Composting
From Swikipedia
Introduction
The biodegradation of organic matter such as yard and food waste by micro-organisms like bacteria, fungi and yeast is known as Composting. As a result of the action of enzymes, the organic compounds are first converted into simpler intermediates like alcohol or organic acids, and later into simple compounds like sugars. This results in humic acid and available plant nutrients in the form of soluble inorganic minerals like nitrates, sulphates and phosphates, which is finally used as manure for the plants.
Brief Description
Indicator for Final Compost:
The compost should have the following qualities before it can be used as a soil conditioner:
• Absence from the smell of ammonia
• Completion of the reaction and stabilization of the compost as indicated by the low or ambient temperature
• A dark brown colour
• Presence of at least three species of anthropods: the sow and pill bug, ground beetle, and centipede.
What to compost?
The following items can be composted: Animal manure, Cardboard rolls, Clean paper, Coffee grounds and filters, Cotton rags, Dryer and vacuum cleaner lint, Eggshells, Fireplace ashes, Fruits and vegetables, Grass clippings, Hair and fur, Hay and straw, Houseplants, Leaves, Nut shells, Sawdust, Shredded newspaper, Tea bags, Wood chips, Wool rags, and Yard trimmings.
Different Methods of Composting:
1. Heap method: A layer with 15-20 cm of hard material base such as stalks and wood and 20 cm of soft material such as straw and saw dust is created. This layer is covered with 10 cm thick biomass. The total heap height should be 1-1.5 m and is covered with soil and dry leaves. Periodical mixing is required every 7-10 days in this method.
2. Pit Method: A pit of 0.6-0.75 m depth and 1.5 m width is dug and filled with organic waste and soil. It is mixed once in every 15 days.
3. Lagoon Method: A vessel or a digester is lined with brick or concrete and filled with crop residues, cow dung and biodegradable waste. It is similar to other techniques, except that occasional mixing of water is required
4. Chamber Method: It consists of a series of eight chambers filled with waste and inoculum (household municipal waste and cow dung slurry). These contents are transferred from one chamber to another week after week. For waste generated from a colony of 500 houses, the digester size should be 4 x 9 m. Occasional sprinkling of water is required.
5. Berkeley’s Method: It is similar to the heap method. The waste to inoculum ratio is 2:1 and waste is filled up to a height of 1.5m. Twice a week the contents are mixed and water is sprinkled occasionally.
6. Nadep Method: A brick tank of dimensions 3.0 x 1.5 x 1.0 m is built with perforated sides and a shade is provided on top to maintain the moisture levels. The first layer of waste is up to 15 cm (100 kg) and is followed by a layer of cow dung mixture (4 kg of cow dung and 100 litres of water). This is covered with a 2 cm layer of dry soil. Till the tank is full, these layers are repeated in the same order, but not more than 10-11 layers should be created. Finally the tank is covered with 7.5 cm of soil plastered with cow dung.
Vermicomposting:
Worm composting or vermicomposting is a method using Red Wiggler worms in a container to process kitchen waste. Moistened high-carbon bedding such as shredded paper is used as a base to which the food waste is added, and the worms and micro-organisms convert the materials to rich compost called worm castings, a nutrient and microbially rich material. Worm composting can be done indoors, allowing year-round composting, and providing apartment dwellers with a means of recycling food waste.
References:
The Energy and Resources Institute. Sustainable Building Design Manual, Volume 2. p.p 49-51.
http://en.wikipedia.org/wiki/Composting
