2017 年 1 巻 1 号 p. 15-25
On-site resource oriented sanitation system is one of expectable concepts to address a protection of water resources in developing countries due to low installation cost and resource recovery from human excretes. The present study investigated fates of indicators and pathogens originated from greywater and compost in soil to assess microbial risks when the greywater and compost are reused. Compost and greywater obtained from pilots in Burkina Faso were amended in experimental field with lettuce cultivation and the fate of pathogens in the soil was measured. The results suggested that (i) bacterial fates in compost reuse were fitted to log normal linier and those in greywater were maintained in field soil (ii) the bacterial end-off kinetics in Soudano-Sahelian climate were more rapid than that of reference values. (iii) the reduction of E. coli and Salmonella in the present condition was significantly different but that of Salmonella and Enterococci had no difference. (iv) effect of contaminated soil on annual risk probability was lower than direct handling of greywater and compost but not negligible. The present assessment also suggested that presented current model were required further technical improvement from the view of the biological risks.
