WASTEWATER TREATMENT BY MEANS OF MEMBRANE PROCESSES. A CASE STUDY OF PETROCHEMICAL INDUSTRY

Abstract

This paper studies the treatment of secondary effl uent from a wastewater treatment plant of a petrochemical industry by using reverse osmosis (RO) for wastewater reclamation. The petrochemical industry requires a large amount of water with a conductivity less than 100 µS/cm for use in several production processes. The water from the wastewater treatment plants stations of this type of industry has a high conductivity (> 5000 µS/cm), and therefore is not suitable for reuse. A possible solution is a specifi c treatment (tertiary treatment) by membrane technologies. The proposed system considers an initial fi ltration step to remove suspended solids and colloidal matter. Then the effl uent is introduced to a reverse osmosis system, which operates at low pressure in two stages. The methodology used includes two sections. On the one hand the experimental tests to defi ne the critical parameters of the membrane process design, and on the other the scale at the industry level to estimate the costs of the proposed treatment. This system has succeeded in recovering 75% of the effl uent, as water with suffi cient quality for reuse (<100 mS / cm). The cost of reclaimed water (0.76€/m3 ) allows to consider the industrial implementation of the process.