Green Alternatives to Chemical Coagulants: Cactus and Spinach Bioflocculants for Textile Wastewater Traetment

Abstract The intensive use of chemical coagulants in textile wastewater treatment raises environmental and health concerns related to toxic residues and non-biodegradable sludge. This study investigates the efficiency of plant-based bioflocculants derived from Opuntia ficus‑indica (cactus) and Spinacia oleracea (spinach) as sustainable alternatives to conventional chemical agents for textile effluent treatment. Cactus gel, cactus powder, and spinach powder were prepared, characterized, and applied either alone or in hybrid systems with aluminum sulfate and the synthetic flocculant Preastol 2539. Experiments were conducted on real textile wastewater collected from the Sebdou industrial zone (Algeria). Treatment performance was evaluated through turbidity and chemical oxygen demand (COD) removal, as well as changes in physicochemical parameters. The chemical control achieved the highest removal efficiencies (91.48% turbidity and 71.53% COD). However, spinach powder used in hybrid mode reached comparable turbidity removal (91.18%) with substantial COD reduction (66.34%). Cactus gel and cactus powder also demonstrated high turbidity abatement (up to 89.95%), particularly under optimized dosage and salinity conditions. The results confirm that plant-based bioflocculants, especially spinach powder, can significantly reduce reliance on synthetic reagents while maintaining high treatment efficiency. These findings support the integration of locally available, biodegradable materials into sustainable textile wastewater management strategies