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International Biodeterioration & Biodegradation 75 (2012) 131e137

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International Biodeterioration & Biodegradation

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Electricity generation from acidogenic food waste leachate using dual chambermediator less microbial fuel cell

Satish S. Rikame, Alka A. Mungray*, Arvind K. Mungray*

Department of Chemical Engineering, Sardar Vallabhabhai National Institute of Technology, Surat 395007, India

a r t i c l e i n f o

Article history:Received 25 July 2012Received in revised form7 September 2012Accepted 15 September 2012Available online 23 October 2012

Keywords:Acidogenic fermentationMicrobial fuel cellPower densityBio-electricityFood waste leachate

* Corresponding authors. Tel.: þ91 (0) 2612201716.E-mail addresses: satishrikame@yahoo.com (S.S. R

(A.A. Mungray), akm@ched.svnit.ac.in (A.K. Mungray)

0964-8305/$ e see front matter � 2012 Elsevier Ltd.http://dx.doi.org/10.1016/j.ibiod.2012.09.006

a b s t r a c t

The acidogenic fermentation and electrochemical performance of mediator less dual chamberedmicrobial fuel cell (MFC) with carbon electrodes for food waste leachate was studied. COD and pH of thefood waste leachate were found 135.11 g/L and 3.93 respectively at the end of 58th day of fermentation.The potassium permanganate as a cathode solution with food waste leachate was the substrate source toan anodic chamber. After electrochemical evaluation of MFC for food waste leachate, it was observed thatmaximum 1.12 V open circuit voltage (OCV) was obtained for the COD load of 5000 mg/L. At optimumcondition, MFC gave 66.75 A/m3 of current density and 15.14 W/m3 of power density along with thesubstrate removal of 90% in terms of COD. It was observed that ion exchange capacity (IEC) was reduceddue to membrane fouling. The Scanning electron microscope (SEM) and Fourier transform infraredspectroscopy (FTIR) analysis shows the deposition of microorganism and cations on fouled membrane,which significantly deteriorate the MFC performance. This study reveals the possibilities to reduce thequantity of food waste along with the production of bio-electricity.

� 2012 Elsevier Ltd. All rights reserved.

1. Introduction

Leachate has a complex structure and high pollution load. It isquite difficult to treat and to meet the discharge standards. Enor-mous amount of municipal solid waste (MSW) is produced yearlyand safe disposal of MSW has always been a cause of concern forthe authorities. As per the report (MOEF, 2010), it is estimated thatin India, we need to manage 0.573 million metric ton (MMT) ofMSW per day of which 60% is organic waste amounting to0.343 MMT/day. Food waste accounts for about 27% of total MSW(Behera et al., 2010). Leachate obtained from food waste containslarge amount of organic matter (Kang et al., 2002) as well asNHþ

4eN, heavy metals, chlorinated organic and inorganic, salts etc.These heavy pollutants of leachate may cause ground and surfacewater contamination. In India, disposal of leachate is basically doneby land filling. Organic matter of leachate may improve the fertilityof soil but causes vermin attraction, offensive odour emanation andproduce putrefying gases (Han et al., 2005). The composition andconcentration of contaminant in leachate are influenced mainly bythe age of landfill (Tatsi and Zouboulis, 2002).

ikame), bag@ched.svnit.ac.in.

All rights reserved.

There are biological, physical and chemical treatments such asanaerobic and aerobic digestion, ultrafiltration, nanofiltration,reverse osmosis, coagulation-flocculation, chemical precipitationand ammonia stripping (Chan et al., 2006; Kurniawan et al., 2006)to treat the leachate. Because of high biodegradability of theleachate biological treatment may seem the most ideal one, butpresence of ammonia, sulfides and metals in substantial amountsinhibit (Chen et al., 2008) and reduce the treatment efficiency ofbiological processes. Some researchers have widely used combinechemical e physical treatment to treat leachate such ascoagulation-ozonation (Ramirez and Orta, 2004), ozone-activatedcarbon dsorption (Rivas et al., 2006) and precipitation-prefiltration-reverse osmosis (Renou et al., 2008). However, withthe age of leachate, the efficiency of these processes decreases andcostly to operate. The food waste leachate large in quantity may betroublesome for handling, storage and transportation. There isa need to choose some inexpensive and easy treatment options tominimize the quantity of food waste and also for satisfyingdischarge quality standards.

