Irradiation of Filter Media for Wastewater Treatment in MBBR Systems

In the Philippines, clean water shortage still poses a major threat to the Filipino people and is primarily caused by limited infrastructure and resources. This hinders effective wastewater management, mainly in rural and densely populated parts of the country. The Moving Bed Biofilm Reactor (MBBR) has been advocated as a decentralized biological treatment technology meant for wastewater treatment that retains the benefits including small size, high treatment capacity, and operational flexibility. Still, presently MBBR systems have restrictions tied to energy consumption and insufficient biofilm development on carrier media, which in turn impact the efficiency of the whole treatment. This study introduced the irradiation of plastic carrier media surfaces used in MBBR systems to improve the hydrophilicity and thus get better biological affinity, with the intention that improved biofilm will be formed and higher rate of wastewater pollutant removal will be achieved. This study also integrated the development of a small scale MBBR system that replicates a real life application of the treatment plant. It was observed that irradiated carriers were found to have an increased surface roughness and hydrophilicity which in turn resulted in a denser and more stable biofilm growth in comparison to the case of unmodified controls. This physical modification shows a significant difference in the removal of organic and nutrient contaminants across four parameters namely, BOD, TSS, TN, and TP. Every irradiated treatment showed a significant pollutant reduction from the raw untreated wastewater parameters, compared to the unirradiated control (Treatment E, 38.2%). Treatments A (25 kGy) and B (50 kGy) using electron beams achieved reductions of 82.4% and 86.5%, respectively, while Treatments C (25 kGy) and D (50 kGy) using gamma rays achieved 78.0% and 72.3%.