RADIOACTIVE WASTE

Radioactive materials, such as the radioactive waste from power stations, can be danger to real heath and environmental hazard. So, it is essential that nuclear waste be kept in secure nuclear facilities with appropriate protection measures.
It is a fact that nuclear waste do not stay radioactive forever. Each radioactive material has hat is called 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 wastes remain a dangerous threat to both humanity and the planet.  

NUCLEAR WASTE

Nuclear waste is the material the nuclear fuel becomes after a nuclear reaction has taken place. It looks 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 you stood within a few meters of it while it was unshielded, you would receive a lethal radioactive dose within a few seconds, and would die of radiation sickness in a few days.
therefor, 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 accidents 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 treat is increasing day by day.

E-WASTE

E-waste is the word used from electronic items that are thrown after use. Discarded computers, VCR`s, stereos, copiers, fax machines, electric lamps, cell phone, audio equipment and batteries all make up e-waste. E-waste considered dangerous, as certain components of some electronic products contain that hazards both to our health, and to the environment. These materials 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 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 particular problem faced in many regions across globe.
                                                                       

PYROLYSIS

Pyrolysis is process by which organic materials are decomposed chemically. This is done by heating the material at extremely high temperature in the absence of oxygen. The heat changes the chemical composition of the material. There are many methods for pyrolysis. The final product is determined by the temperature and speed at which pyrolysis done.
Fast pyrolysis produces liquid fuel, slow pyrolysis produce gases and solid charcoal. For example, pyrolysis of waste plastics can produce millions of liters of fuel.
 Similarly, the pyrolysis of waste tyres can produce high energy gas, hydrocarbon oil, char, and steel. Biomass can be pyrolised to generat oil also. So, pyrolysis is one of the ways in which waste can be managed, and used for energy recovery.

  

ENERGY RECOVERY

Waste materials hat cannot be recycled can be converted into different forms of energy by using variety of processes. These processes include combustion, anaerobic digestion, gs recovery from landfills, and pyrolysis. pyrolysis is 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 plastics, which may contain higher energy value than coal, can also be converted into energy, such as electricity, or into alternative fuels like synthetic gas.
                 

  

BIOLOGICAL REPROCESSING

Organic waste materials such as food scarps and paper products can be reused after a process called biological reprocessing. Different biological technologies, including composting and anaerobic digestion are used in biological reprocessing. Composing is a natural biological process, carried out under control conditions. In this process various microorganism including bacteria and fungi, break down organic matter into simple substances.
Composting produces valuable fertilizers. Anaerobic  digestion is a series of biological processes in which microorganism break down into bio degradable material in the absence of oxygen. One of the end of the product is bio gas, which is used generate heat and electricity. Biological reprocessing is usually used for solid waste management.

  

INCINERATION

Incineration is simply another word for controlled burning at very high temperatures. It is a method for waste disposal that is used in many countries.
 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 extremely high temperatures as high as 2000 degree Fahrenheit.
  The high temperatures convert most poisons into harmless inert matter. Incineration removes water from hazardous sledge, reduces its 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.