Department of Civil and Environmental Engineering, University of California, Irvine, CA 92697-2175, USA.
J Environ Manage. 2012 Jan;93(1):209-17. doi: 10.1016/j.jenvman.2011.09.011. Epub 2011 Oct 12.
In regions characterized by water scarcity, such as coastal Southern California, groundwater containing chromophoric dissolved organic matter is a viable source of water supply. In the coastal aquifer of Orange County in California, seawater intrusion driven by coastal groundwater pumping increased the concentration of bromide in extracted groundwater from 0.4 mg l⁻¹ in 2000 to over 0.8 mg l⁻¹ in 2004. Bromide, a precursor to bromate formation is regulated by USEPA and the California Department of Health as a potential carcinogen and therefore must be reduced to a level below 10 μg l⁻¹. This paper compares two processes for treatment of highly coloured groundwater: nanofiltration and ozone injection coupled with biologically activated carbon. The requirement for bromate removal decreased the water production in the ozonation process to compensate for increased maintenance requirements, and required the adoption of catalytic carbon with associated increase in capital and operating costs per unit volume. However, due to the absence of oxidant addition in nanofiltration processes, this process is not affected by bromide. We performed a process analysis and a comparative economic analysis of capital and operating costs for both technologies. Our results show that for the case studied in coastal Southern California, nanofiltration has higher throughput and lower specific capital and operating cost, when compared to ozone injection with biologically activate carbon. Ozone injection with biologically activated carbon, compared to nanofiltration, has 14% higher capital cost and 12% higher operating costs per unit water produced while operating at the initial throughput. Due to reduced ozone concentration required to accommodate for bromate reduction, the ozonation process throughput is reduced and the actual cost increase (per unit water produced) is 68% higher for capital cost and 30% higher for operations.
在水资源匮乏的地区，如南加州沿海地区，含有发色溶解有机物的地下水是一种可行的供水来源。在加利福尼亚州奥兰治县的沿海含水层中，沿海地下水抽取导致的海水入侵使抽取地下水的溴化物浓度从 2000 年的 0.4 毫克/升增加到 2004 年的 0.8 毫克/升以上。溴化物是溴酸盐形成的前体，受美国环保署和加利福尼亚州卫生部监管，被认为是一种潜在的致癌物质，因此必须将其浓度降低到 10μg/L 以下。本文比较了两种处理高色度地下水的工艺：纳滤和臭氧注入结合生物活性炭。为了去除溴酸盐，需要降低臭氧氧化过程的产水量，以补偿增加的维护要求，并且需要采用具有相关增加的单位体积资本和运营成本的催化活性炭。然而，由于纳滤过程中没有氧化剂的添加，因此该过程不受溴化物的影响。我们对这两种技术进行了工艺分析和资本与运营成本的比较经济分析。研究结果表明，对于南加州沿海地区的研究案例，纳滤具有更高的产水量和更低的单位体积资本和运营成本，与臭氧注入结合生物活性炭相比。与纳滤相比，臭氧注入结合生物活性炭的资本成本高出 14%，单位产水量的运营成本高出 12%，而初始产水量相同。由于需要降低臭氧浓度以适应溴酸盐的减少，臭氧氧化过程的产水量减少，实际成本增加（单位产水量）的资本成本增加 68%，运营成本增加 30%。
