Coconut-Fibre Biofilm Wastewater Treatment System in Sri Lanka: Microcosm Experiments for Evaluating Wastewater Treatment Efficiencies and Oxygen Consumption

This study evaluated the performance of a coconut-fibre biofilm wastewater treatment system (COTS) by utilizing microcosm experiments in the laboratory.In the microcosm experiments, two types of wastewater, synthetic sewage and leachate, with different pollutant loads were used.Three coconut-fibre conditions, a single bundle (low fibre density), two bundles (high fibre density), and no coconut fibre (blank) were set in the experiments.Water quality parameters (pH, DO, EC, BOD, COD, TC, TOC, TN and TP) of effluents were measured at one-week intervals, and removal % of BOD, COD, TC, TN and TP was evaluated.There was a clear increase in the oxygen consumption for the synthetic leachate with increasing the coconut fibre density.Besides, the removal % of pollutants was highly dependent on the load conditions, implying that the proper control of pollutant loads is effective to enhance the treatment efficiencies in COTS.