मंगलवार, 2 अक्तूबर 2018

What filling does this have ?????

Where on the earth , even after fifty years , would you find a shower cap that you can use ; a glass bottle that is still intact ; and a newspaper that is almost entirely readable ? A landfill , of course ! 

Not quite pits ! 

Landfills are large open grounds , far away from cities , where waste is dumped . Landfills used to be mountains of trash , but today , they are well - designed pits that keep the garbage dry . A basic landfill is an enormous pit that is dug up and lined with thick plastic and clay , which stops water or trash from leaking into the ground . Garbage is not just simply tossed into a landfill . It is offloaded in old and new sections of the landfills . It is then covered with dirt everyday . Garbage rots very very slowly here . 

Airy and non - airy landfills 

Most countries around the world use ' sanitary landfills ' . Garbage is squeezed and packed together , and when tonnes of it piles up , no air or oxygen can pass through it . TH e garbage then start to produce greenhouse gasses , methane and carbon dioxide . When rain falls and mixes with the garbage , the liquid turns into leach ate , a poisonous substance . 
 Bio reactor landfills are now being tested is developed countries such as the US and Canada . Air and water are passed through the garbage in a controlled way in these landfills to help waste decompose , or rot , faster . The gases produced are used to make electricity .

Image result for sanitary landfill

What 's wrong with landfills ???

In most landfills , air barely reaches the bottom layers and trash rots very slowly . Scientists from the University of Arizona studying landfills have found twenty - five -year - old hot dogs and grapes that were still recognisable ! 
 Landfills are expensive to build and manage . Even after a landfill is full and not in use , it has to be monitored for years . The two biggest problems are leakages of methane and leach ate . Some landfills , especially the older ones , burn the methane gas to get rid of it . When methane is burned , it destroys the ozone layer in the atmosphere . Methane is also dangerous because it can explode easily . When leach ate leaks into the groundwater and soil , it pollutes them . This can make people seriously ill.

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