TREATMENT EFFICIENCIES OF SAND-BIOCHAR AND SAND FILTRATION SYSTEMS FOR HOUSEHOLD USE

This project focused on the comparative analysis of two household water filtration systems: a conventional sand filter and a hybrid sand-biochar filter. The aim was to develop cost-effective, scalable solutions capable of improving water quality by removing physical, chemical, and biological contaminants, thereby ensuring safer drinking water for domestic use. Filtration media included layers of gravel, coarse sand, fine sand, and a biochar layer produced from carbonized coconut shell agro-waste. The systems were constructed considering media layering and porosity to optimize contaminant removal. Water samples from river upstream, river downstream, and pond sources were treated and analyzed for key parameters including turbidity, pH, electrical conductivity, total dissolved solids, heavy metals (notably lead and iron), nitrate, phosphate, chemical oxygen demand (COD), and microbial indicators (E. coli and total coliforms). Laboratory results demonstrated that both filter systems significantly improved water quality; however, the sand-biochar filter exhibited superior performance, especially in the removal of heavy metals (achieving up to 91.1% lead removal against 26% for sand filter), turbidity (91.5% versus 80.3), and microbial contaminants (E. coli; 71.65% versus 64.76%). The biochar’s high porosity and surface chemistry contributed to enhanced adsorption and antimicrobial effects, surpassing the traditional sand filter in critical contaminant reduction. Nonetheless, neither filter completely eliminated microbial pathogens to meet WHO standards, indicating the necessity of secondary disinfection such as boiling or solar disinfection. Dissolved solids and nitrate removal were limited by both systems. The study concludes that integrating biochar into sand filtration substantially enhances water purification efficacy, making the sand-biochar filter a more effective, sustainable, and affordable option for domestic water treatment in resource-limited settings. Recommendations include promoting sand-biochar filters for household use and incorporating additional disinfection steps to ensure microbiological safety.