Novel Venturi injector reactor design and application in ammonia nitrogen wastewater treatment

The Venturi injector reactor has a robust and durable design and is highly efficient and reliable. The flow field control in the Venturi reactor is an effective way to enhance gas−liquid mass transfer. In this study, a novel Venturi injector reactor with an expandable self-priming air inlet and a second water inlet in the diffusion section was designed by combining particle image velocimetry (PIV) experiments with a computational fluid dynamics simulation. This novel design increased the gas holdup, generated smaller and more uniform bubbles, and enhanced mass transfer. Furthermore, we applied the novel Venturi device to the biological degradation of ammonia nitrogen wastewater. The total gas holdup in the novel Venturi was higher than in the conventional Venturi injector reactor by 0.0056 on average. The minimum bubble diameter was approximately 0.71 mm. Moreover, the ammonia nitrogen removal efficiency of the novel Venturi equipment with the second inlet was 2 and 1.1 times higher than that of conventional aeration and conventional Venturi device, respectively. This study provides a theoretical basis and practical significance for improving the performance and efficient degradation of the ammonia nitrogen concentration in Venturi injector reactors. •A novel Venturi injector reactor is designed.•Bubbles in the novel Venturi are smaller in size and uniform.•Gas holdup is higher than that of the conventional Venturi device.•The novel Venturi device is applied to treat ammonia nitrogen wastewater.•Ammonia nitrogen removal rate is 2 times higher than that of the aeration device.