Removal of Chemical Oxygen Demand (COD) from Domestic Wastewater Using Hybrid Reed Bed System

Abstract

Hybrid reed bed systems (HRBs) have a good potential for wastewater treatment in developing countries due to its simple operation and low implementation costs. HRBs units were constructed at Bukit Putri, in UKM university campus, Malaysia, of which were planted with Scirpus grossus plants, commonly known as club-rush or bulrush (water loving plants). Generally, HRBs are classified into two categories: surface-flow and subsurface-flow. Both systems are capable of removing Chemical Oxygen Demand (COD) from different types of wastewaters. The aim of this study was to determine the percentage removal of Chemical Oxygen Demand (COD) at different concentration of domestic wastewater by using a HRB systems. This hybrid system was arranged in a serial stages consisting of a surface-flow (SF) bed, followed by a vertical-flow (VF) bed and finally by a horizontal-flow (HF) bed. In the present study, the performance of the HRB on domestic wastewater, particularly on COD, with and without plants was investigated. It is observed that the planted system with Scirpus grossus had performed better than the unplanted system. The result shows that the COD removal varied between 60 and 92%, depending on the loading rates (53-86 mg/L/day). The treatment system was operated for three months in the continuous flow process. Based on the results, it can be concluded that the HRB system ensures a more stable removal of organic pollutants (COD) from domestic wastewaters.