Studying Water Network Optimization Plans in a Process Industry to Reduce Water Consumption: Comparing Direct Reuse and Regeneration-Reuse Approaches

In this research, the water network of a process industrial unit has been optimized to reduce water consumption in this industrial unit. During the first step, the water and steam distribution network in the unit is produced and the network is studied as a fixed-flowrate model. Besides, COD, TSS, Oil, TDS, H2S, and NH3 are considered six limiting contaminants. In targeting and retrofitting steps, two approaches of direct reuse and regeneration reuse are applied. In the case of utilizing the direct reuse approach, a reduction of 1.79% in water consumption is obtained. Then, the results of mathematical optimization after using the wastewater treatment unit, show no significant difference from the one obtained from the direct reuse approach. It is because of the high amount of the TDS in the outlet stream from the regeneration unit. Using a membrane system to treat the wastewater discharged from the treatment unit to reduce TDS, the amount of water use reduction will be 35.26%.