PERFORMANCE EVALUATION OF BIOFILM-BASED ROTATING REACTOR SYSTEM FOR SUSTAINABLE MICROPLASTIC TREATMENT

Abstract

Microplastic contamination has emerged as a major environmental concern because synthetic polymers continue to accumulate in aquatic ecosystems at an alarming rate. Conventional wastewater treatment methods are capable of removing only a fraction of these particles and are generally ineffective in achieving complete degradation. As a result, microplastics persist in rivers, lakes, sewage systems, and marine environments, where they may affect both ecological and human health. The present study evaluated the potential of a biofilm-based rotating reactor system for the biodegradation of polyethylene (PE), polypropylene (PP), and polystyrene (PS) microplastics under aerobic conditions. A mixed microbial consortium isolated from wastewater sludge and plastic-contaminated environments was used for biofilm formation on rotating carrier discs. Reactor performance was examined under different operational conditions, including variations in rotational speed, oxygen availability, hydraulic retention time, and biofilm thickness. Different analytical techniques such as weight loss analysis, Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), and Total Organic Carbon (TOC) analysis were employed to evaluate the degradation process. The rotating biofilm reactor demonstrated improved degradation efficiency compared with conventional suspended microbial systems. Among the tested polymers, polyethylene showed the highest degradation, whereas polystyrene exhibited relatively slower breakdown because of its chemically stable aromatic structure. SEM analysis revealed visible surface damage including pits, cracks, and erosion on treated polymer particles, while FTIR analysis confirmed oxidative changes through the appearance of carbonyl and hydroxyl groups. The findings suggest that rotating biofilm reactor systems may provide a sustainable and environmentally safer approach for reducing microplastic pollution in wastewater environments. The study also highlights the importance of optimizing reactor operating conditions to improve large-scale biodegradation efficiency.