Characterization of aqueous streams in a petrochemical industry: A study for the reuse of industrial effluents

Abstract

The scarcity of water is an increasingly alarming issue all over the world, and each sector of society must take action to reduce water use in its activities. In chemical and petrochemical industries, water is a fundamental resource for the production process. This industrial sector has a demand for great quantities of water with specified qualities for each process. As the water runs through the industrial processes, it incorporates several substances and its characteristics modify. It becomes an effluent that must be treated so as to accommodate the emission standards established in the regulations. In most cases, the standards for disposal are less restrictive than the quality standards for industrial reuse of this effluent. If it is not considered for reuse, all related activities will be compromised. This work presents a case study of a Brazilian petrochemical industry where various aqueous streams were characterized to evaluate the quality requirements necessary for water reuse in the production process. The work examines water use and the quality of each aqueous stream, characterizing them with respect to alkalinity, chlorides, electrical conductivity, chemical oxygen demand, total hardness, iron, pH, silica, total solids, sulfates, and turbidity. The study demonstrates that the cooling water stream has elevated concentrations for these parameters and thus demands less quality for water reuse. In general, demineralized water presents the lowest concentrations for the parameters under evaluation and therefore requires greater quality for water reuse.