CHLORINATION OF SURFACE WATERS IN THE BENGAL BASIN

Presented on behalf of Project Well; Arsenic Foundation, Dhaka Communiity Hospital, and UNICEF Dhaka.

After the realization 9 years ago that 50,000,000 people in Bangladesh were drinking water with high levels of arsenic, 10,000,000 have switched to less contaminated wells. But progress has been slow. Some organizations and villages have returned to using surface waters. The traditional Dugwells have been improved by strictly following WHO guidelines, but that seems not to be enough. Many of these soon developed excessively high levels of coliform bacteria. Fortunately there was no widespread increase of diarrheal diseases. I will present data taken in the last two years from each of these there groups showing how chlorination by chlortek or bleaching powder at least every 2 weeks appears to solve this problem and brings the bacteria level down to acceptable levels.