The Effect of Disinfectants on Waste Water from Medical Centers

Abstract

Microbiological, physicochemical study on waste water, and the determination of concentrations of disinfectants in waste water obtained from medical centers were performed. The components of waste water from the medical centers were classified into the following four patterns based upon time-course variations; Coliform group and total colonies, time-course variation of which showed close relation with patients population movement, were classified as group 1. BOD, COD, SS and Kje-n which showed the similar time-course variation as those in group 1, but in higher range of variation were cassified as group 2. Disinfectants such as phenols, formaldehyde and chlorhexidine which showed an original pattern of time-course variation unrelated with those group 1 and 2 were classified as group 3. Chloride ion, pH and metals which present almost constant time-course phase were classified as group 4. It was considered that those which belonged to group 1 and 2 were mainly influenced by the waste water originated in the daily life, whereas those which belonged to group 3 and 4 were much more influenced by the waste water originated in the medical treatment.
Since the concentrations of the disinfectants detected in this study were considerably lower compared to the concentrations of other components in waste water, it was therefore clarified that the disinfectants in waste water did not show interference for the bioactivation of activated sludge.