“Poop Humour” Counterproductive to Biogas Technology

The biogas process, which produces fuel from animal and human waste, is prompting many supposedly amusing posts that could have a negative effect. Googling “biogas and poop” gives 12 800 hits including The Power of Poop, California Cow Poop Power and Turning Cow Poop into Car Power. This is counter productive as it distracts from the potential that biogas holds for both developing and developed countries.

Besides the comical slant of the titles, it is surprising that biogas is often presented as something amazing & unknown although it has been around for hundreds of years, is used in tens of millions of rural household and is a significant contributor to Europe’s renewable energy production.

Biogas - Amazing Natural Technology

The fermentation of organic material such as biomass, manure, sewage, farm waste, municipal waste, green waste and energy crops in the absence of air produces biogas. The same anaerobic fermentation produces swamp, marsh and landfill methane.

• » See also: SAB Miller Uses Brewery Waste from Alrode Brewery in South Africa to Reduce Carbon Footprint
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Biogas consists mainly of methane and can be used directly for lighting, heating and electricity generation. With purification it can be added directly to natural gas systems. The byproduct of the process is a much reduced mass of waste which is more stable, less offensive and can be used as a fertiliser.

Methane is a 23 times stronger greenhouse gas than CO2 so replacing natural waste fermentation in the open, with enclosed methane production that will be used as fuel, significantly reduces greenhouse gasses. Because the carbon in biogas is generally recently extracted from the atmosphere by plants it adds less total atmospheric carbon than fossil fuels. This and the fact that methane has a higher specific energy value than many other fuels makes it an attractive “Green Fuel”.

The anaerobic fermentation process was first recognised and used in the 19th century, for example it was being used to light streets in Exeter at the start of the 20th century.

Biogas - Household Solution in Developing Countries

In the middle of the 20th century United Nations organisations recognised the potential of household scale biogas in rural development and India and China started supporting the process in the mid seventies. There are estimated to be between 10 and 20 million household biogas plants around the world.

Basic anaerobic fermentations can run with very little control and handle a variety of feeds. It is a slow (fermentation takes about 30 days) and inexpensive process (low capital, little labour, no sterilisation, and no processing aids or ingredients).

The biogas process can be installed and run at the household level with simple training and support. A household biogas plant consists of a tank (often an underground brick pit) where manure and other organic materials are mixed with water and allowed to ferment. The gas produced by the fermentation flows continually to a buffer tank from where it is taken off and burnt as needed. The solid material which is much reduced in mass, is more stable and less offensive. It is drawn off periodically and can often be used as a fertiliser.

This process really deserves much wider use in developing countries because of its broad and diverse impact, having the potential to:

• improve health through the introduction of sanitation and a smokeless cooking fuel which improves household air quality
• improve the environment by reducing deforestation, waste and greenhouse gas emissions
• improve the quality of life through the elimination of firewood collection, improved agriculture, improved nutrition, saving of money and time and the creation of business opportunities

Biogas- Green Fuel in Developed Countries

The changes in the energy sector and particularly the focus on global warming have boosted the interest in biogas as a renewable and green fuel.

Large scale modern plants run optimised anaerobic fermentations which are essentially the same as that used in a household process.

Countries of the Europe Union produced some 4.7 million toe (tons of oil equivalent) of biogas in 2005. Two thirds of this was derived from landfill sites, while sewage, agricultural, and other wastes were the source for the remainder.

Germany like many countries, supports biogas production through guaranteed prices for electricity and gas as well as subsidies on capital investment. It had 1 250 plants installed in 2000. Although the base for these plants is agricultural manure almost half of the material converted is grass, maize stover or other non food biomass. It is estimated that, by processing food industry waste, biogas could provide 3% of Germany’s stationary energy needs or 11% of its gas consumption.

Biogas produces 0.16% of the US’s electricity, 75% of this coming from some 500 land fill facilities. On farm manure digesters have been used in the US since 1975. However, they lost favour as a result of early technology problems and were not economics in the 90s . The 2002 Farm Bill introduced subsidies encouraged a second wave which results in there currently being some 200 plants in the USA.

In some of the latest news Danish companies Novozymes and Xergi have created a joint venture focussed on increasing the countries conversion of manure to biogas by substantially increasing the energy yield and improving the quality of the byproduct and WELtec BioPower GmbH has started construction on what will be the biggest biogas plant in world processing 120 million tons/year of feed.

So this is a serious opportunity that would be better served by some more serious communication.

Photo credits:

Bacteria Plate by kaibara87 on Flickr under a Creative Commons License.

Rural Biogas Plant Gas Chamber by Ajay Tallam on Flickr under a Creative Commons License.

Lübeck Waste Treatment Facility by Vortexrealm on Wikipedia under a Creative Commons License.

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