scholarly journals Διεργασίες ενεργειακής αξιοποίησης γλυκερόλης με παραγωγή βιοαερίου, βιοϋδρογόνου ή/και ηλεκτρικού ρεύματος με μικροβιακή κυψελίδα καυσίμου

2011 ◽  
Author(s):  
Θεόφιλος Βλάσσης
Keyword(s):  
Anaerobic Digestion ◽  
Hydrogen Production ◽  
Electric Current ◽  
Production Rate ◽  
Methane Production ◽  
Continuous Production ◽  
Maximum Yield ◽  
Glycerol Concentration ◽  
Production Of Hydrogen ◽  
Methane Production Rate

This study focused on the valorization of glycerol which is an important by-product of the biodiesel industry corresponding to 10 % of the produced biodiesel amount. This fact contributed to the increase of the global production of biodiesel, to a point at which the industries which traditionally consumed glycerol could not absorb. This situation should be overcome through new outlets on glycerol exploitation. Usually, glycerol is treated by chemical processes in order to form new chemical compounds.On the other side, biochemical processes like anaerobic digestion and fermentation or the technology of microbial fuel cells could potentially transform glycerol into methane, hydrogen and electric current respectively. These processes, which are the subject of this Ph.D, are preferable to their chemical counterparts due to the low energy demand and reduced environmental pollution.The anaerobic digestion process was conducted in a conventional CSTR reactor and in a high rate reactor, the PABR. The experiments dealt with the effect of glycerol concentration on the methane production rate. The obtained results showed that the CSTR could not withstand organic loadings above 0.25 g COD/L/d, however PABR operated at organic loading 10 times higher than CSTR such as 3 g COD/L/d and resulted to a methane production rate of 0.982 ± 0.089 L/L/d. A model was developed for both the CSTR and the PABR digesters. Fermentative hydrogen production was conducted successfully in batch reactors. The effect of the initial glycerol concentration and initial pH on hydrogen production was studied. A maximum yield, 27.3 mL H2/ g COD glycerol, was obtained when glycerol concentration was 8.3 g COD/L and the pH 6.5. Moreover, the fermentation of glycerol took place in a CSTR in order to investigate the continuous production of hydrogen. Hydrogen production was unstable, possibly due to the washout of proper biomass from the reactor.For electricity generation from glycerol, an H-type microbial fuel cell was used in batch mode. The effect of the initial glycerol on the electric current was studied. A maximum Coulombic efficiency (CE) 34.09% was obtained at a glycerol concentration of 3.2 g COD/L. A further increase of glycerol drove to a drop of the CE. Probably, this happened since the electrochemical microorganisms were inhibited by the high glycerol concentration.

Effects of thermochemical pretreatment on the anaerobic digestion of waste activated sludge

1997 ◽  
Vol 35 (8) ◽  
pp. 209-215 ◽  
Author(s):  
Shuzo Tanaka ◽  
Toshio Kobayashi ◽  
Ken-ichi Kamiyama ◽  
Ma. Lolita N. Signey Bildan
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Production Rate ◽  
Methane Production ◽  
Waste Activated Sludge ◽  
Batch Experiments ◽  
Industrial Wastewaters ◽  
Thermochemical Pretreatment ◽  
Chemical Heating ◽  
Methane Production Rate

Effects of pretreatment on the anaerobic digestion of waste activated sludge (WAS) were investigated in terms of VSS solubilization and methane production by batch experiments. The methods of pretreatment studied are NaOH addition (chemical), heating (thermal) and heating with NaOH addition (thermochemical) to the domestic WAS and to the combined WAS from domestic, commercial and industrial wastewaters. The thermochemical pretreatment gave the best result among three methods in the combined WAS, i.e., the VSS was solubilized by 40-50% and the methane production increased by more than 200% over the control when the WAS was heated at 130°C for 5 minutes with the dose 0.3 g NaOH/g VSS. In the domestic WAS, the VSS solubilization rate was 70-80% but the increase of the methane production was about 30% after thermochemically pretreated. The domestic WAS consists of 41% protein, 25% lipid and 14% carbohydrate on COD basis, and the solubilization rate of protein, which is the largest constituent of the WAS, was 63% in the thermochemical pretreatment. Although the effect of the thermochemical pretreatment on the methane production was higher to the combined WAS than to the domestic WAS, the methane production rate was 21.9 ml CH4/g VSSWAS·day in the domestic WAS and 12.8 ml CH4/g VSSWAS·day in the combined WAS.

scholarly journals Treatment of sago mill effluent for methane production using anaerobic sequencing batch reactor (ASBR)

2018 ◽  
Vol 2 (1) ◽  
pp. 18-22
Author(s):  
Rafiqqah Mohamad Sabri ◽  
Keyword(s):  
Anaerobic Digestion ◽  
Production Rate ◽  
Methane Production ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Cod Removal ◽  
Production Yield ◽  
Anaerobic Sequencing Batch Reactor ◽  
Methane Production Rate

