The impetus for waste minimization and water recycle in the metal processing industry comes from increasingly stringent environmental regulations and dwindling water supplies. Tougher discharge permits often dictate additional waste water treatments, which can make water recycle and waste minimization an attractive option. The most challenging part in the design of a water recycle system is to minimize the capital and operating costs while meeting the water quality requirements of the process. Computer simulation of water recycle alternatives provides: (i) “expected” water chemistry, (ii) steady-state mass and energy balance for the plant water system, (iii) performance of the water treatments considered in the water recycle scheme, and (iv) relative economics based on capital and operating costs. The computer simulation study recommends the best wastewater recycle scheme based on economics and technical merits. Benefits of a computer simulation study in the design of water recycle and wastewater minimization processes are illustrated by a case study in the metal processing industry. Keywords: waste, minimization, water, reuse, recycle, simulation, casting, modeling, zero discharge