Microbial fuel cells (MFC), one of the efficient electrochemicaltechnologies to treat wastewater, can also provide clean energy formankind. Microorganisms can be used in MFC to catalyse theconversion of organic matter present in wastewater into electricity(Allen and Bennetto, 1993; Kim et al., 2002; Bond and Lovley, 2003;Gil et al., 2003). The benefit of MFC for wastewater treatment

S.S. Rikame et al. / International Biodeterioration & Biodegradation 75 (2012) 131e137132

counts safe, clean, efficient and direct electricity production alongwith organic matter removal. Conventionally, MFC consist of anodeand cathode chamber separated by proton exchange membrane(PEM). Bacteria oxidises the substrate and produce protons andelectrons. Electrons transferred through external circuit and protonthrough PEM. Most of the bacterial species are inactive for trans-port of electrons to anode surface, so mediators like neutral red,methylene blue, thionine and humic acid (Park and Zeikus, 2000)are used to transport electrons to anode surface. These mediatorsare expensive and toxic to bacterial culture (Delaney et al., 1984).

Today it’s accentuated to configure mediator less MFC with highelectricity generation and reduction in its operational cost. Manyresearchers has been demonstrated that an Fe reducing bacteriaShewanella putrefaciens, Geobacteraceae and few other bacteria candirectly transfer electrons to electrodes using electrochemicallyactive redox enzymes (Kim et al., 1999a,b). Single chambermembrane-less, air cathode with platinum catalyst MFC was alsostudied recently (Cavdar et al., 2011). They observed small amount ofbio-electricity and columbic efficiencywith costly platinum catalyst.

Food waste is valuable organic and easily biodegradablesubstance, available in high quantity and difficult to manage.Therefore the objective of this paper was to reduce the quantity offood waste by producing bio-electricity by using mediator-less dualchambered MFC. Emphasis was given to evaluate the effectivenessof MFC in terms of the removal of substrate, increasing powerdensity and columbic efficiency by optimizing the parameters likesubstrate and external loads. Membrane fouling characteristics andparticle size distribution was also studied for electrochemicalperformance of MFC.

2. Materials and methods

2.1. Production and characterization of food waste leachate

For experimental work, foodwaste leachatewas produced in thelaboratory in an anaerobic acidogenic reactor (Fig. 1). Reactor wasmade from cylindrical acrylic sheet with 24.0 cm diameter and64.5 cm height. Total active volume of reactor was 12 L. The screenwas fixed at the bottom of rector with conical head. The reactor hadone inlet port, one port for temperature measurement and one portto release the gas from the top of reactor. Reactor was charged bythe food waste collected from one of the dining hall of the Institute.

The food waste, seed sludge (taken from 100 million litre perday (ML/d) up flow anaerobic sludge blanket (UASB) reactor basedfull scale sewage treatment plant, Surat, Gujrat, India), saw dust andsoil were mixed in proportion. The weight of food waste and sludge

Fig. 1. Acidogenic reactor for the production of food waste leachate.

was 8.8 kg and 2.2 kg. Half kg of wood powder was used as supportand porous media in the reactor. Food waste was shredded andhomogenized food waste was then applied for hydrolysis and leftfor fermentation in acidogenesis reactor. The soil layer of 2 cmthickness was also placed on the top of reactor. The formed leachateflowed down through the bed and out of the system from conicalbottom. The temperature of reactor was maintained at 35 � 2 �C.The condition was strictly maintained anaerobic in the system. Tapwater of 750 mL was added on 21st and 51st day. Table 1 shows thecharacteristics of the produced leachate with respect to time in thereactor.

