- Email: [email protected]
Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/he
Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation Suwimon Kanchanasuta a,b,*, Nipon Pisutpaisal c,d a
Department of Environmental Health Sciences, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand b Center of Excellence on Environmental Health and Toxicology, Bangkok, Thailand c Department of Agro-Industrial, Food and Environment Technology, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok, Bangkok 10800, Thailand d Biosensor and Bioelectronics Technology Centre, King Mongkut's University of Technology North Bangkok, Bangkok 10800, Thailand
article info
abstract
Article history:
Co-feedstock of palm oil decanter cake with the both functions of substrate and micro-
Received 2 October 2016
bial source in biogas fermentation was examined in this study. Decanter cake with the
Received in revised form
characteristic of high biodegradable organic contents and nutrient rich compositions is
24 December 2016
an attractive feedstock for biogas production. The various types of bacteria of the
Accepted 28 December 2016
indigenous microbes from decanter cake resulted in the enhancement of the biogas
Available online xxx
productivity based on biogas potential production (Hmax) and energy recovery including glycerol waste utilization. Decanter cake with 2% TS w v1 used as co-feedstock with
Keywords:
varying glycerol waste concentration in the range of 7.5e45 g L1 were used for the biogas
Glycerol waste
production in 0.5 L batch reactors under the condition of initial pH 7 and 37
Co-feedstock
Comparative performance of the biogas production using combined decanter cake as co-
Palm oil decanter cake
feedstock and indigenous microbes and sole glycerol waste fermentation with anaerobic
Biohydrogen
sludge as inocula was evaluated. Types of inoculum seeds displayed strong effect on the
C.
biogas compositions and glycerol waste utilization. CH4 was the predominant biogas composition, while no H2 was observed in the sole glycerol waste fermentation. H2 production was predominantly detected in the combined decanter cake fermentation. The presence of the anaerobic sludge appeared to promote only methanogenesis resulting shorter fermentation period, lower glycerol waste utilization and biogas production potential (Hmax). The increase of the glycerol waste concentration depressed CH4 production and glycerol waste utilization. On the contrary, this work demonstrated the
* Corresponding author. Department of Environmental Health Sciences, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand. Fax: þ66 2354 8525. E-mail addresses: [email protected], [email protected] (S. Kanchanasuta). http://dx.doi.org/10.1016/j.ijhydene.2016.12.134 0360-3199/© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
2
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
addition of decanter cake as co-feedstock and microbial source, containing hydrolytic and acedogenic bacteria, yielded a better performance in the biogas production and simulate glycerol waste utilization at the same time. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Introduction Glycerol is a by-product from biodiesel industry. Because biodiesel production is rapidly expanding in Thailand in order to meet the increasing energy demand of transportation the glycerol waste generated from the transesterification of vegetables oils, has also been generated in a large quantity. Although the various applications such as pure glycerol in food, pharmaceutical, cosmetics, and many other industries have been reported, they are too costly to refine the crude glycerol to a high purity, particularly for medium and small biodiesel producers. Moreover, some period of over biodiesel in the market results in the low cost of glycerol waste, so burning is the disposal method of this case. Many previous researches have been conducted and utilized of the glycerol waste to produce the valuable products such as biohydrogen [1e4], 1,3 propanediol [5], bioethanol [6]. However, bioenergy and biofuels have been extensively explored to replace finite and environmentally harmful fossil fuels. Utilization of glycerol waste contained the other impurities such as methanol, salts, long chain fatty acids by microorganisms makes the limitation of bioenergy production from glycerol waste. Co-feedstock with the other organic-rich wastes contained the indigenous microbes is an alternative procedure for improvement of glycerol waste utilization and the overall production of bioenergy and biofuels. Decanter cake is one type of waste produced from palm oil industry in the step of oil purification. Previous studies reported that typical palm oil mills generate 3.5% of oil palm decanter cake (OPDC) for each tonne of fresh fruit brunches (FFB) [7,8] and 42 kg per tonne fresh fruit brunches [9]. High biodegradable organic contents and nutrient rich compositions make palm oil decanter cake as an attractive feedstock for biogas production. Over the last decade, most decanter cake has been used as fertilizer and animal feed, a raw material for cellulose and polyose [10,11], bio-surfactant [12], biobutanol [13], bio-diesel [14] and bio-oil productions [15]. Biogas production from agro-industrial waste plays an alternative sustainable waste management. Sharing waste utilization among the same industry and continuous industry (Palm oil mill and biodiesel production) leads to the effective waste management in both increasing the value and reduction the disposal cost of waste. For many previous studies, researchers attempted to use glycerol as co-digestion in biogas fermentation with various substrates to enhance the biogas yield such as sewage sludge [16e18], cattle manure [19], orange peel waste [20] and pig manure [21]. There are few literature reported the utilization of decanter cake as the codigestion in the biogas fermentation process.
Our previous study displayed the feasibility of decanter cake to be an indigenous source of inocula seed in anaerobic digestion process [22]. Under the indigenous microbe fermentation, H2 was the predominant biogas composition while no CH4 was observed. However, better performance of biogas yield, specific production rate and energy recovery were obtained in the combined seed fermentation. Furthermore, there is no study reported the feasibility of biogas fermentation from co-digestion of glycerol waste and decanter cake. Therefore, in the present study, the comparative of combined decanter cake as co-feedstock and inocula; and sole glycerol waste with the anaerobic sludge in the biogas production at the optimum condition with varying glycerol waste concentrations (7.5e45 g L1) was evaluated based on biogas composition, biogas production potential, waste reduction, glycerol utilization and energy recovery.
Materials and methods Glycerol waste Brownish glycerol waste with 63.9% glycerol purity was obtained from Trang Palm Oil Co., Ltd. Trang, Thailand. The characteristic of the glycerol waste is as shown in Table 1.
