Combined disinfection method of chlorite and chloramine in water distribution system

摘要

The inventors conducted a research on the control of a bacterial biofilm consisting of ammonia-oxidizing bacteria and heterotrophic bacteria for continuous chlorite administration with or without chloramines application. The inventors tested whether or not the residual concentration for disinfection is maintained with stability by fixing pH at 9.0 after applying chlorite and monochloramine to water. The AOB concentration of the biofilm during the application of chlorite or the application of a combination of chlorite and monochloramine decreased from 6.81.310^2MPN/cm^2 to below a detection limit level (0.6 MPN/cm^2). The AOB of the biofilm was deactivated much faster when the chlorite was used alone than when the chlorite-monochloramine combination was treated. The treatment of the chlorite alone had no effect on the heterotrophic bacteria control, but the treatment based on the chlorite-monochloramine combination showed a significant heterotrophic bacteria disinfection effect. The declines in the average log of the heterotrophic plate counts (HPC) in the bioflim and the water following the disinfection process based on the chlorite-monochloramine combination were 2.80.5 and 2.90.3 compared to pre-disinfection, respectively. In conclusion, the inventors invented the disinfection method based on the Chlorite-monochloramine combination as an effective method for controlling the bacterial biofilm consisting of AOB and heterotrophic bacteria in a water supply pipe.