Green Technology-V(Mains special) ; publishes about Green Technology in Q & A format. It growing relevance in real life and for UPSC exams, enables us to learn about it. Green Technology-I ,Green Technology-II, Green Technology-III


Q: What is e-waste?
  • E- waste is the term used for electronic I teams that are thrown away after use.
  • Discarded computers, television, VCRs, stereors, copiers, fax machines, electric lamps, cell phones, audio equipment and batteries all make up e-waste.
  • E-waste is considered dangerous, as certain components of some contaminated materials that are hazardous both to our health, and to the environment. These material can contaminate the soil and ground water . for example, the average 14-inch computer monitor uses a tube that contains an estimated 2.5 kgs of lead.
  • The lead can seep into the ground water from landfills, there by contaminating it . if the tube is crushed and burned, it emits toxic fumes into the air.
  • Disposal of e-waste is a particular problem faced in many regions across the globe.
Q:What is nuclear waste?
  • Nuclear waste is the material that nuclear fuel becomes after a nuclear reaction has taken place.
  • It look exactly like the fuel that was loaded into the reactor before the reaction. However, the spent fuel or nuclear waste is now dangerously radioactive.
  • It is so toxic that if it while it was unshielded, you would receive a lethal radioactive dose within a few second, and would die of radiation sickness in a few days.
  • Therefore, nuclear waste is always kept shielded underwater. After a few years, the radiation decays to levels that can be shielded by concrete in large storage casks.
  • However unfortunate accident can occur, and if the nuclear waste is exposed, it can cause terrible damage to both humans and the environment.
  • Nuclear power plants and research labs where nuclear medicine is practiced, all produce nuclear waste, and the threat is increasing day by day.
Q:Why is it said that the effects of radioactive waste last for centuries?
  • Radioactive materials. Such as the radioactive waste from power station, can be a real health and environmental hazard.
  • So, it is essential that nuclear facilities with appropriate protection measures. It is a fact that nuclear wastes do not stay radioactive forever.
  • Each radioactive material has what is called a half-life. This is a period after which it will have only half the activity it had before after another half-life, the activity is down to a quarter.
  • Eventually, the activity will reach safe levels however, the whole process can sometimes take centuries. Till then nuclear waste remain a dangerous threat to both humanity and the planet.
Q:What is sewage treatment?
  • Wastewater from your shower, bathtub, washing machine, dishwasher, kitchen sink and toilet is all considered sewage. Interestingly, sewage is actually 99.8 per cent water .
  • A typical 4-person household produces around 400-500 litres of sewage every day. Liduid waste  from business and industry is considered sewage or wastewater as well. Sewage disposal is the process by which sewage is transported through cities and inhabited areas to sewage treatment plants.
  • Here , the sewage is then treated to remove contaminates, and produce environmentally-safe waste.
  • Many modern cities have sewage disposal systems. Technological advances have resulted in more environmentally friendly and healthy solutions to disposing and treating sewage.
Q:Why is water purification important?

  • In happier times, it was possible to drink water directly from a bubbling stream, or  clear pond. However, over the years, all that has changed.
  • Today, most of our sources of drinking water are heavily contaminated, parasites, bacteria, algae, viruses and fungi pollute our rivers and streams, lakes and ponds.
  • Drinking this unclean water can cause many waterborne diseases including diarrhea hepatitis a, cholera, botulism, typhoid, dysentery, and polio. Therefore, it is very important that water should be purified before use.
  • Therefore are many processes by which this can be achieved. However, the goal remains the same- to remove all undesirable contaminants and chemicals so as to get the clean, safe water that is necessary for good health.
Q:What is the pre-treatment process in purification of water?
Image result for pre treatment of water purification
  • Before water is purified it must go through a pre- treatment stage.
  • Pre-treatment is used to kil disease causing organisms, and help control teste and odour causing substance. The first step is to pump water from a lake or reservoir into holding tanks.
  • The second stage involves, screening where large debris is removed.
  • For this. Screen may be used to remove Rocks, sticks , levels, and other debris; water is then stored.this is the pre- sedimentation stage.
  • The purpose of this stage is to allow sand, grit,and gravel to settle down. In the next stage, chemicals may be added to control the growth of algae and bacteria. After pre-treatment, the actually purification process begins.
Q: What are the different stages of water purification?
  • After being pre-treatment water is purified in several stages.
  • The first stage is coagulation. This removes dirt and other particles suspended in water.bacteria or microorganisms that may be in the water.
  • After sedimentation, clear water from the top moves on to the filtration process.
  • Here, the water passes through filters, some made of layers of sand, gravel, and charcoal that help remove even smaller particles.
  • Next, small amount of chlorine, or some other disinfectant method is used to kill any bacteria or microorganisms that may be in the water. This is called disinfection.
  • The water is placed in a closed tank or reservoir in order for disinfection to take place. It then flows through pipes to various buildings. Water may be treated differently in different communications, depending on the quality of the water which enters the plant.
  • Groundwater is water located underground, and typically, requires less treatment than Walter from lakes, rivers and streams.
Q: What is air pollution?
  • We know that the Earth is surrounded by a blanket of air made up of various gases. This is known as the atmosphere.
  • It helps to protect the Earth, and is essential for life to exist. Any other additional gas, chemicals, particles, smoke, or dust that is introduced into the atmosphere upsets the natural balance of gases. This is called air pollution.
  • Air pollution can be caused both by human activity , and also by natural causes. Things that pollute the air are called pollutants. Examples of pollutants include gases that are usually released from factories. Sand, or dust particles that enter the atmosphere are also pollutants.
Q:How does air pollution harm our health?
  • Our bodies have natural defenses that protect our lungs from germs and particles like dust and pollen.
  • Air pollution harms lung tissue directly, and weakness those important defenses.
  • Air pollution can be make your eyes water, irritate your nose, mouth, and throat, and make you cough and wheeze. But most important, it can worsen lung diseases like asthma and bronchitis. It can cause cancer, and even kill.
  • Even for Healthy people, polluted air can cause respiratory irritation or breathing difficulties during exercise, or outdoor activities.
Q: How are fumes and smoke harmful to man and nature? 
  • The problem of air pollution started with the burning of coal in homes and factories.
  • Coal, when burnt, creates a lot of smoke, which makes the air very dirty. With the coming of the industrial revolution, factories were built, and even more coal was burnt.
  • Today, more and more factories are manufacturing more and more goods. These factories release vast quantities of fumes that pollute the atmosphere.
  • Exposure to fumes from factories and vehicles, have both instant, and long-term effects on the body.
  • Smoke and fumes contain very high levels of carbon dioxide that can cause respiratory diseases in the population. High levels of carbon dioxide in the air also cause global warming, and climate changes.
Q:What are the ways to reduce air pollution?
  • There are many things that we can do reduce air pollution.
  • We can try and buy only products that are friendly to the environment. As far as possible, reuse and recycle products instead of throwing them away,  or burning them.
  • We must promote the use of cleaner fuels like bio-diesel. Electric vehicles can also help in reducing air pollution. Whenever possible, walk, ride a bike, or use public transportation so that less vehicles are on the road, emitting toxic fumes.
  • It has also been established that plants are helpful in removing harmful gases like carbon monoxide from the air. So, a very good way to reduce air pollution is to grow more plants!

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