors.forename: Yalei
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D019149:Bioreactors / Q000382:microbiology*; D003080:Cold Temperature; D058465:Nitrification; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology
chemical_list: D012722:Sewage; D062065:Wastewater
keywords: Acclimation; Immobilization; Low temperatures; Nitrification; Sequencing batch reactor (SBR)