Enhancing biodegradation of plastic wastes by adding used tire rubber: A sustainable solution for mitigating environmental pollution

The global accumulation of plastic and rubber waste (used tires) materials poses a significant environmental challenge due to their persistence and limited biodegradation under natural conditions. Conventional recycling methods for these materials often result in downcycling or energy recovery, offering only partial solutions within the circular economic framework. This research investigates a sustainable alternative by mixing used ground tire rubber (GTR) with plastic waste to enhance biodegradation. The key objectives include characterizing microbial communities capable of degrading both materials, quantifying degradation rates through kinetic degradation rate, predicting material's half-life and also assessing the environmental feasibility of this approach compared to traditional waste management practices. With a thermally blended composition ratio of 70:30 (plastic: GTR), the biodegradation behaviour has been examined under varying conditions such as GTR particle size (150-300 µm), experimental temperature (20°C, 30°C and 37°C) and degradation periods (30, 60, 90 and 120 days). The kinetic degradation rate ranged from 0.0000066 to 0.00055, corresponding to half-lives between 105,022.3 and 1,260.26 days, depending on aging time and temperature. In addition, the microscopic image analysis discovers in-depth information about the biodegradation of the material. These findings indicate that improved degradation rates with the addition of GTR significantly increases the porosity of the plastic materials and support the potential for GTR to serve as a carbon source for microbes. Finally, the results of this study are expected to inform policy and industrial practices, supporting the transition towards sustainable material management and reduced environmental burden.