Chronic Arsenic (As) poisoning has become a worldwide issue of public health. Therefore, efficient removal of As from wastewater before drainage is of great importance. This paper aimed at designing a novel reactor containing an immersed multi-start distributor for sulphide feeding to remove As from dirty acid wastewater by precipitation. The experimental results showed that, by using this novel device, an improved performance of sulphide precipitation was achieved even at stoichiometric molar ratio of sulphide and arsenic. By combining this novel sulphide feeding process with lime FeSO4 precipitation to treat dirty acid wastewater in industrial scale, the residual concentrations of As and other heavy metals (Cu, Cd and Pb) in effluent are below the discharge standard specified by the Chinese govemment(GB 3838-2002). (C) 2015 Elsevier B.V. All rights reserved.