Table 1 e Characteristics of glycerol waste, sludge seed and palm oil decanter cake. Parameter Total solids (TS) Total volatile solids Total COD Soluble COD Total carbon Total nitrogen Cellulose Hemicellulose Lignin pH Conductivity FOG Methanol Monoglyceride Diglyceride Triglyceride TOC
Glycerol waste
Sludge seed
Decanter cake
NA
22,233 mg L1 197,670 mg kg1
NA
19,700 mg L1 169,740 mg kg1
443,262 mg kg1 115,248 mg kg1 NA NA NA NA NA 8.76 529 ms cm1 5222 mg L1 0.36% v v1 0.03% w w1 0.02% w w1 0.07% w w1 414,666 mg L1
40,153 mg L1 2881 mg L1 NA NA NA NA NA NA NA NA NA NA NA NA NA
NA NA 47.35% w w1 4.34% w w1 50.07% w w1 30.74% w w1 10.40% w w1 NA NA NA NA NA NA NA NA
NA ¼ Not Analyzed.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
3
Microbial inoculum
Batch fermentation
Anaerobic sludge seed was obtained from a full-scale upflow anaerobic sludge blanket reactor treating beverage processing wastewater (Sermsuk Industry Co. Ltd., Pathumtani, Thailand). The anaerobic sludge seed have the characteristics shown in Table 1. Prior to use, the granule was sieved to the size <0.5 mm to remove coarse matters and then washed twice with tap water. The anaerobic granule sludge was re-cultivated in 0.5% (w v1) glucose solution until reach to steady state regarding the CH4 content and volume of CH4 production and then washed with the distilled water twice before used as a seed microbial inoculum for the biogas fermentation.
Batch fermentation system was set up in 500 mL screw-cap bottles with a working volume of 500 mL. In each reactor, the anaerobic sludge was fixed at 6.73 g total volatile solids (VS) (125 mL) for the sole glycerol waste fermentation. Decanter cake at 2% w v1 total solid (10 g TS in 500 mL of water) was added in the combined co-feedstock fermentation with varying glycerol waste concentrations between 7.5 and 45 g L1. The initial pH was adjusted to 7.0 with 6 N NaOH or concentrated H3PO4. The system was flushed with nitrogen gas to generate anaerobic condition. Biogas fermentation was conducted at 37 C with rotary shaking at 150 rpm. All experiments were set up in triplicate. During the fermentation experiment, total gas volume and composition were periodically monitored by gas counters and gas chromatography, respectively. The liquid samples were analyzed for pH, COD, residual glycerol and volatile fatty acids (VFAs) every 6e12 h.
Decanter cake Decanter cake, a feedstock for the biogas production and a source of indigenous microbes, was collected from palm oil milling plant, Suksomboon palm oil industry in Chonburi, Thailand. The sample was stored at 4 C before use. The characteristic of palm oil decanter cake is as shown in Table 1.
Analytical methods Total solids (TS) and chemical oxygen demand (COD) were measured according to Standard Methods 2540 G and 5220 B,
Fig. 1 e Volumetric and cumulative CH4 under the sole glycerol waste fermentation (A and B) with varying glycerol concentration of 7.5 (), 15 (C), 30 (,), 45 (-) and 90 (D) g L¡1 and volume and cumulative H2 under glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (C and D) with varying glycerol concentration of 7.5 (), 15 (C), 30 (,), 45 (-) g L¡1. Each data point represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation. Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
4
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
respectively [23]. Glycerol was spectrophotometrically determined by chromotropic acid method (modified from Handel, 1961) [24]. The amount of generated biogas was recorded using liquid displacement gasometers. Biogas content (H2, CH4, and CO2) was measured periodically every 6e12 h using a gas chromatograph (Shimadzu GC-8A, Kyoto, Japan) equipped with a thermal conductivity detector (TCD) with a Unibeads C 60/80 column (GL Sciences, Inc., Tokyo, Japan). Helium was used as a carrier gas. The temperatures of the injection port and the detector were 150 and 80 C, respectively. VFAs were analyzed by gas chromatography (Shimadzu GC-7A system equipped with a flame ionization detector and a Stabilwax DA capillary column; Restek Corporation, PA, USA). The temperatures of the injection port and detector were maintained at 240 C [25].
Kinetics analysis The modified Gompertz equation (Eq. (1)) was used to fit cumulative hydrogen/methane production data obtained from each batch experiment [26]. This model has long been used for describing hydrogen, methane, or biogas production in batch fermentation experiments. Rm $e ðl tÞ þ 1 HðtÞ ¼ P$exp exp P
(1)
where H(t) is cumulative biogas production (mL) during the incubation time, t (h), P (Hmax) is the biogas production potential (mL), Rm is the maximum production rate (mL h1), l is the lag phase duration (h), and e is the exp(1) ¼ 2.718.
Biogas yield (Y) is calculated by dividing the hydrogen production potential at 72 h (combined seed reactor) and 60 h (indigenous microbe reactor) by the amount of TS and COD removed.
