Electrochemical iron production to enhance anaerobic membrane treatment of wastewater. (15th October 2022)

• Record Type: Journal Article
• Authors: Hu, Zhetai; Zheng, Min; Hu, Shihu; Hong, Pei-Ying; Zhang, Xueqing; Prodanovic, Veljko; Zhang, Kefeng; Pikaar, Ilje; Ye, Liu; Deletic, Ana; Yuan, Zhiguo
• Is Part Of: Water research. Volume 225(2022)
• Publication Date: 2022-10-15
• Subjects: Electrochemical iron dosing -- Sulfide control -- Anaerobic wastewater treatment -- Membrane fouling control; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2022.119202
• Languages: English
• ISSNs: 0043-1354

Abstract

Highlights: Electrochemical Fe-dosing decreases TSS, COD, dissolved S 2−, and P concentrations. Electrochemical Fe-dosing also decreases H2 S and CO2 contents in biogas. Electrochemical Fe-dosing can mitigate organic fouling of membrane filtration. The in-situ electrochemical Fe-dosing can generate more benefits than the ex-situ . Electrochemically generated iron is cost-effective compared to use of iron chemicals. Abstract: 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 Fe 2+ and Fe 2+ (Fe 3+ )2 O4, 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 performance of anaerobic membrane processes, and this particularly facilitates wastewater management in a decentralized scenario. Graphical abstract: Image, graphical abstract