Abstract
Sediment microbial fuel cells (SMFCs) have previously been successfully used to reduce phosphate release from the sediments of eutrophic lakes. In this study, we investigate the risk that SMFCs stimulate sediment decomposition with the unwanted side effect being the release of legacy pollutants stored in sediments. Electrode pairs (16 m2 each) were installed in a eutrophic lake in Denmark and the electricity production was monitored over more than a year at three electrode fields. Equations were derived that allow calculation of the substrate turnover by the SMFCs from the working potential, the open circuit potential, and the external resistance of the SMFCs. The resulting turnover data suggest that the decomposition of the sediment is only slightly expedited by the SMFCs, and that the decomposition process is not significantly stimulated by the type of SMFCs installed in the lake. The measured maximum power density with stainless steel electrodes in the lake sediment was 0.9 mW/m2, which was sufficient to reduce P outflux from sediment. At this power density, the decomposition half-life of the lake sediment (top 5 cm) is calculated to be 277 years, which is only about 10% of natural lake sediment decomposition half-lives. Higher power densities are not necessary for P fixation but inadvertently increase the risk that legacy pollutants buried in the sediment are released.
Highlights
Users may download and print one copy of any publication from the public portal for the purpose of private study or research
We investigate the risk that SMFCs stimulate sediment decomposition with the unwanted side effect being the release of legacy pollutants stored in sediments
Sediment organic matter (SOM), which is the substrate for the SMFC, consists of long-chain polymeric material mostly composed of the decaying necromass of algae and microbes, with the major fraction composed of amino acids and deaminated peptides (Hardison et al, 2013; Miltner et al, 2012; Abdulla et al, 2018)
Summary
Users may download and print one copy of any publication from the public portal for the purpose of private study or research. Sediments store pollutants such as heavy metals, pesticides, polycyclic hydrocarbons, organochlorine chemicals and other organic micro-pollutants emitted to the environment (US EPA, 2004). Even a sediment layer of only a few centimeters contains more organic components, more nutrients and more pollutants than the whole water column of a lake (Avnimelech et al, 1984; Haxthausen et al, 2021a). Many of these chemicals are among the most hazardous compounds to humans and wildlife, due to their comparatively very high ecotoxicity (Johnson et al, 2017). Capping and stabilization of contaminated sediments have been suggested and tested as in situ remediation strategies for contaminated sediments (US EPA, 2005), and the continuing burial of this worldwide toxic reminder of a careless past in deeper sediment layers is probably the easiest and cheapest strategy
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