Results and discussion Biogas production Enhancement of the efficiency of biogas fermentation based on the biogas production potential (Hmax) and energy recovery was observed under the combined palm oil decanter cake with glycerol waste fermentation. Types of the inoculum seeds played the vital role on the biogas compositions. In the presence of anaerobic sludge (glycerol as the sole feedstock), CH4 was the main composition (24e44%) in the biogas, and H2 was not detectable. On the contrary, H2 was found in the range of 28e43% and CH4 was not detected, in the combined decanter cake with glycerol waste fermentation. Not only decanter cake was the co-feedstock, it was also used as inoculum seed in the fermentation. Lignocellulosic fraction (50% of cellulose and 31% of hemicellulose; Table 1) and hydrolytic bacteria from decanter cake make fermentation periods under the combined feedstock (96e108 h) longer than the sole feedstock (36e48 h) for all cases. Patterns of biogas production in the sole feedstock reached the peak after 12 h fermentation and then rapidly declined to zero while the peak of biogas production in the combined feedstock was
Fig. 2 e Biogas production potential (Hmax) and lag time (l) under the sole glycerol waste fermentation (A and C) and glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (B and D). Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation. Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
5
obtained after 36 h fermentation for most cases (except at 30 g L1 glycerol waste condition) and then it could be detected until 96 h fermentation (Fig. 1A and C). The cumulative CH4 and H2 fermentation profile data were S-shape trend and well fitted to the modified Gompertz equation (R2 > 0.99) for all experiments (Fig. 1B and D). The kinetics data from the equation, hence, was statistically significant. Volume of H2 throughout the fermentation and cumulative H2 production in the combined feedstock were obviously higher than those in the sole feedstock for all cases (Fig. 2A and B). Environmental conditions and types of existing active organism groups play the important role of the efficiency of bioproduct production in the overall fermentation. In general, microorganisms related to the anaerobic fermentation process consist of diverse bacterial groups such as hydrolytic bacteria, acidogens, acetogens, and methanogens. The hydrolytic bacteria degrade complex substrates or polymeric substrates to simple structures, which are further converted to various products such as volatile fatty acids (e.g. acetic, propanoic, lactic, and butylic acids) and alcohol [27]. The results of the biogas production under the combined feedstock with the presence of the indigenous microbes in the decanter cake indicated that these microbes contained no methanogen, but hydrolytic, acidogenic, and acetogenic bacteria. On the contrary, in the presence of the sludge seed under the sole feedstock, contain including methanogenic bacteria, hydrolytic, acidogenic, and acetogenic bacteria which worked syntrophically and completely converted the common intermediate in the CH4 production pathway such as short-chain fatty acid, H2 and CO2 to methane in the later step (Eq. (2)).
CO2 þ 4H2 / CH4 þ 2H2O
(2)
The enhancement of the biogas production potential and glycerol waste utilization suggested that the indigenous seed composed of hydrolytic, acidogenic, and acetogenic bacteria can degrade and uptake the decanter cake for their growth and further convert to the other by-products such as H2, VFAs. At the same time, they can stimulate glycerol utilization in the increase concentration of glycerol waste (15e45 g L1) conditions rather than that in the fermentation with anaerobic sludge composed of methanogens (Fig. 3). Longer lag times (10e18 h) were required for the H2 productions compared to those for the CH4 production (2e7 h) for all cases (Fig. 2C and D). CH4 production potential was maximized at low glycerol waste concentration of 7.5 g L1 and dropped as the concentration increased. The short fermentation period (12 h) and low biogas production potential (lower than 80 mL) suggested that only glycerol waste as sole feedstock in the biogas fermentation by the anaerobic sludge was not the suitable carbon source due to some components such as methanol, salts and long chain fatty acids. These affect directly the digestion and conversion of the glycerol waste to CH4 by syntrophic microbes in the reactors. Organic loading and cofeedstock also strongly affected the biogas production. Combined decanter cake and glycerol waste obviously enhance the efficiency of hydrolysis process resulting higher glycerol waste utilization. On the contrary, at the same organic loading of glycerol waste, although the anaerobic sludge was added
Fig. 3 e Glycerol utilization under the sole glycerol waste fermentation (A) and glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (B). Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation.
Fig. 4 e Total solid removal under glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation. Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
6
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
Waste reduction and energy recovery Under co-feedstock with 2% TS decanter cake fermentation, the maximum TS removal of 53.5 was observed at the 7.5 g L1 glycerol waste (Fig. 4). Trend of TS reduction was decreased at the high organic loading. Similarly, glycerol utilization was decreased at the high organic loading condition. High efficient waste utilization in the H2 or CH4 fermentation potentially benefits the management of the glycerol waste and palm oil decanter cake from palm oil industry. Energy recovery in the combined decanter cake fermentation as feedstock recovered energy significantly greater than that in the sole glycerol waste fermentation in all cases (Fig. 3A and B). Maximum energy recovery in the combined decanter cake fermentation as feedstock found at 15 g L1 glycerol waste is equivalent to 7.4 104 kWh (Fig. 5A and B), which is 10 times greater than that recovered in the sole glycerol waste fermentation. Waste reduction and energy recovery indicated that the combined decanter cake fermentation as feedstock is more beneficial than the sole glycerol waste fermentation.
Conclusions
Fig. 5 e Energy recovery under the sole glycerol waste fermentation (A) and glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (B). Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation. into the fermentation system and methane production was observed, CH4 fermentation was significantly decreased at the increased organic loading (7.5e90 g L1 glycerol waste). Results of glycerol waste utilization indicated that high organic loading of glycerol waste had strongly resulted in reduction of the efficiency of hydrolytic and methanogen bacteria able to hydrolyze and further convert to CH4 as the end product. Previous study reported that long chain fatty acids (LCFAs) derived from glycerol waste in the fermentation had been covered the membrane of bacteria resulting in the process of food uptake into its cell [28]. However, to improve the efficiency of biogas production and waste utilization from glycerol waste and decanter cake, dominant microbial communities in each fermentation periods in the reactors and suitable conditions for their growth and activities have been further investigated.
The efficiency of glycerol utilization and biogas production were obtained under the combined decanter cake fermentation with glycerol waste. Types of fuel gases produced from the fermentation were governed by the types of inocula. Combined decanter cake fermentation yielded H2, but the sole glycerol waste fermentation yielded CH4. More significant performance in the fermentation with the combined decanter cake as co-feedstock regarding the biogas potential production, glycerol utilization and energy recovery were archived. The total energy recovery from the combined decanter fermentation was improved by 10 times compared to the sole glycerol waste fermentation. Decanter cake was not used only co-feedstock, but it was also used as the source of inocula for fermentation. The performance of H2 and CH4 production from the glycerol waste and decanter cake fermentation could be more effectively improved by using two-stage fermentation where H2 and CH4 productions are the first and second steps, respectively. Besides, investigation of microbial communities in the reactor is necessary for improvement of the overall biogas fermentation.
