The process of biodegradation happens naturally over time. Depending on the material, the time frame for complete degradation may vary. In the case of plastics, due to the strong polymers that make up their chemical structure, this process typically takes hundreds to thousands of years to complete.
The biodegradation process contains mainly 4 steps, which includes:
1. Aerobic Phase:
In this phase, enzymes and decomposition chemicals act as catalysts for the biofilm covering the plastic. During this period, aerobic microorganisms began to accumulate, and the moisture in the garbage was also accumulating. Standard plastics moisture absorption capacity is relatively small, but additives can cause further expansion and weaken the bonds in polymers. This creates molecular spaces for the growth of microorganisms, thus initiating the aerobic degradation process of converting oxygen to carbon dioxide.
2. Anaerobic, Non-Methanogenic Phase:
Anaerobic stage, non-methane producing: Once the oxygen concentration has decreased sufficiently, the anaerobic process begins. During the initial stage (hydrolysis), the microbial colonies eat the particles, and through an enzymatic process, reduce large polymers into simpler monomers. Organic additives cause further expansion and opening of polymer chains and increase quorum sensing. This further stimulates the microorganisms to increase their colonization and consumption of polymer chains. Over time, acidification occurs with the conversion of simple monomers to fatty acids. CO2 production occurs rapidly at this stage.
3. Anaerobic, Methanogenic Unsteady Phase:
The microbe colonies continue to grow, eating away polymer chains and creating ever-larger molecular spaces. During this phase, acetogenesis occurs, converting fatty acids into acetic acid, carbon dioxide and hydrogen. As this process continues, the CO2 rate drops and hydrogen production eventually stops.
4. Anaerobic, Methanogenic Steady Phase:
Stable anaerobic methane production stage: The final stage of decomposition involves methane production. As the microbial colony swallows the polymer’s remaining surface, acetate is converted to methane and carbon dioxide, and hydrogen is consumed. This process continues until the remaining element is humus. This nutrient-rich soil creates a better environment for microorganisms and improves the final stage of decomposition.