Abulikemu Gulizhaer, Mistry Jatin H, Wahman David G, Alexander Matthew T, Kennicutt Alison R, Bollman Jacob D, Pressman Jonathan G
Pegasus Technical Services, Inc., 46 E Hollister St., Cincinnati, OH 45219; Graduate Student, College of Engineering and Applied Science, Univ. of Cincinnati, Cincinnati, OH 45221.
Region 6, US Environmental Protection Agency, Dallas, TX 75270.
J Environ Eng (New York). 2022 Oct 27;149(1):1-12. doi: 10.1061/(asce)ee.1943-7870.0002062.
Four chloraminated drinking water distribution systems (CDWDSs) required to maintain numeric versus "detectable" residuals were spatially and temporally sampled for water quality and associated trihalomethane (THM) and haloacetic acid (HAA) formation. Monochloramine decreased from entry point (EP) to maximum residence time (MRT) samples while THMs and HAAs initially increased and then stabilized or slightly decreased. Subsequently, EP and MRT samples were used in laboratory-held studies to further evaluate disinfectant residual stability, chloramine speciation, and nitrification occurrence. MRT water exhibited a faster monochloramine concentration decline compared to EP water, indicating a decreasing disinfectant residual stability from increasing water age through distribution. Using a simple technique based on published inorganic chloramine chemistry, samples were also investigated for nondisinfectant positive interference (NDPI) on total chlorine measurements. NDPI concentrations represented up to 100% of the total chlorine concentration when total chlorine concentrations decreased to 0.05 mg-Cl/L, indicating little to no effective disinfectant residual remained.
对四个需要维持数值与“可检测”余氯的氯化饮用水分配系统（CDWDSs）进行了空间和时间上的水质采样，以及相关的三卤甲烷（THM）和卤乙酸（HAA）生成情况采样。从入口点（EP）到最大停留时间（MRT）的样本中，一氯胺含量下降，而THM和HAA最初增加，然后稳定或略有下降。随后，将EP和MRT样本用于实验室研究，以进一步评估消毒剂余氯稳定性、氯胺形态和硝化作用的发生情况。与EP水相比，MRT水的一氯胺浓度下降更快，这表明随着水在分配过程中的老化，消毒剂余氯稳定性降低。利用基于已发表的无机氯胺化学的简单技术，还对样本进行了总氯测量中无消毒剂正干扰（NDPI）的研究。当总氯浓度降至0.05 mg-Cl/L时，NDPI浓度占总氯浓度的比例高达100%，这表明几乎没有有效的消毒剂余氯残留。
