Study of the mechanisms of gamma rays in purification and disinfection of sewage sludge

With increasing in construction and operation wastewater treatment plants, production and use of sewage sludge have been increased as an organic waste. Due to disabilities of common methods used for purification and stabilization of sludge in complete elimination of the pathogens and prevent its re-growth, elimination of complex organic chemicals and other pollutants, agricultural use or disposal of sludge in the environment could be dangerous for agricultural crops production, human and animal health and must be disinfected before using or disposal. Lack of comprehensive study on new methods of sludge disinfection in Iran, reveals the introduction of these technologies and their impacts mechanisms. The best way to remove the pathogen of sewage sludge during the disinfection methods regardless of economic issues is thermal pasteurization and ionizing radiation. Between the ionizing radiation, gamma radiation and electron beam may be used for disinfection of sewage sludge, but the benefits of gamma rays on the electron beam that make extensive use of the gamma rays. In sewage sludge under gamma radiation may be observed processes such as oxidation of organic matter, destruction of inorganic and organic molecules buildings, changes in the colloidal system and death of pathogens.