2.2. Experimental setup

2.2.1. Microbial fuel cell reactorLaboratory scale dual chamber MFC was used in this study. The

basic concept of design was taken from Logan (2005). The twochambers were designed with 1.5 L capacities made from borosil-icate glass material. Theworking volume of each chamber was 1.2 L.The anode compartment was covered with hemispherical head formaintaining anaerobic condition and for collecting biogas ifproduced. The anode chamber had two openings for inlet andoutlet with two opening ports for sampling. Pure carbon electrodeswere used with 1.5 cm in diameter and 15 cm in length in the study.Total of 8 electrodes each in anode and cathode chamber wereused. The surface area of each single carbon electrode was74.22 cm2. Total area of electrodes was 594 cm2 with effective areaof 405 cm2. In similar fashion cathode chamber was set. Electrodewere placed equal distance from membrane. The internal distanceof each electrode was fixed i.e. 0.5 mm. The terminal of eachelectrode were connected with copper conceal wires. The twochambers with membrane coupling assembly were fixed withstainless steel screws. The anode chamber was washed withnitrogen gas to remove traces of oxygen so as to maintain theanaerobic condition. Each electrode has drilled and soldered toconnect with copper wires. Both the compartments were con-nected with PEM (Ultrex, Membrane International Inc. USA) byusing nozzle coupling arrangement. The schematic diagram and theactual photograph of dual chambered MFC is given in Fig. 2. Theaerobic chamber was open to air. Air was sparged from the bottomof compartment by means of air pump. The anode and cathode wasconnected by means of copper wires with the variable resistance.

2.2.2. Operational conditionsMFC was operated in batch fed mode. The anode chamber was

inoculated with 500 mL anaerobic sludge (29.2 g TSS per L) takenfrom 100 ML/d full scale UASB based sewage treatment plant,-Surat, Gujrat India. For inoculation and start up of MFC, thesynthetic wastewater was prepared with NH4Cl (0.5 g/L), KH2PO4

(0.25 g/L), K2HPO4 (0.25 g/L), FeCl3 (0.025 g/L), NiSO4 (0.016 g/L),

Table 1Food waste leachate characteristics at the end of 58th days of acidogenesis.

Parameter Unit Food waste leachate

pH e 3.97COD g/L 135.11SS g/L 120.00NH4

þ-N g/L 20.53TP mg/L 73.05Conductivity mS/cm 21.93Temperature �C 28.3Chlorides g/L 14.39Sulphate mg/L 29.32Sulphide mg/L 15.65VFA g/L 20.61

Fig. 2. (a) Schematic details and (b) actual photograph of duel chambered MFC used inthe study.

S.S. Rikame et al. / International Biodeterioration & Biodegradation 75 (2012) 131e137 133

MgCl2 (0.3 g/L), CoCl2 (25 mg/L), ZnCl2 (11.5 mg/L), CuCl2(10.5 mg/L), CaCl2 (5 mg/L), MnCl2 (15 mg/L) and 3 g/L of glucose.The 0.2 g/L potassium permanganate (analytical grade, Finarchemicals, Ahemadabad) solution was used as a cathodic mediumduring start up. At the starting condition MFC was operated inopen circuit voltage (OCV) mode. The influent pH of the solutionwas 7.54 in anode and 7.01 in cathode. The pH was adjusted bypreparing the solution by using 50 mM phosphate buffer solu-tion. The MFC was operated 2 times for 10 days of retention timeeach with glucose as substrate medium with 3 g/L concentration.After stable voltage generation, MFC was switched to 4 days ofretention time for different food waste leachate concentration todecide the optimum organic influent rate. The influent concen-tration was tested for 1000 mg/L, 2000 mg/L, 5000 mg/L,10,000 mg/L and 20,000 mg/L of organic matter as COD. As theconductivity of food waste leachate was 21.93 mS/cm, so therewas no need to add any electrolyte. It was believed that higherconductivity would give better MFC performance (Logan et al.,2006).

