Fixed-bed column sorption kinetic rates on the removal of both biochemical oxygen demand (BOD5) and chemical oxygen demand (COD) in domestic greywater by using palm kernel activated carbon

Abstract

The increasing organic loads, specifically Biochemical Oxygen Demand (BOD5) and Chemical Oxygen Demand (COD), in water bodies has necessitated greywater treatment before disposal. Limited studies have explored sorption kinetics of BOD5 and COD removal using activated carbon from palm kernel shell in fixed-bed columns. This study investigated continuous sorption using activated carbon from palm kernel in removing BOD5 and COD from domestic greywater. The activated carbon had a density of 0.46 g cm−3 and a surface area of 584 m2 g−1. The experiment was conducted in a 37 cm high, 2.5 cm diameter Perspex column, with varying flowrates of 5–15 mL min−1, and bed depths of 10, 15, and 20 cm. Greywater with BOD5 concentration of 251 mg L−1 and COD of 421 mg L−1 was used for this study. Effluent was collected at specified time intervals, analyzed for BOD5 and COD, and fitted to the Thomas, Yoon-Nelson, Adam-Bohart, and Bed Depth Service Time (BDST) models. The Yoon-Nelson model exhibited good agreement, as compared to Thomas and BDST while the Adam-Bohart model showed lower fit. The adsorbent demonstrated sorption capacities of 34 mg g−1 for BOD5 and 56 mg g−1 for COD, suggesting its potential for greywater treatment, particularly in BOD5 and COD removal.