Study of performance of existing pond sand filters in different parts of Bangladesh

Pond Sand Filter (PSF), a small scale filtering unit has been widely used in the saline problem areas of Bangladesh. Recently it has also been used in arsenic problem areas of the country. In this study the performance of the existing 61 nos. PSF in 13 upazilas with arsenic and saline problem areas were investigated. A survey was carried out among the beneficiaries to get their opinion towards the existing PSFs and evaluate the social aspects of PSFs. The study also compared the PSFs models designed by DPHE, NGO Forum and Danida. The study examined the effectiveness of various treatment unit of three model PSFs. Turbidity, colour, faecal coliform were tested for the raw and treated water at various steps of the treatment process. Turbidity removal of DPHE, NGO forum and Danida Model was 93.19%, 87.5% and 92.25% respectively. Only 6% of PSF treated water found coliform-free. Performance assessment of PSFs were done in terms of quality of filtered water, ease of operation and maintenance, production capacity, efficiency of filter and acceptability.