Interplant water network design with multiple water reuse headers and regeneration units in practical configurations

The synthesis of interplant water networks (IPWNs) in eco-industrial parks (EIPs) has been studied for more than a decade to foster industrial symbiosis and circular economy. A centralized utility hub (CUH) with water reuse headers and regeneration units is commonly employed in EIPs for viability and manageability. In this paper, the concept of indirect interplant water integration (IPWI) via a CUH is used to provide water recovery solutions for real-life EIPs. Multiple participating plants, multiple water quality indices, and practical IPWI configurations incorporating water reuse headers and regeneration units are considered together with technical and environmental constraints (e.g., treatment system performance and effluent discharge limits). A mathematical programming model for IPWI in EIPs is formulated and optimized to determine the most cost-effective solution that the total annualized cost (TAC) is minimized, which includes the costs of freshwater supply, wastewater regeneration, cross-plant piping, and headers. Various scenarios with alternative IPWI configurations and additional constraints (e.g., forbidden matches) are analyzed and discussed to broaden the options and enhance the practicality for decision-making. The optimal configuration of indirect IPWI is found to be in-plant regeneration units and centralized water reuse headers at a CUH, achieving TAC savings of up to 17.2 %.