Composting is one of the options for treatment of solid waste. In composting process the organic matter breaks down under bacterial action resulting in the formation of humus like material called compost.
The value of compost as manure depends on the quantity and quality of feed materials poured into the compost pit. Composting is carried out in two ways:
Aerobically (in presence of oxygen) and
Anaerobic ally (in absence of oxygen).
During aerobic composting, aerobic micro – organisms oxidizes organic compounds in the solid waste to carbon dioxide, nitrite and nitrate. The carbon from organic compounds is used as a source of energy while nitrogen is recycled. Due to exothermic reactions, temperature of the mass rises.
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During anaerobic process, the anaerobic micro-organisms, while metabolizing the nutrients, break down the organic compounds through a process of reduction. A very small amount of energy is released during the process and the temperature of the composting mass does not raise much.
The gases evolved are mainly methane and carbon dioxide. An anaerobic process is a reduction process and the final product is subjected to some minor oxidations when applied to land.
Read Also : Criteria for Hygienic Storage of Solid Waste
Manure from composting gives better yield to a farmer and it is also environment friendly. Biodegradable solid waste can be composted either in compost pit or in a Vermi compost pit.
Compost pit can be underground unlined compost pit or over-ground compost – heap method or over-ground brick line compost pit. Vermi compost can be done in Vermi tank (four pit model) or Vermi-compost in sheds.
Composting of bio degradable solid waste can take place in biogas plants also. Slurry from the biogas plant can also be utilized for production of Vermi compost.
Composting (ManurePit) Description
Composting is carried out in a simple manure pit or garbage pit (lined or unlined). in this process aerobic microorganisms oxidise organic compounds to carbon- dioxide and oxides of nitrogen and carbon from organic compounds is used as a source of energy, while nitrogen is recycled.
As discussed above, in the composting process, due to exothermic reactions, temperature of mass rises. In areas/regions with higher rainfall composting in over ground heaps is advisable.
The factors affecting the composting process are: (a) micro-organisms; (b) moisture, (c) temperature and (d) carbon/ nitrogen (C/N) ratio.