【摘要】 目的评价城市回用污水中病毒对人体健康的风险。方法于2002年5～11月对西安北石桥污水净化中心二级处理出水和常规再生工艺处理后的回用水中的总大肠杆菌和粪大肠菌进行检测并进行数据的正态分布假设检验。同时观察了液氯消毒对污水中大肠杆菌的去除效果。利用评价饮用水中病原微生物感染概率的beta-Possion模型和MonteCarlo模拟方法对城市回用污水中病毒对人体健康的风险进行评价。结果二级处理出水和回用水中粪大肠菌群浓度呈对数正态分布。污水中大肠杆菌去除率在7mg/L和15mg/L液氯接触20min时分别为4log和5log。城市回用污水用于城市绿化和灌溉农田时,水中病毒对人体健康的年风险均值分别为1.21×10-6和4.31×10-8,且其最高风险均低于美国EPA地表水处理规范(SWTR)规定的生活饮用水可接受年风险(10-4),即使回用于对人体暴露量较大的景观娱乐用水(如游泳),其年风险值<10-4的概率也在90%以上。结论城市回用污水用于城市绿化和灌溉农用时,水中病毒对人体健康风险很小。更多还原

【Abstract】 Objective To carry out the risk assessment on health effects of viruses in reused wastewater in city.Methods During May-November in2002,the concentration of total coliform and fecal coliform in water sample s collected from waste water after secondary treatment of wastewater treatment plant and reused waste water treated by conventional wastewater-reuse technical process in Xian Baishiqiao Wastewater Treatmen t Center were determined,and the hypothesis testing on the normal distribution of monitoring data was carried out.Meanwhile the removal efficacy of coliform in wastewater with chlorine disinfection was ob-served.The beta-Possion model,the model for evaluating the infection probability of pathogenic microorganism in drinking water,and Monte Carlo simulated method were used for the risk assessment on health effects of viruses in reused wastewater in city.Re sults The monitoring data on concentrations of fecal coliform in water samples collected from secondarily treated wastewater and reused wastewater showed log-normal distribution.The removal efficacies of coliform from wastewater were4log at condi-tions of7mg /L chlorine and20-minute contact time,and5log at conditions of15mg /L chlorine and20-minutes-contact time.The means of annual risk value of health effects of viruses in reused wastewater were1.21×10 -6 for the reuse of wastewater in greening and4.31×10 -8 for the reuse in irrigation of farmland respectively,the highest risk values for these two reuse methods were all below10 -4 ,the acceptable annual risk value for drinking water ruled by Surface Water Treatment Rules published by USEPA.The probability of annual risk value<10 -4 was even more than90%in reuse for natural and artificial landscape and entertainment (eg.swimming).Con clu sion The viruses in the reused wastewater after conventional treatment for greening and irrigation of farmland presented less risk to human health.更多还原