Waste is any material, which have little or no value to producer or consumer. Humans with nearly all activities produce waste.
The major component of municipal solid waste represent organic fraction, mostly from domestic, agricultural and industrial sources. There are many different methods of managing municipal waste streams. These include physical, chemical and biological methods. Conventional waste management practices usually involve one negative consequence or the other. This necessitated the search for and development of biological techniques, including the use of microorganisms that produce environmental-friendly outcomes.
All of the microorganisms which grow in a given industrial waste disposal system contribute to its overall characteristics, both good and bad. It is important to recognize the contributions made by each type of organism to the overall stabilization of the organic wastes if the waste treatment system is to be properly designed and operated for maximum efficiency.
Bacteria are the basic biological units in aerobic waste treatment systems. The diverse biochemical nature of bacteria makes it possible for them to metabolize most, if not all, organic compounds found in industrial wastes.
Growth of any particular species is dependent upon its competitive ability to obtain a share of the available organic material in the system. Bacterial predominance will normally divide itself into two major groups: the bacteria utilizing the organic compounds in the waste, and the bacteria utilizing the lysed products of the first group of bacteria.
The bacteria utilizing the organic compounds in the waste are the most important group and will determine the characteristics of the treatment system. The species with the fastest growing rate and the ability to utilize the majority of the organic matter will predominate. The extent of secondary predomination will depend upon the length of starvation.
Microorganisms are vital for humans and for the environment, as they participate in the carbon and nitrogen cycles, as well as in fulfilling other vital roles like recycling other organisms, decomposition of dead remains and waste products. Microorganisms also have an important place in most higher-order multicellular organisms as symbioses.
Solid waste management : Management of solid waste reduces or eliminates adverse impacts on the environment and human health and supports economic development and improved quality of life. Composting is the most frequently used biological solid waste treatment method which is the controlled aerobic decomposition of organic waste materials by the action of small invertebrates and microorganisms. Composting is a technique in which organic waste materials (food, plants, paper) are decomposed and then recycled as compost for use in agriculture and landscaping applications. The most common composting techniques include static pile composting, vermin-composting, windrow composting and in-vessel composting.