A treatment feasibility study of a cellulose acetate manufacturing wastewater

Abstract

Physical-chemical treatment has been shown to be highly successful in treating certain wastewaters and, to some degree, this treatment approach has been promoted as a panacea for all wastewater treatment problems. This project was designed to investigate the best method of treating a wastewater composed primarily of soluble organic material resulting from a cellulose acetate manufacturing process. Both physical-chemical and biological treatment processes were applied to the wastewater to determine whether the performance of the physical-chemical approaches would be less than, equal to, or greater than the performance of the biological treatment system. A further intention of the study was to help in generating guidelines concerning the limitations, if any, of physical-chemical systems. Experimental results showed that chemical treatment using lime or ferric chloride produced only marginal reductions in the COD of the wastewater. From these chemical experiments it was discovered that the wastewater had an extremely high buffering capacity. Adsorption with granular carbon produced a significant reduction in COD provided that a sufficient detention time was allowed. However, final COD values were still too high for discharge under most conditions. In a fairly short aeration period, activated sludge treatment produced an effluent COD value almost one-third the minimum effluent COD value from carbon adsorption. It was therefore concluded that for the wastewater studied t biological treatment was much more efficient than a chemical or physical treatment approach.