Acknowledgements The authors would like to express their gratitude to Agricultural Research Development Agency (Public Organization) for the financial support (Grant no. PRP5805020300).
references
[1] Jitrwung R, Yargeau V. Optimization of media composition for the production of biohydrogen from waste glycerol. Int J Hydrogen Energy 2011;36:9602e11.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
[2] Mangayil R, Karp M, Santala V. Bioconversion of crude glycerol from biodiesel production to hydrogen. Int J Hydrogen Energy 2012;37:12198e204. [3] Lo YC, Chen XJ, Huang CY, Yuan YJ, Chang JS. Dark fermentative hydrogen production with crude glycerol from biodiesel industry using indigenous hydrogen producing bacteria. Int J Hydrogen Energy 2013;38:15815e22. [4] Chookeaw T, O-Thong S, Prasertsan P. Biohydrogen production from crude glycerol by immobilized Klebsiella sp.Tr17 in a UASB reactor and bacterial quantification under non sterile conditions. Int J Hydrogen Energy 2014;39:9580e7. [5] Kivisto A, Santala V, Karp M. Non sterile process for biohydrogen and 1,3 propanediol production from raw glycerol. Int J Hydrogen Energy 2013;38:11749e55. [6] Varrone C, Giussani B, Izzo G, Massini G, Marone A, Signorini AA. Wang, Statistical optimization of biohydrogen and ethanol production from crude glycerol by microbial mixed culture. Int J Hydrogen Energy 2012;37:16479e88. [7] Ooi HS, Kumar SS. Co-composting for sustainable crude palm oil production in Malaysia. Jarutera bulletin. The Institute of Engineers Malaysia (IEM); 2008. p. 22e6. [8] Ng FY, Yew FKN, Basiron Y, Sundram K. A renewable future driven with Malaysia palm oil based technology. J Oil Palm Environ 2011;2:1e7. [9] Chavaparit O, Rulkens WH, Mol APJ, Khaodhair S. Options for environmental sustainability of the crude palm oil industry in Thailand through enhancement of industrial ecosystems. Environ Dev Sustain 2006;8:271e87. [10] Nafis M, Razak A, Ibrahim MF, Yee PL, Hassan MA, AbdAziz S. Utilization of oil palm decanter cake for cellulose and polyoses production. Biotechnol Bioprocess Eng 2012;17:547e55. [11] Zanirun Z, Bahrin E, Lai-Yee P, Hassan M, Abd-Aziz S. Effect of physical and chemical properties of oil palm empty fruit bunch, decanter cake and sago pith residue on cellulose production by Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2. Appl Biochem Biotechnol 2014;172:423e35. [12] Naporat P, Maneerat S, Saimmai A. Utilization of palm oil decanter cake as a novel substrate for biosurfactant production from a new and promising strain of Ochrobactrum anthropic 2/3. World J Microbiol Biotechnol 2014;30:865e77. [13] Loyarkat S, Cheirsilp B, Umsakul K. Decanter cake waste as a renewable substrate for biobutanol production by Clostridium beijerinckii. Process Biochem 2013;48:1933e41. [14] Maniam GP, Hindrywati N, Nurfitri I, Jose R, Ab Rahim MH, Dahalan FA. Decanter cake as a feedstock for biodiesel production: a first report. Energy Convers Manage 2013;76:527e32.
7
[15] Dewayanto N, Isha R, Nordin MR. Use of palm oil decanter cake as a new substrate for the production of bio-oil by vacuum pyrolysis. Energy Convers Manage 2014;86:226e32. [16] Nartker S, Ammerman M, Aurandt J, Stogsdil M, Hayden O, Antle C. Increasing biogas production from sewage sludge anaerobic co-digestion process by adding crude glycerol from biodiesel industry. Waste Manage 2014;34:2567e71. [17] Fountoulakis MS, Petousi I, Manios T. Co-digestion of sewage sludge with glycerol to boost biogas production. Waste Manage 2010;30:1849e53. [18] Nghiem LD, Nguyen TT, Manassa P, Fitzgerald SK, Dawson M, Vierboom S. Co-digestion of sewage sludge and crude glycerol for on-demand biogas production. Int Biodeter Biodegr 2014;95:160e6. [19] Castrillon L, Fernandez-Nava Y, Ormaechea P, Maranon E. Optimization of biogas production from cattle manure by pre-treatment with ultrasound and co-digestion with crude glycerin. Bioresour Technol 2011;102:7845e9. [20] Matin MA, Fernandez R, Serrano A, Siles JA. Semi-continuous anaerobic co-digestion of orange peel waste and residual glycerol derived from biodiesel manufacturing. Waste Manage 2013;33:1633e9. [21] Astals S, Nolla-Ardevol V, Mata-Alvarez J. Anaerobic codigestion of pig manure and crude glycerol at mesophilic conditions: biogas and digestate. Bioresour Technol 2012;110:63e70. [22] Kanchanasuta S, Pisutpaisal N. Waste utilization of palm oil decanter cake on biogas fermentation. Int J Hydrogen Energy 2016;41(35):15661e6. [23] APHA Standard. Methods for the examination of water and wastewater. 21st ed. Washington, DC, USA: American Public Health Association, American Water Works Association, Water Environment Federation; 2005. [24] Handel EV. Suggested modification of the micro determination of triglycerides. Clin Chem 1961;7(3):249e51. [25] Nathao C, Sirisukpoka U, Pisutpaisal N. Production of hydrogen and methane by one and two stage fermentation of food waste. Int J Hydrogen Energy 2013;38(35):15764e9. [26] Lay JJ, Lee YJ, Noike T. Feasibility of biological hydrogen production from organic fraction of municipal solid waste. Water Res 1999;33:2579e86. [27] Valdez-Vazquez I, Poggi-Varaldo HM. Hydrogen production by fermentative consortia. Renew Sust Energy Rev 2009;13:1000e13. [28] Viana MB, Freitas AV, Leitao RC, Pinto GAS, Santaella ST. Anaerobic digestion of crude glycerol: a review. Environ Technol Rev 2012;1:81e92.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/he
Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation Suwimon Kanchanasuta a,b,*, Nipon Pisutpaisal c,d a
Department of Environmental Health Sciences, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand b Center of Excellence on Environmental Health and Toxicology, Bangkok, Thailand c Department of Agro-Industrial, Food and Environment Technology, Faculty of Applied Science, King Mongkut's University of Technology North Bangkok, Bangkok 10800, Thailand d Biosensor and Bioelectronics Technology Centre, King Mongkut's University of Technology North Bangkok, Bangkok 10800, Thailand
article info
abstract
Article history:
Co-feedstock of palm oil decanter cake with the both functions of substrate and micro-
Received 2 October 2016
bial source in biogas fermentation was examined in this study. Decanter cake with the
Received in revised form
characteristic of high biodegradable organic contents and nutrient rich compositions is
24 December 2016
an attractive feedstock for biogas production. The various types of bacteria of the
Accepted 28 December 2016
indigenous microbes from decanter cake resulted in the enhancement of the biogas
Available online xxx
productivity based on biogas potential production (Hmax) and energy recovery including glycerol waste utilization. Decanter cake with 2% TS w v1 used as co-feedstock with
Keywords:
varying glycerol waste concentration in the range of 7.5e45 g L1 were used for the biogas
Glycerol waste
production in 0.5 L batch reactors under the condition of initial pH 7 and 37
Co-feedstock
Comparative performance of the biogas production using combined decanter cake as co-
Palm oil decanter cake
feedstock and indigenous microbes and sole glycerol waste fermentation with anaerobic
Biohydrogen
sludge as inocula was evaluated. Types of inoculum seeds displayed strong effect on the
C.
