Wastewater treatment processes are typically complex dynamic processes. They are also energy-intensive processes. Using a more accurate control method is an effective solution to reduce the running cost of an entire wastewater treatment system. In this paper, a fuzzy sliding control scheme is proposed to control the aeration process of a sequencing batch reactor wastewater treatment process. It controls the aeration process by regulating the oxygen transmission coefficient according to the dissolved-oxygen index. Simulation results show that the proposed control scheme can deliver effective control.