Water and wastewater minimization in a petrochemical industry through mathematical programming

Petrochemical industries have large water demands in their operations, such as distillation, extraction, washing processes and cooling systems. The present work discusses water and wastewater minimization in the production process of a Brazilian petrochemical industry, applying mass integration via mathematical programming. This research is a case study applied in industrial scale, using data from a petrochemical plant. Alternatives for water reuse were evaluated by analyzing water consumption and wastewater generation processes by using a superstructure and a nonlinear mathematical programming model. The concentration of chemical oxygen demand in effluents was considered as a limiting factor. The alternatives found in this study could lead to total economy of 280,320 m(3)/y of water, and 236,520 m(3)/y of wastewater that would no longer be generated. This volume would sufficiently supply 4626 inhabitants for one year, considering the average water consumption per capita in Brazil, which is of 166 L per capita per day. Using this process, potential benefits could be achieved with water reuse. (C) 2017 Elsevier Ltd. All rights reserved.