4.2 Reducing eutrophication
In Britain, water supply companies have tended to regard eutrophication as a serious problem only when it becomes impossible to treat drinking water supplies in an economic way. Threshold concentrations at which action is taken to reduce nutrient loadings thus depend on economic factors, as well as wildlife conservation objectives.
There are two possible approaches to reducing eutrophication:
Reduce the source of nutrients (e.g. by phosphate stripping at sewage treatment works, reducing fertilizer inputs, introducing buffer strips of vegetation adjacent to water bodies to trap eroding soil particles).
Reduce the availability of nutrients currently in the system (e.g. by removing plant material, removing enriched sediments, chemical treatment of water).