Role of Large Scale Composting in Waste Management

OVERVIEW:

The best way to treat any waste is to recycle them. Most of the waste can be recycled if they can be isolated. Municipal waste stream has both organic and non-organic materials. One way of recycling organic waste is to compost them. This paper is an attempt to introduce current technologies for large scale composting to help administrators to address the alarming issues of the pollution caused by unmanaged organic waste. These composting methods are also used to produce organic fertilizers commercially.

Prevention of issues is always better than curing them later. But in the case of waste, it is different. Completely stopping waste production is not possible while it can be substantially reduced if proper guidelines are introduced and followed. Most of the wastes can be recycled and that has to be done in a timely manner. Failing to do this will cause environmental pollution. It affects human life directly.

Organic waste is being produced as along as there is life. Organic waste constitutes 55 to 60 percentage of the total municipal waste. Successful treatment of this component of the waste would be a huge leap in waste management. When the amount of waste produced exceeds the waste disposed or recycled manually or naturally they will have to be addressed seriously. Waste generation is not going to wait for anybody; their accumulation continues to grow every minute if they are not controlled. If proper procedures are followed it will become a routine activity for the stake holders. But most of the time priorities change and managing the waste gets the lowest resulting in unwanted or improper accumulation. A large scale treatment is necessary when that happens.

COMPOSTING THEORY

Municipal Solid Waste [MSW] contains degradable and non-degradable materials. Degradable materials are organic; they are anything that once grew. Food waste, waste from vegetable, fish and meat markets, slaughtering facilities and food processing centers are organic.

Every organic material decomposes when it is exposed - that is the law of nature. There are two types of decomposition - Anaerobic [the wrong way] and Aerobic [the right way]. Anaerobic decomposition is done with lack of oxygen. This process emits gases like Methane (CH4), Carbon Monoxide (CO), Hydrogen Sulfide (H2S), short chain of fatty acids and Ammonia (NH3). All these gases have bad odor or are toxic. This type of decomposition causes the pollution. When large amount of organic wastes are disposed into a dumping area and let them expose, they will undergo anaerobic decomposition. This is because only the top layer of the waste gets the oxygen and that too, for a short period of time. This short time period is not enough to go through the decomposition cycle. Organic material decomposing with oxygen is an aerobic process. When the organic waste is allowed to decompose aerobically, it would become compost. Aerobic decomposition generates Carbon Dioxide (CO2), Water vapor (H2O), Nitric Acid (HNO3), Sulfates and Stable phosphates. These are odorless and non-toxic. When a right recipe is made from the available organic waste and is allowed to decompose in an aerobic way, the end product will be high quality humus compost which is nothing but organic fertilizer. Organic fertilizer has picked up a huge international market recently because of its quality being recognized worldwide. Humus compost is polymerized chain of tiny decomposed organic particles which carries energy and water, and is nutritious to soil. This reduces soil erosion, keeps balanced soil structure, helps the plants to grow healthy and reduces the need for herbicides and pesticides. The fruits and vegetables that come out of organic farms are tastier and healthier.

TECHNOLOGY:

The idea is to let the organic waste to undergo aerobic process and produce high quality humus compost. This means that the materials participating in the decomposition process should get sufficient oxygen. Every organic material is made up of large amount of Carbon and a small amount of Nitrogen. Carbon carries energy and Nitrogen protein. The process of composting gets its optimal performance when the Carbon portion of the mix is approximately 25 to 30 times that of Nitrogen. Decomposition slows down when the composting mix has excess carbon and generates foul odor when carbon is less. To maintain this C:N ratio of the waste additional materials may have to be added. The type and amount of the additional materials depend on that of organic waste source.

Aerobic composting is a microbial process. Microbes cause the decomposition and they need oxygen to live and work. They cannot survive high temperatures and can work best within a specific moisture range. They prefer synchronized ingredients with C:N ratio being within 25 to 30. During decomposition, heat is generated, microbes consume oxygen and they expel Carbon Dioxide. The best composting practice is therefore to monitor and control the heat, CO2 and moisture to keep a balanced and livable environment for microbes.

There are proven technologies available to perform composting in a large scale. Requirements and implementation details varies from place to place. Please fill out the following form with as much details as you can if you need help on requirements and how to implement a composting site in your area.