Development of microbial fuel cell as biosensor for detection of organic matter of wastewater

The removal of biodegradable organic matters (BOM) is a very important aspect of evaluating the treatment efficiency in a wastewater treatment plant. However, conventional Biochemical Oxygen Demand (BOD) method is time consuming (3 or 5 days) and not suitable for online process monitoring. Instead biosensors can be used to measure BOD. Microbial Fuel Cell (MFC) biosensor which uses electroactive biofilms as sensing element has the advantage of long-term stability and minimizes the replacement of sensing elements. BOM could be directly converted to electricity via MFC, where MFC itself is an integration of signal generator and transducer. Proton Exchange Membrane (PEM) is a very important component of MFC and the most widely used Nafion PEM (NPEM) is costly (Jurado and Colomer, 2002; Liu et al., 2006, Jana et al., 2010). Previously, researchers have successfully used low cost clayware separators as PEM (CWPEM) with improved performance of MFC (Behera et al., 2009, Jana et al., 2010). Comparative studies has been carried out between MFC-1 (NPEM) and MFC-2 (CWPEM) to evaluate the performance of MFC as biosensor using mixed anaerobic culture with synthetic wastewater containing acetate as source of carbon. MFC-1 biosensor responds linearly between COD (Chemical Oxygen Demand) concentration of 22 mg/L and 51 mg/L (R2=0.954) with a response time between 120 min and 210 min. Similarly, MFC-2 biosensor responds linearly between a concentration 64 mg/L and 212 mg/L (R2=0.949) with a response time between 310 min and 120 min. The variation in rate of proton conductivity (PC) and thickness of the separators is suspected to be the cause for variation in range of detection and response time. The current market price of NPEM is very high i.e. Rs. 4000/10 cm2 and that of CWPEM is Rs. 4/10 cm2. With improvement in PC of CWPEM, low cost MFC biosensor can be successfully developed. Once successfully developed, such low cost MFC based sensors can be calibrated for BOD

Fouling resistant nitrogen doped carbon powder with amino-tri-methylene-phosphate cathode for microbial fuel cell

Abstract Long term stable performance of a microbial fuel cell (MFC) is difficult to achieve because of scale formation on cathode. Nitrogen doped carbon powder (NDCP) was used as cathode along with amino-tri-methylene-phosphate (ATMP) as an anti-scaling agent in a MFC. Maximum power density of 66 mW/m2 obtained in the MFC using NDCP as cathode, was 2.2 times higher than that obtained with simple carbon powder. High electroactive surface area and meso-porous structure of the NDCP improved electrochemical performance of the MFC having NDCP cathode. After 40 days of operation, the maximum power density decreased by only 12.5% in the MFC using NDCP and having ATMP in its cathode as compared to a 55.6% decrease in the MFC using only carbon powder in cathode due to fouling. Ultrathin shell structure of NDCP catalyst molecules, as evident from transmission electron microscopy (TEM) images, ensured high catalyst performance providing good electron transfer for enhancing oxygen reduction reaction (ORR). Less deposition of calcite molecules on cathode surface, illustrated via X-ray diffraction (XRD) after 40 days of operation, clearly reveals high anti-fouling property of ATMP as a cathode material. ATMP being a commercial anti-scaling agent has inherent chelation properties to stop chemical fouling and thus helped in demonstrating stable long term performance of cathode in the MFCs. NDCP along with ATMP could be used for fabrication of a cost effective fouling resistant cathode for long term use by increasing ORR in MFCs to achieve stable power generation by minimizing scale formation on cathode and effective wastewater treatment simultaneously. Graphical abstrac

Polyacrylic co-maleic acid as an anti-scaling binder for air–cathode microbial fuel cell: An oxygen reduction reaction perspective

Polydimethylsiloxane (PDMS) is a binder commonly used in air–cathode MFC fabrication. Herein, the performance of poly acrylic co-maleic acid (PMA) as a binder and anti-scaling agent for cathode was evaluated for application in an air–cathode MFC. Two different cathode catalysts were tested for applicability in MFC, viz., (a) Vulcan-XC: with PMA (MFC-1), with PDMS (MFC-3), and (b) Nitrogen-doped carbon catalyst (NDCP) with PDMS (MFC-2) and with PMA (MFC-4). The PMA, as an alternative to costly PDMS, prevented scale formation on the cathode surface and helped to sustain the performance of MFC-3 and MFC-4 for over 30 days. As evidenced by the cyclic voltammetry and electrochemical impedance spectroscopy, MFC-4 (NDCP and PMA) showed the best cathodic current density owing to the core–shell structure formed by nitrogen and carbon atoms in NDCP. In the future, using PMA can prevent scale formation over the (air) cathode surface and deliver a stable performance of MFC without any need for costly binder agents, such as PDMS

