Improvement of Biodegradability Index of Industrial Wastewater Using Different Pretreatment Techniques

Biological treatment of industrial wastewater is often the most cost-effective alternative when compared to other available treatment techniques. The wastewater from an industry may contain residues of chemicals, color stuff, high degree of pollutants with high total dissolved solids and suspended solids and high biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentration, as well as much more recalcitrant materials. The biodegradation is therefore a challenge to the wastewater treatment facilities. The biodegradability index (BI) is an indicator of the toxicity of the wastewater and is defined as the ratio between BOD and COD. Its value varies from zero to unity. For the complete biodegradation of an effluent, its BI value must be above 0.3. To improve the BI value, various advanced oxidation process (AOP) techniques have been used as a pretreatment technique. This chapter discusses various AOP pretreatment techniques to improve the BI value and make the effluent suitable for biological wastewater treatment.