Topic 4 Flashcards
Desalination
Desalination plants: removal of salt from seawater
: A-Distillation:
Water is boiled and released as vapor, leaving salt behind.
O The vapor is then condensed as liquid water and can
be used.
It uses a lot of energy.
B-Reverse osmosis: pumping water at high pressure
through a fine membrane.
It requires less energy than distillation.
Fresh water supply
Surface water: water in lakes, rivers and swamps.
Ground water: water in the soil, and in rocks under the surface of the ground.
Potable water: safe to drink.
Aquifers: water stored in porous rocks under the ground.
o Alternating layers of permeable and impermeable rocks trap the water in permeable rock.
Permeable rocks on the surface receive new supplies of rainwater.
Water is stored in the limestone and sandstone (porous) rocks below the water course.
Mechanical pumps or human labor are used to raise water to the surface.
Artesian aquifer: an aquifer in which the water is under
pressure. Water from well sunk into an artesian aquifer will rise to the surface without the need for pump.
Advantages of desalination
Advantages of desalination:
1. It’s safe as there are no heavy metals or water pollution. 2. Reduces the risk of water related diseases.
3. Provide job opportunities.
4. Well-known technology.
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5. A huge supply as salty water cover 97% of Earth’s water.
Drawbacks of desalination
Drawbacks of desalination:
1. The process is very expensive.
2. The process needs a lot of energy.
3. The process requires skilled workers.
4. Countries have no access to seas and oceans.
5. Greenhouse gas emission happens if fossil fuel is used
6. Some marine species are killed in the desalination plan
7. Causes damage to marine ecosystem due to waste salt.
8 already have freshwater
Potable is water
Potable water supply
• Surface Lakes Ring Swamps
Ground water aquifer by making a well Rain water harvesting
From glaciers and ice caps
• Reservoir to store water
(6 Bottled Water
(7 desalination of water from seas and ocean
Water usage
4.4 Water usage
Domestic Use
The demand increases due to increasing population:
1. At home for drinking and cooking.
3. Washing clothes.
4. Gardening.
2. Washing and flushing the toilet
5. Washing cars.
6. Lost in leaks.
Industrial use
Industry expands and uses
more water in factories for:
Cooling.
Bottling and canning.
Mixing and making products
Power generation.
Agricultural Use Increased agriculture uses of water due to increased population
1. Mainly for irrigation (plants need water for transporting minerals, for photosynthesis, and for the prevention of wilting). 2. For domestic animals.
Water rick countries
O Countries with plentiful fresh water supplies.
Rich countries so have many water infrastructure as sewage system distribution system and dams
o High precipitation temperature low
O Some with the world’s greatest rivers flowing through them e.g., Amazon, River Nile.
o Low population so low demand for water.
o Ground water supply (aquifers).
o Countries with big areas are usually water rich as they have plenty of land for rain to fall
on (e.g., Russia). However, big areas do not ensure water availability due presence of desert within.
Water poor country
Water-poor countries:
O Countries with scarce fresh water supplies.
Lack of rain (limited precipitation).
O Water is geographically inaccessible
Lack of infrastructure (e.g.: distribution system or dams and treatment) due to economic
reasons.
Long term drought.
O Water might be frozen.
O Rocks may be impermeable so no ground water.
Water stores maybe contaminated (water related diseases) and lack of treatment.
The demand is too high compared to the supply due to large/scattered population.
urban areas have higher access to safe drinking water because:
Cities are more wealthy places with factories and offices.
on average, people’s incomes are higher.
Easier to put pressure on the politicians or leaders to make improvements.
o Wealthy people are more likely to live in cities.
on average the population density in urban areas are higher so, water pipes are easier and
cheaper to build when a lot of people live close together.
O Tourists are more likely to visit if clean water is available.
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o Some rural problems terrain makes it difficult to install water system.
Multipurpose dam
Multipurpose dam: are constructed for multiple use for example irrigation and electricity. Single purpose dam: are constructed for particular use, maybe irrigation or electricity.
• Choice of site:
o High precipitation to provide sufficient water.
o Low temperature to prevent evaporation.
o Narrow, steep sided valley for good storage.
O Built on strong impermeable rock so water doesn’t drain and has a good foundation.
o Built high up to have good potential for hydro-electric power.
o Rivers and lakes nearby to provide water.
Disadvantage and advantages of building a dam
Economic, environmental & social impacts of a dam:
Advantages
1. Generation of electricity in hydro-electric power plants which is renewable source of
energy & doesn’t produce greenhouse
gases.
2. Flood control.
3. Sustainable irrigation.
4. Creates land for tourism.
5. Provision of water.
6. Creation of habitat for wetland species.
7. Reduces fossil fuel consumption.
8. Creates more jobs.
Disadvantages
1. Relocating people.
2.Dam may break causing flooding.
3.Reducing soil enrichment downstream of the dam so reduces jobs for farmers when farms are affected.
4. Altering water supply for people downstream the dam.
5. Noise, air, visual pollution when being built
6.Loss of habitat so loss of biodiversity.
7.Disruption of food webs.
8. Danger of water related diseases because no
water is flowing.
9. Very expensive to build.
10. Requires maintenance.
water
о Reservoir can become silted due to material carried into it by rivers.
O Dam structure can be under a lot of pressure so may deteriorate and eventually fail
o Have negative effects on fish population.
Sources of water pollution
Domestic waste:
Rubbish is washed or dumbed in water courses.
Untreated Sewage: waste that is rich in organic matter, so microbial organisms can thrive in it.
O
o Sewage carries many pathogenic micro-organisms, increasing the content of nitrates and phosphates in rivers.
