RESUMO
Use of Grewia biopolymer as a natural coagulant aid was explored in a dual-coagulant system (conventional coagulant + biopolymer) for wastewater treatment. Such use not only improved turbidity removal efficiency over a wide pH range (5-9) but also helped reducing the concentration demand of inorganic coagulants by 25-50 %. Response surface methodology was employed for investigating the interaction between factors (initial pH, coagulant, and biopolymer concentration) affecting coagulation/flocculation of aqueous laterite suspension, and process optimization for more than 80 % turbidity removal in the desired final pH range (6-7). Mechanisms potentially involved in coagulation/flocculation using biopolymer was elucidated. Techno-economic assessment indicated the feasibility of pilot-scale production of the biopolymer and its use in wastewater treatment. This study demonstrates that Grewia biopolymer has the potential to be used as a coagulant aid and will help researchers select appropriate markets for further cost reduction and successful implementation of biopolymer-based wastewater treatment.
