Compost is a soil amendment necessary to maintain the soil balance and its productivity. It is the aerobically decomposed remnants of organic matter, such as kitchen waste, leaves, grass or fruits, through the action of macro or microorganisms at a certain oxygen level and at specific temperatures.
This process called composting can also be controlled and accelerated by men.
At the industrial level, in fact, composting is the activity finalised to processing the moist fraction of municipal solid waste turning it into compost. Industrial composting allows a careful control on the process phases and balance, limiting the presence of external polluting factors in the matter collected (such as heavy metals residues or inert waste) or of pathogenic micro-organisms for agriculture.
Organic residues that can become compost are:
- nitrogen-rich waste such as vegetable, garden and household waste and green leaves;
- carbon-rich waste such as hedge clippings, dry leaves and straw;
- coffee grounds, tea bags, egg shells, dried fruit shells, vegetables;
- natural fabrics such as cotton and wool.
Over the latest years the domestic composting practice has become very popular. It consists in the recovery of the moist fraction in appropriate "composting bins" (containers or limited spaces that can favour the organic matter oxygenation) located in communal green areas or private gardens, where a very good compost is produced and used to fertilise the same areas or gardens.
Recovering the moist fraction, even by giving it to the collection services organised by the Municipality for the citizens, allows a reduction by 30-40% of the amount of waste that usually ends up in the trash bins and that will have to be transported and disposed of.
A "quality" compost can be obtained through separate collection of organic waste and can be used in agriculture as organic fertiliser, avoiding the use of chemical pesticides. Compost can also be used as fertiliser before fields ploughing, improving the soil structure and the bio-availability of nutritional elements.