Behavior Analysis and Risk Evaluation of Paftogens for the Water Utilization System in the Watershed

为了解决流域水资源短缺的问题，在水资源利用系统中经常采用回用水和循环用水。本研究的目的是建立水资源利用中病原体传染风险的评价模型，取得了以下结果：1）为减轻缺水危害而进行的污水再生中病原体的风险评价在各种情景下，对阿武熊流域污水再生中脊髓灰质炎病毒的传染风险进行了评价。为预测评价流域缺水状况，采用连续两天流量同时发生概率矩阵表示饮用水取水口处河流流量的波动。水质（总大肠菌群和SS）也被确定与流量和它们之间的矩阵。当消毒对脊髓灰质炎病毒的灭活率大于99.9%时，污水回用可以在不增加传染风险的情况下减轻缺水的危害。2）病原病毒在河水中的行为研究以脊髓灰质炎病毒1型为材料，通过实验分析了病原病毒在河水中悬浮物（SS）上的吸附和灭活办公室（非吸附）病毒的情况。据观察，病毒吸附到SS的比率与SS浓度成比例地增加。河水中的游离病毒在最初两天内急剧灭活。两天后病毒浓度为初始浓度的十分之一。从第2天开始，病毒灭活率逐渐降低，约23天灭活90株病毒。以上结果可为建立流域内最小化传染风险的水资源利用系统提供参考。

In order to solve the water shortage in the watershed, water reuse and recycling often have been employed in the water utilization system. The purpose of this study was to develop the evaluation model for infectious risks by pathogens in the water utilization.The following results were obtained:1) Risk evaluation of pathogens in wastewater reclamation for reducing the damage of water shortageInfectious risks by poliovirus through wastewater reclamation in the Abukuma watershed were evaluated under various scenarios. For predictive evaluation of water shortage in the watershed, fluctuation of river flow rate at the intake point of drinking water were represented with the matrix of simultaneous probability of flow rates in consecutive two days. Water qualities (total coliforms and SS) were also determined with matrices between flow rate and them. When the inactivation efficiency of poliovirus by disinfection was higher than 99,9%, the damage of water shortage could be reduced by wastewater reclamation without any increase of infectious risk. In case of tower inactivation efficiency, infectious risks would exponentially increase with reduction of damage of water shortage.2) Studies on the behaviors of pathogenic viruses in river waterThe adsorption of pathogenic vims to suspended solids (SS) and the inactivation office (not adsorbing) virus in river water wete analyzed through some experiments using poliovirus type 1. It was observed that the ratio of viruses adsorbing to SS was increased in proportion to the SS concentration. Free viruses in river water woe drastically inactivated in first two days. The viral concentration after two days was onetenth of initial concentration. Since the second day, the inactivation rate of fiee viruses became smaller and it took about 23 days that ninety peicents of vims weie inactivated.Above results witt be able to contribute to establishment of the water utilization system minimizing infectious risks in the watershed.