부산대학교 도서관

A household-installed water treatment system makes it possible to establish a sustainable water supply in depopulated areas, but the health risks of the system users need to be protected properly because the quality of source water is not always excellent. To manage the users’ health risks, we calculated the microbial risk of Legionella pneumophila (causing a significant pneumonia to the elderly) and chemical risk of disinfection byproducts. It was found that the loss of disability-adjusted life years per peron per year (DALY loss pppy) were significantly below the tolerable disease burden proposed by World Health Organiation (WHO) (10-6 DALY loss pppy) when the initial concentration of free chlorine in a tank was adjusted to 0.5 mg/L. It takes for about 80 days until cumulative risk of infection exceeds tolerable risk (10-4 infection/person/year)proposed by USEPA when the presence of Acanthamoeba, the host of L. pneumophila, was assumed in the storage tank of treated water even the injestion ratio of free chlorine was 2.5 mg/L. The disease burden caused by trihalomethane as a disinfection byproduct was about one hundred times smaller than the WHO tolerable disease burden at all conditions of the free chlorine concentration. These result mean that the initial free chlorine concentration of 2.5 mg/L and replacement of membrane after 2 months can be available as critical limits of critical control point in the Water Safety Planning for the household-istalled water treatment system.