Wastewater treatment is an integral component in the sustainable development of our society. Optimal control and operation is critical to the efficiency and economics of a wastewater treatment plant. In this work, we apply economic model predictive control (EMPC) to a wastewater treatment plant and compare its performance with two commonly used control methods. Specifically, we take advantage of the benchmark simulation model no. 1 provided by the International Water Association to simulate a biological wastewater treatment plant. A computationally efficient EMPC developed recently is adopted in this work to optimize the effluent quality and operating cost directly. The performance of the EMPC is compared with a proportional-integral (PI) control scheme and a regular tracking model predictive control (MPC) scheme from different perspectives including effluent quality and operating cost. The simulation results demonstrate that EMPC has the potential to significantly improve effluent quality and reduce operating cost simultaneously compared with PI and MPC schemes.