System analysis of total water systems for water minimization

Abstract

System-wide analysis of water systems to minimize water use in process industries has been carried out when charges for effluents from the process are simultaneously considered with cost of freshwater intake and in-house water treatment in the design of water and effluent systems. It has been demonstrated that the degree of wastewater regeneration and recycling is heavily dependent on the charges associated wastewater effluent. The reusability of water and its techno-economic impacts are examined with both a graphic-based manual technique and an automated design method using mathematical optimization, with which conceptual insights are sought in a systematic manner to evaluate different integrated options including water reuse, regeneration and recycling. For the optimization model, new solution strategy has been proposed for solving the MINLP problem of total water systems which carries out rigorous economic trade-offs existed in an integrated water network, together with wastewater charges.