2.2.3. Analysis and calculationsVoltage was verified directly by using digital multimeter (UNI-T

brand Digital Multimeter 1000 V) for every hour. Current (I) andpower (P ¼ IV) were recorded. The columbic efficiency (CE) wascalculated for batch fed mode system by using the formula (Loganet al., 2006) as:

CE ¼8Ztb

0

Idt

FwanDCOD

where DCOD is the substrate concentration for batch fed modesystem by the time ¼ tb, F is the faradays’ constant, wan liquidvolume in anode chamber, I, is the current in ampere. The powerdensity was normalized to anode surface area and anode voidvolume. The polarization curve was prepared for measuring stablevoltage for various external resistances (50e500 U). The curve thenused to calculate the maximum power density. The current density(Id¼ V/RA) was calculated.Where V (V) is voltage, R (U) is resistanceand A (cm2), the geometric anode surface area. The power density(Pd ¼ V2/RA) was calculated. Internal resistance (Rint ¼ VR/I) ofMFC was calculated by the method mentioned by Pandit et al.(2011). Analysis for chemical oxygen demand (COD; 5220 D,digestion was carried out in COD digester Model 45600,HACH, USA), suspended solid (SS; 2540 D), total phosphorous (TP;4500-P-A), ammoniacal nitrogen (phenate method, 4500 NH3 F),chlorides (4500 Cl�1 D), sulphate ð4500 SO2�

4 Þ, and sulphides(4500 S2�) were done as per APHA (2006). pH and conductivitywere measured by probes (HACH, USA) and VFAwas determined asper the procedure suggested by DiLallo and Albertson (1961). VFAwas determined by centrifuging the 50 mL sample for 10 min at6000 rpm. 25 mL of the supernatant was taken in a beaker andinitial pH of the supernatant was measured. 0.1 N H2SO4 wasadded to the aliquot of 25 mL to lower the pH down to 4.3. Itwas continued till the pH of the sample lowered from the range of3.5e3.3. It was gently boiled for 3 min and then cooled down to theroom temperature. Subsequently 0.05 N NaOH was added to it toraise the pH up to 4.0 first and then to pH 7.0. Volume of NaOHconsumed in raising the pH from 4.0 to 7.0 was noted down andVFA was calculated.

The scanning electron microscope (SEM) analysis of membranebefore and after experiments was carried by S3400, Hitachi inter-national Ltd. For SEM analysis, fouled PEM was dipped in 2.5%glutaraldehyde for 30 min. Then the sample carefully rinsed threetimes with phosphate buffer solution (PBS) (50 mM, pH 7.0) andoncewith deionizedwater. The PEM then dehydrated using ethanolseries (30%, 50%, 70%, 80% and 95%, 30 min for each concentration)and dried at ambient temperature (Xu et al., 2012). The Fouriertransform infrared spectroscopy (FTIR) was carried by A Bruker Ten37 FTIR Spectrometer (Bruker Co., Ltd.). The FTIR spectra of the rawand fouled PEM samples were recorded with the attenuated totalreflectance (ATR) technique (Xu et al., 2012).

Particle size distribution (PSD) was carried by Nano ZS90,ZETASIZER. Ion exchange capacity (IEC) of raw and fouledmembrane was measured by using titration method. In thismeasurement the raw and fouled membrane soaked in 2.5 M NaClsolution for about 14 h to ensure and complete replacement ofproton with sodium ion. The equilibrated solution then titratedagainst 0.05 M NaOH solution to neutralize the protons usingphenolphthalein indicator (Hung et al., 2011). The IEC then calcu-lated by using formula, IEC¼ (a.b)/m, where IEC is the ion exchangecapacity (meq/g); a is the added titrant volume at the equivalentpoint (mL); b is the molar concentration of the titrant;m¼ 0.1362 gis the dry membrane weight for both raw and fouled membrane.

3. Results and discussion

3.1. Formation of leachate

The performance of acidogenic reactor was tested for theproduction of food waste leachate under controlled temperature at35 � 2 �C (Table 2). With progression of time, the volume ofleachate was increased with increased COD concentration. pH ofleachate was depleted day by day due to accumulation of volatilefatty acids (VFA) mainly acetic acid > butyric acid > propionicacid > valeric acid > caproic acid (Cavdar et al., 2011). At the end of

Table 2Production of leachate in acidogenesis reactor.

