Introduction. Modern cities and towns generate huge quantities of solid waste every day. A large part of this waste consists of biodegradable organic matter such as vegetable peels, leftover food, yard waste, crop residues and other organic materials. If this waste is simply dumped in open areas or landfills, it leads to foul smell, flies, rodents, leachate and emission of methane gas. Composting is an environment-friendly method which converts such organic waste into useful manure, and therefore occupies a very important place in solid waste management.
Meaning of composting
Composting is a biological process in which microorganisms such as bacteria and fungi decompose organic waste under controlled conditions of moisture, aeration and temperature to produce a dark, earthy, nutrient-rich material known as compost. It is essentially the artificial speeding up of natural decomposition, with the objective of converting waste into a useful soil conditioner.
1. Reduces volume and load on landfills
In most Indian cities, 40–60% of municipal solid waste is biodegradable. If this fraction is diverted to composting instead of dumping, the total volume of waste that has to be transported and landfilled is greatly reduced. This results in:
- Lower transportation cost for municipal bodies.
- Longer life of existing landfill sites.
- Reduction in the need for acquiring new land for dumping grounds.
Thus, composting directly helps in easing the pressure on already overburdened disposal facilities.
2. Resource recovery and production of organic manure
Composting converts “waste” into a valuable resource. The compost produced is rich in organic matter and contains essential plant nutrients such as nitrogen, phosphorus and potassium. Its significance lies in the following points:
- It improves soil structure, porosity and water-holding capacity.
- It enhances soil microbial activity and overall soil health.
- It reduces dependence on costly chemical fertilisers, especially for marginal farmers and in kitchen gardens.
In this way, composting fits well into the principle of “waste to wealth” and promotes a circular economy.
3. Environmental benefits and pollution control
When organic waste is dumped in landfills under anaerobic (oxygen-poor) conditions, it decomposes to produce methane (CH₄), a powerful greenhouse gas. Controlled aerobic composting:
- Reduces methane generation and thus helps in mitigating climate change.
- Minimises bad odour and fly nuisance compared to open dumping of organic waste.
- Decreases leachate formation, thereby lowering the risk of groundwater contamination.
Hence, composting is not only a waste management technique but also an important environmental protection measure.
4. Promotes segregation and community participation
For composting to be effective, segregation of waste at source (separating wet/organic waste from dry/inert waste) is essential. This requirement encourages:
- Greater awareness among households about different types of waste.
- Involvement of residents, schools, institutions and markets in local composting initiatives.
- Decentralised solid waste management through community compost pits, vermicompost units and household composters.
Such participation reduces the burden on municipal authorities and creates a sense of responsibility towards the local environment.
5. Economic and agricultural significance
Composting has both economic and agricultural importance:
- Municipalities save money on waste collection, transport and disposal.
- Farmers and urban gardeners gain access to low-cost organic manure which improves crop yield in the long run by maintaining soil fertility.
- It can generate employment opportunities for self-help groups, NGOs and small enterprises involved in collection and compost production.
Conclusion: In conclusion, composting is a key component of scientific solid waste management. It reduces the volume of biodegradable waste going to landfills, recovers valuable nutrients, improves soil fertility, lowers pollution and greenhouse gas emissions, and encourages community-level participation in waste handling. Therefore, any sustainable solid waste management system, especially in a country like India, must give high priority to composting of organic waste.