Genetic algorithm for multivariable optimal control of activated sludge process

A genetic algorithm for multivariable optimal control with the lowest operational cost by limiting total substrate discharge in activated sludge process was discussed. Based on satisfying the requirements of precision, binary coding was used to express units, and 20 bits of binary digits express DO (Dissolved Oxygen), Q(w) (sewage discharge amount) separately. An improved Euler formula was applied to solve the state equation and the solution was brought in fitness function. In order to transform the restricted problems into unrestricted ones, some penalty items should be added in fitness function to punish the unfeasible solutions. The optimal control can be imitated by manual or semiautomatic control based on the changing principles of optimal control variable DO and Q(w) in the wastewater treatment system. This algorithm avoids the difficulty of guessing iteration initial value and increases calculation efficiency, and the results of this research are practical and realistic.