Electrochemical remediation of industrial waste products represents an economically attractive method to continuously convert waste streams to high value products. Electrochemical remediation has been more limited for processes that are very dry, very acidic, or a combination of both, because the most widely used polymer membranes (for example, Nafion™) need external humidification to maintain conductivity. We show that para-polybenzimidazole (PBI) membranes can be used as an effective polymer membrane separator in these types of harsh environments, improving the performance of the current state-of-the-art aqueous HCl electrolyzer, enabling the first completely anhydrous gas-phase HCl electrolyzer, and pushing the electrolysis of SO2 in the Hybrid Sulfur (HyS) cycle to the point of economic viability. The discussion will also cover how PBI membrane preparation affects electrochemical performance and the development of a Computational Fluid Dynamics (CFD) model that both provides insight into the transport phenomena of the anhydrous electrolyzer and allows us to examine operating parameters that are dangerous experimentally.