biogas compositions and glycerol waste utilization. CH4 was the predominant biogas composition, while no H2 was observed in the sole glycerol waste fermentation. H2 production was predominantly detected in the combined decanter cake fermentation. The presence of the anaerobic sludge appeared to promote only methanogenesis resulting shorter fermentation period, lower glycerol waste utilization and biogas production potential (Hmax). The increase of the glycerol waste concentration depressed CH4 production and glycerol waste utilization. On the contrary, this work demonstrated the
* Corresponding author. Department of Environmental Health Sciences, Faculty of Public Health, Mahidol University, Bangkok 10400, Thailand. Fax: þ66 2354 8525. E-mail addresses: [email protected], [email protected] (S. Kanchanasuta). http://dx.doi.org/10.1016/j.ijhydene.2016.12.134 0360-3199/© 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
2
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
addition of decanter cake as co-feedstock and microbial source, containing hydrolytic and acedogenic bacteria, yielded a better performance in the biogas production and simulate glycerol waste utilization at the same time. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Introduction Glycerol is a by-product from biodiesel industry. Because biodiesel production is rapidly expanding in Thailand in order to meet the increasing energy demand of transportation the glycerol waste generated from the transesterification of vegetables oils, has also been generated in a large quantity. Although the various applications such as pure glycerol in food, pharmaceutical, cosmetics, and many other industries have been reported, they are too costly to refine the crude glycerol to a high purity, particularly for medium and small biodiesel producers. Moreover, some period of over biodiesel in the market results in the low cost of glycerol waste, so burning is the disposal method of this case. Many previous researches have been conducted and utilized of the glycerol waste to produce the valuable products such as biohydrogen [1e4], 1,3 propanediol [5], bioethanol [6]. However, bioenergy and biofuels have been extensively explored to replace finite and environmentally harmful fossil fuels. Utilization of glycerol waste contained the other impurities such as methanol, salts, long chain fatty acids by microorganisms makes the limitation of bioenergy production from glycerol waste. Co-feedstock with the other organic-rich wastes contained the indigenous microbes is an alternative procedure for improvement of glycerol waste utilization and the overall production of bioenergy and biofuels. Decanter cake is one type of waste produced from palm oil industry in the step of oil purification. Previous studies reported that typical palm oil mills generate 3.5% of oil palm decanter cake (OPDC) for each tonne of fresh fruit brunches (FFB) [7,8] and 42 kg per tonne fresh fruit brunches [9]. High biodegradable organic contents and nutrient rich compositions make palm oil decanter cake as an attractive feedstock for biogas production. Over the last decade, most decanter cake has been used as fertilizer and animal feed, a raw material for cellulose and polyose [10,11], bio-surfactant [12], biobutanol [13], bio-diesel [14] and bio-oil productions [15]. Biogas production from agro-industrial waste plays an alternative sustainable waste management. Sharing waste utilization among the same industry and continuous industry (Palm oil mill and biodiesel production) leads to the effective waste management in both increasing the value and reduction the disposal cost of waste. For many previous studies, researchers attempted to use glycerol as co-digestion in biogas fermentation with various substrates to enhance the biogas yield such as sewage sludge [16e18], cattle manure [19], orange peel waste [20] and pig manure [21]. There are few literature reported the utilization of decanter cake as the codigestion in the biogas fermentation process.
Our previous study displayed the feasibility of decanter cake to be an indigenous source of inocula seed in anaerobic digestion process [22]. Under the indigenous microbe fermentation, H2 was the predominant biogas composition while no CH4 was observed. However, better performance of biogas yield, specific production rate and energy recovery were obtained in the combined seed fermentation. Furthermore, there is no study reported the feasibility of biogas fermentation from co-digestion of glycerol waste and decanter cake. Therefore, in the present study, the comparative of combined decanter cake as co-feedstock and inocula; and sole glycerol waste with the anaerobic sludge in the biogas production at the optimum condition with varying glycerol waste concentrations (7.5e45 g L1) was evaluated based on biogas composition, biogas production potential, waste reduction, glycerol utilization and energy recovery.
Materials and methods Glycerol waste Brownish glycerol waste with 63.9% glycerol purity was obtained from Trang Palm Oil Co., Ltd. Trang, Thailand. The characteristic of the glycerol waste is as shown in Table 1.