Day COD (g/L) pH VFA (g/L) Leachatequantity (mL)

6 29.30 6.01 e 129 57.93 5.48 6.69 1713 63.81 5.20 e 3217 67.34 5.10 8.60 4021 81.25 5.54 e 9025 73.25 4.67 12.45 9529 97.53 4.50 13.01 7033 105.09 4.32 e 10035 146.47 4.93 14.60 13237 119.22 5.10 e 13741 122.00 3.76 17.35 15043 159.71 3.52 23.75 10051 106.44 4.10 e 10953 90.45 3.96 17.41 14555 121.04 3.99 e 16056 129.08 3.94 18.62 14058 135.11 3.93 20.61 154

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21st and 51st day, fluctuations were found in pH, COD concentra-tion and volatile fatty acids due to the addition of 750 mL of tapwater. Quantity of leachate was also found increased due to changein bed porosity. The initial pH of leachate was 6.01, and at the end of58th day of incubation pH was 3.93 along with 135.12 g/L of COD.

3.2. MFC performance

Fig. 3(a) shows the performance of MFC during start up and inopen circuit voltage (OCV) mode. During start up, it was decided tooperate MFC almost for 20 days to reach the stable OCV voltage of0.627e0.693 V for 700 mL of anode solution. It means that anodeand cathode were considered fully enriched (Zhang et al., 2011).The permanganate has high theoretical redox potential and itshows better result as an electron acceptor as compare to oxygenand hexacyanoferrate (You et al., 2006). Therefore the cathode was

a

b

Fig. 3. Performance of MFC during (a) open circuit voltage mode and (b) close circuitvoltage for different external load.

filled with 1.2 L, 0.2 g/L potassium permanganate solution. MFCwasfreshly re-inoculated with food waste leachate solution of varyingconcentration of 1000, 2000, 5000,10,000 and 20,000mg/L of COD.

Fig. 3(a) shows the OCV for various COD concentration withrespect to time. It was observed that, at different COD input, MFCgave different OCV. For leachate concentration of 1000, 2000, 5000,10,000 and 20,000 mg/L as COD, the OCV was 0.878 V, 1.012 V,1.118 V, 0.640 V and 0.437 V respectively. It was also observed thatMFC took almost 4 days to develop stable OCV with food wasteleachate. So it was decided to operate MFC for 4 days of retentiontime. Fig. 3(a) shows that the MFC gave maximum voltage of 1.12 Vfor 5000mg/L. After that, voltagewas reduced for further substanceload. This was because of high COD concentration may affect themicrobial activity of anode chamber. It also leads to increase ininternal resistance of anode chamber and may increase the chargetransfer resistance (Nam et al., 2010). Thus, the total substrate withconcentration of 5000 mg/L was considered optimum to study theelectrochemical performance of MFC for various external loads.Goud et al. (2011) studied the performance of single chamber MFCfor canteen based food waste and observed maximum of 0.295 VOCV for 1.13 kg/m3-day of organic load. Thus, in present study, MFCgave almost four times OCV of 1.12 V (5000mg/L of COD) comparedto 0.295 V (1.13 kg/m3-day) by Goud et al. (2011) and 0.398 V(1.02 kg/m3) for landfill leachate by Puig et al. (2011).

A polarization curve was plotted by switching out the circuitload to obtain the cell close circuit voltage. The polarization curvewas used to characterize current as a function of cell voltage. MFCwas tested for close circuit voltage for taking COD concentration of5000 mg/L with varying external loads from 50 to 500 U Fig. 3(b)shows the data set for close cell voltage as a function of externalresistance. It can be seen from Fig. 3(b) that if we reduced theexternal load from 500 to 105 U, close circuit voltage was almoststable. When the resistance varied from 105 to 50 U there wassudden drop in voltage. The maximum close circuit voltage wasachieved almost 1.026 V at 105 U resistance. This means that bymaintaining external load at 105 U, we could achieve good current,as there was small possible drop in OCV. Therefore external resis-tance of 105 U was considered optimum and utilized for furtheranalysis.

