Rubber Processing Effluent Treatment with Chitosan: A Natural Biopolymer in Comparison with a Synthetic Coagulant

Abstract

Chitosan, a naturally occurring biopolymer extracted from prawn heads was used in the treatment of crump rubber processing effluent for safe disposal into the environment. The triplicate analyses of the effluent samples obtained by composite sampling method indicated high levels of pollution which violated the permissible limits of environmental discharge standards; with a low DO of 0.63mg/L, BOD, 312.00±1.32mg/L and COD, 1069.58±2.42mg/L (mean±SD) respectively. Chitosan was analyzed according to standard procedures; it showed good coagulative potentials from the elemental analysis and a degree of deacetylation of 76.5%. The crump rubber processing effluent was treated with chitosan and Iron (III) Chloride respectively by coagulation and flocculation method and the results obtained via the physico-chemical characterization of the treated effluent showed that the use of chitosan as a coagulant compared favourably with Iron (III) Chloride after treatment. DO levels increased from 0.63mg/L to 3.90 mg/L. There were also remarkable reduction in the Turbidity, Biochemical Oxygen Demand (BOD) and the Chemical Oxygen Demand (COD) levels of the treated samples by over 80% respectively and 70% reduction in the nutrient levels. The efficacy of chitosan in comparison with Iron (III) Chloride suggests that it can be used as a replacement for synthetic coagulants based on its availability and environmental friendliness.