RESUMEN
The study was done to determine the effect of bleaching powder, alum and potassium permanganage on contaminated water. The natural water samples were collected in Yangon from February 1989 to January 1990. They were treated with these 3 chemical agents and faecal coliform (FC) count was determined by multipletube method. Bleaching powder and alum could reduce FC by 3 logs and 2 logs within 0.5 and 1 hour respectively. However, potassium permanganate could reduce only 1 log within 1 hour. As expected, the data showed that water treatment with chlorination was the most effective means of providing good microbiological quality of drinking water. After bleaching powder, potash alum was also found to be quite effective in cleaning the pathogens and turbidity from the water.