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 needs for higher efficiencies and lower costs) has introduced the need for improved methods of design for wastewater treatment plant (WWTP) processes. These design methods may include studies of process operability (i.e., flexibility, controllability, and resilience). This paper focuses on flexibility and the tools available to facilitate the study of flexibility. A simple example is used to demonstrate a method of flexibility analysis and a more complex example is used to illustrate the significance of the results to WWTP process design. The most significant result is that the flexibility of a process can sometimes be significantly increased with negligible increases in capital costs.