Microbial counts and pesticide concentrations in drinking water after alum flocculation of channel feed water at the household level, in Vinh Long Province, Vietnam

Low technology water supply, treatment and sanitation techniques were reviewed in a Vietnamese village in the Mekong River Delta as part of an AusAID Project to reduce poverty and to improve the overall living standards and health in the Cuu Long (Mekong) delta for 500,000 rural poor. It was found that dosing of canal water in 200-l ceramic jars with alum, PAC or PAC followed by hypochlorite provides a high level of treatment for drinking water at the household level in a rural village setting in the Mekong River delta. Seventy per cent (7 in total) of the 24 samples collected showed that Escherichia coli levels per 100 ml in the jars after treatment showed a ‘no risk’ profile (0 E. coli 100 ml-1) i.e. the water would be considered to be of very good quality for drinking according to World Health Organization Guidelines for Rural Drinking Water Supply. This included the eight samples that were dosed with hypochlorite. The remaining 30% of samples (seven in total) ranged from 14 to 47 E. coli 100 ml-1 which is considered an intermediate risk (10‒100 E. coli 100 ml-1) according to WHO guidelines. All control water samples (eight in total) were high or very high risk (>100 E. coli 100 ml-1). Pesticide concentrations generally were low and met Vietnamese drinking water quality criteria.