This is how we dumped sewage into the North Sea as late as the
80´s, but is now forbidden.
Sewage
contains a great many nutrients, and a great deal of it ends up
in the sea. Sewage is commonly delivered to a sewage plant where
it is cleaned to varying degrees before it is released into the
environment. At some sewage plants, treatment methods are very simple,
whereas others use very refined methods. The resulting sludge is
often burnt or deposited in quarries. |
Unfortunately certain cities
like Brussels in Belgium release their sewage directly into rivers,
where it quickly reaches the North Sea. Several coastal towns in
Britian release sewage from pipelines that reach several kilometres
out into the sea. In the Netherlands, the sewage is minimally treated
before it is released, for example, from a 11 km long pipeline reaching
out into the North Sea from The Hague.
Some of the resulting sludge from the treatment process
is used as fertilizer on arable land. One of the disadvantages with
this method is that the sludge is often deposited on the fields
at the wrong time of the year so the nutrients leak out into the
groundwater and rivers and eventually out into the sea. The sludge
also can contain traces of poisons that finally end up in agricultural
products. It would be much better if this sewage sludge could be
effectively recycled. Hopefully this problem will be solved, but
there
are those that believe this is impossible as long as we continue
using the present methods of treating sewage and large scale centralized
handling.
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