Synthesis of water networks with mixed batch and continuous process units

Water is an essential resource widely used in the process industries as a raw material, a heat-transfer medium, or a mass separating agent. Common uses in the latter case include steam stripping, liquid-liquid extraction, and various washing operations. Rapid industrial growth has increased fresh water consumption as well as wastewater production, and consequently caused serious water pollution in the world. Concurrently, the scarcity of industrial water (partly due to climate change) and increasingly stringent discharge regulations have led to rising costs of fresh water and effluent treatment. These environmental and economic issues stimulated the recent development of systematic methodologies for efficient and responsible use of water in industry. Particularly, design of water recovery systems through process integration techniques, also known as water network synthesis, has been commonly accepted as an effective means in this regard, with reuse, recycling, and regeneration as possible options for reducing fresh water and wastewater (Wang and Smith 1994).