Installation of a water disinfection system in a Mexico City hospital

With a view to evaluating a small-scale water disinfection system based on production and application of oxidizing gases, the level of equivalent residual chlorine and the degree of contamination by fecal and total coliform bacteria was assessed at various points in the drinking water system of a Mexico City hospital before and after installation of the disinfection equipment. Tests done in May and June 1989, prior to installation of the equipment, showed that residual chlorine concentrations were lower than the national standard in most of the samples and that a sizable portion of these samples were also contaminated with fecal and total coliform concentrations exceeding national standards. After installation of the disinfection system at the main inflow to the hospital's drinking water supply in August 1989, the equivalent residual chlorine concentrations were found adequate and no coliform bacteria were detected. These results indicate that the oxidant mixture generated by the newly installed system was effectively disinfecting the water.