| Wastewater
and sewage is collected from properties and businesses
by underground sewers and flows to treatment works,
where it is separated into liquid and solid elements
which are treated separately.
Surprisingly perhaps, human waste products
form quite a small proportion of the total volume of
treatable sewage – waste liquids and solids are
made up of 99.9% water and just 0.1% solids.
Liquids are purified and returned to
rivers and seas while treated solid matter is disposed
of in different ways; incineration, landfill, and application
to certain types of agricultural land.
Sewage treatment is strictly controlled
to comply with UK codes of practice and European directives.
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