Monday, July 26, 2010

Types of composting technologies

There are four different types of composting technologies, windrow, aerated static pile, and in- vessel composting.

1. Windrow Composting: Triangular piles of waste are created to allow diffusion of O2 and retention of heat. The piles are turned every two-three days using specific mechanical equipment or manually using equipment. This turning is done to let the pile of waste breathe for better decomposition. Insure that the pile is under a roof to prevent exposure to the rain, which can cause a run off.



2. Aerated static pile composting: Mechanical aeration of waste piles is done by placing them over a network of pipes connected to a blower, the blower supplies air for composting and hence creates a positives as well as a negative pressure. Air circulation provides oxygen and prevents heat build up. Optimum temperature and moisture are maintained for microbial action. As the piles are not turned during the process in order to get complete destruction of the pathogens, a layer of stabilized compost is placed over the pile to maintain the desired temperature. The retention time for completion of composting is 6-12 weeks.



3. In-vessel composting: This is a controlled process of composting where aeration, moisture, and temperature requirements for composting are maintained in a chamber or vessel. The time taken for composting is 1-4 weeks. The advantage of this system is that there is control of the environmental conditions for rapid composting as they occur inside a closed building, and the problems of malodour and leachate generation are minimal.



4. Vermi-composting: This is a process whereby food material, kitchen waste, vegetables, fruit peelings and paper can be converted into compost by natural action of worms. An aerobic condition is created by exposure of waste to air. Many western countries such as Canada, use this process to convert their organic waste to compost. Asian countries are now adopting this method for waste disposal. Thousands of species of earth worms such as Eisenia foetida and Eisenia Anderei, are actively involved in the decomposition of organic waste. Certain bio-chemical changes in the intestine of the worm result in excreation of cocoons and undigested food known as vermicasting, which is an excellent manure containing vitamins, enzymes, nitrates, phosphates, and potash.



Learn to make compost from kitchen waste at home.

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