Generating electrical power from blackwater using microbial fuel cells
Abstract
Blackwater (BW) contains a high density of chemical energy present in organicmaterials. Each soldier generates an energy content equivalent to ~16 W in BW available for bioenergy harvesting. There are many situations where energy availability is limited and harvesting a fraction of the energy content in BW would be useful or even critical for a soldier~s mission. For example, the collection of energy from BW in a submarine can lead to a significant energy harvest to be used during emergencies or failures. A novel approach to recover the energy in BW is through a microbial fuel cell (MFC), which generates electricity directly and bypasses the typical biogas production and processing. In an MFC, the BW is hydrolyzed and fermented; the fermentation products are consumed byanode-respiring bacteria (ARB), producing and electrical current. This low-voltage electricity can be upgraded to power equipment and/or be stored for future use. Thus, the focus of this project is to develop an efficient MFC to maximize the power output of a lab-scale unit fed with submarine BW by optimizing materials and design. The following objectives determine theresearch path for the project: 1) Optimization of cathode catalyst composition, design, and operation to maximize energy recovery, having a target of >0.25 V operational voltage at > 1 A/m2 in the MFC module to be tested. 2) Adaptation of existing demonstrated MFC technology for use in a modular BW system for submarine operation. Demonstrate consistent power production using the modules tested. 3) Integration of updated MFC technology, and demonstration of energy harvesting at two scales, single MFC (100 mW or > 2 Whr per day) andmultiple MFCs (500 mW /10 Whr per day) to demonstrate modular scale-up potential. Three specific tasks are proposed to achieve these objectives. First, cathode catalysts will be optimized for O2 reduction in the presence of BW, maintaining a low overpotentials and long-term performance. Second, the MFC design and operation will be optimized to maximize voltage output and available current production by BW. Finally, BW-fed MFCs will be evaluated in single and multiple reactor operation for long-term operation and power harvest through aflyback circuit designed by SSCPAC. A commercial MFC product, BETT, will be tested as a 3- reactor unit along the developed MFCs developed in the lab. All reactors will be fed a submarine BW equivalent, designed based on samples analyzed. The results from this project can allow the technological and economic evaluation of energy harvesting from BW and allow for decisions on the benefits of energy recovery in submarines and other possible DoD scenarios.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 24, 2019
- Source ID
- N000141912125
Entities
People
- César I. Torres
Organizations
- Arizona State University
- Office of Naval Research
- United States Navy