Detergents, metals and other manufactured products contain traces of toxic chemicals. It is usually disposed in water bodies, and thus has to be treated.
⚫ Industrial processes:
o Use of chemicals.
The processing of metal ores.
And the leaching of metals from waste heaps and dumps.
cause the presence of metals in water courses (e.g., manganese, mercury, copper).
Gases from industrial chimneys enter the atmosphere, where they dissolve in water and form acid
rain.
Agricultural practices:
o Surpluses of phosphorous and nitrogen.-> fertilizers
o Pesticides, herbicides and fertilizer and animal manure.
IF not absorbed by the plants, will be washed from the land or infiltrate into the ground water.
Impact of water pollution
- Global inequalities in sewage and water treatment:
ground water.
LEDCs have difficulty treating water and sewage compared to MEDCs as people aren’t educated and can’t put pressure on the government (same for rural and urban areas)
2 Risk of infectious bacterial diseases, typhoid and cholera:
Water-borne diseases are caused by drinking contaminated water e.g.: cholera and typhoid. Accumulation of toxic substances from industrial processes in lakes and rivers:
Causes death of fish.
Bioaccumulation of toxic substances in food chains:
Biomagnificetten
Increases concentration of a toxic substance (e.g., Mercury) in the tissues of organisms at successively higher levels in a food chain, causing illness.
Biomagnification: the concentrations increase higher up in the food chain and cause the death of top consumers.
Nutrient enrichment leading to eutrophication:
Excess water containing dissolved fertilizers drain into nearby lakes and rivers, leading to eutrophication, which causes increase of algae growth, so sunlight is blocked, and photosynthesis is reduced, this causes the algae to die and causes increase in bacterial count
to decompose the dead algae. This bacterial increase uses up oxygen. so, aquatic organisms die due to the lack of oxygen.
Environmental Management (680)
Dr. Safwat Hatem (01271300063) & Dr. Carol Elhamy (01005864831)
6. Formation of acid rain:
When volcanoes erupt or fuels burn, Sulphur dioxide (SO2) and oxides of nitrogen (NOx) are released. They are blown long distances and react with water in the atmosphere. SO2 dissolves in water to form sulphuric acid, and NOx dissolves to form nitric acid that fall in
the form of rain having low ph. this is called acid rain.
o pH: measured by acidity or alkalinity.
Ranges from very acidic= 1, to very alkaline =14.
7 is neutral.
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acidic gases released into
he atmosphere
gases carried upwards by the wind
SO, NO, CO,
gases combine with water droplets to
form acids
acid rain
acid rain destroys plants pollutes water sources and so and aroides buildings
he impact of acid rain:
o Acidification of water bodies.
death of aquatic organisms
Lower pH makes the environment intolerable for aquatic life so, reduces fish population. Leaching of heavy metals such as aluminum, lead and mercury from the soil into the water. - Causes damaging of crops.
Causes damage to buildings.
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Strategies for improving water quality
- Improve sanitation separates human wastes from water source, achieved by toilets.
Waste can be removed by:
о
Connection to a system of sewer pipes or sewerage that collects human wastes. o Connection to a septic system, which consists of a settling tank.
Example of toilets:
O
Flush toilet.
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o
Pit latrine.
Treatment of sewage aims to reduce the Biological Oxygen Demand (BOD) of the sewage. Wastewater from homes and industries is taken to a sewage treatment plant.
In a screening tank, large objects are removed from the waste.
Solid organic matter, mainly human waste, settles at the bottom of the tank.
Water is pumped into a tank where oxygen is bubbled through it.
o This encourages the growth of bacteria and microbes that break down organic matter.
o Chlorination produces even cleaner effluent that protects the habitat in which the effluent is released.
Water treatment plant: Treats water to make it potable by undergoing coagulation treatment, being filtered and disinfected before discharging into rivers.
Coagulation: Particles in the water are stuck together and settle to the bottom of the
container.
- Chlorination: To kill remaining pathogens, chlorine is added as a disinfectant. Pollution control and legislation:
Industries are required to monitor the pollution they cause and keep it within set level. International Agreements: a loading limit of phosphorus was set response to eutrophication issues i in the Great Lakes of USA and Canada.
Fines for exceeding set limits.
Companies may be prosecuted and in extreme cases, forced to shut down.
Incentives may be used to encourage companies to take part, such as tax relief, for those that do achieve a reduction in pollution.
Malaria
> Government strategies that can help people to have access to safe drinking
water:
1. Provision of bottled water.
2. Promotion of rainwater harvesting.
3. Education regarding sanitation.
4. Fines against water pollution.
5. Improving water quality by improving sanitation, treatment of sewage, pollution control
and legislation.
4.10 Managing water-related disease
Water-bred disease: carrier breeds in water and spreads the disease by biting its victims. Example: malaria.
•
Malaria: a life-threatening disease which is transmitted through the bite of an infected
Female Anopheles mosquito (vector). Veleasing Plasmodium
Life cycle of the malaria parasite:
1. Female Anopheles mosquito that is infected
with malaria parasite (plasmodium).
2. The mosquito bites human.
3. The human gets infected with malaria that
targets the liver cells.
4. Another mosquito bites the infected human.
5. The second mosquito becomes vector.
Strategies to control malaria:
o Using antimalarial drugs to kill malaria parasite.
o Avoid contact with the mosquito (vector control) by sleeping under mosquito nets and wearing long clothes.
Kill mosquito using insecticides (eradication).
Draining stagnant areas of water to prevent breeding.
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Put kerosene over the tops of pools to stop the breeding.
Use vaccinations and educate people on the risks of malaria by setting up campaigns
and programs. Biological Control
