There are actually two types of wastes one I biodegradable and non biodegradable.
biodegradable wastes- the wastes which can be decomposed by the action of decomposers of environment. the decomposers are the bacteria. when we dump the biodegradable wastes then they get converted or decomposed in the materials that are useful for soil and plants. after decomposing they form nutrients like carbon methane etc. the example of the biodegradable wastes is like kitchen wastes like peels of fruits and vegetables, etc.
non biodegradable wastes - the wastes which cannot be converted or decomposed by the action of nature's decomposers is called the non biodegradable wastes. the decomposers can't decompose them because they are made artificially not by nature. the examples are like plastic bags. etc.