Performance of sand and granular activated carbon filtration coupling in tertiary urban wastewater treatment in Algeria

This work aims to test the efficiency of natural, local and abundant granular media for a tertiary treatment for urban wastewater in Algeria by coupling sand filtration (SF) and granular activated carbon filtration (GACF). The sand media was provided from South Algeria and granular activated carbon (GAC) manufactured by Algerian Company. The pilot consists of two circular columns; the first one filled with sand and the second one with GAC. The SF column was fed by the urban wastewater from the secondary treatment (activated sludge), 5 h a day (5 d week–1) with a constant flow-rate of 30 L h–1, then 5 L of filtered water fed the GACF column. The water was analyzed daily at the inlet and outlet of each filter (SF, GACF). After sixteen weeks of operation, the coupling of sand and activated charbon allowed a reduction of over 75% of the physical–chemical parameters; suspended solids, turbidity, conductivity, biochemical oxygen demand, chemical oxygen demand, hardness, magnesium, calcium, chlorine, nitrates, and phosphates, whereas only 56% has been reached by SF alone and 38% for GACF alone. It can be concluded that coupling sand to activated carbon is efficient to enhance its removal performance and, consequently, improve wastewater quality. Using natural and local materials for treating wastewater is expected to be a promising alternative based on sustainable development.