title: Variations in toxicity of semi-coking wastewater treatment processes and their toxicity prediction.
abstract: Chemical analyses and bioassays using Vibrio fischeri and Daphnia magna were conducted to evaluate comprehensively the variation of biotoxicity caused by contaminants in wastewater from a semi-coking wastewater treatment plant (WWTP). Pretreatment units (including an oil-water separator, a phenols extraction tower, an ammonia stripping tower, and a regulation tank) followed by treatment units (including anaerobic-oxic treatment units, coagulation-sedimentation treatment units, and an active carbon adsorption column) were employed in the semi-coking WWTP. Five benzenes, 11 phenols, and five polycyclic aromatic hydrocarbons (PAHs) were investigated as the dominant contaminants in semi-coking wastewater. Because of residual extractant, the phenols extraction process increased acute toxicity to V. fischeri and immobilization and lethal toxicity to D. magna. The acute toxicity of pretreated wastewater to V. fischeri was still higher than that of raw semi-coking wastewater, even though 90.0% of benzenes, 94.8% of phenols, and 81.0% of PAHs were removed. After wastewater pretreatment, phenols and PAHs were mainly removed by anaerobic-oxic and coagulation-sedimentation treatment processes respectively, and a subsequent active carbon adsorption process further reduced the concentrations of all target chemicals to below detection limits. An effective biotoxicity reduction was found during the coagulation-sedimentation and active carbon adsorption treatment processes. The concentration addition model can be applied for toxicity prediction of wastewater from the semi-coking WWTP. The deviation between the measured and predicted toxicity results may result from the effects of compounds not detectable by instrumental analyses, the synergistic effect of detected contaminants, or possible transformation products.
authors.affiliation: Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Environmental Engineering, Shaanxi Province, China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, China. Electronic address: maxiaoyan@xauat.edu.cn.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Ma
authors.affiliation: Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Environmental Engineering, Shaanxi Province, China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, China. Electronic address: xcwang45@hotmail.com.
authors.forename: Xiaochang
authors.initials: X
authors.lastname: Wang
authors.affiliation: Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Environmental Engineering, Shaanxi Province, China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Environmental Engineering, Shaanxi Province, China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Gao
authors.affiliation: Xi'an University of Architecture and Technology, Xi'an 710055, China; Key Lab of Environmental Engineering, Shaanxi Province, China; Engineering Technology Research Center for Wastewater Treatment and Reuse, Shaanxi Province, China; Key Lab of Northwest Water Resource, Environment and Ecology, MOE, China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, China.
authors.forename: Yongkun
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D048908:Aliivibrio fischeri / Q000187:drug effects*; D000818:Animals; D001555:Benzene Derivatives / Q000032:analysis / Q000633:toxicity; D001681:Biological Assay; D003077:Coke; D003621:Daphnia / Q000187:drug effects*; D010636:Phenols / Q000032:analysis / Q000633:toxicity; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis / Q000633:toxicity; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000737:chemistry / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D018508:Water Purification / Q000379:methods*
chemical_list: D001555:Benzene Derivatives; D003077:Coke; D010636:Phenols; D011084:Polycyclic Aromatic Hydrocarbons; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Bioluminescence inhibition assay; Biotoxicity; Immobilization and lethal assay; Semi-coking wastewater; Toxicity prediction