Bio-hydrogen production from wastewater

2004 ◽  
Vol 4 (1) ◽  
pp. 77-85 ◽  
Author(s):  
H.H.P. Fang ◽  
H. Liu ◽  
T. Zhang
Keyword(s):  
Hydrogen Production ◽  
Microbial Communities ◽  
Organic Pollutants ◽  
Production Efficiency ◽  
Dark Fermentation ◽  
Controlling Factors ◽  
Biomass Density ◽  
Fermentation Conditions ◽  
Step Process ◽  
Sludge Granulation

The technically feasibility of converting organic pollutants in wastewater into hydrogen by a continuous two-step process was demonstrated. Two carbohydrates, i.e. glucose and sucrose, in wastewater were respectively acidified by dark fermentation at pH 5.5 with 6–6.6 hours of hydraulic retention in a 3-l fermentor, producing an effluent containing mostly acetate and butyrate, and a methane-free biogas comprising mostly hydrogen. The acidified effluent was then further treated by photo fermentation for hydrogen production. The overall yield based on the substrate consumed was 31–32%, i.e. 17–18% for dark fermentation and 14% for photo fermentation. It was found that under certain dark fermentation conditions, hydrogen-producing sludge was agglutinated into granules, resulting in a higher biomass density and increased volumetric hydrogen production efficiency. DNA-based analysis of microbial communities revealed that the respective predominant bacteria were Clostridium in dark fermentation and Rhodobacter in photo fermentation. Further investigations are warranted, particularly, in areas such as improving reactor design, treating protein and lipid rich wastewaters, and studying sludge granulation mechanisms and controlling factors.

scholarly journals Optimization of Biohydrogen Production with Biomechatronics

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shao-Yi Hsia ◽  
Yu-Tuan Chou
Keyword(s):  
Hydrogen Production ◽  
Taguchi Method ◽  
Alternative Energy ◽  
Production Efficiency ◽  
Biological Effects ◽  
Dark Fermentation ◽  
Operating Conditions ◽  
Biohydrogen Production ◽  
Process Conditions ◽  
Ultrasonic Frequency

Massive utilization of petroleum and natural gas caused fossil fuel shortages. Consequently, a large amount of carbon dioxide and other pollutants are produced and induced environmental impact. Hydrogen is considered a clean and alternative energy source. It contains relatively high amount of energy compared with other fuels and by-product is water. In this study, the combination of ultrasonic mechanical and biological effects is utilized to increase biohydrogen production from dark fermentation bacteria. The hydrogen production is affected by many process conditions. For obtaining the optimal result, experimental design is planned using the Taguchi Method. Four controlling factors, the ultrasonic frequency, energy, exposure time, and starch concentration, are considered to calculate the highest hydrogen production by the Taguchi Method. Under the best operating conditions, the biohydrogen production efficiency of dark fermentation increases by 19.11%. Results have shown that the combination of ultrasound and biological reactors for dark fermentation hydrogen production outperforms the traditional biohydrogen production method. The ultrasonic mechanical effects in this research always own different significances on biohydrogen production.

scholarly journals Dynamics and Complexity of Dark Fermentation Microbial Communities Producing Hydrogen From Sugar Beet Molasses in Continuously Operating Packed Bed Reactors

2021 ◽  
Vol 11 ◽  
Author(s):  
Anna Detman ◽  
Daniel Laubitz ◽  
Aleksandra Chojnacka ◽  
Ewa Wiktorowska-Sowa ◽  
Jan Piotrowski ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Hydrogen Production ◽  
Sugar Beet ◽  
Microbial Communities ◽  
Packed Bed ◽  
Dark Fermentation ◽  
Shotgun Metagenomics ◽  
Packed Bed Reactors ◽  
Beet Molasses

