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Dr. Abdullah-Al-Mamun

Sultan Qaboos University, Department of Civil and Environmental Engineering, Oman

  

Talk Title
Development of Cost-effective Bio-cathode Microbial Fuel Cell for nutrients removal and electricity recovery

Talk Abstract
 

Microbial fuel cell (MFC) grows attention as a promising technology for converting biochemical energy into electrical energy using bacteria as biocatalysts. Exo-electrogenic biofilm on anode oxidize organics metabolically and produce electrons and protons. The bacteria  transfer electrons from metabolic chain to electrode by their conductive cytochrome c or nano-pilis. Then the electrons move through outer circuit and protons diffused through electrolytes towards the cathode, where they combine with oxygen. The technology can directly recover electrical energy from the wastewater. In last decade, power output of the system increased due to upgradation of microbial, material and electrochemical aspects. The biofilm driven anode has already been considered a cost-effective and sustainable component of MFC. While, the metal (Pt, Pd, Co, Ni, etc)  coated cathodes have made the system costly and unsustainable for large application. Therefore, the current study focused the development of bio-cathode as a cheaper alternative of Pt-coated cathode to optimize the production of bio-electricity and removal of organics and nitrogen from wastewater.

In first phase of bio-cathode development, a batch double-chambered MFC with membrane electrode assemble (carbon cloth paste on both side of membrane) was operated by sewage as anodic substrate and synthetic nitrate (NO3-) as cathodic substrate (Fig. 1). The use of autotrophic denitrifying bio-film on cathode produced a maximum power of 10 mW·m-2. The MFC showed a successful replacement of costly Pt-catalyst by a cost-effective biofilm. The research investigated only the proof-of-concept by denitrifying bio-cathode without considering reactor design.

Based on the previous observations, a second investigation was done using a continuous up-flow baffled reactor MFC with granular graphite electrodes (Fig. 2). The denitrification rate obtained was 88.9±2.2 g NO3--N·m-3 cathode volume (CV)·d-1 with a  power recovery of 6.6 W·m-3 CV. Approximately 30% COD removal achieved by the system due to lower fraction of readily biodegradable substrate in sewage. Here, the granular graphite electrode provided higher surface area for biofilm growth, which significantly generated higher electricity and nitrogen removal. However, at the end of 8 months operation, the graphite anode was clogged by the debris present in sewage.

Considering graphite clogging, a third investigation was performed with a modified up-flow baffled reactor using carbon fiber brush electrode (Fig. 3). The power recovery in this MFC was 7.05 W·m-3 CV without clogging the electrode for 8 month operation. The nitrogen removal was 125.7±6 g NO3--N·m-3 CV·d-1 with an average COD removal of 66%. The higher COD and nitrogen removal achieved by introducing an anaerobic sequencing batch reactor (ASBR) as pretreatment of sewage. Such introduction of ASBR ensured the hydrolytic acidogenic conversion of complex organics to simpler form. The organics and nitrogen removal on anode and cathode was approximately 2.2 and 1.4 times higher respectively, comparing to the same system without ASBR. The results showed the potential benefits of using ASBR pretreatment for practical application of bio-cathode MFC. However, the bio-cathode based MFC was not competitive to the Pt-coated MFC in terms of power production. Besides, the bio-cathode can compensate the low power recovery by the added value of removing nitrogen compounds. Therefore, the use of denitrifying bio-cathode in MFC could be a cost-effective technology for nutrients removal and power recovery from wastewater.

 

 

Fig. 1 Double chamber bio-cathode MFC using membrane electrode assemble, (a) real image, (b) schematic diagram.

 

Fig. 2 (A) Bio-cathode MFC for carbon and nitrogen removal; (B) Internal architecture of up-flow baffled-reactor in each chamber; (C) Assembled MFC with granular graphite electrodes.

Fig. 3 (A) The assembled bio-cathode MFC with carbon fiber brush as electrode; (B) Internal architecture of the up-flow baffled-reactor made by acrylic; (C) Schematic diagram of entire setup with ASBR as pretreatment. 

Short Biography

Dr. Abdullah Al-Mamun received Ph.D. in Civil and Environmental Engineering from National University of Singapore (NUS) in 2010. He aslo worked as Research Fellow in NUS for 6 months. After his postdoc training, he worked as full time faculty in Singapore Republic Polytechnic for 2 years. He has been working as Assistant Professor at the Department of Civil and Architectural Engineering in Sultan Qaboos University since 2012. His key research focuses to optimize Microbial Fuel Cell (MFC) for bio-electricity production, apply MFC for treating petro-chemical wastewater, Microbial electrochemical desalination, investigate the mechanisms of organics and bio-fouling in FO and MBR, convert complex organics to bio-fuels, and apply molecular techniques in environmental microbiology. He filed 1 patient in US patient provision, 27 peer-reviewed journal articles in top ranked environmental engineering and renewable field, more than 40 articles in conference proceedings, and 3 book chapters. Now he is editing one book on Microbial Electrochemistry. He is a member of many professional organizations as International Water Association (IWA), Singapore Water Association (SWA), American Chemical Society (ACS) and Institute of Engineers Bangladesh. He received the top prestigious research award named as His Majesty’s Trust Fund for Strategic Research in Sultanate of Oman in 2017. In 2017, he also received the Nationa Award for the best scientific research article in Oman.

 
Talk Keywords
Microbial fuel cell, Bio-energy, Bio-cathode, Denitrification, Baffled-reactor MFC, Nutrients removal.
 
Target Audience
Students, Post doctoral researchers, Industry partners, University faculties
 
Speaker-intro video
TBA 
 

 

The International Conference on Innovative Applied Energy (IAPE’18)