Study of the variation of ecotoxicity at different stages of domestic wastewater treatment using Vibrio-qinghaiensis sp.-Q67

• Published in: Journal of hazardous materials 2011-06, Vol.190 (1), p.100-105
• Main Authors: Ma, Xiaoyan Y., Wang, Xiaochang C., Liu, Yongjun J.
• Format: Article
• Language: English
• Subjects: Adsorption; Applied sciences; bacteria; bioassays; Biodegradation, Environmental; Carbon; Chemical engineering; chemical oxygen demand; chlorination; coagulation; Crack opening displacement; Domestic; Domestic wastewater; Drinking water and swimming-pool water. Desalination; Ecotoxicity; ecotoxicology; Ecotoxicology - methods; Environmental Monitoring - methods; Exact sciences and technology; General purification processes; Halogenation; Influents; luminescence; Luminescent bacterium; organic matter; oxidation; Pollution; Reduction; Regression; Sewerage works: sewers, sewage treatment plants, outfalls; Solid Phase Extraction; Solid-phase extraction (SPE); Toxicity; Vibrio - metabolism; Wastewater treatment; Wastewaters; Water Pollutants, Chemical - metabolism; Water Purification - methods; Water treatment and pollution
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2011.03.003

A bioassay using the luminescent bacterium Vibrio-qinghaiensis sp.-Q67 associated with solid-phase extraction (SPE) was developed for evaluating the variation of ecotoxicity along with the reduction of organic substances in a domestic wastewater treatment plant employing an oxidation ditch process. With effective elimination of the interference from all inorganic substances by the SPE operation, the ecotoxicity of the water, as expressed by the toxicity impact index, TII 50 (%) after a model-based regression and parameter transformation, was found to decrease from 50.51% in the influent to 25.84% after the grid chamber and then to 1.38% for the secondary effluent, but the final chlorination stage resulted in a slight TII 50 increase. Of the two typical tertiary treatment processes, coagulation could not assist further reduction of the ecotoxicity while carbon adsorption could reduce the TII 50 to as low as 0.96%. When enhanced primary treatment was conducted, the influent TII 50 could be directly reduced to 7.36%. A good correlative relationship was found between the total COD concentration and the TII 50 value at different stages of the wastewater treatment process.