英語演講稿-水污染-英文課件

1、waterenvironment1waterenvironment1Water is the source of all thingsIts the only water, but its the liquid wonder that makes our world possible.Water is able to dissolve more substances than any other liquid.Its takes a lot of water to keep life going.2Water is the source of all thi123Some data water

2、 use& pollution what can we do3123Some data water use& pollut 71% of earths surface is covered with waterAre the water sources abundant?4 71% of earths surface less than 3%Of total waterLow layer0.3% of fresh water5 less than 3%Low layer0.3%China water resource rank fourth in the world.China isnt ri

3、ch in water resources .Obviously, the prospect of Chinese water resources isnt optimistic.Water Issues in China with water resources per capita being2200m3 or so, only 1/4 of that of the world. water resources per capita 6China water resource rank fourSouth:population 53% waterresource:78%North: pop

4、ulation:47% water resource:22%Uneven distribution of water resources 7South:population 53% wateWater is considered polluted if a substance or condition is present that renders the water useless for a particular purposeThe sources of water pollutionDirect sources effluent outfalls from factories, ref

5、ineries( 精煉廠）, waste treatment plants .Indirect sourcescontaminants that enter the water supply from soils/groundwater systems and from the atmosphere via rain water.810/15/2022Water is considered polluted iAgricultural Water UseFour common irrigation methods:Surface / FloodRequires extensive canal

6、systemsSprayUse pumpsTrickleStrategically places openingsSub-irrigationPipes can be used for drainage as well910/15/2022Agricultural Water UseFour comExcessive fertilizer use may lead to eutrophication（水體富營養(yǎng)化） in many aquatic habitats.Agricultural runoff from large, open expanses is major source of

7、water pollution.Agricultural Water Pollution1010/15/2022Excessive fertilizer use may lIndustrial Water UseAccounts for nearly 50% of all water withdrawal in U.S., and 23% worldwide.90% of water used by industry is for cooling, and is returned to the source.Very little actually consumed.Most processe

8、s involve heat exchange.Water used to dissipate and transport waste.Toxic and overload wastes lead Stream and lake degradation.1110/15/2022Industrial Water UseAccounts fIndustrial Water PollutionAll kinds of industry generate trade waste (工業(yè)廢水）Iron and steel industryFood industryComplex organic chem

9、icals industryNuclear industryPollutants: organics, oil, metal, acidMay require special wastewater treatment. 1210/15/2022Industrial Water Pollution 1Domestic Water Use70% used as solvent to carry wastes.30% used for lawn and garden.Very small fraction used for drinking.Natural purification processe

10、s cannot cope with highly concentrated urban wastes.Must be treated before release.1310/15/2022Domestic Water Use70% used as Domestic water pollutionWaste water from Bathing, dishes, toiletsNo toxic substance, abundant in nutrients with nitrogen (N，氮）and phosphorus (P，磷）Eutrophication （水體富營養(yǎng)化）Trash

11、or garbage (e.g. paper, plastic, or food waste) discarded by people on the ground, along with accidental or intentional dumping of rubbish, that are washed by rainfall into storm drains and eventually discharged into surface waters .1410/15/2022Domestic water pollution1410/1For governments1.To estab

12、lish urban sewage treatment system(城市污水處理系統(tǒng))2.To restructure Industrial3.To encourage the development of new water sources4.To strengthen legislation, severe punishment152022/10/15For governments1.To establish For plants1.To reduce water consumption2.To buy equipment of sewage treatment 3.Dont disch

13、arge sewage into water4.To use water recycling system162022/10/15For plants1.To reduce water coFor individuals1 .Dont use cleaner conclude P2. Dont throw the garbage into the rivers 3. To promote awareness of preserving water resources4. To tell the persons around you to protect the water resources172022/10/15For individuals1 .Dont use clWorld Water Day (World Day for Water)On March 22 the United Nations Gen