Combined microbial electrolysis cell–iron-air battery system for hydrogen production and swine wastewater treatment. (February 2021)

• Record Type: Journal Article
• Authors: Han, Xiaoyu; Qu, Youpeng; Li, Da; Dong, Yue; Chen, Dahong; Yu, Yanling; Ren, Nanqi; Feng, Yujie
• Is Part Of: Process biochemistry. Volume 101(2021)
• Page Start: 104
• Page End: 110
• Publication Date: 2021-02
• Subjects: Swine wastewater -- Microbial electrolysis cell -- Iron-air battery -- Hydrogen generation -- Coagulation; Biochemical engineering -- Periodicals; Biotechnology -- Periodicals; Biochemistry -- periodicals; Biotechnology -- periodicals; Chemical Engineering -- periodicals; Génie biochimique -- Périodiques; Biotechnologie -- Périodiques; Biochemical engineering; Biotechnology; Periodicals; 660.63
• DOI: 10.1016/j.procbio.2020.11.002
• Languages: English
• ISSNs: 1359-5113

Abstract

Graphical abstract: Highlights: Microbial electrolysis cell was powered by iron-air battery for H2 production. Iron-air battery generated coagulants for swine wastewater pretreatment. Swine wastewater pretreated by coagulating process improved system performance. The combined system generated 57 L/m 3 /d H2 without additional power. Abstract: Swine wastewater is a typical high-strength animal wastewater. For treatment, it often requires combined processes (i.e., integrated units), such as multiple anaerobic reactors and advanced treatments. Microbial electrolysis cells (MECs) are a promising technology for wastewater treatment and simultaneous hydrogen harvesting. In this study, we constructed a MEC powered by an iron-air battery to treat swine wastewater and produce hydrogen efficiently. The performance of iron-air batteries with different electrolyte concentrations was compared in terms of coagulant production and power generation. The highest coagulation performance was obtained with coagulants generated using a battery with 35 g/L NaCl, which achieved 54 % ± 3%, 27 % ± 2%, 49 % ± 1%, and 34 % ± 3% removal of ammonia, chemical oxygen demand (COD), suspended solids (SS) and turbidity, respectively. Powered by the iron-air battery with 35 g/L NaCl, the hydrogen generation rate of MEC reached approximately 6 L/m 3 ·d using raw swine wastewater and 57 L/m 3 ·d using coagulated swine wastewater. The reduction of organics by coagulating helped improve hydrogen production. The total COD removal by the coagulation process integrated with MEC reached 98 % ± 0.2 %. The iron-air battery–MEC system is a promising method for simultaneous hydrogen production and wastewater treatment without any additional energy input.