Disinfection of Waste water of Hospital by Chlorine Dioxide / 环境与健康杂志

ABSTRACT

Objective To explore the concentration of required residual available chlorine dioxide(ClO 2 )and optimun contact time for ClO 2 disinfection in order to ensure the microbiological indexes of waste water of hospital disinfected by ClO 2 qualified.Meth ods The waste water samples collected from hospital,to which were aritificially added with predetermined con-centrations of bacteria,were disinfected by various concentrations of ClO 2 (2?4?6?8?10?12mg /L)with various contact time (5?10?30?60?90min).After disinfection,the concentration of residual ClO 2 and the contents of microorganism in waste water samples were determined.Re sults After30-min disinfection by10.0mg /L ClO 2 ,the waste water sample originally containing1.52?10 2 /L E.coli showed a bactericidal rate of99.99%and a concentration of residual ClO 2 at2.5mg /L.After10-min disin-fection by10.0mg /L ClO 2 ,the waste water samples originally containing1.12?10 10 /L Salmonella showed a bactericidal rate of100%and a concentration of residual ClO 2 at2mg /L.After5-min disinfection by10.0mg /L ClO 2 ,the waste water samples o-riginally containing M.tu berculosis at concentration of++++showed a negative result and a concentration of residual ClO 2 at3.5mg/L.Conclusion After the primary treatment,ClO 2 disinfection with contact time of30minutes and a residual concentration of ClO 2 at2.5mg /L could ensure the germicidal effect for E.coli,Salmonella and M.tu berculosis in waste water of hospital qualified.