Recycling of used resources and waste, Science

Assignment Help:

Recycling of used resources and waste:

Some of the materials once used need not go waste, these can be  re-used. The process through which the waste resources are again made usable is known as recycling. Scraps and used metals Scrap metal is produced  in  large quantities  in mills and factories. Old used metal of discarded vehicles, machine, aircrafts, ships, buildings etc. can be melted and recycled for useful purposes. Used aluminium utensils, for example, can be collected, melted and shaped into new utensils. We can meet the growing demand of such scarce metals as copper, zinc, lead, platinum etc. by  recycling the used materials. 

Waste water 

Domestic and municipal waste water is rich in organic nutrients. If this kind of water is made free from disease carrying germs and poisonous elements, it can be used for irrigation of farms, gardens and other vegkations. For the removal of germs and toxic elements, the waste water or sewage is treated in a tank or in ponds for several days. In doing so, the heavy particles settle down to the bottom by themselves, while the finer particles are made  to settle down by  adding alumand caustic soda. The clear liquid is then allowed to pass through filters or sand or earth and finally air is blown through it. This treatment not only removes carbon dioxide and hydrogen sulphide which is generally dissolved  in waste water, but also adds oxygen to the filtered water, thus helping in purification. Treatment of water  with appropriate doses of chlorine, known as chlorination, kills all the harmful germs and makes water usable.  


Related Discussions:- Recycling of used resources and waste

When a steep mountain stream flows abruptly on a flat plain, Which will mos...

Which will most likely form when a steep mountain stream flows abruptly onto a flat plain alluvial fan

Emergence of zoology , Zoology: The domestication of animals  like hors...

Zoology: The domestication of animals  like horses and elephants and their use in warfare necessitated the study of their anatomy and physiology. A survey of Vedic literature h

Optics used in golden era, Optics: The prevalence of  eye diseases  in t...

Optics: The prevalence of  eye diseases  in the desert and tropical countries led to the study of  the eye by Arab doctors. Surgical treatment of the eye led to renewed interest

Method of science, Method of science: We have seen above that science i...

Method of science: We have seen above that science is an enaeavour  to understand nature and to mould it to satisfy human needs. In earlier units we have seen that, in  this pr

How is the parathyroid hormone secretion regulated, How is the parathyroid ...

How is the parathyroid hormone secretion regulated? It is simple. An increase in parathyroid hormone causes an increase in calcium absorption from the intestine and renal tubul

Objectives radiation and chemical hazards, Objectives After studying th...

Objectives After studying this unit, you should be able to: 1.  Categorise different radiations into ionising and no ionising types, 2.  Explain the effects of radiations

Explain about the alluvial soils, Explain about the Alluvial soils All...

Explain about the Alluvial soils Alluvial soils are characterised by their extreme depth, often several hundred feet, and a grey or greyish brown colour. Their texture varies

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd