Influence of biofilms on iron and manganese deposition in drinking water distribution systems
Influence of biofilms on iron and manganese deposition in drinking water distribution systems
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DOI：
10.1080/08927014.2010.547576
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发表时间：
2011-01-01
期刊：
影响因子：
2.7
通讯作者：
Plumb, Jason
中科院分区：
文献类型：
--
作者：
Ginige, Maneesha P.;Wylie, Jason;Plumb, Jason
虽然水变色对健康的危害很小，但这种水仍然是澳大利亚大多数供水公司收到的主要投诉之一。散装水中铁（Fe）和/或锰（Mn）水平升高与水变色事件有关。这两种元素在分配系统中的积累被认为是造成这种高水平的主要原因之一。在这项研究中报告的贡献管壁生物膜对铁和锰沉积，和变色水事件的调查。操作八个实验室规模的反应器以一式两份测试四种不同的条件。四个反应器暴露于低铁（0.05毫克l-1）和锰（0.02毫克l-1）的浓度，其余四个暴露于较高的（0.3和0.4毫克l-1的铁和锰，分别）浓度。两个四个反应器，收到低和高的铁和锰浓度氯化（3.0毫克l-1的氯）。在这些反应器中的玻璃环上的生物活性（以ATP测量）非常低（1.5ngcm-2环）。高浓度的铁和锰在散装水和活性生物膜导致增加的沉积铁和锰的玻璃环。此外，随着生物活性的增加，Fe和Mn沉积增加。实验室规模的实验中的观察结果与使用生物膜监测器进行的现场观察的结果一致。现场数据还证明了季节的影响，在夏末和初秋期间在管壁生物膜上观察到的生物膜活动增加被发现与Fe和Mn的沉积增加有关。相比之下，在较冷的月份，生物膜活动的幅度较低，沉积的金属浓度也显着减少（即下降68%的铁和86%的锰）。基于实验室规模的调查，由于细胞死亡或流动动力学导致的管壁生物膜的分离可以将截留的Fe和Mn释放到本体水中，这可能导致水变色事件。因此，管理饮用水管道上的生物膜生长应考虑由自来水公司，以尽量减少分配网络中的铁和锰的积累。
Although health risk due to discoloured water is minimal, such water continues to be the source of one of the major complaints received by most water utilities in Australia. Elevated levels of iron (Fe) and/or manganese (Mn) in bulk water are associated with discoloured water incidents. The accumulation of these two elements in distribution systems is believed to be one of the main causes for such elevated levels. An investigation into the contribution of pipe wall biofilms towards Fe and Mn deposition, and discoloured water events is reported in this study. Eight laboratory-scale reactors were operated to test four different conditions in duplicate. Four reactors were exposed to low Fe (0.05 mg l-1) and Mn (0.02 mg l-1) concentrations and the remaining four were exposed to a higher (0.3 and 0.4 mg l-1 for Fe and Mn, respectively) concentration. Two of the four reactors which received low and high Fe and Mn concentrations were chlorinated (3.0 mg l-1 of chlorine). The biological activity (measured in terms of ATP) on the glass rings in these reactors was very low (1.5ngcm-2 ring). Higher concentrations of Fe and Mn in bulk water and active biofilms resulted in increased deposition of Fe and Mn on the glass rings. Moreover, with an increase in biological activity, an increase in Fe and Mn deposition was observed. The observations in the laboratory-scale experiments were in line with the results of field observations that were carried out using biofilm monitors. The field data additionally demonstrated the effect of seasons, where increased biofilm activities observed on pipe wall biofilms during late summer and early autumn were found to be associated with increased deposition of Fe and Mn. In contrast, during the cooler months, biofilm activities were a magnitude lower and the deposited metal concentrations were also significantly less (ie a drop of 68% for Fe and 86% for Mn). Based on the laboratory-scale investigations, detachment of pipe wall biofilms due to cell death or flow dynamics could release the entrapped Fe and Mn into the bulk water, which could lead to a discoloured water event. Hence, managing biofilm growth on drinking water pipelines should be considered by water utilities to minimize accumulation of Fe and Mn in distribution networks.