A membrane filtration system is a switching system that operates in a sequence of two operating modes: filtration and cleaning. The aim of this paper is to find the optimal switching instants in order to improve the water production of the process. The dynamic behavior of the membrane filtration system described by a filtration model suitable for optimization and control purposes. The is solved using two different optimization solvers (and PatternSearch) of the MATLAB software. Then, the optimal solution is considered to design the optimal control operating strategy.