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About 18,000,000
tonnes of MSW is produced each year in the nation's homes and
businesses. About 78,000,000 tonnes is Industrial Waste. These
figures are only estimates, because only about 40% of waste is
weighed before disposal. Today 88% of MSW is buried in the 4,000
licensed landfills up and down the UK. |
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Gases
Landfill is the cheapest way of disposing MSW, but all efforts
to get rid of waste pollute the environment to some extent. In
landfills the disadvatages are that gases and chemicals are released
into the air we breathe. Experiments show that the gases and
chemicals released from landfill sites are harmful to animals.
Doctors suspect, therefore, that it is harmful to humans also.
A major disadvantage is the release of Methane gas. This gas
can be explosive and in the USA there have been over 30 explosions
linked with Methane released from landfill sites. People have
died as a result!
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Early Landfills
Early landfills were put in convenient
locations on the least expensive land. The waste was 'out of
sight out of mind'. People did not realise that as the waste
rots and decomposes, it can release toxic chemicals. |
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As rain washes through the waste
tip, it dissolves some of the solids and mixes the liquids. The
water can become acidic and eat into the waste in containers.
All this produces a contaminated fluid called leachate. Leachate
escapes from most old landfills. It can pollute or contaminate
drinking water in the ground, modern landfills are designed to
protect the environment from pollution. More recently, landfills
have had barriers designed to keep in the leachate. Engineers
line the quarry With clay or synthetic materials Which the leachate
cannot easily pass through. Pipes then collect the leachate for
storage in tanks and special treatment.
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Bacteria
However, there is another problem with landfills, whether lined
or not. Bacteria in the soil, break down organic matter in the
landfill, such as vegetable peelings. As they do so, they release
methane gas. Methane is not a poison, but it has two drawbacks.
Firstly, it is a greenhouse gas. It contributes to the greenhouse
effect that will eventually cause global warming. Secondly it
is explosive. If it seeps from the landfill and finds its way
into a building, it can build up unnoticed. One day someone lights
a match and
..BANG!!!
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Greenhouse
Effect
The Greenhouse Effect is caused by so called 'greenhouse gases'
in the atmosphere. These gases, such as carbon dioxide, methane,
and water vapour have existed naturally for millions of years.
The amount of these gases has gradually increased, causing the
earth to get warmer. The temperature of the Earth changes naturally
by a few degrees, but it should take thousands of years. Over
the next forty years the temperature could rise by another 1.50C
to 4.50C, a speed of increase never experienced before on Earth.
This increase in temperature could cause the huge polar ice caps
to melt. This would cause sea levels to rise by about 1.5 metres
over the next sixty years. Low Iying areas of land will be flooded
and millions of people will lose their homes. So, Britain is
at risk, especially coastal towns such as Greenock and Gourock.
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Incineration
Another method is incineration, a method becoming scarce, therefore
making it more expensive. One advantage of incineration is that
energy can be produced from the burning waste and there are now
some 'energy from waste' schemes in operation. With this method,
some large lanfills generate enough electricity for 10,000 homes!
One disadvantage of incineration is that even more gases are
produced, contributing further to global warming.
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