摘要:
腈纶废水毒性较强且难以去除,对腈纶废水毒性及污水处理过程毒性削减能力进行评价,可为开发该类废水毒性减排技术提供科学依据。利用大型蚤及斑马鱼评价某腈纶废水的急性毒性和遗传毒性,及厌氧-好氧工艺对该废水毒性的削减能力。采用大型蚤活动抑制率和斑马鱼致死率表征废水急性毒性,采用斑马鱼肝细胞彗星尾矩表征废水遗传毒性。腈纶废水处理前对大型蚤和斑马鱼的急性毒性单位(TU)分别为1.2和2.9,经厌氧-好氧工艺处理后分别降至<0.4和0.5。遗传毒性结果表明腈纶废水对斑马鱼肝细胞造成DNA损伤作用,经处理后遗传毒性仍显著高于阴性对照组。理化指标与毒性指标相关性分析表明,该废水氨氮与毒性显著相关,推测氨氮可能是该废水中的重要致毒因子之一。研究结果表明该腈纶废水采用现有厌氧-好氧工艺无法有效削减毒性,对受纳水体水生态环境造成潜在危害。
Abstract:
The acrylic fiber wastewater exhibits relatively high toxicity, which is difficult to be removed. The evaluation for the toxicity of the acrylic fiber wastewater and its reduction during the treatment process would facilitate the improvement of toxicity removal when optimizing the wastewater treatment technique. Daphnia magna and Danio rerio were applied to evaluate the acute toxicity and genotoxicity of acrylic fiber wastewater, and the toxicity removal by anaerobic-aerobic (A/O) treatment process. The acute toxicity of the acrylic fiber wastewater was tested by Daphnia magna immobilization and Danio rerio mortality. The genotoxicity was evaluated by comet tail moment of Danio rerio hepatocyte. The acrylic fiber wastewater samples were collected from a representative chemical industry located in Fushun, Liaoning Province. The removal of COD and ammonia by the A/O process were 81.6% and 57.7%, respectively. The COD and the ammonia of the effluent from the treatment process were 36.2 and 30.7 mg·L-1, respectively, which fell within the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant" in China. The wastewaters induced acute toxicity to Daphnia magna and Danio rerio, with the acute toxicity units at 1.2 and 2.9 before treatment, <0.4 and 0.5 after A/O treatment, respectively. Acrylic fiber wastewater caused DNA damage to Danio rerio hepatocyte, and the genotoxicity of the effluent was still significantly higher than that of the negative control group. Correlation analysis between physiochemical indexes and toxicity indicator showed that ammonia concentrations were significantly correlated with the toxicity, suggesting that ammonia may be one important toxicity factor in the acrylic fiber wastewater. The results suggested that the current A/O treatment process was limited in remove the toxicity of the acrylic fiber wastewater, and the discharged wastewater would pose potential hazard to the aquatic ecosystems of the receiving water.
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