title: Reverse osmosis pretreatment method for toxicity assessment of domestic wastewater using Vibrio qinghaiensis sp.-Q67.
abstract: Luminescent bacterial test is a fast and sensitive method for acute toxicity assessment of water and wastewater. In this study, an improved toxicity testing method was developed using the freshwater luminescent bacteria Vibrio qinghaiensis sp.-Q67 that involved pretreatment of water samples with reverse osmosis (RO) to eliminate the interferences caused by nutrients in concentrated samples and to improve the reliability and sensitivity of the analysis. Because water samples contain low concentrations of several target toxic substances, rapid acute toxicity testing method that is commonly employed does not achieve enough sensitivity. The proposed RO pretreatment could effectively enrich organic and inorganic substances in water samples to enable a more effective and sensitive toxicity evaluation. The kinetic characteristics of toxicity of raw sewage and secondary effluent were evaluated based on the relative luminescence unit (RLU) curves and time-concentration-effect surfaces. It was observed that when the exposure time was prolonged to 8-h or longer, the bacteria reached the logarithmic growth stage. Hence, the stimulating effects of the coexisting ions (such as Na(+), K(+), NO3(-)) in the concentrated samples could be well eliminated. A 10-h exposure time in proposed Q67 test was found to quantitatively evaluate the toxicity of the organic and inorganic pollutants in the RO-concentrated samples.
authors.affiliation: Key Lab of Northwest Water Resources, Environment and Ecology, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an 710055, China.
authors.forename: Xiaoyan Y
authors.initials: XY
authors.lastname: Ma
authors.forename: Xiaochang C
authors.initials: XC
authors.lastname: Wang
authors.forename: Huu
authors.initials: H
authors.lastname: Hao Ngo
authors.forename: Wenshan
authors.initials: W
authors.lastname: Guo
authors.forename: Maoni N
authors.initials: MN
authors.lastname: Wu
authors.forename: Na
authors.initials: N
authors.lastname: Wang
mesh_terms: D001681:Biological Assay / Q000592:standards; D009995:Osmosis; D015203:Reproducibility of Results; D013997:Time Factors; D018675:Toxicity Tests / Q000379:methods*; D014733:Vibrio / Q000187:drug effects*; D062065:Wastewater / Q000633:toxicity*
chemical_list: D062065:Wastewater
keywords: Domestic wastewater; Reverse osmosis; Time-dependent toxicity; Vibrio qinghaiensis sp.-Q67