Design and Evaluation of a Hybrid MBBR-Inspired Air Filtration System for the Removal of Airborne Microbial and Gaseous Pollutants

Indoor air pollution is a significant public health concern, especially in hospitals, laboratories, public transportation hubs, and densely populated indoor environments. Airborne microorganisms, particulate matter (PM), and volatile organic compounds (VOCs) can cause respiratory diseases, allergies, and the spread of infectious agents. Conventional air purification systems, including HEPA filters, activated carbon, and ultraviolet-C (UV-C) irradiation, address some of these pollutants but have limitations. HEPA filters effectively remove particles ≥ 0.3 µm but do not inactivate microorganisms; activated carbon adsorbs VOCs but saturates quickly; and UV-C irradiation kills microbes but does not remove chemical pollutants.This study proposes a hybrid air filtration system inspired by Moving Bed Biofilm Reactor (MBBR) technology. The system integrates four sequential stages: (1) HEPA pre-filtration to remove particulate matter, (2) activated carbon adsorption for VOCs, (3) a mobile biofilm chamber with non-pathogenic microbial carriers to biologically degrade VOCs, and (4) UV-C irradiation for microbial inactivation. The hybrid approach combines mechanical, chemical, biological, and photonic purification, enhancing multi-pollutant removal, energy efficiency, and system sustainability.A laboratory-scale prototype is constructed and tested under controlled environmental conditions. Microbial aerosols and VOC concentrations are monitored at multiple stages to evaluate the system's performance. Equations for removal efficiency, UV dose, and air contact time are applied. Safety protocols include biosafety level 1 microbial handling, proper electrical and UV shielding, and safe chemical handling. The system is expected to achieve > 99% microbial reduction, 70–90% VOC removal, and low energy consumption. This research demonstrates a practical solution for improving indoor air quality in healthcare, public, and industrial settings, while integrating advanced biofiltration concepts with conventional air purification technologies.