Phosphate-Based Corrosion Inhibition in Drinking Water Systems and Effects on Disinfectant Decay and Biofilm Growth
Phosphate-Based Corrosion Inhibition in Drinking Water Systems and Effects on Disinfectant Decay and Biofilm Growth
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DOI：
10.1089/ees.2023.0065
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发表时间：
2023-10
影响因子：
1.8
通讯作者：
Conghui Huang;T. Ginn;Gemma G. Clark;Farzana R Zaki;Jungeun Won;S. Boppart;Thanh H. Nguyen
中科院分区：
文献类型：
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作者：
Conghui Huang;T. Ginn;Gemma G. Clark;Farzana R Zaki;Jungeun Won;S. Boppart;Thanh H. Nguyen
在停滞期间，分配网络中的生物膜导致消毒剂腐烂，这可能导致机会性病原体的传播，从而危及饮用水安全。将磷酸盐基缓蚀剂应用于该系统可以通过为房屋管道内生长的生物膜提供营养来加剧消毒剂的腐烂。在这项研究中，我们评估了腐蚀抑制剂对在房屋管道中形成的生物膜的结构和化学性质的影响，以及由此产生的对消毒剂衰变的影响。两种常用的磷酸盐基（磷酸盐混合物和磷酸盐）缓蚀剂分别添加到模拟饮用水的生物膜的发展超过1至2年。光学相干断层扫描（OCT）成像显示所研究的生物膜的厚度、孔隙率和多孔结构在暴露于游离氯24 h或一氯胺120 h后没有改变。与地下水生物膜相比，磷酸盐基生物膜具有最高的总孔隙度，这是由于它们之间有许多连接通道。磷酸盐生物膜消耗游离氯或一氯胺的速度比地下水生物膜。实验结果表明，磷酸盐基生物膜消耗更多的单氯胺接触后96小时比其他生物膜。一组单独的实验，涉及消毒剂与悬浮生物质材料的衰减，连同OCT结果，提供了一个简化的准一阶反应扩散模型的参数，以便预测模型的衰减在停滞条件下的生物膜可以尝试没有参数拟合。生物膜模拟结果提供了一个接近的估计游离氯衰减，而低估了一氯胺衰减。与实验结果一致，模型结果表明，磷酸盐为基础的生物膜导致略快的自由氯消耗和一氯胺消耗比地下水生物膜，并表明生物膜的孔结构消毒剂衰减的扩散限制是重要的。研究结果表明，使用磷酸盐基缓蚀剂可能会导致在生物膜存在下停滞期间残留消毒剂的快速耗尽。
Disinfectant decay by biofilms in distribution networks during stagnation can allow opportunistic pathogens' transmission and thus compromise drinking water safety. Applying phosphate-based corrosion inhibitors to the system can exacerbate disinfectant decay by providing nutrients to biofilms growing inside premise plumbings. In this study, we evaluate the impacts of corrosion inhibitors on biofilms' structural and chemical properties that form in premise plumbing, and the resulting implications for disinfectant decay. Two commonly used phosphate-based (phosphate blends and phosphate) corrosion inhibitors were added separately to simulated drinking water for biofilm development over 1 to 2 years. Optical coherence tomography (OCT) imaging showed that the studied biofilms' thickness, porosity, and porous structure did not change after exposure to free chlorine for 24 h or monochloramine for 120 h. Compared with groundwater biofilms, phosphate-based biofilms had the highest overall porosity due to their many connecting channels. The phosphate-based biofilms consumed free chlorine or monochloramine at a faster rate than groundwater biofilms. Experimental results showed that phosphate-based biofilms consumed more monochloramine after 96 h of contact than other biofilms. A separate set of experiments involving disinfectant decay with suspended biomass material, together with the OCT results, provided parameters for a simplified quasi-first-order reaction–diffusion model so that predictive modeling of decay in biofilms under stagnation conditions could be attempted without parameter fitting. The biofilm modeling results provided a close estimate for free chlorine decay while underestimating monochloramine decay. In agreement with the experimental results, the model results indicate that the phosphate-based biofilms led to slightly faster free chlorine consumption and monochloramine consumption than groundwater biofilms and indicate that diffusion limitation imposed by biofilm pore structure on disinfectant decay is important. The study results suggest that using phosphate-based corrosion inhibitors may lead to a rapid depletion of residual disinfectant during stagnation in the presence of biofilms.