Correlation between Biochemical Oxygen Demand and Chemical Oxygen Demand for Various Wastewater Treatment Plants in Egypt to Obtain the Biodegradability Indices

Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD) are the most commonly used parameters for the characterization of wastewaters. Both of these parameters have advantages and disadvantages, and the choice usually depends on many factors such as the time period required to determine each one of them. It is essential to obtain a correlation between BOD5 and COD for various wastewater treatment plants, to help in the design and operation of these plants. In this paper, the biodegradability indices (B.I) for several wastewater treatment plants were obtained. The chosen WWTPs covered different regions in Egypt. The obtained correlation between BOD5 and COD will help in evaluating the treatment processes, which in turn leading to improve the performance of these plants. The average B.I. of all investigated wastewater plants was found to be 0.67. This indicates that generally Egyptian wastewater is fairly biodegradable. El Beheira governorate was found to have the highest mean B.I. of 0.88, while the lowest mean B.I. was found to be 0.49 in Alexandria.