Fig. 4(a) shows the variation of voltage and power density withcurrent density for a fixed resistance of 105 U. It can be seen fromFig. 4(a) that at optimum condition i.e. 5000 mg/L of substrateload and 105 U resistances, current density was reached up to66.75 A/m3. Power density was also found increased up toa maximum value of 15.14 W/m3 then decreased. This was becauseof various parameters like membrane fouling (Xu et al., 2012) andpotential losses like activation losses, ohmic losses and concen-tration polarization (Larminie and Dicks, 2000). Cavdar et al. (2011)reported 43.1 A/m3 current density and 8.55 W/m3 of powerdensity in a single chambered MFC. Similarly less power density of6.82 W/m3 was also reported by You et al. (2006) for singlechambered MFC fed with acidogenic landfill leachate. Reasonbehind the better performance in this study may be the multianode and cathode arrangement (Fig. 2), which gave higherconductive surface for electron production and transport. Due totriangular pitch arrangement, transfer of electron on anode surfacewould be easy, which would reduce the internal resistance oftransport. Jiang et al. (2011) also demonstrated that power gener-ation of MFCs increased with multi anodes/cathodes.

While generating power in MFC operation, we also seek toextract as much of the electrons stored in the biomass as possible ascurrent, and to recover as much energy as possible from the system.The recovery of electrons is referred to as Columbic efficiency,defined as the fraction (or percent) of electrons recovered ascurrent versus that in the starting organic matter. The CE reflects

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Fig. 4. (a) Variation in voltage with current density for a fixed resistance of 105 U (b)variation of columbic efficiency (%) with current density for 105 U.

Fig. 6. SEM images of PEM (a) before and (b) after use in MFC.

S.S. Rikame et al. / International Biodeterioration & Biodegradation 75 (2012) 131e137 135

the coulombs recovered as a current out of total coulombsproduced during the degradation of substrate (Logan, 2005).

Fig. 4(b) shows the columbic efficiency variationwith the currentdensity for 105 U resistance. It was observed that as the currentdensity increased up to 66.75 A/m3, CE also increased from 12 to66.4%. The rate of increase in CE was steep up to 46% but after that itwas moderate. At higher current density there may be the masstransfer or kinetic limitation of the cell, which may lead to unstablevoltage output. Sometimes it may occur due to the oxygen diffusioninto the anode chamber,which leads towastage of electron to reducethe diffused oxygen. This was also attributed by Zhang et al. (2011)for glucose as a substrate. This increase in CE was attributed due tothe higher conductive surface as well as higher conductivity of foodwaste leachate. Cavdar et al. (2011) obtained CE value maximum of22%. Better results are attributed because of themultiple electrodes,which recovered more and more electron from substrate.

3.2.1. Effect on substrate removalFig. 5 shows the change in substrate removal as COD with

respect to time while treating the food waste leachate. After startup period, MFC was inoculated with COD of 1000 mg/L, 2000 mg/L,5000 mg/L, 10,000 mg/L and 20,000 mg/L food waste leachatesolution in an anode for 4 days of retention time each. It wasobserved that for COD value 5000 mg/L, COD reduction was almost90%. After that it was 74.52% and 62.70% for 10,000 mg/L and20,000 mg/L respectively. It may be due to the inhibition ofmicrobial activity due to higher COD load into MFC. Also, it wasobserved from Fig. 3(a) that for COD value of 5000 mg/L higherstable OCV of 1.12 V was obtained as compare to other

concentration. For 10,000 mg/L it was 0.64 V and for 20,000 mg/L itwas 0.437 V. Goud et al. (2011) observed that almost 64.83% CODwas removed from single chamber MFC for 1.13 kg/m3-day oforganic load. This may be attributed due to the better microbialgrowth on anode surface. This can also be justified from Fig. 4(b)that as CE was higher means better organic degradation into elec-trons and protons, which results into higher COD removal.

3.2.2. Membrane foulingFig. 6(a) shows the SEM image of fresh proton exchange

membrane (PEM). It was observed that membrane was mosaic instructure. Fig. 6(b) shows the SEM image of PEM after the appli-cation in MFC. The fouling may alter the ion exchange capacity,

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S.S. Rikame et al. / International Biodeterioration & Biodegradation 75 (2012) 131e137136

permeability of membrane due to physical blockage, conductivityof proton transfer etc (Xu et al., 2012).

