Stewart M H, Wolfe R L, Means E G
Water Quality Laboratory, Metropolitan Water District of Southern California, La Verne 91750.
Appl Environ Microbiol. 1990 Dec;56(12):3822-9. doi: 10.1128/aem.56.12.3822-3829.1990.
Bacteriological analyses were performed on the effluent from a conventional water treatment pilot plant in which granular activated carbon (GAC) had been used as the final process to assess the impact of GAC on the microbial quality of the water produced. Samples were collected twice weekly for 160 days from the effluents of six GAC columns, each of which used one of four different empty-bed contact times (7.5, 15, 30, and 60 min). The samples were analyzed for heterotrophic plate counts and total coliforms. Effluent samples were also exposed to chloramines and free chlorine for 60 min (pH 8.2, 23 degrees C). Bacterial identifications were performed on the disinfected and nondisinfected effluents. Additional studies were conducted to assess the bacteriological activity associated with released GAC particles. The results indicated that heterotrophic plate counts in the effluents from all columns increased to 10(5) CFU/ml within 5 days and subsequently stabilized at 10(4) CFU/ml. The heterotrophic plate counts did not differ at different empty-bed contact times. Coliforms (identified as Enterobacter spp.) were recovered from the nondisinfected effluent on only two occasions. The disinfection results indicated that 1.5 mg of chloramines per liter inactivated approximately 50% more bacteria than did 1.0 mg of free chlorine per liter after 1 h of contact time. Chloramines and chlorine selected for the development of different bacterial species--Pseudomonas spp. and Flavobacterium spp., respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
对一个常规水处理中试工厂的出水进行了细菌学分析，该中试工厂使用颗粒活性炭（GAC）作为最后一道工序，以评估GAC对所产水微生物质量的影响。在160天内，每周两次从六个GAC柱的出水中采集样本，每个GAC柱使用四种不同空床接触时间（7.5、15、30和60分钟）中的一种。对样本进行了异养平板计数和总大肠菌群分析。出水样本还分别用氯胺和游离氯处理60分钟（pH 8.2，23摄氏度）。对消毒和未消毒的出水进行了细菌鉴定。还开展了其他研究以评估与释放的GAC颗粒相关的细菌学活性。结果表明，所有柱出水中的异养平板计数在5天内增至10⁵CFU/ml，随后稳定在10⁴CFU/ml。不同空床接触时间下的异养平板计数没有差异。仅在两次未消毒出水中检测到大肠菌群（鉴定为肠杆菌属）。消毒结果表明，接触1小时后，每升1.5毫克氯胺比每升1.0毫克游离氯多灭活约50%的细菌。氯胺和氯分别促使不同细菌种类——假单胞菌属和黄杆菌属生长。（摘要截短于250字）
