Multiperiod Planning of Optimal Industrial City Direct Water Reuse Networks

The minimization of the water footprint of industrial cities or parks requires the development of efficient water reuse strategies. Current methods for water integration do not consider industrial city planning horizons in the development of optimal water reuse and recycle strategies. This article presents a multiperiod planning approach for water integration within industrial cities. The initial formulation considers direct reuse of water between plants and involves water streams with several pollutants. A source sink water mapping model was implemented such that available water sources can be either allocated to water sinks or discharged as wastewater streams. Freshwater streams were made available to mix with water sinks as necessary, to enable reuse between plants. The work presents two optimization models to determine the minimum freshwater use in the industrial city through maximum direct water reuse regardless of cost (model 1) and the lowest-cost design for direct water reuse (model 2). Several illustrative examples are presented to demonstrate the proposed methods. The results indicate great potential for achieving considerable savings of resources when integration strategies for plants are developed over an entire planning period rather than individual time periods.