Electrochemical Pretreatment of Wastewater from Color Photograph Processing Unit

Abstract

Wastewater emanating from color photograph processing units is usually in small quantities (5–20 L per day) and contains high concentrations of recalcitrant organic compounds. Disposal of such highly recalcitrant wastewater into a public sewer may result in an inhibiting effect on biological treatment system of a sewage treatment plant and thus these persistent organics can escape to receiving water bodies. A continuous full-scale treatment unit for such a small quantity of wastewater is not a viable option, economically and technically. In this study, a small batch type of an electrochemical reactor has been utilized to investigate the feasibility of electrochemical treatment of wastewater from a color photograph processing unit. The treatability studies were conducted using cast iron electrode. It was found that the cast iron electrode was efficient in removing both chemical oxygen demand and biochemical oxygen demand to the levels that meet the standards for discharge to surface water and public sewer. The energy consumption to meet the standards for sewer disposal was less compared to that of surface water disposal. The electrochemical reactor was found to be cost effective in both installation and operation for meeting the sewer disposal standards. It was concluded that the wastewater could be partially treated (pretreatment) electrochemically to meet the standard for sewer disposal rather than that of surface water disposal.