permaculture

["Lawrence F. London, Jr." <lfl@intrex.net>]

Looks like they're standing pat with this situation. If they put the dung on the farm field and grew their own food with 
it, made do (npi) with in season crops (and craps), they would save far more $$$ by eliminating buying food brought in 
from out of area, and build wonderful soil to boot. -dirtfarmer

<http://news.bbc.co.uk/2/hi/uk_news/education/6180773.stm>
Last Updated: Sunday, 24 December 2006, 00:39 GMT
E-mail this to a friend         Printable version
College harnesses cow pat power
Dairy cows
Methane contributes 7% to the UK's global warming gasses
The humble cow pat could become the latest weapon in the fight against global 
warming.

An agricultural college is using methane from the muck produced by its dairy 
herd to power its working farm.

The dairy cows at Walford and North Shropshire College are housed for eight months a year and their dung is collected 
and pumped into a digester.

There it is converted into methane and used to power a generator. This 
produces enough energy to run the farm.

Adrian Joynt, farm manager at the college's new £2.7m environmentally-friendly Harris Centre, said: "Everything that 
comes out of the back end of an animal goes in [the digester].

"And what we get out is 7,500 kilowatts - or £7,500 worth. We actually get enough energy to supply the farm's 
electricity for a year."

He added: "If you are going to put food in one end of the cow, we have to 
accept what comes out of the other.

"It's about what we do with it.

"We can either spread it on the field or we can put it through this digester and 
get the methane gas out of it."

Methane emissions

Not only does the anaerobic digester produce electricity, it also reduces the amount of methane - which accounts for 
around 7% of the UK's greenhouse gas emissions - produced by the dairy herd.

There are 2.2m dairy cows in the UK which, along with sheep, produce a 
quarter of the UK's methane emissions.

Roger Higman, of green pressure group Friends of the Earth, said: "Anaerobic digestion is a great idea - not least 
because manure from animals is also a major cause of water pollution."

The digester works by collecting the cows' dung, in liquid form, and pumping 
it into an airtight tank.

Here it is heated to a temperature of 35C (95F) - the temperature at which 
methane producing bacteria are made.

The methane produced is then fed into an engine which runs on the gas and is attached to a generator which produces 
electricity.

The heat produced by the engine is then recycled into the system to heat the 
cow dung to the required level.

The technology is used at more than 1,000 farms in Germany but only at a 
handful in the UK.