Tratamento primário da água produzida com coagulação lastreada utilizando microareia

Abstract

Produced wate (PW) is the effluent from the oil industry producend in the largest volume during upstream oil exploration and production activities. In addition to the high volume generatend, its composition includes various contaminants, such as organic, inorganic, and metallic compounds originating from the geological formation of the reservoir and chemical additives added during the production process. Due to its composition, this efluente requires adequate treatment before reinjection into wells for production stimulation purposes, or before discharge into water bodies, aiming to mitigate potential impacts associated with its disposal and compliance with current environmental legislation. In this contexto, thi study aimed to evaluate the performance of conventional coagulation/flocculation, using aluminum sulfate (coagulante), and coagulation/flocculation ballasted with microsand in the primary tretment of producend water from the Carmópolis oil field, Sergipe. The tests were carried out in a Jar Test, using aluminum sulfate (0.2 g.L-1 ), at pH 7.0 and 9.0, exclusively with the coagulante agente and associated whit microdand (0.5 g.L-1 and 5.0 g.L-1 ). The results demonstrated high effficiency in turbidity removal, ranging from 86.45% to 98.39%, with the best performance obtained under conditions ballasted at pH 9.0. The incorporation of microsand favored the formation of denser and more settleable flocs, and in both dosages evaluated, the turbidity removal performance was similar, indicating potential for reducing input consumption without compromising tretment effciency. Regarding total suspended solids (TSS), a reduction was observed after treatment, although to a lesser extent compared to turbidity removal, highlighting that these parameters Should be interpreted complementarily in evaluating the efficiency of the process. Thus, it us concludend that conventional coagulation/flocculation and microsandbased coagulation/flocculation constitute promising alternatives for the treatment of Produced water. Among the conditions evaluated, the tretment conducted pH 9.0, using aluminum sulfate (0.2 g.L-1 ) and microsand (0,5 g.L-1 ), presented the best balance between turbidity removal efficiency and input consumption.