Present status of environmental application of electron beam accelerator in Brazil

The necessity to decrease the environmental contamination caused by toxic flue gases, liquid and solid effluent delivered by industries, have resulted in search of new treatment technologies. The oxidation processes with OH radicals are the most efficient to mineralize organic compounds, and there are various methods to generate OH radicals as the use of ozone, hydrogen peroxide and ultraviolet radiation (AOP - Advanced Oxidation Process). The most simple and efficient method for generating OH radicals in situ is the interaction of ionizing radiation with water. The irradiation of aqueous solutions with high-energy electrons results in the excitation and ionizing of the molecules and rapid (10-14 - 10-9 s) formation of reactive intermediates. The most reactive species are the reducing radicals solvated electron (e-aq), and H. atoms and the oxidizing radical hydroxyl, OH, the unique process that produce the reducing specie e-aq is the electron beam irradiation These reactive species will react with organic compounds present in industrial effluent inducing their decomposition. The primary products from water irradiation tend to react with the functional groups present in an organic molecule rather than with the molecule as a whole. This paper presents the evaluation of ionising radiation effectiveness in actual effluents from different industries such as chemical, petroleum, wastewater treatment plant, and drinking water , using Electron Beam Facility with a 1.5 MeV, Dynamitron from Radiation Dynamics Inc. The ionizing radiation was efficient on destroying organic compounds delivered in industrial effluents, independent on the physical-chemical characteristics and origin. The efficiency of ionizing radiation in presence of Titanium dioxide (TiO2) catalyzed photoreaction, to treat industrial effluent with high organic pollutant concentration is discussed. The main objective to combine these technologies is to improve the efficiency for high contaminated effluents and decreasing the required absorbed doses for future implementation to large-scale design. The Gd values presented show that the electron beam processing is more effective when high number of organic molecules are present, because the reaction among reactive transients produces more radicals and the process continue. Besides the high necessary absorbed doses, it is a promising process for future field implementation because, the high complexity of the effluent become its treatment by others technologies, very expensive and not so efficient