<p>Acid wastewater (AWW) from the non-ferrous metal smelting industry is characterized by a high level of acidity and a high concentration of As. Sulfiding agents are commonly used for arsenic removal from acid wastewater because of their high efficiency. To address the issues associated with traditional sulfiding agents, such as the release of harmful hydrogen sulfide gas and the introduction of large amounts of sodium ions, this paper proposes a new process of ultrasound-enhanced ZnS for arsenic removal from acid wastewater by sustained release in situ. The low solubility of ZnS provides the advantages of matching the reaction rate to arsenic removal efficiency, inhibiting the escape of H₂S gas, and preventing the introduction of other cations. Ultrasound can open the ZnS surface encapsulation and accelerate the reaction rate. Experimental research has shown that the arsenic removal rate reached 99.96% and the arsenic concentration was only 0.42&#xa0;mg/L at an acidity of 120&#xa0;g/L, S/As molar ratio of 3:1, reaction temperature of 60°C, and ultrasonic power of 100 W for 120&#xa0;min. The development of this process is of great significance as an application prospect for the arsenic removal from acid wastewater in zinc smelting.</p>