Tratamento de efluentes oleosos em reator contínuo por integração dos processos de eletrofloculação e coagulação química.

Abstract

The objective of this work was to study the use of electroflocculation (EF), chemical coagulation (QC) and the association between both processes, aiming at the development and operation of a continuous system for the treatment of oily wastewater. For this, this study was divided into two stages. In the first stage, a comparative study of the treatment of synthetic oily water was carried out, varying the percentages of electroflocculation and/or chemical coagulation in a batch reactor with a capacity of 2 L, consisting of a stirring system and an adjustable electrochemical system. It was found that it is possible to efficiently treat the oily effluent using only EF or (EF and QC) associated, obtaining removals around 97% for O&G, turbidity, and COD. The process conditions would be the application of an electric current between 1.45A and 0.72A in the EF and a dosage of 0g to 3.88g of aluminium sulfate in the QC. Based on these results, the second stage of the work was developed, which consisted of the study and development of a continuous system applied in the treatment of synthetic oily water using isolated EF and (EF and QC) associated. The reactor was designed with two chambers, where the electrochemical cell connected to a DC source was inserted. Upstream of the reactor, a tank with effluent and another with aqueous chemical coagulant was installed, which fed the reactor at flow rates of 0.03 and 0.02 Lmin1, respectively. The performance of the reactor was analyzed by carrying out a matrix of experiments, varying the initial pH and the percentage by mass of coagulants applied to the isolated EF and associated (EF and QC). With the results, it was statistically verified that the reactor can remove about 96% of oily contaminants operating at an initial pH of 8 and with 100% of electroflocculation, for an average cost of R$ 4.64 per m³ of treated effluent. Furthermore, it was verified that the division of the reactor into two chambers effectively contributed to the removal of sludge and the minimization of secondary contamination of the treated effluent. It was also found that the treatment of oily effluent could be efficient using only EF, or (EF and QC) associated, ranging from 100% EF to (50% EF and 50% QC).