Water
Water is essential to all life and is man’s most important provision. Potable water becomes sewage after being used by people – sewage that has to be treated in order not to cause too much eutrophication of lakes, rivers and seas.

Water is essential to all life and is man’s most important provision. Potable water becomes sewage after being used by people – sewage that has to be treated in order not to cause too much eutrophication of lakes, rivers and seas.

