|
Landfill gas
Rubbish tips are the source of landfill gas and in the UK
25 million tonnes of household waste were collected in 2000/01*
- that's about 1,200kg of waste per household every year!
 Around
50% of UK rubbish comes from packaging and a high proportion
of it is aluminium cans and milk cartons. But most of our
rubbish can be recycled and some local councils are now providing
households with a recycling box for sorting glass, paper,
cans and other waste packaging.
The waste matter that reaches landfill sites is left to decompose.
But some of the rubbish that doesn't decompose naturally is
burnt and this produces Carbon Dioxide (CO2)
emissions which cause climate change. After as little
as one year, the decomposed waste matter emits a natural methane-rich
biogas that is used as a cheap and easily accessible energy
source. To capture biogas for using as heat or power, landfill
sites have to be prepared with an impervious lining prior
to dumping of waste. Centrifugal compressors extract the gas
through vertical wells, drilled into the waste and finally
the gas is filtered before it is used to generate energy.
Using landfill as a source of power prevents the highly toxic
methane gas from being emitted into the atmosphere. It is
20 times more dangerous to the environment than CO2.
Not all the biogas produced on landfill sites is used and
in 1994 landfill leakage made up 46% of total UK methane emissions
in 1994. Under the Non-Fossil Fuel Obligation (NFFO) landfill
gas production has flourished. There are currently around
174 landfill projects in the UK providing enough electricity
for around 660,000 homes. Around 40 million tonnes of organic
waste are dumped on landfill sites every year and this could
generate around 6.75 TWh of electricity. That's enough to
power 1.6 million homes. But the answer isn't in converting
our rubbish into energy. We need to reduce the amount of waste
we produce.
So next time you go shopping, try NOT to buy products that
are wrapped in excess packaging. Minimize
your rubbish and recycle
as much as you can.
<< Back
|
