Biodegradable pollutants are those that can be broken down into simple elements and substances by the action of bacteria and other decomposers. These pollutants are degraded slowly by microbes. When the production of these pollutants is more than the degrading capacity it results in pollution.
From the biological point pollution can be of two types biodegradable and non-degradable pollutants. The degradable pollutants are those which can be degraded, decomposed, removed or reduced to acceptable limits either by the natural processes or by man-made systems like the sewage treatment plants. Degradable pollutants can be of two types rapidly degradable or non-persistent pollutants and slowly degradable or persistent pollutants.
Pollutants that are non-persistent are like sewage and agricultural waste can be normally decomposed quickly if the system is not overloaded. Persistent degradable pollutants like some radioactive materials decompose slowly but they are broken down completely or they are reduced to harmless levels.
Degradable pollutants are organic substances like the wastes from sewage and industries and are dead organisms which can undergo decomposition naturally. Biodegradable pollutants include substances which can undergo physical degradation or decay. Some substances like the radioactive isotopes have long half-life and may be practically considered as non-degradable. Some substance may be degradable or other may be slowly degradable.
Biodegradable substances are those pollutants which are decomposed or degraded by the action of microorganism. These waste products show quite rapid degradation. Generally these substances do not accumulate in the environment. These pollutants can be used to produce useful products like manure, compost and biogas.