As per Fig. 4(a), power density was found maximum of15.14 W/m3, after that, it was decreased. Reduced performancemay be the reason of membrane fouling because of bacterial cellencased in extracellular polymers as well as sludge particles andinorganic salt precipitation. The cation transfer limitation due tofouling causes some cathodic potential loss, which alleviate theconsequent loss in MFC performance. Xu et al. (2012) were

Fig. 8. (a) Particle size distribution of raw food waste leachate of total COD concentration offor total COD reduction of almost 90%.

observed 32.3% decreases in power production due to membranefouling. Membrane fouling and consequently decreased perfor-mance can also be explained by its ion exchange capacity (IEC)which was found decreased upto 0.513 � 0.1 meq/g from1.62 � 0.1 meq/g (for raw membrane).

Fig. 7 shows the FTIR spectrumof rawand fouledPEM. The spectraobtained in raw and fouled membrane depict the characteristics ofcontaminants on the fouled PEM. If we compare the fouled spectrawith the raw spectra of PEM, some new peaks were observed in thespectrum of the fouled PEM. The raw membrane shows peaks at1676.20 cm�1 of alkynyl C]C stretching (amide I group) and 2966 to2902 cm�1 of asymmetric methyl stretching of carbon chaincompounds (Liang et al., 2004). The fouled membrane shows somenewpeaks at 2850.88 cm�1means symmetric stretching vibration ofCH2 indicates carbon chain compound in biofilm. The peaks at1653.05 cm�1means CeO stretching indicates proteins probably dueto microorganism. Therefore, an FTIR spectrum confirms membranefouling which affects ion exchange capacity, its conductivity andultimately increases the internal resistance of MFC.

3.2.3. Particle size distribution (PSD) analysisFig. 8(a) and (b) show the particle size distribution for raw

food waste leachate and leachate after MFC treatment. It wasobserved fromFig. 8(a) thatmost of the particles are in the size rangeof 458e713 nm. The maximum volume percentage of 33.8% and44.7% for 531 nm and 615 nm particles respectively was observed.

5000 mg/L (b) particle size distribution of food waste leachate after treating with MFC

S.S. Rikame et al. / International Biodeterioration & Biodegradation 75 (2012) 131e137 137

After MFC treatment the size of the particles was reduced andparticles were distributed in the size range of 78e713 nm.Reduction of particle size was due to the solubilization of organicmatter owing to anaerobic treatment by microorganism. A clearshift appears from Fig. 8(a) and (b). After treatment, particles of531 nm and 615 nm were reduced to 12.8% and 9% respectively.The other size particle mainly was distributed in smaller range of78e342 nm. Smaller particle sizes also enhance the process in termsof the liberationofmore electrons. Rezaei et al. (2009) also tested theeffect of particle size on power density, power durability and CEusing different sized chitin particles. They observed that themaximum power densities of 176 mW/m2 and 272 mW/m2 for0.78mmand 0.28mmparticle sizes respectively. In present case, weobserved more power density with smaller particle size ranges.

4. Conclusions

This particular study demonstrated the usage of MFC for foodwaste leachate treatment and electricity generation due to multianodes and cathodes arrangement. Whereas, with the optimized5000mg/L of substrate concentration, themaximumpower densityabout15.14 W/m3 and 1.12 V open circuit voltage and 90% CODremoval is achieved. At high substrate concentration up to20,000 mg/L, MFC shows the decreased power output and less CODremoval due to microbial inhibition in anode chamber. The factoridentified to affect the performance of dual chambered MFCincludes the resistance due to membrane fouling which confirmsby SEM and FTIR analysis. The IEC of membrane was significantlyreduced due to fouling; consequently MFC performance wasdepleted for continuous use which can be reduced by chemicaltreatment for further operation.

Acknowledgements

The first author acknowledges the financial support from SardarVallabhbhai National Institute of Technology (SVNIT), Surat, India.

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