Purpose The purpose of this paper is to apply reverse osmosis (RO) to the treatment of industrial wastewater from a large petrochemical complex in Southern Brazil, in order to verify the conditions of liquid effluent reuse and improve them, especially to reduce the consumption of natural water by some production structures such as boilers and cooling towers. Design/methodology/approach The petrochemical wastewater was submitted to pretreatment using a sand filter and activated carbon filters. Tests were conducted using RO equipment with a production capacity of 0.25 m3h−1 composed of a spiral membrane module with a membrane area of 7.2 m². Pressures of 8, 12 and 15 bar were applied with reject flow maintained constant at 10 Lm−1. Findings The experiment results indicated optimum RO performance since more than 90 percent extraction was obtained for most of the compounds present in the petrochemical wastewater. Originality/value By checking the aspects involved, as well as providing some relevant considerations about, this study promotes the application of RO to get a satisfactory water reuse in similar industries, thereby decreasing both the volume of water extracted from wellsprings and the amount of wastewater released into water bodies.

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This work evaluated the performance of an electrochemical oxidation process (EOP), using boron-doped diamond on niobium substrate (Nb/BDD), for the treatment of a reverse osmosis concentrate (ROC) produced from a petrochemical wastewater. The effects of applied current density (5, 10, or 20 mA·cm−2) and oxidation time (0 to 5 h) were evaluated following changes in chemical oxygen demand (COD) and total organic carbon (TOC). Current efficiency and specific energy consumption were also evaluated. Besides, the organic byproducts generated by EOP were analyzed by gas chromatography coupled to mass spectrometry (GC–MS). The results show that current densities and oxidation time lead to a COD and TOC reduction. For the 20 mA·cm−2, changes in the kinetic regime were found at 3 h and associated to the oxidation of inorganic ions by chlorinated species. After 3 h, the oxidants act in the organic oxidation, leading to a TOC removal of 71%. Although, due to the evolution of parallel reactions (O2, H2O2, and O3), the specific energy consumption also increased, the resulting consumption value of 66.5 kW·h·kg−1 of COD is considered a low energy requirement representing lower treatment costs. These results encourage the applicability of EOP equipped with Nb/BDD as a treatment process for the ROC.

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