供水管网余氯衰减变化规律及模型研究

研究了水温T、总有机碳TOC及初始氯浓度C0对主体水余氯衰减系数kb的影响;通过管网水质模拟中试装置探究初始氯浓度、流速对管网总余氯衰减的影响;推算管壁余氯衰减系数kw,并分析余氯、细菌总数、浊度及UV(254)指标间的相关性。结果表明,一级模型可以较好地描述管网总余氯衰减变化,在主体水中仅水温较高时一级模型相关系数较高,而平行一级模型拟合度不易受水温影响,相关系数>0.96;各因素对kb影响的主次关系为T>TOC>C0;总余氯衰减系数k、kw与管网初始氯浓度及流速均呈正相关,kw与雷诺数之间存在良好的指数关系;细菌总数(HPC)与初始氯浓度呈负相关、与浊度无明显相关性、与UV(254)呈正相关,浊度与UV(254)相关性良好。

Decay Pattern and Model of Residual Chlorine in Water Supply Network

The effect of water temperature(T),total organic carbon(TOC)and initial chlorine concentration(C0)on the decay coefficient kb of residual chlorine in bulk water was studied through pilot-scale experiments.The effect of C0 and flow velocity on the decay of total residual chlorine in water supply network was explored,and the decay coefficient kw of residual chlorine in pipe wall was calculated.Moreover,the correlations among residual chlorine,total bacteria,turbidity and UV254 indices were analyzed.The experimental results showed that the first order model properly described the decay of total chlorine in the pipe network,but the correlation coefficient of the first order model was high only when the temperature was high in the bulk water.The parallel first order model was insensitive to water temperature,and the correlation coefficient was beyond 0.96.The influences of the factors to kb was T>TOC>C0;total residual chlorine decay coefficient k and kw were both positively correlated with C0 and flow velocity.Strong exponential relationship between the kw and the Reynolds number was identified.HPC showed a negative correlation with C0,insignificant correlation with the turbidity,and a positive correlation with UV254.Turbidity was well correlated with UV254.