12th Zoology

Management of hazardous wastes

Management of hazardous wastes

Hazardous wastes may remain dangerous for thousands of years.
The hazardous waste include radioactive refuse, metallic compounds,
organic solvents, acid asbestos, organic cyanides, pathological hospital
wastes, disposable medical equipments and tools.
The following methods are adopted for the disposal of hazardous

1. Land fills : (Management of hazardous wastes)

There are permanent storage facilities for military related
liquid and radioactive waste materials in secured lands. High level radio
active wastes are stored in deep underground storage.
Wastes are carefully contained to prevent cross – mixing of reactive
substances. The land fill is capped with impervious clay to prevent infiltration
and percolation of water through the fill. Fill bottom is lined and provided
with drainage system to contain and remove any leakage that occurs.
Monitoring the wells provides a final check.

2. Deep – well injection : Management of hazardous wastes

It involves drilling a well into dry, porous material below groundwater. Hazardous waste liquids are pumped into the well. They are soaked into the porous material and made to remain isolated indefinitely. However fractures in the impermeable layer may permit the injected wastes to escape and contaminate ground water.

3. Surface impoundments : Management of hazardous wastes

This method is used to dispose large amounts of water carrying relatively small amounts of chemical wastes. Surface impoundments are simple excavated depressions (ponds) into which liquid wastes are drained. Solid wastes settle and accumulate while water
evaporates. If the pond bottom is well sealed and if evaporation equals
input, wastes may be stored in the impoundment indefinitely.

4. Incineration : Management of hazardous wastes

The hazardous biomedical wastes are usually
disposed off by means of incineration. Human anatomical wastes, discarded
medicines, toxic drugs, blood, pus, animal wastes, microbiological and
biotechnological wastes etc are called Bio-medical wastes.

5. Bioremediation : Management of hazardous wastes

This is another rapidly developing clean up
technology. Cleaning the environment with biological options such as
microbes and plants is called bioremediation. Some naturally occurring
bacteria and other microorganisms have the capability to degrade or absorb
or detoxify the wastes such as heavy metals. Many plant materials are
successfully used as adsorbents for xenobiotics (phytoremediation).
Genetically Engineered Microorganisms (GEMS) are currently produced in
large scale to remove the hazardous radionuclides and heavy metals such as
mercury, chromium, cadmium etc. Certain plants such as Gibberella fusarium
were able to breakdown cyanide and reduce it to a non-toxic form. The
bacteria Pseudomonas, nicknamed as ‘super – bug’ are capable of
degrading variety of toxic compounds and also degrade oil.

Related Topics in Zoology:

Bio Zoology All Important Topics

  1. Human population and explosion

  2. Population Explosion

  3. Growing Population and Environmental impacts

  4. Global warming – Green house effect

  5. Ozone layer depletion

  6. Prevention and Effect of Ozone depletions

  7. Waste management – Classification

  8. Management of hazardous wastes

  9. Management of non hazardous wastes

  10. Waste water treatment and management

  11. Biodiversity

  12. Conservation of Biodiversity

  13. Characteristics of a Bioreserve

  14. Energy crisis and its environmental impact

  15. Steps to be taken to resolve energy crisis

  16. Environmental impacts of Power Sources

  17. Poverty and environment

  18. Fresh water crisis and management

Unit 6. APPLIED BIOLOGY Topic List Zoology

  1. Livestock and Management

  2. Important cattle breeds and their characteristics

  3. Milch breeds (or) Dairy breeds

  4. Dual purpose breeds & Draught breeds

  5. Exotic breeds of cattle

  6. Common diseases and control in Cattle – Contagious diseases

  7. Non-contagious diseases – Cattle

  8. Techniques adopted in cattle breeding

  9. Poultry Breeds

  10. Farming methods

  11. Poultry byproducts

  12. Fish Pond

  13. Edible Fishes Of Tamilnadu

  14. Medical Lab Techniques – Stethoscope

  15. Sphygmomanometer

  16. Haemocytometer

  17. Urine Sugar analysis

  18. ECG Electrocardiogram

  19. Computed Tomography CT

  20. Endoscopy (Laproscopy) techniques , Artificial Pacemaker

  21. Autoanalyser

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