School of Chemical Engineering, The University of New South Wales, Sydney, NSW 2052, Australia.
Australian Water Quality Centre, SA Water Corporation, 250 Victoria Square, Adelaide, SA 5100, Australia; Centre for Water Management and Reuse, School of Natural and Built Environments, University of South Australia, SA 5095, Australia.
J Environ Sci (China). 2017 Jul;57:170-179. doi: 10.1016/j.jes.2016.11.007. Epub 2016 Nov 28.
The management of chloramine decay and the prevention of nitrification are some of the critical issues faced by water utilities that use chloramine as a disinfectant. In this study, potential association between high performance size exclusion chromatography (HPSEC) data obtained with multiple wavelength Ultraviolet (UV) detection from two drinking water distribution systems in Australia and nitrification occurrence was investigated. An increase in the absorbance signal of HPSEC profiles with UV detection at λ=230nm between apparent molecular weights of 200 to 1000Da was observed at sampling sites that experienced rapid chloramine decay and nitrification while its absorbance signal at λ=254nm decreased. A chloramine decay index (C.D.I) defined as the ratio of area beneath the HPSEC spectra at two different wavelengths of 230 and 254nm, was used in assessing chloramine decay occurrences. The C.D.Is of waters at locations that experienced nitrification were consistently higher than locations not experiencing nitrification. A simulated laboratory study showed that the formation of nitrite/nitrate and/or soluble microbial products and/or the release of extracellular polymeric substances (EPS) during nitrification may contribute to the C.D.I. increase. These findings suggest that C.D.I derived from HPSEC with multiple wavelength UV detection could be an informative index to track the occurrence of rapid chloramine decay and nitrification.
氯胺衰减的管理和硝化的预防是使用氯胺作为消毒剂的水公用事业公司面临的一些关键问题。在这项研究中，研究了从澳大利亚两个饮用水分配系统中用多波长紫外线（UV）检测获得的高性能尺寸排阻色谱（HPSEC）数据与硝化发生之间的潜在关联。在经历快速氯胺衰减和硝化的采样点，在表观分子量为 200 至 1000Da 之间，用 UV 检测在 230nm 处获得的 HPSEC 图谱的吸光度信号增加，而在 254nm 处的吸光度信号降低。定义为在两个不同波长 230nm 和 254nm 下的 HPSEC 光谱下的面积之比的氯胺衰减指数（C.D.I），用于评估氯胺衰减的发生。经历硝化的位置的 C.D.I 值始终高于未经历硝化的位置。模拟实验室研究表明，硝化过程中形成的亚硝酸盐/硝酸盐和/或可溶性微生物产物和/或细胞外聚合物物质（EPS）的释放可能导致 C.D.I 的增加。这些发现表明，用多波长 UV 检测从 HPSEC 获得的 C.D.I 可能是跟踪快速氯胺衰减和硝化发生的有用指标。
