Slow Sand Filter Performance Enhancement Using Bioaugmentation for Rural Drinking Water Supply Systems

Abstract

Slow sand filtration is a widely adopted and low-cost drinking water treatment technology for rural communities due to its operational simplicity, minimal energy requirements, and effective removal of suspended solids and microbial contaminants. However, conventional slow sand filters may exhibit limited efficiency under fluctuating raw water quality conditions and elevated organic loading. The present study investigates the enhancement of slow sand filter performance through bioaugmentation for rural drinking water supply systems under controlled operating conditions. The research focuses on evaluating microbial activity, contaminant removal efficiency, filtration stability, and water quality improvement associated with bioaugmented filtration systems. Experimental analysis was conducted to examine the influence of bioaugmentation inoculum, filtration rate, sand media characteristics, hydraulic retention time, and influent water quality on the removal of turbidity, organic matter, pathogenic microorganisms, and dissolved contaminants. Results demonstrate that bioaugmentation significantly improves biological degradation processes within the schmutzdecke layer, resulting in enhanced removal of organic pollutants and microbial contaminants. The study further reveals that optimized microbial inoculation and operational conditions contribute to stable biofilm development and improved filtration performance under varying environmental conditions. Increased biological activity within the filter bed enhanced nutrient transformation and reduced pathogen survival, thereby improving treated water quality and operational reliability. Comparative assessment with conventional slow sand filtration systems confirms the advantages of bioaugmented filters, including improved contaminant removal efficiency, reduced maintenance frequency, and enhanced adaptability for decentralized rural water treatment applications.