Biodegradable pollutants are those that can be degraded through the microbial action e.g., sewage, livestock wastes etc. Such pollutants can easily be disposed off or degraded through natural processes or waste treatment and can be turned into compost, manure etc. Pollutants like DDT, BHC, polythene, plastics, glass etc., can not be decomposed by microbes or broken down into harmless material. They are difficult to manage or treat.