Valorization of the Moroccan Opuntia ficus indica cactus racket juice in the coagulation-flocculation for the hospital effluents treatment

Abstract

The major challenge facing water treatment specialists is to find an effective, ecological, and efficient bioflocculant to depollute aqueous media while avoiding the harmful impacts of chemical flocculants on public health and the environment. This research aims to evaluate the effectiveness of Opuntia ficus indica (OFI) cactus racket juice as a bioflocculant in the treatment of organically-laden hospital liquid waste, using the process of coagulation with aluminum sulfate followed by flocculation. To this end, the study consists of optimizing the removal of chemical oxygen demand (COD) by controlling the key factors of this technology, namely solution pH, aluminum sulfate concentration, and bioflocculant (OFI) concentration using response surface methodology (Box Behnken design).  The COD removal rate was close to 92.72% for a pH of 4, a volume of aluminum sulfate of 14 ml, and a volume of cactus racket juice (OFI) of 14 ml. This coagulation-flocculation by OFI also showed a 46% reduction in 5-day Biological Oxygen Demand (BOD5), 85% in nitrate ions, and 75% in phosphate ions. In light of these results, which provide a roadmap for prospective research to replace synthetic flocculants with low-cost natural bio-flocculants, this technology could be applied on an industrial scale.