| 市政污水A/DAT-IAT系统中溶解性有机物表征与生态安全 |
| 摘要点击 2412 全文点击 1445 投稿时间：2013-05-31 修订日期：2013-07-10 |
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| 中文关键词 市政污水 A/DAT-IAT工艺 溶解性有机物 相对分子质量分布 三维荧光 毒性 |
| 英文关键词 municipal wastewater A/DAT-IAT process dissolved organic matter relative molecular weight distribution 3D-EEM toxicity |
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| 中文摘要 |
| 为了解决市政污水处理出水水质安全与无害化问题，以改良的SBR——A/DAT-IAT工艺为依托，对A/DAT-IAT工艺进水，连续曝气池（DAT）上清液及间歇曝气池（IAT）出水的溶解性有机物（dissolved organic matter，DOM）采用超滤膜法进行了相对分子质量分级，并进行了TOC、UV254、3D-EEM及发光菌毒性测试，探索市政污水毒性的主要物质来源. 结果表明，实验室规模的A/DAT-IAT工艺对市政污水各分子量区间的有机物均有较好的去除效果. 腐殖质是污水处理厂出水中主要物质，且天然水体中难去除的腐殖质及处理过程中形成的腐殖质成分是二级出水中主要的荧光物质. 沿污水处理流程，DOM的组成呈现出由低分子量向高分子量转化的趋势，相对分子质量<1×103区间的物质芳香性显著增加，导致IAT出水与氯的反应活性增高，产生消毒副产物的风险增加. 与进水毒性主要来源于原水中相对分子质量<1×103的小分子物质相同，IAT出水的毒性也主要来源于相对分子质量<1×103的小分子物质，但与原水中的小分子物质不同，主要是生物处理过程中产生的类腐殖质. 结合对TOC、UV254、3D-EEM及毒性的分析，小分子的类腐殖质是二级出水有机物含量达标、氯化消毒副产物控制及毒性控制应该重点考虑去除的对象. 在之后的研究中，应该根据这部分物质进行工艺调节及针对性处理单元的添加. |
| 英文摘要 |
| To ensure the water-quality safety and harmlessness of effluent from municipal wastewater, based on the lab-scale improved SBR—A/DAT-IAT process, dissolved organic matter (DOM) in municipal wastewater, demand aeration tank (DAT) supernatant and final effluent were classified and separated by applying the ultrafiltration membranes, and indexes such as TOC, UV254, 3D-EEM and toxicity were measured, to find out the sources of the toxic substances. The results showed that the lab-scale A/DAT-IAT process performed well on each molecular-weight fraction of DOM. The main composition in the effluent was humic-like substance. Along the process, The DOM distribution presented a trend of shifting to high molecular weight. Meanwhile, the aromaticity of DOM in the fraction with relative molecular weight below 1×103 increased significantly, leading to the increase in the reactivity of effluent with chlorine, which then increased the risk of disinfection by-products. In the raw wastewater, the toxic effects were originated from the fraction with relative molecular weight below 1×103, although the toxic effects were still originated from the same fraction in the effluent, they came from the biological treatment itself instead of the raw wastewater. Based on the analysis of TOC, UV254, 3D-EEM and toxicity, the removal of low molecular-weight humic-like substance should be emphasized to achieve the effluent organic emissions standards and to control the risk of chlorination by-products and toxicity. Therefore, future studies should focus on the removal of this fraction of DOM by adjusting technological parameters or adding a targeted processing unit. |
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