根据第1阶段消毒副产品规则（DBP），公共设施 必须符合0.080的三卤甲烷（THM）最大污染物水平（MCL） mg/L和0.060 mg/L的卤乙酸（HAA）MCL。THM和 HAA受总有机碳、溴、pH、温度、， 氯剂量和接触时间。随着米德湖的不断升高 由于干旱，这些水质参数将减少 更有利于形成THM和HAA的变化可能在 MCL。目前的规章制度加上水质的变化 促使内华达州南部水务局（SNWA）进行调查 降低THM和HAA浓度的各种策略。台秤 进行实验以确定优化电流的方法 在没有重大资本改善的情况下处理厂的绩效。 结果表明，臭氧氧化在1.0-log下将THM浓度降低4-7% 隐孢子虫失活，2.0对数隐孢子虫灭活率为7-17% 灭活。生物过滤没有提供任何实质性的THM(< 5%）或HAA（<10%）减少。再氯化结果降低了THM 当使用1.8 mg/L游离余氯时，浓度为10-15% 48小时后用0.7 mg/L Cl2再氯化，与初始游离氯相比 氯残留量为2.5 mg/L。温度从16.7°C升高至 23.7°C会使氯的衰减率增加30-40%，并增加THM 形成30%。这些实验室规模的结果提供了SNWA替代方案 继续遵守第一阶段DBP规则和提议的第二阶段 DBP规则，无需重大资本改善。包括表格，数字。

According to the Stage 1 Disinfection Byproduct Rule (DBP), utilities must comply with a trihalomethane (THM) maximum contaminant level (MCL) of 0.080 mg/L and a haloacetic acids (HAA) MCL of 0.060 mg/L. The formation of THMs and HAAs are impacted by total organic carbon, bromide, pH, temperature, chlorine dose, and contact time. As the elevation of Lake Mead continues to decrease due to drought, these water quality parameters will result in changes more conducive to forming THMs and HAAs potentially near the MCL. The current regulations coupled with water quality changes have prompted the Southern Nevada Water Authority (SNWA) to investigate various strategies to reduce THM and HAA concentrations. Bench scale experiments were performed to identify ways to optimize the current treatment plant performance without a major capital improvement. Results showed ozonation reduced THM concentrations 4-7% at a 1.0-log Cryptosporidium inactivation, and 7-17% at a 2.0-log Cryptosporidium inactivation. Biological filtration did not provide any substantial THM (< 5%) or HAA (<10%) reduction. Rechlorination results lowered THM concentration by 10-15% when a 1.8 mg/L free chlorine residual was rechlorinated with 0.7 mg/L Cl2 after 48 hours, compared to an initial free chlorine residual of 2.5 mg/L. A temperature increase from 16.7°C to 23.7°C increased the chlorine decay rate 30-40% and increased THM formation by 30%. These bench scale results provide SNWA alternatives to continue compliance with the Stage 1 DBP Rule and proposed Stage 2 DBP rule without requiring a major capital improvement. Includes table, figures.