Electro-degradation and biological oxidation of non-biodegradable organic contaminants

The speciality chemical process requires large volumes of water of high purity and generates equally large volumes of wastewater. The generated wastewater is complex and highly variable with respect to its nature, containing high levels of chemical oxygen demand (COD), dissolved and suspended solids, a medium to low level of biochemical oxygen demand, a considerable amount of total organic halogen and an intense colour. In the present study the actual effluent was collected from the organic industry and various experiments were conducted to reduce the pollution load and reuse treated wastewater.The wastewater typically contains COD about 48,000 mg L−1. When it was distilled, the COD of the condensate reduces to 17,000 mg L−1 which was subjected to electrolytic degradation and subsequently biological oxidation. The operation was continued using various microorganisms such as Bacillus subtilis, Pseudomonas aeruginosa and Proteus vulgaris in a batch reactor. Minimum of 80% reduction of COD was obtained in the combined process.