Performance of horizontal roughing filter technology for safe drinking water access in rural developing economies

Abstract

There is tremendous reduction of the available fresh water sources due to competing uses and uncontrolled pollution leading to global water scarcity. Worldwide, urban areas are well served with improved quality water unlike the rural areas, with a wide gap in the rural developing regions suffering from limited financial resources and other competing needs. Developing regions’ rural population has resorted to using raw surface water, rendering them vulnerable to water-related infections. This study aims to achieving improved drinking water quality using an easy to build horizontal roughing filter (HRF), to be used as a pre-treatment unit for variably turbid surface water before using slow sand filtration (SSF) units. The HRF comprises locally sourced gravel of different sizes filled into different compartments. The system was operated at filtration rates of 0.35, 0.70, 1.10, 1.45, and 2.00 m/h, with a model suspension of varied turbidity level ranging between 300–450 NTU. The results showed a significant reduction of turbidity level to an average range of 8.8–25.02 NTU for the respective filtration rates that conform to the WHO requirements of <50 NTU for subsequent treatment using SSF units. An overall average removal efficiency of 93.68% was observed for the system operation. It was concluded that the HRF system is a suitable alternative to conventional treatment units for use in rural developing regions, for improving the quality of surface water before using SSF as a final purification unit. Compared to conventional systems, the HRF system impresses with its simple design and low costs.