Biogas production is achieved as the result of the controlled microbial breakdown of organic materials such as animal manures or food scraps in an anaerobic digester. An anaerobic digester is the name of the plant that makes the gas and is operated at a controlled temperature, pH and loading rate to encourage the growth of microorganisms that eat the organic matter and produce biogas and a more biologically stable liquid effluent.

Biogas is a mixture of about 60-70% methane (natural gas), 30-40% carbon dioxide and other trace gases, such as hydrogen sulfide. The heat content of this gas is based on the amount of methane it contains and is about 600 BTUs per cubic foot.

Anaerobic digesters produce biomethane along with electricity generation and saleable end product biosolids which allows animal production enterprises to become neighborhood and environment friendly, as well as producing another revenue flow for themselves.

Running a biogas plant on a dairy farm works best for farms which hold at least 800 cows. Economically viable ystems for dairies under 800 cow level are possible, but need evaluation on a farm by farm basis to decide whther there will be adequate cost effectiveness. No farm or combinations of farms is ever likely to be too large for such a system.

Whether a particular farm, your farm perhaps, would be suitable for a biogas plant depends on assessing the budget costs of the investment, against the potential earnings from generated electricity sales and from end product bio-solid sales. The economic return period for any farm can be estimated this way. If the return period is short enough and an investor can be found there is a lot to be said for going ahead.

Many people will ask you to demonstrate that the new plant does not have a negative impact on the surrounding environment. Let us assure you that a well designed and run biogas plant improves the environment significantly and is neither odorous nor dangerous. Such plants can be placed near production facilities which will often be the best customers for the power and heat produced.

Equipment is fitted to the digester plants to suit climate conditions. The bioreactors have thermal insulation and are heated by heating and also have a cooling system for summer use. In cold winters a biogas plant can consume up to 50% of its produced heat power.

The liquid that results from the anaerobic digestion process has solids which are separated out, composted, and sold to local gardeners, landscapers and farmers. Some farmers use the solids as bedding for their cows and sell it as bedding to neighbors. The liquids are returned to the farmer as nutrient rich natural fertilizer, which replaces imported nutrients and thereby cuts costs.

There is an issue, and it is a fallacy, going around that Anaerobic Diesters always smell. We would contest this. Anaerobic digesters actually tend to alleviate odor problems when on a well run, especially as suburban growth surrounds farms and introduces neighbors who complain about manure smells most often due to nearby farming activities and not the AD plant at all.

By installing an anaerobic digester, the conscientious farmer can actually solve odor issues to everyone's satisfaction. Since the digesters are airtight, the smell stays within, and the liquids and solids coming out of the digester have only a very slight odor compared to the raw slurry.