不同消毒方式对饮用水生物活性炭出水消毒效果的对比研究

针对水厂生物活性炭深度处理工艺可能产生的细菌泄露问题,采用上海徐泾水厂生物活性炭出水,通过对异养菌平板计数和卤代烃气相色谱检测分析,比较了次氯酸钠和氯胺2种消毒方式对出厂水水质安全保障的效果.在水温30℃下,采用NaClO消毒剂进行消毒处理时,初始余氯值达到1.84 mg/L、接触30 min即可保障灭活率lg(N0/...

Disinfection Efficiency for Outlet Water from Biological Activated Carbon Process by Different Disinfecting Modes

Lab-scale tests were designed to treat the leak of bacteria from BAC process. Water samples from outlet of BAC pool in Xujing Waterworks in Shanghai were disinfected by NaClO and NH2Cl disinfectant to compare the disinfection efficiency. Heterotrophic bacteria in disinfected water were cultivated and counted and halo hydrocarbons were detected by GC. To keep the disinfecting efficacy lg(N0/N)] over 2 under the water temperature of 30 degrees C, NaClO should have an initial concentration more than 1.84 mg/L total chlorine and contact with bacteria for about 30 minutes. As to NH2Cl disinfection, the initial concentration should be more than 2.20 mg/L total chlorine and contacting time should be prolonged to about 90 minutes. The production of CHCl3 ranged from 4.97 to 7.10 microg/L and CCl4 ranged from 0.01 to 0.71 microg/L in NaClO disinfection tests with a initial disinfecting concentration in the range of 1.53-2.42 mg/L total chlorine values. In NH2Cl disinfecting tests, CHCl3 ranged from 4.43 to 5.55 microg/L and CCl4 ranged from 0.01 to 0.64 microg/L when initial disinfecting concentration limited in the range of 2.10-2.86 mg/L total chlorine values. All was below the state drinking water standard. The results showed that the disinfection process can be divided into fast step and slow step. NaCl0 has higher disinfecting efficiency on bacteria than NH2Cl, but neither can reach 100% effectivity. Meanwhile the risk of producing halo hydrocarbon over standard was proved to be negligible.