Impact of sand depth on pollution parameters removal in treated wastewater from the Kaf Doukhane STWW (Ghardaïa – Algeria)

In the Mzab, treated wastewater constitutes a fraction of water resources. This article discusses a methodology for valorizing these resources to support local sustainable development. Filtration processes constitute a simple, ecological means of treatment. Our study examines the influence of sand depth in submerged sand filters on the removal of pollution parameters in treated water from the Kaf Doukhane station, upstream of the Mzab valley. We studied the impact of four sand depths (25, 55, 85 and 110 cm) on the removal of suspended solids (SM), turbidity, NO3-, NO2-, NH4+, PO4H2, COD and BOD5. Filtration tests were carried out on a test strip at the laboratory of the University of Ghardaïa using three types of sand as filter media. Our results indicated that sand from the Metlili Valley quarry was the most effective and a sand depth of 110 cm achieved the highest performance. However, the purification efficiencies at different depths varied considerably, reaching up to 97%, and the treated waters met WHO standards for potability and irrigation. Therefore, any sand depth between 110 and 300 cm would be suitable for sizing the submerged sand filter intended for the treatment of effluents from the Kaf Doukhane STWW.