污水再生处理反渗透浓缩水化学污染物特征解析与安全控制原理

Wastewater reclamation and reuse are considered as viable and effective approaches to solve severe water shortages. Reverse osmosis (RO) process has been widely applied in tertiary wastewater treatment to obtain high quality reclaimed water. However, environmental risks of the reverse osmosis concentrate (ROC) should not be ignored, which is generated simultaneously with the filtrate. The objective of this proposal is to investigate the characteristics of chemical pollutants of ROC and the safety control principles. The characteristics of chemical pollutants will be presented by organic fractions, material composition and genotoxicity effect. The secondary effluents from municipal wastewater treatment plants (WWTPs) are the influent of RO process. Based on investigation concerning relations of the chemical pollutants in the secondary effluents and ROC, the influence of effluent organic matter (EfOM) in the secondary effluents to the characteristics of chemical pollutants and its genotoxicity effect in ROC will be evaluated. The influence of the typical chemical reagents of antiscalant, disinfectant, reductant and non-oxidizing biocides usually used a RO process, will be studied to clarify the mechanism of toxicity effects in ROC generated by typical chemical additives. The control method and pricinple for chemical pollutants will be accomplished by two steps. First, optimize operating parameters of chemical reagents in RO process to abate the genotoxicity in the ROC. Second, obtain effective method and verify the principle to control chemical pollutants in ROC, by identify the priority controlling toxicity factors in the ROC, and evaluate the treatment process on abatement genotoxicity in ROC. Based on the above findings, the control principles of the chemical pollutants and genotoxicity of ROC will be clarified to provide the support to the RO process for water reclaimed treatment.

污水再生利用是解决水资源危机的必要途径和重要战略，MF/UF-RO（微滤/超滤+反渗透）工艺是获得高标准再生水的重要技术，但RO浓缩水的环境风险不容忽视。 本课题以RO浓缩水的安全控制为目标，围绕其化学污染物的分布特征、影响机制和控制原理开展研究。化学污染物特征采用组分分离、物质组成表征和遗传毒性评价等方法进行解析。评价RO系统进水（即二级处理出水）EfOM组分对浓缩水水质的影响规律，研究RO系统中化学药剂（阻垢剂、氧化性消毒剂、非氧化性消毒剂和还原剂）对二级处理出水EfOM组分和遗传毒性生成潜势的影响，揭示浓缩水化学污染物及其遗传毒性效应的影响机制。优化典型化学药剂的工艺操作参数，消减浓缩水遗传毒性的生成。采用毒性因子的识别方法，筛选浓缩水中优先控制毒性因子，研究可消减遗传毒性方法的控制原理。综合以上成果，阐明再生水处理RO浓缩水化学污染物及其遗传毒性风险的影响机制和控制原理。

污水再生利用是解决水资源危机的必要途径和重要战略，污水再生处理反渗透系统（mWRRO）是获得高标准再生水的重要技术，但该系统所产生的副产物反渗透浓缩水（ROC）的环境风险不容忽视。mWRRO系统RO浓水中的COD、DOC、NH3-N、NO3-和PO43-可分别达60~184、19.2~62、0.3~37.5、3.1~296和10~39 mg/L。mWRRO系统进水的氯化消毒，会导致工艺运行过程中消毒副产物的生成和其他生物毒性物质的生成。.将RO浓水中的溶解性有机物（DOM）分离为疏水酸性物质（HOA）、疏水碱性物质（HOB）、疏水中性物质（HON）、亲水酸性物质（HIA）、亲水碱性物质（HIB）和亲水中性物质（HIN）六个组分。HOA、HOB和HIN不仅占到RO浓水总DOC的96%，RO浓水中DOM的主要分子量范围是1-3 kDa；少量分子量为3-10 kDa的有机物存在于组分HOA、HIA 和HIN。组分HOA和HON含有高的芳香类蛋白质、腐殖/富里酸类物质和溶解性微生物代谢产物。RO浓水的遗传毒性和抗雌激素活性分别是1795.6 ± 57.2 lg 4-NQO /L和2.19 ± 0.05 mg TAM/L，组分HON、HOA和HIN显现出抗雌激素活性，HOA, HON, 和 HIN显示出抗雌激素活性；且HIN 的遗传毒性高达 1007.9 ± 94.8 lg 4-NQO /L。HOA的抗雌激素活性（1.3 ± 0.17 mg TAM /L）最高。建立了混凝-活性炭对RO浓水的优化处理方法，对DOC、UV254 和TDS去除率达到91.8, 96, 和76.5 %。混凝预处理对高分子量有机物的去除效果优于低分子量的有机物混凝预处理去除的主要是大分子量有机物，对分子量>5 KDa且具有遗传毒性的DOM的去除率达到50.2%，但是对于<5 KDa和5～10 KDa组分抗雌激素活性的去除效果基本相同；而活性炭吸附去除的则主要是小分子量有机物，且ROC经混凝-活性炭吸附工艺处理后，遗传毒性和抗雌激素活性均为未检出。.该课题研究成果，对于控制RO浓缩水化学污染物毒性风险，开发RO浓缩水安全有效的控制技术，具有重要的理论意义和实际价值。