In this research, sago mill effluent was treated using anaerobic sequencing batch reactor (ASBR). Seven HRT from 10 to 1.5 days were tested to evaluate the methane production from sago mill effluent. The findings revealed the highest methane production rate was found at 1.288 L CH4/L reactor. d under HRT of 2 days The results showed that COD removals decreased from 70% to 47% as HRT was reduced from 10 to 2 days. The HRT 1.5 days was found critical for the studied system, which leads to decreased in methane production, yield and COD removal. Overall, ASBR was capable to treat sago mill effluent in producing methane by means of anaerobic digestion.

scholarly journals Coproduction of hydrogen and methane in a CSTR-IC two-stage anaerobic digestion system from molasses wastewater

2019 ◽  
Vol 79 (2) ◽  
pp. 270-277 ◽  
Author(s):  
Qiaoyan Li ◽  
Yongfeng Li
Keyword(s):  
Hydrogen Production ◽  
Production Rate ◽  
Methane Production ◽  
Oxygen Demand ◽  
Organic Loading Rate ◽  
Continuous Stirred Tank Reactor ◽  
Two Stage ◽  
Molasses Wastewater ◽  
Methane Production Rate ◽  
Stage Process

Abstract A continuous hydrogen and methane production system in a two-stage process has been investigated to increase energy recovery rate from molasses wastewater in this study. This system consisted of a continuous stirred-tank reactor for hydrogen production and an internal circulation (IC) reactor for methane production, and was studied under the influent organic loading rate (OLR) of 18, 24, 30 and 36kg COD/(m3·d) (COD: chemical oxygen demand). The maximum volumetric hydrogen production rate of 2.41 L/(L·d) was obtained at the OLR of 30kg COD/(m3·d) with a hydrogen content of 42%, and the maximum volumetric methane production rate of 2.4 L/(L·d) with a methane content of 74.45% was obtained at the OLR of 36kg COD/(m3·d) using the effluents of hydrogen fermentation as substrate. The maximum of 71.06% of the molasses wastewater energy was converted to biogas (hydrogen and methane) at the OLR of 30kg COD/(m3·d).

Co-production of hydrogen and methane from herbal medicine wastewater by a combined UASB system with immobilized sludge (H2 production) and UASB system with suspended sludge (CH4 production)

2015 ◽  
Vol 73 (1) ◽  
pp. 130-136 ◽  
Author(s):  
Caiyu Sun ◽  
Ping Hao ◽  
Bida Qin ◽  
Bing Wang ◽  
Xueying Di ◽  
...  
Keyword(s):  
Herbal Medicine ◽  
Hydrogen Production ◽  
Production Rate ◽  
Methane Production ◽  
Oxygen Demand ◽  
H2 Production ◽  
Organic Loading Rate ◽  
Anaerobic Sludge ◽  
Organic Loading ◽  
Production Of Hydrogen

An upflow anaerobic sludge bed (UASB) system with sludge immobilized on granular activated carbon was developed for fermentative hydrogen production continuously from herbal medicine wastewater at various organic loading rates (8–40 g chemical oxygen demand (COD) L−1 d−1). The maximum hydrogen production rate reached 10.0 (±0.17) mmol L−1 hr−1 at organic loading rate of 24 g COD L−1 d−1, which was 19.9% higher than that of suspended sludge system. The effluents of hydrogen fermentation were used for continuous methane production in the subsequent UASB system. At hydraulic retention time of 15 h, the maximum methane production rate of 5.49 (±0.03) mmol L−1 hr−1 was obtained. The total energy recovery rate by co-production of hydrogen and methane was evaluated to be 7.26 kJ L−1 hr−1.

scholarly journals Effect Of Co-Digestion Of Source Separated Organics And Manure On Methane Production

2021 ◽  
Author(s):  
Devarshi Sevak ◽  
Elsayed Elbeshbishy
Keyword(s):  
Anaerobic Digestion ◽  
Production Rate ◽  
Methane Production ◽  
Gas Production ◽  
Mixture Ratio ◽  
Biomethane Potential ◽  
Methane Production Rate ◽  
Biomethane Production ◽  
Mesophilic Condition

Anaerobic co-digestion (AcoD) is more advantageous than conventional mono-digestion, because of higher gas production rate. This study was aimed to study the effect of mixture ratio in codigestion of manure and source separated organics (SSO) in mesophilic condition. Manure and SSO at different mixture ratios of 9:1, 7:3, 5:5, 3:7, and 1:9 on a volumetric basis were used to determine the effect of the mixture ratios on methane production in biomethane potential assay (BMP). Results showed that co-digestion of SSO and manure at the ratio of 1:9 (V/V) resulted in the highest biomethane production rate of 46 mL CH4 /day. In comparison, the maximum methane production rate for anaerobic digestion of manure alone was 43 mL CH4 /day. When manure is mixed with SSO at a ratio of 5:5, about 15% higher cumulative methane production has been achieved. This research also verified the advantages of co-digestion over mono-digestion. Keywords: Anaerobic Digestion, Co-digestion, Source Separated Organics (SSO), Manure

scholarly journals Assessment of Single- vs. Two-Stage Process for the Anaerobic Digestion of Liquid Cow Manure and Cheese Whey

