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Biogas Plants Receive Political Backing in Many Countries

Biogas plants produce a gas similar to natural gas and use the anaerobic digestion (AD) process. The Biomass is digested in simple plants and in a wide range of much more complex and larger plants, where the gas produced is stored and used.

For the larger projects surplus electricity and heat are used in what is known as CHP (Combined Heat and Power) installations.

The green benefits from AD are substantial and in an increasing number of countries grants, subsidies and tax breaks are becoming available for these plants, backed by governments, politicians, and a wide range of political parties.

Biogas plants can be found in countries such as India, China, Philippines, Germany, Austria and Turkey. India and China have both had large government-backed schemes to encourage the adoption of these systems for use in the household for cooking and lighting. It is well reported fact that AD systems in Nepal help save 400,000 tons of firewood and 800,000 liters of kerosene and prevent 600,000 tons of greenhouse gases from escaping into the atmosphere annually. Denmark already has 20 centralized biogas plants and more than 35 farm scale plants.

There are biogas plants for farm and community sanitary wastes, for biofuel using specially grown crops, and large commercial plants which treat municipal solid waste usually taking the segregated organic content. These plants can be installed at sewage works as well, and can create gas from high Chemical Oxygen Demand (COD) industrial effluents.

The farm type biogas plant digests dairy cattle manure and organic residues originating from the farm and the surrounding food processing units. These plants implement biogas production from manure waste, chicken litter, and during waste water treatment. In fact the possibilities are so wide ranging that it is impossible to list them all in a short article.

A biogas plant normally consists of two components: a digester (or fermentation tank) and a gas holder. The reaction in the plant takes place in the absence of oxygen and the gas contains up to 70 percent methane and 30 percent carbon dioxide. Acidogenic bacteria, through the production of acids, reduce the pH of the tank. Care is needed to ensure that the pH range is maintained within limits or the biological process will be inhibited and gas production will reduce.

The following points should be kept in mind when deciding on a site for biogas plant construction. The success or failure of any these systems mainly depends upon the quality of the design and of the construction works. From small fermenting to large city CHP plants the many components must be precisely matched to one another ensure long life for the equipment and overall systems. There must be careful work before the design starts to assess the available feedstock materials and to ensure that the design matches the quality, type, and quantity of those materials which will be available.

All owners of biogas plants appreciate the need for high calorific feedstocks in their feed mix, and many are digesting food waste which is a very good feed material, and also waste fats are good high methane producing feedstocks for digestion within their plants.


Production of biogas is inefficient if fermentation materials are too dilute or too concentrated, resulting in, low production and insufficient fermentation activity, respectively.

It must be noted that segregation of the input to ensure that the right nutrients are present to feed the process, and this is of utmost importance for smooth running of all AD plants. Success of any biogas plant depends a great deal on proper segregation of the kitchen waste from large pieces of material grit and dust which can clog and block the plant.

The Future

The future will see greatly increased use of biogas as a fuel. This is a primary target in many countries to help reduce greenhouse gas emissions, water pollution and soil degradation. Last, but not least, the adoption of this waste processing technology will change the agriculture sector in many countries worldwide to produce both food and energy - not just food. This diversity will help farming businesses to remain more profitable in years when the market price for their food crops is low.

Want to know more about building a biogas plant? Steve Last is web master for the fact filled Anaerobic Digestion Community web site where much more biogas digester information is available.

Steve Last is also a regular contributor of dog breed related articles at The Dog Breeds Compendium.

Source: www.articlesbase.com