Increasing flexibility in the design of wastewater treatment processes

An increasing focus on the design of biological nutrient removal processes and the development of new and varied designs (propelled by increasing need s for higher efficiencies and lower costs) has introduced the need for impr oved methods of design for wastewater treatment plant (WWTP) processes. The se design methods may include studies of process operability (i.e., flexibi lity, controllability, and resilience). This paper focuses on flexibility a nd the tools available to facilitate the study of flexibility. A simple exa mple is used to demonstrate a method of flexibility analysis and a more com plex example is used to illustrate the significance of the results to WWTP process design. The most significant result is that the flexibility of a pr ocess can sometimes be significantly increased with negligible increases in capital costs.