Postdoctoral Research Associate, University of Utah
From polluted hypersaline solution and wastewater to energy generation
A microbial fuel cell (MFC) is a bio-electrochemical system that uses bacteria to convert the chemical energy of organic pollutants present in wastewater into electrical energy. Accordingly, MFCs can be applied to different purposes, such as wastewater treatment, power generation and biosensing. However, MFCs are normally studied and operated in conditions of low salinity due to cell plasmolysis taking place in hypersaline conditions (water diffusing "out" from the bacterial cell that will dehydrate and shrink). Saline and hypersaline solutions account for approximately 5% of effluents worldwide and their treatment is critical to avoid the release of toxic substances. Moreover, the contribution of hypersaline wastewater is expected to increase as new saline wastewater industries are emerging. The possibility to utilize halotolerant extremophile bacteria, capable to tolerate high level of salinity, is critical for the successful application of MFCs as a system to treat contaminated saline waters. An "hypersaline MFC" would avoid the release of toxic substances with the concomitant production of electricity, for the self-powered and on-line monitoring of the treatment process.
Abstract: Publication date: 1 February 2017 Source:Journal of Power Sources, Volume 340 Author(s): Andrea Schievano, Alessandra Colombo, Matteo Grattieri, Stefano P. Trasatti, Alessandro Liberale, Paolo Tremolada, Claudio Pino, Pierangela Cristiani A new type of floating microbial fuel cell (fMFC) was developed for power supply of remote environmental sensors and data transmission. Ten operating fMFCs generated a cell potential in the range 100–800 mV depending on the external resistance applied. Power production peaked around 3–3.5 mW (power density of 22–28 mW m−2 cathode) after about 20–30 days of start-up period. The average of daily electrical energy harvested ranged between 10 and 35 mWh/d. Long-term performances were ensured in the presence of dense rice plants (Oryza Sativa). A power management system, based on a step-up DC/DC converter and a low-power data transmission system via SIGFOX™ technology, have been set up for the fMFCs. The tested fMFCs systems allowed to: i) harvest produced energy, ii) supply electronic devices (intermittent LED-light and a buzzer); iii) transmit remote data at low speed (three message of 12 bites each, in 6 s). Several ‘floating garden’ MFCs were set in the context of demonstrative events at EXPO2015 world exposition held in Milan between May–October 2015. Some of the ‘floating garden’ MFCs were operating for more than one year. Graphical abstract
Pub.: 25 Nov '16, Pinned: 28 Jun '17
Abstract: Microbial fuel cells are an emerging technology for wastewater treatment, but in order to be commercially viable and sustainable, the electrode materials must be inexpensive, recyclable and reliable. In this paper, recyclable polymeric supports were explored for the development of anode electrodes to be applied in-field in single chamber microbial fuel cells operated in hypersaline conditions. The support was covered with a carbon-nanotube (CNT)-based conductive paint and biofilms were able to colonize the electrodes. The single chamber microbial fuel cells with Pt-free cathodes delivered a reproducible power output after 15 days of operation, achieving 12 ± 1 mW m-2 at a current density of 69 ± 7 mA m-2. The decrease of performance in long-term experiments was mostly related to inorganic precipitates on the cathode electrode and did not affect the performance of the anode, as shown by experiments replacing the cathode that regenerated the fuel cell performance. The results of these studies show the feasibility of carbon nanotube-based paint coated polymeric supports for microbial fuel cell applications.
Pub.: 01 Mar '17, Pinned: 28 Jun '17
Abstract: The treatment of hypersaline wastewater (approximately 5% of the wastewater worldwide) cannot be performed by classical biological techniques. Herein the halotolerant extremophile bacteria obtained from the Great Salt Lake (Utah) were explored in single chamber microbial fuel cells with Pt-free cathodes for more than 18 days. The bacteria samples collected in two different locations of the lake (Stansbury Bay and Antelope Island) showed different electrochemical performances. The maximum achieved power output of 36 mW m−2 was from the microbial fuel cell based on the sample originated from Stansbury Bay, at a current density of 820 mA m−2. The performances throughout the long-term operation are discussed and a bioelectrochemical mechanism is proposed.
Pub.: 18 Dec '16, Pinned: 28 Jun '17