考虑THM的管网水质服务水平多目标优化

Multi-objective Optimization of Water Quality Performance Considering THM in Water Distribution Systems

针对供水管网中余氯及氯仿(THM)服务水平优化问题,提出了一种衡量THM服务水平的表达式,推导了THM-I/O模型,建立了以管网余氯服务水平最大化、THM服务水平最大化以及加氯费用最小化的多目标优化模型。考虑了主体水余氯衰减系数、基于余氯消耗的THM生成比例系数、出厂水THM浓度、加氯点数量4个影响因素对优化结果Pareto前沿面的影响。结合一管网算例,采用EPANET_MSX模拟余氯衰减和THM生成,利用实数编码的非支配排序遗传算法Ⅱ(NSGA-Ⅱ)进行优化,可得到各种情况下的Pareto前沿面。计算结果表明,随着主体水余氯衰减系数减小,加氯费用减少,THM服务水平增加。基于余氯消耗的THM生成比例系数和出厂水THM浓度的减小均能提高THM服务水平,但对加氯费用没有影响。增加加氯点虽然能减少余氯投加,但加氯站建设费用加大了总加氯费用。降低主体水余氯衰减系数是提高管网水质服务水平最经济有效的方法。

As for optimizing performance of chlorine systems, an expression measuring THM performance And a multi-objective optimization model considering level of THM performance and minimizing cost of chlo bulk chlorine decay coefficient, coefficient of propor initial THM concentration in treated water and numhe Pareto front of the multi using EPANET - MSX. and trihalomethane （THM） in water distribution and a derivation of THM-I/O model were proposed. maximizing level of chlorine performance, maximum rination was also established. tionality between THM and r of boosters, were evaluated objective optimization model. An improved non-dominated Chlorine decay and THM Four factors, including chlorine consumption, to study their effects on generation were simulated sorted genetic algorithm-Ⅱ with integer code was proposed to optimize the model, and Pareto fronts could be obtained under different conditions. Results show that with the decrease of bulk chlorine decay coefficient, cost of chlorination can be reduced and level of THM performance will be improved. Diminishing coefficient of proportionality between THM and chlorine consumption and initial THM concentration out of reservoir can both improve the level of THM performance, but can not affect the cost of chlorination. Increasing number of boosters can reduce dosage of chlorine, but booster station construction will increase total cost of chlorination. There-fore, reducing the bulk chlorine decay coefficient is the most economical and effective method.