Seasonal characterization of municipal solid waste for selecting feasible waste treatment technology for Guwahati city, India

As quantities and composition of municipal solid waste (MSW) vary significantly with seasons, a seasonal characterization study is critical for developing an efficient MSW management system. MSW was characterized in three different seasons for selecting an appropriate waste treatment and management strategy for Guwahati city. Results of the study shows that the major components of the MSW were organics (42.2%) and plastic wastes (25.2%), which show high variations on a seasonal basis (22–49%). The chemical characterization of MSW revealed that on seasonal basis moisture content varies between 43.4% and 58.3%, pH between 5.5 and 6.5, volatile solid content from 32.9 to 58.9%, and the calorific value between 1203 and 3015 kcal/kg. Waste collected in the present study was a mixture of organics, recyclables, and inert material which is difficult and uneconomical for treatment in its present form. However, with proper waste segregation, bio-methanation, and composting could be sustainable waste treatment solutions due to the high moisture and volatile content of the MSW. Due to inadequate quantity, low calorific values, requirement of skilled supervision, and high capital investment, the thermochemical conversion of MSW may not be economically feasible for the present case.  Implications: Present study is a novel attempt to analyze in-depth variation in the municipal solid waste (MSW) composition and properties in different seasons and how does it influence the selection and feasibility of the available waste treatment technologies. Search on Google scholar shows that only seven articles have been published till now which evaluated seasonal impact of MSW. Out to these published studies only one study have calculated energy potential of MSW on seasonal basis which is mainly restricted to incineration only. In-depth analysis of seasonal variation on anaerobic digestion, composting, refuse derived fuel (RDF), pyrolysis, and gasification is yet to determine. Furthermore, to best of our knowledge so far in India there was no such in-depth study has been published related to seasonal variation in MSW on large scale (city level). Present study provides in-depth valuable information regarding degree of variation in MSW composition and how does it affect resource recovery out of waste, which was not studied before in-depth before. Outcomes of the present study will definitely assist engineers and policymaker involved MSW management and planning for large urban areas to fulfil their sustainability goals.publishedVersionPeer reviewe

Influence of ceramic separator’s characteristics on microbial fuel cell performance

This study aimed at evaluating the influence of clay properties on the performance of microbial fuel cell made using ceramic separators. Performance of two clayware microbial fuel cells (CMFCs) made from red soil (CMFC-1) typically rich in aluminum and silica and black soil (CMFC-2) with calcium, iron and magnesium predominant was evaluated. These MFCs were operated under batch mode using synthetic wastewater. Maximum sustainable volumetric power density of 1.49 W m-3 and 1.12 W m-3 was generated in CMFC-1 and CMFC-2, respectively. During polarization, the maximum power densities normalized to anode surface area of 51.65 mW m-2 and 31.20 mW m-2 were obtained for CMFC-1 and CMFC-2, respectively. Exchange current densities at cathodes of CMFC-1 and CMFC-2 are 3.38 and 2.05 times more than that of respective anodes, clearly indicating that the cathodes supported much faster reaction than the anode. Results of laboratory analysis support the presence of more number of exchangeable cations in red soil, representing higher proton exchange capacity of CMFC-1 than CMFC-2. Higher power generation was observed for CMFC-1 with separator made of red soil. Hence, separators made of red soil were more suitable for fabrication of MFC to generate higher power

Influence of ceramic separator’s characteristics on microbial fuel cell performance

<p class="PaperAbstract">This study aimed at evaluating the influence of clay properties on the performance of microbial fuel cell made using ceramic separators. Performance of two clayware microbial fuel cells (CMFCs) made from red soil (CMFC-1) typically rich in aluminum and silica and black soil <br /> (CMFC-2) with calcium, iron and magnesium predominant was evaluated. These MFCs were operated under batch mode using synthetic wastewater. Maximum sustainable volumetric power density of 1.49 W m^-3 and 1.12 W m^-3 was generated in CMFC-1 and CMFC-2, respectively. During polarization, the maximum power densities normalized to anode surface area of 51.65 mW m^-2 and 31.20 mW m^-2 were obtained for CMFC-1 and CMFC-2, respectively. Exchange current densities at cathodes of CMFC-1 and CMFC-2 are 3.38 and 2.05 times more than that of respective anodes, clearly indicating that the cathodes supported much faster reaction than the anode. Results of laboratory analysis support the presence of more number of exchangeable cations in red soil, representing higher proton exchange capacity of CMFC-1 than CMFC-2. Higher power generation was observed for CMFC-1 with separator made of red soil. Hence, separators made of red soil were more suitable for fabrication of MFC to generate higher power.</p