COMPOSTING : types of compost, merits and demerits

Composting

1. COMPOSTING 1

2. COMPOSTING Composting is natural way of recycling. Composting is the microbial process of degradation in which the plant and animal wastes are naturally degraded to produce organic manure. Organic manure is used for enrichment of the soil that helps with the growth of plants. Microorganisms feed on the materials added to the compost pile during the composting process. They use carbon and nitrogen to grow and reproduce, water to digest materials, and oxygen to breathe. 2

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4. INGREDIENTS FOR COMPOSTING The ingredients for composting include a proper balance of the following materials: Carbon-rich materials (“browns”)  can include dry leaves, plant stalks, and twigs. The carbon-rich materials provide food for the microorganisms to consume and digest. Nitrogen-rich materials (“greens”)  include grass clippings and food scraps. The nitrogen-rich materials heat up the pile to create ideal conditions for the material to breakdown.  Water (moisture). Air (oxygen). 4

5. Methods of composting 5

6. 1. Aerobic method Aerobic composting is decomposition of organic matter using microorganisms that require oxygen. The microbes responsible for composting are naturally occurring and live in the moisture surrounding organic matter. Oxygen from the air diffuses in to the moisture and is taken up by the microbes. As aerobic digestion takes place the by-products are heat, water and carbon dioxide (CO2). While CO2 can be classified as a greenhouse gas it’s evolution from the composting process is not counted in emissions. Additionally, CO2 is only 1/20th as harmful to the environment as methane (the main by-product of anaerobic degradation). 6

7. The heat produced in aerobic composting is sufficient to kill harmful bacteria and pathogens as these organisms are not adapted to these environmental conditions. It also helps support the growth of beneficial bacteria species including psychrophilic, mesophilic, and thermophilic bacteria which thrive at the higher temperature levels. From start to finish, the HotRot in-vessel aerobic composting process takes only 8-10 days. No leachate is produced as any surplus moisture is extracted as water vapor which can be condensed and used for watering nearby vegetation. 7

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9. 2. Anaerobic method Anaerobic composting is decomposition that occurs using microorganisms that do not require oxygen to survive. In an anaerobic system the majority of the chemical energy contained within the starting material is released as methane. The process is characterised by very strong odours and only a small amount of heat is generated meaning decomposition takes much longer and doesn’t reach sufficient temperatures to safely kill plant pathogens, weed and seeds. To overcome these limitations external (artificial) heat is normally added. As the material is broken down by anaerobic digestion, it creates a sludge-like material that is even more difficult to break down. This material, digestate, typically requires aerobic composting to complete the stabilisation process. 9

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12. VERMICOMPOSTING 12

13. VERMICOMPOSTING Worm composting, or vermicomposting, is another method of composting by using earthworms. It takes up little space, the materials are simple and inexpensive, and it can be done indoors or outdoors. It need a container or bin, bedding material, worms, and food scraps. If worm bin is properly maintained, it should not emit odors or attract pests. The resulting product is vermicompost, a soil amendment. 13

14. Vermicomposting comprises two methods: Bed Method: This is an easy method in which beds of organic matter are prepared. Pit Method: In this method, the organic matter is collected in cemented pits. However, this method is not prominent as it involves problems of poor aeration and waterlogging. 14

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16. PROCEDURE OF VERMICOMPOSTING To prepare compost, either a plastic or a concrete tank can be used. The size of the tank depends upon the availability of raw materials. Collect the biomass and place it under the sun for about 8-12 days. Now chop it to the required size using the cutter. Prepare a cow dung slurry and sprinkle it on the heap for quick decomposition. Add a layer (2 – 3 inch) of soil or sand at the bottom of the tank. Now prepare fine bedding by adding partially decomposed cow dung, dried leaves and other biodegradable wastes collected from fields and kitchen. Distribute them evenly on the sand layer. 16

17. Continue adding both the chopped bio-waste and partially decomposed cow dung layer-wise into the tank up to a depth of 0.5-1.0 ft. After adding all the bio-wastes, release the earthworm species over the mixture and cover the compost mixture with dry straw or gunny bags. Sprinkle water on a regular basis to maintain the moisture content of the compost. Cover the tank with a thatch roof to prevent the entry of ants, lizards, mouse, snakes, etc. and protect the compost from rainwater and direct sunshine. Have a frequent check to avoid the compost from overheating. Maintain proper moisture and temperature. 17

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20. Advantages Of Vermicomposting The major benefits of vermicomposting are: Develops roots of the plants. Improves the physical structure of the soil. Vermicomposting increases the fertility and water-resistance of the soil. Helps in germination, plant growth, and crop yield. Nurtures soil with plant growth hormones such as auxins, gibberellic acid, etc. 20

21. Disadvantages of Vermicomposting Following are the important disadvantages of vermicomposting: It is a time-consuming process and takes as long as six months to convert the organic matter into usable forms. It releases a very foul odour . Vermicomposting is high maintenance. The feed has to be added periodically and care should be taken that the worms are not flooded with too much to eat. The bin should not be too dry or too wet. The moisture levels need to be monitored periodically. They nurture the growth of pests and pathogens such as fruit flies, centipede and flies. 21

22. REFERENCE https://www.epa.gov/recycle/composting-home#:~:text=Composting%20is%20a%20controlled%2C%20aerobic,crumbly%2C%20earthy%2Dsmelling%20material . https://www.slideshare.net/HarishReddy280/aerobic-composting-method https://www.globalcomposting.solutions/aerobic-vs-anearobic-composting https://byjus.com/biology/vermicomposting/ https://agritech.tnau.ac.in/agriculture/agri_majorareas_smmf06.html 22