Department of Civil and Environmental Engineering , Colorado School of Mines , 1500 Illinois Street , Golden , Colorado 80401 , United States.
National Science Foundation Engineering Research Center for Re-Inventing the Nation's Urban Water Infrastructure (ReNUWIt) , Stanford , California 94305 , United States.
Environ Sci Technol. 2019 Mar 5;53(5):2720-2730. doi: 10.1021/acs.est.8b06897. Epub 2019 Feb 15.
Ozonation followed by biologically active filtration (BAF) (O-BAF) treatment has become an alternative to reverse osmosis in potable wastewater reuse applications because of the ability to produce a high-quality effluent while reducing brine production and disposal. In this study, effluent from a sequencing batch membrane bioreactor (SBMBR) was treated by O-BAF at three specific ozone doses (0.5, 0.7, and 1.0 mg O/mg DOC) and different empty bed contact times (EBCTs; 15-45 min). The reaction of O with granular activated carbon (GAC) (O/GAC) to promote the formation of hydroxyl radicals (·OH) was evaluated at 1.0 mg O/mg DOC followed by BAF at 15-45 min EBCT. The efficacy of these techniques was compared for the removal of O refractory 1,4-dioxane and the reduction in the formation of bromate, 35 regulated and unregulated halogenated disinfection byproducts (DBPs), and 8 N-nitrosamines after chloramination. Conventional ozonation (without the presence of GAC during ozonation) removed 6-11% of 1,4-dioxane, while BAF increased the removal to ∼25%. O/GAC improved the removal of 1,4-dioxane to ∼40%, while BAF increased the removal to ∼50%. No bromate was detected during conventional ozonation. Although O/GAC formed 12.5 μg/L bromate, this concentration was reduced during BAF treatment to <6.8 μg/L. Even though conventional ozonation was more effective than O/GAC for the reduction in chloramine-reactive N-nitrosodimethylamine (NDMA) precursors, BAF treatment after either conventional or enhanced ozonation reduced NDMA formation during chloramination to <10 ng/L. O/GAC was more effective at reducing halogenated DBP formation during postchloramination. Regardless, the reduction in halogenated DBP formation during postchloramination achieved by BAF treatment was ∼90% relative to the formation in the SBMBR effluent after either conventional or enhanced ozonation. The reduction of haloacetic acid (HAA) formation improved moderately with increasing BAF EBCT. Both O-BAF and (O/GAC)-BAF met regulatory levels for trihalomethanes, HAAs, NDMA, and bromate.
臭氧化随后进行生物活性过滤（BAF）（O-BAF）处理，已成为饮用水废水再利用应用中反渗透的替代方法，因为它能够生产高质量的出水，同时减少盐水的产生和处理。在这项研究中，采用序批式膜生物反应器（SBMBR）的出水在三个特定的臭氧剂量（0.5、0.7 和 1.0 mg O/mg DOC）和不同的空床接触时间（EBCT；15-45 min）下通过 O-BAF 进行处理。在 1.0 mg O/mg DOC 下评估了 O 与颗粒活性炭（GAC）（O/GAC）的反应以促进羟基自由基（·OH）的形成，然后在 15-45 min EBCT 下进行 BAF。比较了这些技术在去除难臭氧化的 1,4-二恶烷和减少溴酸盐、35 种受监管和不受监管的卤代消毒副产物（DBPs）以及氯胺化后 8 种 N-亚硝胺方面的效果。常规臭氧化（臭氧化过程中不存在 GAC）去除了 1,4-二恶烷的 6-11%，而 BAF 将去除率提高到约 25%。O/GAC 将 1,4-二恶烷的去除率提高到约 40%，而 BAF 将去除率提高到约 50%。在常规臭氧化过程中未检测到溴酸盐。尽管 O/GAC 形成了 12.5 μg/L 的溴酸盐，但在 BAF 处理过程中，该浓度降低至 <6.8 μg/L。尽管常规臭氧化比 O/GAC 更有效地减少氯胺反应性 N-亚硝二甲胺（NDMA）前体，但在常规或增强臭氧化后进行 BAF 处理可将氯胺化过程中 NDMA 的形成降低至 <10 ng/L。O/GAC 在氯胺化后减少卤代 DBPs 的形成更有效。无论如何，通过 BAF 处理，与常规或增强臭氧化后的 SBMBR 出水相比，卤代 DBPs 在氯胺化后的形成减少了约 90%。随着 BAF EBCT 的增加，卤乙酸（HAA）形成的减少适度改善。O-BAF 和（O/GAC）-BAF 均符合三卤甲烷、卤乙酸、NDMA 和溴酸盐的法规水平。
