Development of a thermal plasma pyrolysis and inerting process applied to the treatment of sludge produced in Sewage Treatment Stations (ETEs)

Abstract

The disposal of sludge from Sewage Treatment Stations (ETEs) in an environmentally correct way is another challenge to be faced by sanitation companies and industries, since the costs of its proper management represent 60% of the operating costs of the units. The first step to overcome this challenge is to abandon the idea of sludge as a non-reverse waste, adding value to it so that it can become a by-product of commercial interest. In this scenario, in order to meet the current regulations for final disposal of waste, it is proposed in this project the use of thermal plasma technology for the development of studies of systems and thermal conversion processes of sludge from ETEs into clean fuel gases suitable for use in the generation of steam or electric energy, as well as in inert solid material of high added value that also meets the characteristics of Class II B material - Inert solid waste according to NBR 10004, which would eliminate the possibility of sending by-products to sanitary landfills. The study proposal consists of the implementation of a conceptual demonstration plant composed of a pre-treatment module for drying ETE sludge, a module for pyrolysis and plasma inerting and a module for the production gases treatment. For the investigations of evaluation of the mass and energy balances for the employed and improved process, will be condutec the procedures of qualitative and quantitative characterization of the sludge samples collected from municipal ETEs in the State of São Paulo, as well as tests by pyrolysis and inertization plasma processes for thermal conversion of the inorganic and organic fraction of the sludge into inert inorganic matter and clean fuel gases for energy production. (AU)