The huge quantities of domestic and industrial waste that we produce cause a major environmental problem. Sometimes waste is buried in vast landfill sites, which are often old quarries. Alternatively, waste can be burned or in some cases recycled.
Waste from our toilets, baths and washing machines is collected in sewers and carried to a treatment plant. Bacterial action breaks down solid waste into a harmless form, and the waste is stirred in huge pools while this process takes place. After treatment, purified water is run off and can safely be drained into rivers. The solid material remaining is usually processed into fertilizer, after further treatment to make sure it contains no dangerous microbes.
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