Composting is a method of making fertilizers for food, food, industrial waste and waste based on the decomposition of local microorganisms. It is an aerobic process (requiring the presence of air) to decompose solid waste. Therefore, raw materials for composting are usually placed in piles and composters (compost boxes, barrels, special structures), and not in compost pits, where it is more difficult to provide oxygen access. In addition to air, composting requires the support of internal biological heat, high stress and the presence of microorganisms.
For efficient processing of organic matter, microorganisms require:
- Carbon is needed for energy, and heat is released during redox reactions involving carbon;
- Nitrogen is an important element for soil organisms (see nitrogen exchange in soil);
- Oxygen is essential for the oxidation of carbon, the decomposition process.
- Water – high humidity is necessary for decomposition processes to occur, but aerobic conditions must be maintained.
The maturation rate of compost is determined by the ratio of these substances. Aeration of the compostable material (shoveling, mixing) is required to maintain sufficient oxygen and the correct moisture level. With an optimal ratio of water and air in the compost, the temperature is set to + 50 … + 70 ° C until then, then the compost matures at a temperature of + 40 … + 50 ° C until the materials are processed. Typically, mature compost can be obtained two years after setting, but with modern composting accelerators or aerating the compost heap, the process is accelerated to one season.
When composting in the organic mass, the content of nutrients available to plants (nitrogen, phosphorus, potassium and others) increases, pathogenic microflora and helminth eggs are rendered harmless, the amount of cellulose, hemicellulose and pectin substances decreases (they cause the transition of soluble forms of nitrogen and phosphorus of the soil into organic forms), the fertilizer becomes free-flowing, which makes it easier to apply it to the soil.
Scale of compost production
Depending on the scale, composting can be centralized or private.
Centralized composting
A plant for the production of compost from organic and agricultural waste in rural Germany. Compostable material is stacked
Centralized composting is carried out by local authorities, waste processing enterprises, agricultural holdings, etc. Centralized anaerobic composting in industrial volumes is carried out in the field or at waste processing plants.
Private composting
Private composting is done by homeowners on their own backyards, backyards, orchards, or in public composters where available nearby. To do this, use compost bins, heaps, composters located on the site. Some gardeners use the technology of composting directly on the beds where cultivated plants are grown. There are also indoor composting technologies, although this requires special technologies to ensure the hygiene of the process (for example, the use of additives – bokashi).