Constructed Wetlands as Unit Operations in Chemical Process Design: Benefits and Simulation

Abstract Sustainability requires chemical processes to respect ecological constraints. Toward meeting this requirement, the idea of including ecosystems as unit operations in process design has been introduced in previous work. To make this idea more practical, this work develops a constructed wetland (CW) simulation module for use in the process simulation tool CHEMCAD. By simulating various combinations of an anaerobic bioreactor (ABR) technology and a CW ecosystem for water treatment, this work shows that CW is most cost-effective if adequate land area is available. Otherwise, a series arrangement with the ABR before the CW makes the most sense. This result introduces a potential design heuristic that technology is better suited than a nature-based solution for a higher concentration of waste. Integrated designs show that cost-effective designs reduce the separation load on distillation by relying more on the lower-cost CW. Recycling water makes economic sense only if the cost of water increases.