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5423
Author(s):  
Margarita Andreas Dareioti ◽  
Aikaterini Ioannis Vavouraki ◽  
Konstantina Tsigkou ◽  
Michael Kornaros
Keyword(s):  
Anaerobic Digestion ◽  
Production Rate ◽  
Methane Production ◽  
Cheese Whey ◽  
Biogas Production ◽  
Single Stage ◽  
Cow Manure ◽  
Two Stage ◽  
Methane Production Rate ◽  
Stage Process

The growing interest in processes that involve biomass conversion to renewable energy, such as anaerobic digestion, has stimulated research in this field in order to assess the optimum conditions for biogas production from abundant feedstocks, like agro-industrial wastes. Anaerobic digestion is an attractive process for the decomposition of organic wastes via a complex microbial consortium and subsequent conversion of metabolic intermediates to hydrogen and methane. The present study focused on the exploitation of liquid cow manure (LCM) and cheese whey (CW) as noneasily and easily biodegradable sources, respectively, using continuous stirred-tank reactors for biogas production, and a comparison was presented between single- and two-stage anaerobic digestion systems. No significant differences were found concerning LCM treatment, in a two-stage system compared to a single one, concluding that LCM can be treated by implementing a single-stage process, as a recalcitrant substrate, with the greatest methane production rate of 0.67 L CH4/(LR·d) at an HRT of 16 d. On the other hand, using the easily biodegradable CW as a monosubstrate, the two-stage process was considered a better treatment system compared to a single one. During the single-stage process, operational problems were observed due to the limited buffering capacity of CW. However, the two-stage anaerobic digestion of CW produced a stable methane production rate of 0.68 L CH4/(LR·d) or 13.7 L CH4/Lfeed, while the total COD was removed by 76%.

scholarly journals Enhanced hydrogen production of Rhodobacter sphaeroides promoted by extracellular H+ of Halobacterium salinarum

2021 ◽  
Vol 71 (1) ◽  
Author(s):  
Jiang-Yu Ye ◽  
Yue Pan ◽  
Yong Wang ◽  
Yi-Chao Wang
Keyword(s):  
Hydrogen Production ◽  
Production Rate ◽  
Rhodobacter Sphaeroides ◽  
Coupled System ◽  
Purple Membrane ◽  
Halobacterium Salinarum ◽  
Control Group ◽  
Hydrogen Production Rate ◽  
Production Of Hydrogen ◽  
The Impact

Abstract Purpose This study utilized the principle that the bacteriorhodopsin (BR) produced by Halobacterium salinarum could increase the hydrogen production of Rhodobacter sphaeroides. H. salinarum are co-cultured with R. sphaeroides to determine the impact of purple membrane fragments (PM) on R. sphaeroides and improve its hydrogen production capacity. Methods In this study, low-salinity in 14 % NaCl domesticates H salinarum. Then, 0–160 nmol of different concentration gradient groups of bacteriorhodopsin (BR) and R. sphaeroides was co-cultivated, and the hydrogen production and pH are measured; then, R. sphaeroides and immobilized BR of different concentrations are used to produce hydrogen to detect the amount of hydrogen. Two-chamber microbial hydrogen production system with proton exchange membrane-assisted proton flow was established, and the system was operated. As additional electricity added under 0.3 V, the hydrogen production rate increased with voltages in the coupled system. Results H salinarum can still grow well after low salt in 14% NaCl domestication. When the BR concentration is 80 nmol, the highest hydrogen production reached 217 mL per hour. Both immobilized PC (packed cells) and immobilized PM (purple membrane) of H. salinarum could promote hydrogen production of R. sphaeroides to some extent. The highest production of hydrogen was obtained by the coupled system with 40 nmol BR of immobilized PC, which increased from 127 to 232 mL, and the maximum H2 production rate was 18.2 mL−1 h−1 L culture. In the 192 h experiment time, when the potential is 0.3 V, the hydrogen production amount can reach 920 mL, which is 50.3% higher than the control group. Conclusions The stability of the system greatly improved after PC was immobilized, and the time for hydrogen production of R. sphaeroides significantly extended on same condition. As additional electricity added under 0.3 V, the hydrogen production rate increased with voltages in the coupled system. These results are helpful to build a hydrogen production-coupled system by nitrogenase of R. sphaeroides and proton pump of H. salinarum. Graphical abstract

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