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13. Recycling:


          Managementof Solid Waste






      OBJECTIVES
      > To recall that humans produce many waste materials
      > To understand that human wastes may become food for disease vectors
      > To appreciate that there are different ways of disposal of human refuse
      > To understand the benefits of recyding



     Human refuse contains such items as metals, plastic bags, glass, remains of food and ash. This
     refuse must not be allowed to accumulate because:
         It is inconvenient, and gets in the way of people, their vehicles and their animals.

         It is unpleasant to look at.
         It could act as a breeding ground for organisms which transmit disease.
     To prevent refuse (rubbish) from building up it can be delivered to refuse tips, landfill sites or
     incinerators.  The  refuse  disposal  sites  are  normally  sited  away  from  residential  areas,  and
     surrounded by fences to stop rubbish blowing away and prevent children from playing in them.
     Two  alternative  ways  of  disposing  of  the  refuse  -  incineration  and  landfil.  Each  of  these
     methods has the advantage that it can provide energy, and so reduce our use of fossil fuels.


     Recycling

     Recycling involves reusing waste products or materials which would otherwise be thrown away.
     This includes reusing items in their original form and sending materials away to special centres
     where they can be melted down or pulped to act as raw materials in industry.
     Items that can be reused include:
         glass milk or soft drink bottles
         plastic shopping bags
         paper that has only been written on one side
         clothes
        ... and materials that can be pulped or melted down include:
         glass bottles
         aluminium cans

         plastic bottles
         paper and card
         scrap metal.


     Plastic bottles can be melted and reused in clothing, for example!


     Non-biodegradable plastics cannot be broken down by natural biological processes. They may
     accumulate and are a danger to fish, birds and mammals. If they can be collected they may be
     recycled.



              Learning Module Organisms and Their Environment | Class 11                                     40
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