New strategies for economic optimal membrane fouling control based on dynamic optimization

Results of fundamental research demonstrate that the dynamics of longterm membrane fouling is affected by the applied settings of operation variables. As a consequence, the operation efficiency will be improved by the application of optimal trajectories of the operation variables. For both a precipitation model and a gel layer model specific trajectories are calculated by dynamic optimization and utilization of an objective function based on the cash flow of the operation. The relevance of dynamically optimal operations is demonstrated by a comparison with statically optimal operations where the optimal constant values of operation variables are applied. For a case study on reverse osmosis of cheese whey (precipitation model), the cash flow rises by up to 25% as a result of improved membrane performance (10%) and reduced energy costs (26%), while for gel layer fouling significant energy savings can be realized (35–55%).