Processo de landfarming para tratamento de resíduos oleosos

Abstract

Various activities of the oil industry such as, drilling, production, processing and distribution generate significant volumes of solid waste, containing various classes of hydrocarbons. Provision of such wastes in the environment may lead to serious environmental problems. According to Resolution No. 001/86 of CONAMA, environmental impact is defined as the change of physico-chemical and biological characteristics of the area. Therefore, treatment of wastes is essential to promote sustainable management of exploration and exploitation of mineral resources. Alternatives of treatment are varied processes including physical, chemical and biological agents in order to remove organic pollutants at concentrations that are undetectable or, if detectable, the concentrations below the limits established as well as acceptable by the laws. Among biotechnologies, process of landfarming presents a considerable emphasis on the basis of the low operational cost, and availability of treatment of large volumes of oily wastes. Landfarming is based on the potential of organisms and/or their products to assist in the removal of hydrocarbons, reactive layer in the prepared soil. This work aims the treatment of oily wastes at an area of 1,000 m 2 . Methodologies were used for this operational biostimulation through humidification, fertilization and aeration. Along side was an isolated area known as ground control. To evaluate the performance of the bioprocess were monitored relevant parameters such as pH, humidity, levels of total organic carbon, phosphorus, nitrogen, chemical elements (Sb, As, Ba, Be, Cd, Pb, Cu, Cr, Fe, Mn, Hg, Ni, Ag, Se, V e Zn), total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAH), heterotrophic aerobic bacteria (BAE), filamentous fungi and heterotrophic anaerobic bacteria (BAN) during 225 days.Results of work were promising by considering the time and initial concentration of contaminants. Content of TPH decreased 89.6% (25,8 mg.Kg-1 .dia-1 of degradation) in the treated soil, while the control soil was negligible degradation of the order of 22.4% (6,5 mg.Kg-1 .dia-1 ). The concentration of PAH decreased 88.7% (0,13mg.Kg-1 .dia-1 ) in the treated soil and control the degradation reached 25.8% (0,04mg.Kg-1 .dia-1 ). Thus, the techniques of biostimulation, i.e. humidification, fertilization and aeration were essential for increasing biodegradation of hydrocarbons. Population of BAE, fungi and BAN showed the average value of 1.4x107CFU.g-1 , 2.6x105 CFU.g-1 and 2.2x106 Cels.g-1 , respectively. The test of ecotoxicity in treated soil was an indication of efficiency of the process can be proved by the degradation of polycyclic aromatic. Thus it was possible of treated about 387 tonnes of solid waste in 7 months.