Treatment of agro-food industrial waste streams using osmotic microbial fuel cells: Performance and potential improvement measures

Osmotic microbial fuel cell (OsMFC) is an emerging wastewater treatment technology which incorporates multiple functions such as bioelectricity generation, organic substrate removal, and wastewater reclamation. This study firstly reported the performance and potential improvement measures of OsMFCs in treating selected agro-food industrial waste streams, i.e., brewery wastewater (BW), sweetener process wastewater (ST), and swine wastewater (SW). BW and SW wastewaters with good biodegradability, showed high power density (11.1 and 9.3 W/m3) and soluble chemical oxidation demand (sCOD) removal (89.2 +/- 4.1 and 70.9 +/- 3.8%) in OsMFCs. In contrast, OsMFC showed low performance with ST wastewater despite its high sCOD load. Possibilities in improving the treatment performance through modifying the operational and process settings were further explored. Shortening anode hydraulic retention time (HRT) was able to improve the bioelectricity generation and water production, whereas slightly compensated the sCOD and nutrient removal efficiencies. However, this approach showed limited effect in enhancing the ST-OsMFC. A pre-fermentation process with a minimum HRT of approximately 20 h was recommended to enhance the treatability of ST wastewater by previously converting the complex organic substrates in the raw water into volatile fatty acid (VFA). (c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Osmotic microbial fuel cell (OsMFC) is an emerging wastewater treatment technology with multiple functions. This study found that OsMFC showed good performance in treating brewery wastewater and swine wastewater, but had limited effectiveness in treating sweetener process wastewater. Modifying the operational and process settings can improve the treatment performance, but it has limited effect on sweetener process wastewater. A pre-fermentation process is recommended to enhance the treatability of sweetener process wastewater.