Green Technology-IV(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 waste management?

  • Huge amounts of waste matter are produced every day in every country of the world. In fact, almost every from of human activity produces waste in some form or the other.
  • Source of waste include household waste, municipal waste, agricultural waste, industrial waste and medical waste.
  • There is also waste from construction and demolition sites, as well as the waste produced by discarded electronic appliances and automobiles.
  • Waste can be  solid or liquid, organic, or hazardous. The challenge today is manage this waste in a manner that is beneficial to both mankind, and the planet.
  • Waste management involves finding ways to generate less waste, as well as collecting transporting, monitoring, treating, reusing and disposing of the waste that is produced, safely and efficiently.
Q:What are some waste disposal methods?
  • The most common methods of waste disposal are landfills, and incineration or burning.
  • Landfills require a large plot of land away from living areas where the waste from a town can be deposited after it is sorted out.
  • Incineration results in solid waste being converted into gaseous products. Waste can also be recycled, and made into new products as often is done in the case of plastic.
  • Biological re- processing is another process in which recoverable products like plant material, food scraps, and paper products can be decomposed to from other organic materials. Of Course , the best method is to produce as little waste as possible to dispose of!
Q: Why are landfills the most common method of waste disposal?
Landfills are the easiest method of waste disposal, and therefore, the most common too.
Waste is collected, sorted, and taken to a site far away from where people live and work.
Here it is dumped, and a layer of soil is added every day to cover the trash on top. When a landfill is complete, it can be reclaimed, built on, or made into a park.
However, landfills can pollute the air, water , and soil. They can attract animals and insects, and cause diseases that spread to nearby communication.
Landfills can also increase the chances of global warming by releasing methane , a dangerous greenhouse gas .  so, waste disposal through landfills, though convenient, also poses several problems too.
Q: What is incineration?
  • Incineration is simply another word for controlled burning at very high temperature. It is a method for waste disposal that is used in many countries.Image result for incineration
  • Incineration is widespread, especially in countries like Japan where land is very scarce the material is first shredded and ground, and then placed in a furnace which has extremely high temperatures as high as 2000 degrees Fahrenheit.
  • The high temperatures convert most poisons into harmless inert matter.
  • Incineration removes water from hazardous sludge, reduces it’s mass and volume, and converts it to a non- burnable ash that can be safely disposed of. The process converts waste materials into heat, gas, steam, and ash.
  • However, incinerators do increase air pollution. As a result, incineration is a highly controversial method of waste disposal.
Q: What is biological reprocess?
  • Organic waste materials such as food scraps and paper products can be reused after a process called biological re- processing.
  • Different biological technologies, including composting and anaerobic digestion are used in biological re- processing.
  • Composting is a natural biological process, carried out under controlled conditions. In this processes, various microorganisms, including bacteria and fungi, break down organic matter into similar sub- stances.
  • Composting produce valuable fertilizers. Anaerobic digestion is a series of biological reprocess in which microorganisms break down biodegradable material in the absence of oxygen.
  • One of the end production is biogas , which is used to generate electricity and heat. Biological reprocessing is usually used for solid waste management.
Q: Why is energy recovery an important part of waste management?
  • Waste materials that cannot be recycled can be converted into different forms of energy by using a variety of process.
  • These processes include combustion, anabolic digestion, gas recovery from landfills, and pyrolysis, pyrolysis is a term for the transformation of a substance by the action of heat.
  • Pyrolysis can transform the organic matter in municipal garbage into oil, gas, and carbon. Another example of energy recovery is when biomass is processed to provide electricity.
  • Some non-recycled plastic, which may contain a higher energy value than coal, such as electricity, or into alternative fuels like synthetic gas.
Q: Why is waste reduction so important? 
  • We know that prevention is better than cure similarly, it is better to prevent waste being generated, than to try and manage if after huge quantities have been produced.
  • Of course, it is not possible to cut down waste totally. But we certainly can reduce the amount of waste that is being produced.
  • We can do this by repairing broken things instead throwing them away, buying second hand products instead of new ones, and opting for reusable cotton shopping bags instead of throwaway plastic ones.
  • We can also vent waste being generated by buying only rechargeable batteries that can be used again and again, and of course, by not wasting, or throwing away any food.
  • Above all, we must avoid the use of disposable items that pile up after they are used to form mountains of waste.
Q: What is pyrolysis ?
  • Pyrolysis is a process by which organic materials are decomposed chemically. Image result for pyrolysis
  • This is done by heating the material at extremely high temperatures in the absence of oxygen.
  • The heat changes the chemical composition of the material. There are many methods of pyrolysis. The final product is determined by the temperature and speed at which pyrolysis is done.
  • Fast pyrolysis produce liquid fuel, while slow pyrolysis produce gases and solid charcoal. For example, pyrolysis of waste plastics can produce millions of litres of fuel.
  • Similarly, the pyrolysis of waste tyres can produce high energy gas, hydrocarbe pyrolised to generate oil also. So, pyrolysis is one of the ways in which waste can be managed, and used for energy recovery.

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