标题：Combating Accidental Microbial Episodes by Back-Ground Chlorine Residuals in a Scaled-up Distribution Network (Rig) Using a Central Composite Design (CCD)
期刊名称：International Journal of Environmental Science and Development
印刷版ISSN：2010-0264
出版年度：2015
卷号：6
期号：2
页码：122-127
DOI：10.7763/IJESD.2015.V6.573
摘要：AbstractA quadratic model (p＜0.0001) was developed by using a central composite design of 50 experimental runs (42 non-center + 8 center points) to assess the efficiency of background chlorine residuals in combating accidental microbial episodes in a scaled-up distribution network (DN) (rig). A known amount of background chlorine residuals were maintained in the DN and a required number of bacteria, Escherichia coli K-12 strain, was introduced by an injection port in the pipe-loop system. Samples were taken at various time intervals at different pipe lengths. A spread-plate count was performed to count the bacterial number. Microbial concentration and time (p ＜0.0001), pipe length (p＜0.022), background chlorine residuals (p＜0.07) and time2 (p＜0.09) were observed as significant factors. The model that was developed was significant. The ramp function of variables shows that, at the microbial count of 10^6, at 0.76 L/min, with a pipe length of 133 meters, a back ground residual chlorine of 0.16mg/L was enough for the complete inactivation of a microbial episode in approximately 18 minutes.
关键词：Central composite design (CCD); distribution network; Escherichia coli; residual chlorine
