Transcript Water footprint - Urspringschule

Water footprint
By Elisabeth Küttim, Falko Behr, Thomas Wiedemann and
Lewis Morrison.
Direct & indirect water use
People use lots of water for drinking, cooking and washing,
but even more for producing things such as food, paper,
cotton clothes, etc.
The water footprint is an indicator of water use that looks at
both direct and indirect water use of a consumer or
producer.
Water footprint of products
Potato
The global average water footprint of potato is 290 litre/kg.
Potato chips cost 1040 litres of water per kilogram of potato chips.
66% green, 11% blue, 22% grey
•
Leather (bovine)
A bovine animal at the end of its life time has an average water footprint of 1,890
The major fraction (83%) of the water footprint of the animal is attributed to the d
while, on average, 5.5% is attributed to the bovine leather (and the remaining frac
products).
A fully grown beef cow weighing 250 kg will produce 6 kg of leather so that the w
of bovine leather is 17,000 litre/kg.
93% green, 4% blue, 3% grey
Cotton
Coffee
Coffee
Global average water footprint: 130 litres for one cup of
coffee.
About 18900 litres of water are needed to produce 1 kg
of roasted coffee. For a standart cup of coffee (152 ml)
we requier 7 gram of roasted coffee, so that a cup
coffee costs 130 litres of water.
96% green, 1% blue, 3% grey water
Chocolate
Chocolate
When we assume that chocolate consist of 40% cocoa paste (with a water footprint of
24,000 litre/kg), 20% cocoa butter (34,000 litre/kg) and 40% cane suger (1800 litre/kg), we
can calculate that chocolate has a water footprint of about 17,000 litre/kg.
98% green, 1% blue, 1% grey water
Cotton
Tomato
Beef
•
Beef
•
The water footprint of meat from beef cattle (15400 litre/kg as a global average) is
much lager than teh footprint of meat from sheep ( 10400 litre/kg), pig (6000 litre/kg),
goat (5500 litre/kg) or chicken (4300 litre/kg).
•
93% green, 4% blue, 3% grey water
Beer & Bio-diesel
Beer (from barley)
The global average water footprint of barley is 1420 litre/kg. When we consider the amount of
malted barley to produce beer, the water footprint of beer is 298 litre of water per litre of beer.
This means that one glass of beer (250 ml) costs 74 litre. This excludes the water footprint of
other (smaller) ingredients used in the beer production process.
Bio-diesel (from soybean)
The global average water footprint of soybean is 2145 litre/kg. Assuming a dry mass fraction of
92%, a fat content in the dry mass of 18%, a biodiesel yield of 1 gram per gram fat and a
biodiesel density of 0.88 kg/litre, we can calculate that the water footprint of biodiesel from
soybean is 11400 litre of water per litre of biodiesel.
Environmental impact of biodiesel
•
The environmental impact of biodiesel is
diverse.
•
Greenhouse gas emissions
LCA
A life-cycle assessment is a technique
to assess environmental impacts
associated with all the stages of a
product's life from-cradle-to-grave .
LCA example
Apples shipped from New
Zealand are more eco-friendly
than storing apples in a local
place eg. Germany.
Sources
http://www.waterfootprint.org/?page=files/Wate
rFootprintLogo
http://en.wikipedia.org/wiki/Lifecycle_assessment
http://www.waterfootprint.org/?page=files/hom
e