预氯化对管道生物膜净水效能影响及性能恢复

Influence of pre-chlorination on pipeline biofilm water purification efficiency and recovery process

以环状膜生物反应器BAR模拟实际输水管道,研究了预氯化对管壁生物膜净水效能的影响及其性能恢复过程.结果表明:冲击性加氯后生物膜中异养菌数量迅速降低,几乎检测不出氨氧化细菌,然而,短时的冲击利于生物膜更新,增加了细菌生长潜能,恢复运行240h及144h之后预氯化生物膜中异养菌和氨氧化细菌数量均高于对照组.氯冲击明显降低了生物膜对氨氮的去除效果,余氯为0.5,1.5,3.0mg/L的BAR对氨氮去除率由对照组的79.01%分别降到32.10%、14.46%和9.88%,并出现了显著的亚硝酸盐氮积累,恢复运行120h和216h,管道生物膜即可恢复对氨氮和亚硝酸盐氮的去除效果.余氯量达到1.5mg/L时造成出水总磷浓度升高,恢复运行264h之后4台BAR对总磷的去除率均达到20%以上.氯对生物膜的氧化作用使得出水高锰酸盐指数升高,运行192h之后生物膜净水效果恢复.

Influence of pre-chlorination on pipeline biofllm water purification efficiency and recovery process were studied using BAR reactors simulating water delivery pipeline. The results showed that the amount of heterotrophic bacteria quickly reduced after chlorination and almost no ammonia oxidizing bacteria was detected. However, short impact was conducive to biofllm update and bacterial regrowth potential was enhanced. Having resumed operation for 240 and 144 hours, the amount of heterotrophic bacteria and ammonia oxidizing bacteria of pre-chlorination biofilm was higher than control group. Ammonia nitrogen degradation was evidently reduced after chlorination, removal efficiency dropped from 79.01% to 32.1%, 14.46% and 9.88% respectively at residual chlorine of 0.5,1.5 and 3.0mg/L. Moreover, significant nitrite nitrogen accumulation appeared, effect of ammonia nitrogen and nitrite nitrogen removal was recoveried after 120 and 216 hours. Effluent total phosphrous concentration increased when residual chlorine was up to 1.5mg/L and total phosphrous removal rate was all more than 20% after run for 264 hours. Permanganate index was increased because of oxidation caused by chlorine and water purification efficiency was rerecoveried after 192 hours.