Processing plants can be of three types:
- Aerobic treatment plants, from which compost is obtained
- Anaerobic treatment plants, from which biogas is obtained
- Integrated plants, from which both compost and biogas are obtained
Aerobic treatment plants
Once the different organic materials have been suitably mixed to give the mass the porosity necessary to ensure air circulation, they first undergo a degradation process by different types of microorganisms (bio-oxidation stage), which operate under controlled humidity and aeration conditions.
During bio-oxidation, the biological processes of natural decomposition are triggered and the material loses water and volume. The microbial activity consumes oxygen and produces heat, causing a sharp rise in temperature that sanitises the biomass and creates a favourable environment for other microorganisms resistant to high-temperatures, which in turn produce compost.
Anaerobic treatment plants
The process takes place in the absence of free oxygen, through bacteria that obtain the oxygen they require from the biomass. The process occurs through a number of stages within a hermetically sealed system in a vacuum. The plant works at temperatures higher than the ambient temperature, a condition required by the bacteria that degrade organic matter. The process transforms organic waste into two products: a biogas (methane and carbon dioxide) that can be used for energy production; and an organic material (digestate) that becomes compost through aerobic composting.
The composting process results in a biologically stable, inert and odourless product, with an organic component with a high degree of maturity. Rich in humus, active microbial flora and microelements, compost is the ideal solution to soil desertification and carbon depletion, as well as a product for agricultural use (fertiliser for floriculture and field crops).
No bioplastic residue remains, demonstrating the complete biodegradation of certified products. Certified compostable plastics currently account for 3.9% of total organic waste by weight (source: CIC).
Let's listen to composting plants: watch the videos
Let's find out together how the industrial stages of composting take place in practice by watching the videos shot in some different Italian plants (in Puglia, Abruzzo, Sardinia, Piemonte and Veneto), from the hands of those who manage them.