Table 1 e Characteristics of glycerol waste, sludge seed and palm oil decanter cake. Parameter Total solids (TS) Total volatile solids Total COD Soluble COD Total carbon Total nitrogen Cellulose Hemicellulose Lignin pH Conductivity FOG Methanol Monoglyceride Diglyceride Triglyceride TOC
Glycerol waste
Sludge seed
Decanter cake
NA
22,233 mg L1 197,670 mg kg1
NA
19,700 mg L1 169,740 mg kg1
443,262 mg kg1 115,248 mg kg1 NA NA NA NA NA 8.76 529 ms cm1 5222 mg L1 0.36% v v1 0.03% w w1 0.02% w w1 0.07% w w1 414,666 mg L1
40,153 mg L1 2881 mg L1 NA NA NA NA NA NA NA NA NA NA NA NA NA
NA NA 47.35% w w1 4.34% w w1 50.07% w w1 30.74% w w1 10.40% w w1 NA NA NA NA NA NA NA NA
NA ¼ Not Analyzed.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
3
Microbial inoculum
Batch fermentation
Anaerobic sludge seed was obtained from a full-scale upflow anaerobic sludge blanket reactor treating beverage processing wastewater (Sermsuk Industry Co. Ltd., Pathumtani, Thailand). The anaerobic sludge seed have the characteristics shown in Table 1. Prior to use, the granule was sieved to the size <0.5 mm to remove coarse matters and then washed twice with tap water. The anaerobic granule sludge was re-cultivated in 0.5% (w v1) glucose solution until reach to steady state regarding the CH4 content and volume of CH4 production and then washed with the distilled water twice before used as a seed microbial inoculum for the biogas fermentation.
Batch fermentation system was set up in 500 mL screw-cap bottles with a working volume of 500 mL. In each reactor, the anaerobic sludge was fixed at 6.73 g total volatile solids (VS) (125 mL) for the sole glycerol waste fermentation. Decanter cake at 2% w v1 total solid (10 g TS in 500 mL of water) was added in the combined co-feedstock fermentation with varying glycerol waste concentrations between 7.5 and 45 g L1. The initial pH was adjusted to 7.0 with 6 N NaOH or concentrated H3PO4. The system was flushed with nitrogen gas to generate anaerobic condition. Biogas fermentation was conducted at 37 C with rotary shaking at 150 rpm. All experiments were set up in triplicate. During the fermentation experiment, total gas volume and composition were periodically monitored by gas counters and gas chromatography, respectively. The liquid samples were analyzed for pH, COD, residual glycerol and volatile fatty acids (VFAs) every 6e12 h.
Decanter cake Decanter cake, a feedstock for the biogas production and a source of indigenous microbes, was collected from palm oil milling plant, Suksomboon palm oil industry in Chonburi, Thailand. The sample was stored at 4 C before use. The characteristic of palm oil decanter cake is as shown in Table 1.
Analytical methods Total solids (TS) and chemical oxygen demand (COD) were measured according to Standard Methods 2540 G and 5220 B,
Fig. 1 e Volumetric and cumulative CH4 under the sole glycerol waste fermentation (A and B) with varying glycerol concentration of 7.5 (), 15 (C), 30 (,), 45 (-) and 90 (D) g L¡1 and volume and cumulative H2 under glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (C and D) with varying glycerol concentration of 7.5 (), 15 (C), 30 (,), 45 (-) g L¡1. Each data point represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation. Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
4
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
respectively [23]. Glycerol was spectrophotometrically determined by chromotropic acid method (modified from Handel, 1961) [24]. The amount of generated biogas was recorded using liquid displacement gasometers. Biogas content (H2, CH4, and CO2) was measured periodically every 6e12 h using a gas chromatograph (Shimadzu GC-8A, Kyoto, Japan) equipped with a thermal conductivity detector (TCD) with a Unibeads C 60/80 column (GL Sciences, Inc., Tokyo, Japan). Helium was used as a carrier gas. The temperatures of the injection port and the detector were 150 and 80 C, respectively. VFAs were analyzed by gas chromatography (Shimadzu GC-7A system equipped with a flame ionization detector and a Stabilwax DA capillary column; Restek Corporation, PA, USA). The temperatures of the injection port and detector were maintained at 240 C [25].
Kinetics analysis The modified Gompertz equation (Eq. (1)) was used to fit cumulative hydrogen/methane production data obtained from each batch experiment [26]. This model has long been used for describing hydrogen, methane, or biogas production in batch fermentation experiments. Rm $e ðl tÞ þ 1 HðtÞ ¼ P$exp exp P
(1)
where H(t) is cumulative biogas production (mL) during the incubation time, t (h), P (Hmax) is the biogas production potential (mL), Rm is the maximum production rate (mL h1), l is the lag phase duration (h), and e is the exp(1) ¼ 2.718.
Biogas yield (Y) is calculated by dividing the hydrogen production potential at 72 h (combined seed reactor) and 60 h (indigenous microbe reactor) by the amount of TS and COD removed.
Results and discussion Biogas production Enhancement of the efficiency of biogas fermentation based on the biogas production potential (Hmax) and energy recovery was observed under the combined palm oil decanter cake with glycerol waste fermentation. Types of the inoculum seeds played the vital role on the biogas compositions. In the presence of anaerobic sludge (glycerol as the sole feedstock), CH4 was the main composition (24e44%) in the biogas, and H2 was not detectable. On the contrary, H2 was found in the range of 28e43% and CH4 was not detected, in the combined decanter cake with glycerol waste fermentation. Not only decanter cake was the co-feedstock, it was also used as inoculum seed in the fermentation. Lignocellulosic fraction (50% of cellulose and 31% of hemicellulose; Table 1) and hydrolytic bacteria from decanter cake make fermentation periods under the combined feedstock (96e108 h) longer than the sole feedstock (36e48 h) for all cases. Patterns of biogas production in the sole feedstock reached the peak after 12 h fermentation and then rapidly declined to zero while the peak of biogas production in the combined feedstock was
Fig. 2 e Biogas production potential (Hmax) and lag time (l) under the sole glycerol waste fermentation (A and C) and glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (B and D). Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation. Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
5
obtained after 36 h fermentation for most cases (except at 30 g L1 glycerol waste condition) and then it could be detected until 96 h fermentation (Fig. 1A and C). The cumulative CH4 and H2 fermentation profile data were S-shape trend and well fitted to the modified Gompertz equation (R2 > 0.99) for all experiments (Fig. 1B and D). The kinetics data from the equation, hence, was statistically significant. Volume of H2 throughout the fermentation and cumulative H2 production in the combined feedstock were obviously higher than those in the sole feedstock for all cases (Fig. 2A and B). Environmental conditions and types of existing active organism groups play the important role of the efficiency of bioproduct production in the overall fermentation. In general, microorganisms related to the anaerobic fermentation process consist of diverse bacterial groups such as hydrolytic bacteria, acidogens, acetogens, and methanogens. The hydrolytic bacteria degrade complex substrates or polymeric substrates to simple structures, which are further converted to various products such as volatile fatty acids (e.g. acetic, propanoic, lactic, and butylic acids) and alcohol [27]. The results of the biogas production under the combined feedstock with the presence of the indigenous microbes in the decanter cake indicated that these microbes contained no methanogen, but hydrolytic, acidogenic, and acetogenic bacteria. On the contrary, in the presence of the sludge seed under the sole feedstock, contain including methanogenic bacteria, hydrolytic, acidogenic, and acetogenic bacteria which worked syntrophically and completely converted the common intermediate in the CH4 production pathway such as short-chain fatty acid, H2 and CO2 to methane in the later step (Eq. (2)).
