90% of water used by industry is for cooling, and is returned to the source. Very little actually consumed. Most processes involve heat exchange.
Water used to dissipate and transport waste. Toxic and overload wastes lead Stream and lake degradation.
Agricultural runoff from large, open expanses is major source of water pollution.
Industrial Water Use
Accounts for nearly 50% of all water withdrawal in U.S., and 23% worldwide.
Uneven distribution o水f 资w源at分e布r r不e均sources
% 100 80 81%
60
40
38%
20
0
南方
水资源
62%
19%
北方
土地资源
• No北rth方: pwoa人 G水ptDue口 资 Plra:rt源 :4ei4os:4%no7:u2%4r27c%% e:22% Sou南th方: 人口: 53% popGuDPla:tio5n6%53% wa水ter资re源so:u7r8c%e:78%
• China isn't rich in water resources .
• Obviously, the prospect of Chinese water resources isn't optimistic.
30000 (m3/yr/ca) 25000
26600
20000
15000 10000
Sub-irrigation
Pipes can be used for drainage as well
Agricultural Water Pollution
Excessive fertilizer use may lead to eutrophication（水体富营养化） in many aquatic habitats.
Water is considered polluted if a substance or condition is present that renders the water useless for a particular purpose
The sources of water pollution11000 Nhomakorabea8800
5000 2200 1047 3347 0 China North South World USA Russia china China
• with water resources per capita being2200m3 or so, only 1/4 of that of the world.
• It’s takes a lot of water to keep life going.
1
Some data 2 water use& pollution 3 what can we do
71% of earth’s surface is covered with water
Are the water sources abundant?
environment
Water is the source of all things
• It’s the only water, but it’s the liquid wonder that makes our world possible.
• Water is able to dissolve more substances than any other liquid.
Industrial Water Pollution
All kinds of industry generate trade waste (工业废水）
Iron and steel industry Food industry Complex organic chemicals industry Nuclear industry Pollutants: organics, oil, metal, acid May require special wastewater treatment.
Direct sources
effluent outfalls from factories, refineries( 精 炼厂）, waste treatment plants ...
Indirect sources
contaminants that enter the water supply from soils/groundwater systems and from the atmosphere via rain water...
Low layer
0.3% of fresh water
less than 3% Of total water
Water Issues in China
water resources per capita
• China water resource rank fourth in the world.
Agricultural Water Use
Four common irrigation methods:
Surface / Flood
Requires extensive canal systems
Spray
Use pumps
Trickle
Strategically places openings
Domestic Water Use
70% used as solvent to carry wastes. 30% used for lawn and garden. Very small fraction used for drinking.