燃煤电厂脱硫废水处理过程中有机物组分及生物毒性解析

ANALYSIS OF ORGANIC COMPOUNDS CONTENT AND BIOTOXICITY DURING TREATMENT PROCESS OF FLUE GAS DESULFURIZATION WASTEWATER IN A COAL-FIRED POWER PLANT

燃煤电厂脱硫废水有机物成分复杂,极大地影响零排放系统的高效低耗运行,并存在一定的生物毒性风险。采用现场测试和模拟实验的方法,对某燃煤电厂脱硫废水处理过程中的有机物组分及生物毒性进行解析。结果表明:“两级澄清法”和“高效絮凝剂法”虽不能有效去除脱硫废水的有机物,但能降低废水中的腐植酸类物质。纳滤浓水的回流作用使调节池出水色氨酸和酪氨酸类蛋白质占比降低至30%,但腐植酸类物质占比大幅升高至60%。脱硫废水中污染物的分子量主要集中在2084,612 Da附近,纳滤浓水污染物的分子量相比预处理出水略小,污染物可能通过吸附、堵塞孔隙等导致膜污染。“两级澄清法”和“高效絮凝剂法”能大幅削减调节池出水的生物毒性,发光细菌发光抑制率分别由46.23%下降至12.45%和2.57%;而纳滤浓水富集了大量腐植酸等生物毒性物质,发光抑制率升高至49.05%。脱硫废水有机物较低的分子量导致较高的纳滤膜污染,而腐植酸等的富集增加了纳滤浓水的生物毒性。

The complex organic composition of desulfurization wastewater in coal-fired power plants greatly affected the high efficiency and low-consumption operation of zero-emission systems,and there was a certain risk of biological toxicity.The organic components and biological toxicity in the desulfurization wastewater treatment process of a coal-fired power plant were analyzed by field test and simulation experiments in this study.The results showed that the two-stage clarification method and the high-efficiency flocculant method could not effectively remove the organic matter in the desulfurization wastewater,but could reduce the humic acid substances in the wastewater.The reflux of nanofiltration concentrate reduced the proportion of tryptophan and tyrosine protein in the effluent of the regulating tank to 30%,but greatly increased the proportion of humic acid substances to 60%.The molecular weights of the pollutants in the desulfurization wastewater were mainly around 2084 Da and 612 Da,and the molecular weight of the pollutants in the nanofiltration concentrate was slightly smaller than that of the pretreated effluent,which may cause membrane fouling by adsorption and plugging pores.The two-stage clarification method and high-efficiency flocculant method could all remarkably reduce the biological toxicity of the effluent of the regulating tank,and the luminescence inhibition rate of luminescent bacteria decreased from 46.23%to 12.45%and 2.57%,respectively.The nanofiltration concentrate enriched a large number of biological toxic substances such as humic acid,and the luminescence inhibition rate increased to 49.05%.The lower molecular weight of the organic matter in the desulfurization wastewater resulted in higher risk of nanofiltration membrane fouling,and the enrichment of humic acid increased the biological toxicity of nanofiltration concentrate.