Intermediate to long term optimization of dead-end ultrafiltration

Ultrafiltration (UF) is increasingly used as a technology for surface water purification. UF membranes have high selectivity and became economically attractive during the last fifteen years. However, membrane performance is influenced by fouling. For this reason frequent cleaning of the membrane is required. In the short term the membrane is cleaned by means of backwashing and in the long term the membrane is cleaned with cleaning chemicals. Although backwashing and chemical cleaning are useful methods to prevent fouling, the execution of such procedures is often based on rules of thumb and/or pilot plant studies. It is expected that process optimization will lead to significant reduction in operating costs and improved control. This thesis deals with the formulation of a hierarchical control structure to optimize the overall ultrafiltration process. Models, experimental protocol and optimization routines were developed and successfully tested and implemented.