Biology (NTSE/Olympiad)  

8. Our Environment


Waste are useless left over or discarded materials. They can be gaseous, liquid or solid.
Biodegradable Wastes -
They are wastes which are broken down and disposed of naturally by saprophytes or decomposers.
Biodegradable wastes generally organic wastes, e.g., garbage, sewage, livestock waste, used tea leaves.
They can also be diposed of through waste treatment plants or converted into an agricultural resource of manure and compost.
Non-biodegradable wastes :
They are the wastes which cannot be broken down by decomposers because they do not have enzymes for the same.
Most of the nonbiodegrable wastes are human made, e.g., plastic, crockery, metallic cans, glass articles, polythene bgas, synthene fibres, silver foil, many pesticides (e.g., BHC, DDT).
Some of the soluble but nonbiodegradable chemicals enter food chains, persists, undergo biomagnification and harm the consumers of various levels includings humans.


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