Biocathodic Reduction of Nitrate and Perchlorate in Microbial Fuel Cells

Abstract

Microbial Fuel Cells (MFCs) are devices that convert organic matter into electricity through redox processes, allowing electron transfer from an oxidation at the anode to a reduction at the cathode. The principle behind MFC technology can be used to develop integrated systems for the treatment of two different types of contaminated aqueous streams simultaneously. The main objective of this study was the development of a biocathode MFC system that treats organic waste in the anode chamber while treating inorganic contaminants in the cathode chamber. A working biocathode MFC system that treats both organic matter (anode) and inorganic contaminants (cathode) was established by the following a series of steps that built on one another. First, enrichment cultures of denitrifying and perchlorate-reducing microorganisms were developed from a mixed bacterial culture collected from a wastewater treatment process. This followed the development of a two-chambered bioanode and biocathode MFC system using an activated sludge inoculum from a Membrane Bio-Reactor (MBR) plant in Masdar city as a biocatalyst for the anode, and the previously grown denitrifiers and perchlorate reducers as bio-catalyst for the cathode. Voltage measurements were obtained for the electrochemical monitoring process of the MFC. The evaluation of denitrification (NO3-) and perchlorate (ClO4-) reducing activity of the system was established using an ion chromatography – mass spectrometry (IC-MS). In addition, denaturing gradient gel electrophoresis (DGGE) was preformed to compare the microbiology of systems under conditions of substrate and electrochemical variability. Biocathode MFCs are one technology that can potentially be applied to future sustainable cities, starting with Masdar city. This thesis is one that can promote the goals of Masdar city's 80% recycling program. The biocathode MFCs developed as part of this thesis achieved a maximum concentration removal of 17.5% per day or 34.9 mg/day of NO3- in a denitrifying MFC while attaining a maximum concentration rate of 19.0% per day or 6.48mg/d maximum removal of ClO4- in a perchlorate reducing MFC.

Date of Award	2011
Original language	American English
Supervisor	Farrukh Ahmad (Supervisor)