CO2 þ 4H2 / CH4 þ 2H2O
(2)
The enhancement of the biogas production potential and glycerol waste utilization suggested that the indigenous seed composed of hydrolytic, acidogenic, and acetogenic bacteria can degrade and uptake the decanter cake for their growth and further convert to the other by-products such as H2, VFAs. At the same time, they can stimulate glycerol utilization in the increase concentration of glycerol waste (15e45 g L1) conditions rather than that in the fermentation with anaerobic sludge composed of methanogens (Fig. 3). Longer lag times (10e18 h) were required for the H2 productions compared to those for the CH4 production (2e7 h) for all cases (Fig. 2C and D). CH4 production potential was maximized at low glycerol waste concentration of 7.5 g L1 and dropped as the concentration increased. The short fermentation period (12 h) and low biogas production potential (lower than 80 mL) suggested that only glycerol waste as sole feedstock in the biogas fermentation by the anaerobic sludge was not the suitable carbon source due to some components such as methanol, salts and long chain fatty acids. These affect directly the digestion and conversion of the glycerol waste to CH4 by syntrophic microbes in the reactors. Organic loading and cofeedstock also strongly affected the biogas production. Combined decanter cake and glycerol waste obviously enhance the efficiency of hydrolysis process resulting higher glycerol waste utilization. On the contrary, at the same organic loading of glycerol waste, although the anaerobic sludge was added
Fig. 3 e Glycerol utilization under the sole glycerol waste fermentation (A) and glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (B). Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation.
Fig. 4 e Total solid removal under glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation. Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
6
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
Waste reduction and energy recovery Under co-feedstock with 2% TS decanter cake fermentation, the maximum TS removal of 53.5 was observed at the 7.5 g L1 glycerol waste (Fig. 4). Trend of TS reduction was decreased at the high organic loading. Similarly, glycerol utilization was decreased at the high organic loading condition. High efficient waste utilization in the H2 or CH4 fermentation potentially benefits the management of the glycerol waste and palm oil decanter cake from palm oil industry. Energy recovery in the combined decanter cake fermentation as feedstock recovered energy significantly greater than that in the sole glycerol waste fermentation in all cases (Fig. 3A and B). Maximum energy recovery in the combined decanter cake fermentation as feedstock found at 15 g L1 glycerol waste is equivalent to 7.4 104 kWh (Fig. 5A and B), which is 10 times greater than that recovered in the sole glycerol waste fermentation. Waste reduction and energy recovery indicated that the combined decanter cake fermentation as feedstock is more beneficial than the sole glycerol waste fermentation.
Conclusions
Fig. 5 e Energy recovery under the sole glycerol waste fermentation (A) and glycerol waste combined with 2% w v¡1 TS of palm oil decanter cake fermentation (B). Histogram bar represents average value of triplicate experiments (n ¼ 3). Error bar represents standard deviation. into the fermentation system and methane production was observed, CH4 fermentation was significantly decreased at the increased organic loading (7.5e90 g L1 glycerol waste). Results of glycerol waste utilization indicated that high organic loading of glycerol waste had strongly resulted in reduction of the efficiency of hydrolytic and methanogen bacteria able to hydrolyze and further convert to CH4 as the end product. Previous study reported that long chain fatty acids (LCFAs) derived from glycerol waste in the fermentation had been covered the membrane of bacteria resulting in the process of food uptake into its cell [28]. However, to improve the efficiency of biogas production and waste utilization from glycerol waste and decanter cake, dominant microbial communities in each fermentation periods in the reactors and suitable conditions for their growth and activities have been further investigated.
The efficiency of glycerol utilization and biogas production were obtained under the combined decanter cake fermentation with glycerol waste. Types of fuel gases produced from the fermentation were governed by the types of inocula. Combined decanter cake fermentation yielded H2, but the sole glycerol waste fermentation yielded CH4. More significant performance in the fermentation with the combined decanter cake as co-feedstock regarding the biogas potential production, glycerol utilization and energy recovery were archived. The total energy recovery from the combined decanter fermentation was improved by 10 times compared to the sole glycerol waste fermentation. Decanter cake was not used only co-feedstock, but it was also used as the source of inocula for fermentation. The performance of H2 and CH4 production from the glycerol waste and decanter cake fermentation could be more effectively improved by using two-stage fermentation where H2 and CH4 productions are the first and second steps, respectively. Besides, investigation of microbial communities in the reactor is necessary for improvement of the overall biogas fermentation.
