Evaluation of Plastic Household Biosand Filter (BSF) In Combination with Solar Disinfection (SODIS) For Water Treatment

Efficiency of a household plastic biosand filter (BSF) for the removal of turbidity and fecal contamination was evaluated. Water of river Ravi was used as influent. Water filtered through BSF was further treated using Solar Disinfection (SODIS). The study was conducted for raw water with low pollution level (total coliforms <500 MPN/100 ml) and high pollution level (total coliforms between 500-20,000 MPN/100 ml). The average value of turbidity removal by BSF was 94.5 % with 0.9 NTU as average turbidity of effluent. For raw water with low pollution level, the BSF was able to achieve a maximum of 2.2 log(10) unit reduction (99.4 %) for total coliforms (39 MPN/100 mL in effluent) and 1.95 log(10) unit reduction (98.5 %) for fecal coliforms (9 MPN/100 mL in effluent). While for raw water with high pollution level, the maximum removal of 1.5 log(10) unit (97.5 %) for total coliforms (1430 MPN/100 mL in effluent) and 1.8 log(10) units (98.4 %) for fecal coliforms (387 MPN/100 mL in effluent) was achieved in BSF. To make the effluent fit for drinking it was further treated using SODIS, which rendered the BSF effluent fit for drinking with zero fecal coliforms count (for full sunny and partially cloudy conditions). Newly proposed plastic BSF could be a good replacement of already used concrete household BSF (used in more than 63 countries) being cheaper in cost and lighter in weight by 85% and 80%, respectively than the concrete BSF.