Performance Assessment of an Aerated Biofiltration Systems Based on Coconut Residues

This study investigates the effectiveness of an aerated biofiltration process employing coconut-based filter media for the treatment of domestic wastewater. To achieve this, a semi-industrial pilot system was constructed, consisting of five biofiltration columns packed with different proportions of coconut fibers and husks. The experimental design included an initial 30-day acclimation phase to allow biofilm establishment, followed by a 60-day monitoring period during which the system’s performance was systematically evaluated. The influent wastewater, collected from a hotel, was first characterized and classified as urban wastewater with relatively low biodegradability, as indicated by a COD/BOD<sub>5</sub> ratio of 3.94. The results demonstrate that the biofiltration system provided high removal efficiencies for several key pollutants. Turbidity removal reached up to 88%, while ammonium and nitrites were reduced by more than 75%. Similarly, reductions exceeding 70% were observed for total phosphorus and total Kjeldahl nitrogen. COD removal, however, remained moderate at around 50%, highlighting limitations in the system’s ability to eliminate carbonaceous compounds. Overall, the findings indicate that the coconut-based biofiltration process is particularly effective in nitrogen and turbidity removal, reflecting the suitability of coconut husk and fibers as sustainable filter media in decentralized wastewater treatment applications. Nevertheless, the study also reveals important constraints regarding carbon and phosphorus removal. These were attributed to the presence of refractory transphilic and hydrophobic organic fractions in the influent, as well as the limited availability of biodegradable carbon required to support complete phosphorus degradation. The outcomes of this research underscore both the potential and the limitations of coconut-based aerated biofiltration and provide insights for optimizing low-cost, nature-based treatment systems aimed at improving wastewater quality in resource-constrained settings.