Performance Assessment of a Locally Constructed Wastewater Sludge Filter in the Tolon District of the Northern Region of Ghana

Abstract

Wastewater sludge has attracted global interest due to its source, volume, quality, treatment, disposal, and reuse. It impacts human life and ecosystems, especially in areas facing water scarcity caused by factors such as climate change, increasing global population, urbanisation, and water pollution. The study evaluated the performance of a locally constructed filter for treating wastewater sludge, aiming for potential reuse in irrigation and non-critical applications. The filter was constructed using materials like chippings and river sand with varying grain sizes, arranged in three layers. Parameters considered for evaluation included up-flow velocity, hydraulic retention time, flow rate, and filtration velocity. The porosity of the filter materials, such as crushed stones and river sand, was 44.7% and 5.9%, respectively. The pH of the wastewater sludge slightly increased from 6.20 before filtration to 6.61 after filtration. TDS levels decreased from 102.67 mg/L to below detection limits while turbidity reduced from 8198.67 to 19.0 NTU post-treatment. Salinity levels dropped significantly from 201 to 0.002 mg/L, indicating a 99.99% removal efficiency. Dissolved oxygen (DO) and other parameters also improved. The counts of total coliform, faecal coliform, and E. coli decreased markedly from 200 to 100 CFU/100 ml, 60 to 8 CFU/100 ml, and 25 to 4 CFU/100 ml, respectively. The designed filter effectively improved the quality of wastewater sludge post-treatment, bringing it within acceptable limits. Future research could examine the filtered and unfiltered wastewater sludge produced at the Savannah Agricultural Research Institute water treatment plant for irrigating various vegetables and monitoring their growth and yield.

Keywords: Wastewater sludge, filter design, filtration, wastewater quality, irrigation