Biodegradable waste is the waste which can easily be broken down into non-poisonous, simple substances by physical, chemical and biological processes.
If all the waste we generate is biodegradable, it will have very little impact on the environment as most of the waste will be decomposed by decomposers and nutrients will be released back into the nutrient pool (soil). Only few gases like methane (C$H_{4}$),ammonia (N$H_{3}$), carbon dioxide (C$O_{2}$) and hydrogen sulphide ($H_{2}$S) will be released into the environment but this will have very little ill effect on the environment.