Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes.
Effect of sulfate on the transformation of corrosion scale composition and bacterial community in cast iron water distribution pipes.
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DOI：
10.1016/j.watres.2014.04.003
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发表时间：
2014-08
期刊：
影响因子：
12.8
通讯作者：
Fan Yang;Baoyou Shi;Yaohui Bai;Huifang Sun;D. Lytle;Dongsheng Wang
中科院分区：
文献类型：
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作者：
Fan Yang;Baoyou Shi;Yaohui Bai;Huifang Sun;D. Lytle;Dongsheng Wang
给水管网中铁腐蚀膜的化学稳定性和生物膜微生物群落对铁的腐蚀和腐蚀产物的释放有很大的影响，特别是在水源切换的情况下，可能会导致“红水”问题。通过建立实验管路，研究了硫酸盐对旧铸铁管道中铁腐蚀产物和细菌群落的动态转化特性的影响。所有的测试管道都是从不同水源供水历史的现有DWDS中挖掘出来的，测试水的硫酸盐浓度在50~350 mg/L之间，用16S rRNA的焦磷酸测序进行细菌群落分析。结果表明，当给水硫酸盐浓度突然升高时，有地下水补给历史的管道铁素释放量显著增加，甚至出现“红水”现象。而仅有地表水供水历史的管道，即使给水硫酸盐成倍增加，铁的释放量也变化不大，颜色不明显。有地表供水历史的管道上厚层腐蚀垢(或密集分布的结节)具有较高的稳定性，这是因为其上壳层中稳定成分(主要是Fe3O4)所占比例较大；而有地下水供水历史的管道上较薄、较均匀的无层腐蚀垢中含有较高比例的不稳定铁氧化物(如β-FeOOH、FeCO3和绿锈)。随着硫酸盐浓度的增加，稳定性较差的腐蚀膜趋于稳定，表现为铁的释放量逐渐减少，稳定的铁氧化物逐渐增多。细菌群落分析表明，当改用高硫酸盐水时，腐蚀垢稳定的管道中铁还原细菌(IRB)占优势，而腐蚀膜不稳定的管道中硫氧化细菌(SOB)、硫酸盐还原细菌(SRB)和铁氧化细菌(IOB)的数量明显增加。
The chemical stability of iron corrosion scales and the microbial community of biofilm in drinking water distribution system (DWDS) can have great impact on the iron corrosion and corrosion product release, which may result in “red water” issues, particularly under the situation of source water switch. In this work, experimental pipe loops were set up to investigate the effect of sulfate on the dynamical transformation characteristics of iron corrosion products and bacterial community in old cast iron distribution pipes. All the test pipes were excavated from existing DWDS with different source water supply histories, and the test water sulfate concentration was in the range of 50–350 mg/L. Pyrosequencing of 16S rRNA was used for bacterial community analysis. The results showed that iron release increased markedly and even “red water” occurred for pipes with groundwater supply history when feed water sulfate elevated abruptly. However, the iron release of pipes with only surface water supply history changed slightly without noticeable color even the feed water sulfate increased multiply. The thick-layered corrosion scales (or densely distributed tubercles) on pipes with surface water supply history possessed much higher stability due to the larger proportion of stable constituents (mainly Fe3O4) in their top shell layer; instead, the rather thin and uniform non-layered corrosion scales on pipes with groundwater supply history contained relatively higher proportion of less stable iron oxides (e.g. β-FeOOH, FeCO3and green rust). The less stable corrosion scales tended to be more stable with sulfate increase, which was evidenced by the gradually decreased iron release and the increased stable iron oxides. Bacterial community analysis indicated that when switching to high sulfate water, iron reducing bacteria (IRB) maintained dominant for pipes with stable corrosion scales, while significant increase of sulfur oxidizing bacteria (SOB), sulfate reducing bacteria (SRB) and iron oxidizing bacteria (IOB) was observed for pipes with less stable corrosion scales.