Application of slow sand filter for greywater treatment at GETFund hostel, UENR, Sunyani

Greywater reuse is essential in light of the growing water scarcity, which has left one-third of the world's population without access to clean water. Greywater treatment and reuse is an alternative method to alleviate freshwater withdrawal pressures and reduction of wastewater (pollutants) discharge into the environment. In this pilot-scale experimental study, a slow sand filter system (SSF) was constructed to treat greywater for non-potable use at the GETFund hostel of the University of Energy and Natural Resources (UENR), Ghana. The treatment efficiency of the constructed SSF was assessed and the results compared with the GEPA standards. A grab sampling technique was used, and six samples of greywater were collected in February 2025. The slow sand filter was set-up using fine sand, coarse sand, gravel and stones of diameters 0.2–0.5 mm, 1–2 mm, 2– 4 cm and 6 cm, respectively. The fine sand filter had a uniformity coefficient (UC) of 1.83, porosity of 0.35 and a specific density of 1.48 mg/m3. The slow sand filter has a hydraulic retention/residence time (HRT) of 12 h and a hydraulic loading rate (HLR) of 0.48 m3 per day. The treated greywater effluent was compared with the Ghana Environmental Protection Agency (GEPA) standards for discharge of wastewater. The average effluent values and corresponding percentage reduction efficiencies for physicochemical parameters, including COD, turbidity, BOD, alkalinity, EC, TDS, colour, bicarbonate, pH, and temperature, are 85.99 %, 77.95 %, 75.00 %, 70.04 %, 53.80 %, 53.67 %, 53.62 %, 8.48 %, 8.00 % and 7.80 %, respectively. SSF technology removed most contaminants, but showed low efficiency with respect to bicarbonate, pH, and temperature. The treated greywater complied with the GEPA guidelines; however, for practical usage, the test should be extended to incorporate microbiological characteristics and nutrients, which are essential for greywater reuse. This pilot study is a prelude to an extensive investigation on SSF.