Acknowledgements The authors would like to express their gratitude to Agricultural Research Development Agency (Public Organization) for the financial support (Grant no. PRP5805020300).
references
[1] Jitrwung R, Yargeau V. Optimization of media composition for the production of biohydrogen from waste glycerol. Int J Hydrogen Energy 2011;36:9602e11.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 7 ) 1 e7
[2] Mangayil R, Karp M, Santala V. Bioconversion of crude glycerol from biodiesel production to hydrogen. Int J Hydrogen Energy 2012;37:12198e204. [3] Lo YC, Chen XJ, Huang CY, Yuan YJ, Chang JS. Dark fermentative hydrogen production with crude glycerol from biodiesel industry using indigenous hydrogen producing bacteria. Int J Hydrogen Energy 2013;38:15815e22. [4] Chookeaw T, O-Thong S, Prasertsan P. Biohydrogen production from crude glycerol by immobilized Klebsiella sp.Tr17 in a UASB reactor and bacterial quantification under non sterile conditions. Int J Hydrogen Energy 2014;39:9580e7. [5] Kivisto A, Santala V, Karp M. Non sterile process for biohydrogen and 1,3 propanediol production from raw glycerol. Int J Hydrogen Energy 2013;38:11749e55. [6] Varrone C, Giussani B, Izzo G, Massini G, Marone A, Signorini AA. Wang, Statistical optimization of biohydrogen and ethanol production from crude glycerol by microbial mixed culture. Int J Hydrogen Energy 2012;37:16479e88. [7] Ooi HS, Kumar SS. Co-composting for sustainable crude palm oil production in Malaysia. Jarutera bulletin. The Institute of Engineers Malaysia (IEM); 2008. p. 22e6. [8] Ng FY, Yew FKN, Basiron Y, Sundram K. A renewable future driven with Malaysia palm oil based technology. J Oil Palm Environ 2011;2:1e7. [9] Chavaparit O, Rulkens WH, Mol APJ, Khaodhair S. Options for environmental sustainability of the crude palm oil industry in Thailand through enhancement of industrial ecosystems. Environ Dev Sustain 2006;8:271e87. [10] Nafis M, Razak A, Ibrahim MF, Yee PL, Hassan MA, AbdAziz S. Utilization of oil palm decanter cake for cellulose and polyoses production. Biotechnol Bioprocess Eng 2012;17:547e55. [11] Zanirun Z, Bahrin E, Lai-Yee P, Hassan M, Abd-Aziz S. Effect of physical and chemical properties of oil palm empty fruit bunch, decanter cake and sago pith residue on cellulose production by Trichoderma asperellum UPM1 and Aspergillus fumigatus UPM2. Appl Biochem Biotechnol 2014;172:423e35. [12] Naporat P, Maneerat S, Saimmai A. Utilization of palm oil decanter cake as a novel substrate for biosurfactant production from a new and promising strain of Ochrobactrum anthropic 2/3. World J Microbiol Biotechnol 2014;30:865e77. [13] Loyarkat S, Cheirsilp B, Umsakul K. Decanter cake waste as a renewable substrate for biobutanol production by Clostridium beijerinckii. Process Biochem 2013;48:1933e41. [14] Maniam GP, Hindrywati N, Nurfitri I, Jose R, Ab Rahim MH, Dahalan FA. Decanter cake as a feedstock for biodiesel production: a first report. Energy Convers Manage 2013;76:527e32.
7
[15] Dewayanto N, Isha R, Nordin MR. Use of palm oil decanter cake as a new substrate for the production of bio-oil by vacuum pyrolysis. Energy Convers Manage 2014;86:226e32. [16] Nartker S, Ammerman M, Aurandt J, Stogsdil M, Hayden O, Antle C. Increasing biogas production from sewage sludge anaerobic co-digestion process by adding crude glycerol from biodiesel industry. Waste Manage 2014;34:2567e71. [17] Fountoulakis MS, Petousi I, Manios T. Co-digestion of sewage sludge with glycerol to boost biogas production. Waste Manage 2010;30:1849e53. [18] Nghiem LD, Nguyen TT, Manassa P, Fitzgerald SK, Dawson M, Vierboom S. Co-digestion of sewage sludge and crude glycerol for on-demand biogas production. Int Biodeter Biodegr 2014;95:160e6. [19] Castrillon L, Fernandez-Nava Y, Ormaechea P, Maranon E. Optimization of biogas production from cattle manure by pre-treatment with ultrasound and co-digestion with crude glycerin. Bioresour Technol 2011;102:7845e9. [20] Matin MA, Fernandez R, Serrano A, Siles JA. Semi-continuous anaerobic co-digestion of orange peel waste and residual glycerol derived from biodiesel manufacturing. Waste Manage 2013;33:1633e9. [21] Astals S, Nolla-Ardevol V, Mata-Alvarez J. Anaerobic codigestion of pig manure and crude glycerol at mesophilic conditions: biogas and digestate. Bioresour Technol 2012;110:63e70. [22] Kanchanasuta S, Pisutpaisal N. Waste utilization of palm oil decanter cake on biogas fermentation. Int J Hydrogen Energy 2016;41(35):15661e6. [23] APHA Standard. Methods for the examination of water and wastewater. 21st ed. Washington, DC, USA: American Public Health Association, American Water Works Association, Water Environment Federation; 2005. [24] Handel EV. Suggested modification of the micro determination of triglycerides. Clin Chem 1961;7(3):249e51. [25] Nathao C, Sirisukpoka U, Pisutpaisal N. Production of hydrogen and methane by one and two stage fermentation of food waste. Int J Hydrogen Energy 2013;38(35):15764e9. [26] Lay JJ, Lee YJ, Noike T. Feasibility of biological hydrogen production from organic fraction of municipal solid waste. Water Res 1999;33:2579e86. [27] Valdez-Vazquez I, Poggi-Varaldo HM. Hydrogen production by fermentative consortia. Renew Sust Energy Rev 2009;13:1000e13. [28] Viana MB, Freitas AV, Leitao RC, Pinto GAS, Santaella ST. Anaerobic digestion of crude glycerol: a review. Environ Technol Rev 2012;1:81e92.
Please cite this article in press as: Kanchanasuta S, Pisutpaisal N, Improvement of glycerol waste utilization by co-feedstock with palm oil decanter cake on biohydrogen fermentation, International Journal of Hydrogen Energy (2017), http://dx.doi.org/10.1016/ j.ijhydene.2016.12.134