precious resource
o Without water human,
animal and plant life is impossible
o Human beings can manage up to 30 days without food but
only 3 days without water
o Humans need about 2 to 3 litres of drinking water a day to survive
o The sun's energy guarantees continuous water circulation
o Water evaporates at the surfaces of oceans and continents,
condenses at higher altitudes by forming clouds and returns to earth
in form of precipitation and rain
o Water consumption has increased throughout the process of
industrialization
o Statistically, every German citizen uses 145 l of drinking water daily
(40 years ago it was 85 l per day, 60 years ago 10 l a day)
o Reasons: improved sanitary equipment in homes and apartments
o Utilization of water-consuming devices
o Consequently, waste water has become a problem of industry and
private households
What to do with the water?
Private households add mostly easily degradable pollutants to water
These pollutants can be treated with micro-organisms
Agriculture pollutes water in a worse way:
Fertilizers contain phosphates
When fertilizers get into water they accelerate the growth of algae and
aquatic plants which, in turn, extract oxygen from the water.
As a result, fish die and the plant balance of the water collapses.
Inorganic chlorine compounds, such as solvents and cleaning agents,
cause the greatest damage. Polluted water as well as fish, clams and
other organisms in the water reach humans. Thus, the food chain can be harmed.
Further damages are caused by oil tankers, the mining industry and
fertilizer salts.
It is therefore necessary to treat water, our most precious
| resource, well! | 
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