title: Recovery of nitrification in cadmium-inhibited activated sludge system by bio-accelerators.
abstract: Cadmium (Cd) is toxic to nitrifying bacteria, but current studies on recovery process in Cd-inhibited activated sludge system are limited, especially on intensify-recovery processes with developing and optimizing nontoxic bio-accelerators. In this study, bioactivity recovery effects were demonstrated with respect to effluent NH4(+)-N, NO2(-)-N, NO3(-)-N concentrations, specific oxygen uptake rates and cadmium distribution in five parallel SBRs. Results indicated that bioactivity of nitrifying bacteria was mainly inhibited by surface-bound Cd. Dosing biotin, l-aspartic acid and cytokinin simultaneously was the most effective. Linear chain, together with amide (NH) and carboxyl (COOH) groups, may be important factors in fast nitrification recovery process. In terms of dosage and dosing mode, six-multiple dosage of optimal mixture with dosing at each cycle evenly was the most effective and bioactivities of nitrifying bacteria could 100% recovered within 7days. The bio-accelerators and optimum usage can be potentially applied to cope with heavy metal shock-loading emergency situations.
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; Tianjin Engineering Center of Urban River Eco-Purification Technology, Tianjin 300072, China.
authors.forename: Min
authors.initials: M
authors.lastname: Ji
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; Tianjin Engineering Center of Urban River Eco-Purification Technology, Tianjin 300072, China. Electronic address: yingxinzhao@tju.edu.cn.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China; Tianjin Engineering Center of Urban River Eco-Purification Technology, Tianjin 300072, China.
authors.forename: Hongyan
authors.initials: H
authors.lastname: Zhai
mesh_terms: D000327:Adsorption; D001419:Bacteria / Q000187:drug effects / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D002104:Cadmium / Q000302:isolation & purification / Q000633:toxicity*; D058465:Nitrification / Q000187:drug effects*; D010100:Oxygen / Q000032:analysis; D012722:Sewage / Q000382:microbiology*
chemical_list: D012722:Sewage; D002104:Cadmium; D010100:Oxygen
keywords: Activated sludge; Bio-accelerator; Cadmium inhibition; Nitrification; Recovery