Disinfection methods for package water treatment plants

The disinfection performance of 7 locally produced package plants was evaluated at Umgeni Water's Process Evaluation Facility, South Africa, in terms of the WHO guidelines for the microbiological quality of drinking water. The disinfection technologies evaluated include: ceramic membrane ultrafiltration, ultraviolet radiation, cross-flow microfiltration, slow sand filtration and two methods of chlorination. The plants using pre-chlorination, ultraviolet radiation and ceramic membrane ultrafiltration conformed to the WHO guidelines. The treated water from the slow sand filter did not consistently conform to the WHO guidelines, possibly as a result of the relatively high raw water turbidity (> 4000 NTU). The initial results obtained from the cross-flow microfilter did not support a conclusion as the samples were not necessarily representative of the final water quality.