Electrochemical iron production to enhance anaerobic membrane treatment of wastewater

Although iron salts such as iron(III) chloride (FeCl3) have widespread application in wastewater treatment, safety concerns limit their use, due to the corrosive nature of concentrated solutions. This study demonstrates that local, electrochemical generation of iron is a viable alternative to the use of iron salts. Three laboratory systems with anaerobic membrane processes were set up to treat real wastewater; two systems used the production of either in -situ or ex-situ electrochemical iron (as Fe2+ and Fe2+(Fe3+)(2)O-4, respectively), while the other system served as a control. These systems were operated for over one year to assess the impact of electrochemically produced iron on system performance. The results showed that dosing of electrochemical iron significantly reduced sulfide concentration in effluent and hydrogen sulfide content in biogas, and mitigated organics-based membrane fouling, all of which are critical issues inherently related to sustainability of anaerobic wastewater treatment. The electrochemical iron strategy can generate multiple benefits for wastewater management including increased removal efficiencies for total and volatile suspended solids, chemical oxygen demand and phosphorus. The rate of methane production also increased with electrochemically produced iron. Economic analysis revealed the viability of electrochemical iron with total cost reduced by one quarter to a third compared with using FeCl3. These benefits indicate that electrochemical iron dosing can greatly enhance the overall operation and perfor-mance of anaerobic membrane processes, and this particularly facilitates wastewater management in a decen-tralized scenario.

Automated summary

This study demonstrates that electrochemical generation of iron is a viable alternative to the use of iron salts in wastewater treatment. The use of electrochemical iron significantly reduces sulfide concentration and membrane fouling, while increasing removal efficiencies of various pollutants. The economic analysis shows that electrochemical iron is cost-effective compared to the conventional method of using iron salts.