CONTENTS Introduction Composting Ingradients in composting Processes involved Fate of pathogens Steps in composting Various methods of composting Conclusion
INTRODUCTION Composting can generally described as a thermophillic aerobic decomposition process. Solid substrates are degraded over a period of weeks ,by a succession of microbial population to form a dark brown, granular, humus like end product sometimes described as “loamy”. Soil conditioner, improving the characteristics of soil. Domestic refuse disposal. The composting of domestic refuse in Europe has received significant attention since the 1920s. The composting process is an environmentally beneficial means of recycling organic materials. Municipal solid wastes in India contain up to 70% organic waste. Environmentally sound.
COMPOST It is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. Compost can be rich in nutrients. It is used in gardens, landscaping and agriculture. The compost itself is beneficial for the land in many ways, including as a soil conditioner, a fertilizer.
INGRADIENTS IN COMPOSTING Composting organisms require four equally important things to work effectively- Carbon. Nitrogen. Oxygen. Water. Urine. Manure and bedding.
MICROORGANISMS IN COMPOSTING Bacteria- The most numerous of all the micro organisms. Actinomycetes- Necessary for breaking down paper products. Fungi- Molds and yeast help break down materials that bacteria cannot. Protozoa- Help consume bacteria, fungi and micro organic particulates. Rotifers- Rotifers help control populations of bacteria. Earthworms
COMPOSTING PROCESSES Physical process. Chemical process. Biological process.
Biological process. Bacteria, fungi and actinomycetes as well as larger organism insects, earthworms. They decompose the organic material, they break down organic matter and produce carbon dioxide, water, heat and humus (the relatively stable organic end product). This humus end product is compost.
Four stages- Mesophilic or moderate temperature phase. Thermophilic or high temperature phase. Cooling phase. Curing phase or maturation.
Mesophilic or moderate-temperature phase: Compost bacteria combine carbon with oxygen to produce carbon dioxide and energy. The microorganisms for reproduction and growth use some of the energy and the rest is generated as heat. When a pile of organic refuse begins to undergo the composting process, mesophilic bacteria increases, raising the temperature of the composting mass up to 44oC. This is the first stage of the composting process.
Thermophilic or high-temperature phase: In the second stage of the process, the thermophilic microorganisms are very active and produce heat. This stage can continue up to about 70o C, although such high temperatures are neither common nor desirable in compost. This heating stage takes place rather quickly and may last only a few days, weeks, or months. It tends to remain localized in the upper portion of a compost pile where the fresh material is being added.
Cooling phase: During this phase, the microorganisms that were replaced by the thermophiles migrate backinto the compost and digest the more resistant organic materials. Fungi and macroorganisms such as earthworms and sow bugs that break the coarser elements down into humus also move back in.
Maturation or curing phase: The final stage of the composting process is called curing or maturing stage, and is a long and important one. A long curing period (e.g., a year after the thermophilic stage) adds a safety net for pathogen destruction. Many pathogens have a limited period of viability in the soil, and the longer they are subjected to the microbiological competition of the compost pile, the more likely they will die a swift death. Immature compost can be harmful to plants.
FATE OF PATHOGENS The thermophilic nature of composting process is widely claimed to be effective in reducing the number of viable organisms present. The temperature is the most critical factor. A temperature in excess of 56deg c will usually be sufficient to inactivate 99% organisms.
STEPS IN COMPOSTING PROCESSES There are five basic steps involved in all composting practices. Preparation. Digestion. Curing. Screening or finishing. Storage or disposal.
Bin composting Rotating drums Transportable containers silos silos Rotating drum Bin
Vermicomposting The earthworm species (or composting worms) most often used are Red Wigglers (Eiseniafoetida or Eiseniaandrei) European nightcrawlers (Eiseniahortensis) could also be used. European nightcrawlers by a variety of other names, including dendrobaenas, dendras, and Belgian nightcrawlers.
CONCLUSION It is the best method of recycling the waste. Composting can significantly reduce the amount of disposable garbage. The organic fertilizer can be used instead of chemical fertilizers. It act as a plant nutrients. It increases the soil’s ability to hold water and makes the soil easier to cultivate. It helped the soil retain more of the plant nutrients. This method is very cheap as compare to others.
REFERENCES www.hdra.org.ok On firm composting methods- by R.V. Mishra and R. N. Roy. FAO, Rome. http://en.wikipedia.org/wiki/Compost http://www.vegweb.com/composting Microbiology and chemistry for environmental scientists and engineers. Second edition. J. N. Lester and J.W. Birkett. Taylor and Francis group.