A highly water-efficient corn refinery: design of a water network with a treatment unit

Water recovery through water networks aims to reduce wastewater discharge and freshwater consumption in industrial plants. Total water networks are those equipped with treatment (aka regeneration) units to partially treat effluents, maximizing water recovery and minimizing wastewater discharge to the environment. This study considers the design of a total water network with a central treatment unit for the Glucosan corn refinery in Iran. To this end, a water network superstructure with the objective of minimizing both freshwater and treatment costs is formulated and optimized using a deterministic global solver. TDS and COD are two limiting contaminants considered in the design formulation. The resulting network is compared with that without a treatment unit, as obtained previously for the same process. In comparison, the new water network can reduce freshwater consumption and wastewater discharge by 43 % and 47 %, respectively. This demonstrates the effectiveness of including regeneration-reuse water networks in retrofit of existing plants, especially in the food industry, which is known to be a large water-consuming sector.