Organic waste can be recycled at the household level to produce compost manure. Composting is the most simple and common method for recycling household organic waste. Composting is the process of optimizing the environment in the waste for microbial activity to decompose organic matter into valuable nutrients for the soil. Household composting involves the following three stages: waste preparation, degradation of waste and finishing of waste.
Waste needs to be sorted and prepared for rapid degradation. This includes the following steps:
Mix the waste to ensure that the carbon to nitrogen ratio (C:N) is close to 25:1. If the waste has too much carbon (normally brown waste such as dried leaves, saw dust) it should be mixed with waste that has high nitrogen content (also known as green waste such as kitchen waste). Kitchen waste only normally has a suitable C:N ratio for composting.
Chop the waste into small pieces. Large pieces of organic waste should be cut to small pieces to accelerate the composting process. Adjust the moisture content to about 50 per cent. A compost pile with 50% moisture should feel moist but water should not be dripping from it. Add a starter such as mature compost or effective microorganisms (EM) to speed up the composting process.
Compost can be made in bags or bins. Normally holes are made in the bin or bags to allow aeration. Compost bins can be made from 100 to 200 liter plastic bins or barrels. In order to allow proper aeration, the bin is normally divided into two sections with a grill separating the two sections. Organic waste is put into the top section and allowed to degrade and once the compost is prepared it is removed from the bottom section. Because of the natural draught created in the bin by the grill and the holes, frequent turning of the waste is not required in this method.
Why compost organic waste?
To manage the waste problem
We know that waste is a huge problem in many cities of developing countries and that organic waste represent almost 80% of the amount of waste. By composting this organic waste, we can help alleviate a large part of the waste management problem.
To produce a new useful and valuable product
Knowing that chemical fertilizers are mining the soil and are not available for every potential client (they are often expensive and not always accessible), we can offer a more accessible product that is eco-friendly available at a stable price.
To reduce Greenhouse gas emissions
In opposition to uncontrolled anaerobic fermentation of organic waste in landfills, compost and the composting process do not produce methane and therefore do not add any Greenhouse gas to the atmosphere. Methane has a global warming potential 24 times stronger than CO2.
To produce organic fertilizer
The demand for organic food is increasing in Kathmandu valley, but organic farmers experiment a lack of fertilizer, as chemicals can’t be used in organic farming.
NOTE: Writer is no expert this are his experience as part of training on Bio Degradable Solid Waste Management in Bin. The training was organized by Global Powershift Nepal to as training to trainer.