This study describes the dynamics and complexity of microbial communities producing hydrogen-rich fermentation gas from sugar-beet molasses in five packed-bed reactors (PBRs). The bioreactors constitute a part of a system producing hydrogen from the by-products of the sugar-beet industry that has been operating continuously in one of the Polish sugar factories. PBRs with different working volumes, packing materials, construction and inocula were tested. This study focused on analysis (based on 16S rRNA profiling and shotgun metagenomics sequencing) of the microbial communities selected in the PBRs under the conditions of high (>100 cm3/g COD of molasses) and low (<50 cm3/g COD of molasses) efficiencies of hydrogen production. The stability and efficiency of the hydrogen production are determined by the composition of dark fermentation microbial communities. The most striking difference between the tested samples is the ratio of hydrogen producers to lactic acid bacteria. The highest efficiency of hydrogen production (130–160 cm3/g COD of molasses) was achieved at the ratios of HPB to LAB ≈ 4:2.5 or 2.5:1 as determined by 16S rRNA sequencing or shotgun metagenomics sequencing, respectively. The most abundant Clostridium species were C. pasteurianum and C. tyrobutyricum. A multiple predominance of LAB over HPB (3:1–4:1) or clostridia over LAB (5:1–60:1) results in decreased hydrogen production. Inhibition of hydrogen production was illustrated by overproduction of short chain fatty acids and ethanol. Furthermore, concentration of ethanol might be a relevant marker or factor promoting a metabolic shift in the DF bioreactors processing carbohydrates from hydrogen-yielding toward lactic acid fermentation or solventogenic pathways. The novelty of this study is identifying a community balance between hydrogen producers and lactic acid bacteria for stable hydrogen producing systems. The balance stems from long-term selection of hydrogen-producing microbial community, operating conditions such as bioreactor construction, packing material, hydraulic retention time and substrate concentration. This finding is confirmed by additional analysis of the proportions between HPB and LAB in dark fermentation bioreactors from other studies. The results contribute to the advance of knowledge in the area of relationships and nutritional interactions especially the cross-feeding of lactate between bacteria in dark fermentation microbial communities.

Effects of heat treatment on microbial communities of granular sludge for biological hydrogen production

2012 ◽  
Vol 66 (7) ◽  
pp. 1483-1490 ◽  
Author(s):  
Luca Alibardi ◽  
Lorenzo Favaro ◽  
Maria Cristina Lavagnolo ◽  
Marina Basaglia ◽  
Sergio Casella
Keyword(s):  
Heat Treatment ◽  
Hydrogen Production ◽  
Microbial Communities ◽  
Granular Sludge ◽  
Dark Fermentation ◽  
Anaerobic Granular Sludge ◽  
Batch Test ◽  
Ph Values ◽  
Pre Treatment ◽  
Selection Of

Dark fermentation shares many features with anaerobic digestion with the exception that to maximize hydrogen production, methanogens and hydrogen-consuming bacteria should be inhibited. Heat treatment is widely applied as an inoculum pre-treatment due to its effectiveness in inhibiting methanogenic microflora but it may not exclusively select for hydrogen-producing bacteria. This work evaluated the effects of heat treatment on microbial viability and structure of anaerobic granular sludge. Heat treatment was carried out on granular sludge at 100 °C with four residence times (0.5, 1, 2 and 4 h). Hydrogen production of treated sludges was studied from glucose by means of batch test at different pH values. Results indicated that each heat treatment strongly influenced the granular sludge resulting in microbial communities having different hydrogen productions. The highest hydrogen yields (2.14 moles of hydrogen per mole of glucose) were obtained at pH 5.5 using the sludge treated for 4 h characterized by the lowest CFU concentration (2.3 × 103CFU/g sludge). This study demonstrated that heat treatment should be carefully defined according to the structure of the sludge microbial community, allowing the selection of highly efficient hydrogen-producing microbes.

scholarly journals Zeolite addition to improve biohydrogen production from dark fermentation of C5/C6-sugars and Sargassum sp. biomass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. M. Silva ◽  
A. A. Abreu ◽  
A. F. Salvador ◽  
M. M. Alves ◽  
I. C. Neves ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Anaerobic Bacteria ◽  
Dark Fermentation ◽  
Inorganic Materials ◽  
Biohydrogen Production ◽  
High Rate ◽  
Continuous Reactor ◽  
Organic Loading Rate ◽  
Fermentation Products ◽  
Zeolite Type

AbstractThermophilic biohydrogen production by dark fermentation from a mixture (1:1) of C5 (arabinose) and C6 (glucose) sugars, present in lignocellulosic hydrolysates, and from Sargassum sp. biomass, is studied in this work in batch assays and also in a continuous reactor experiment. Pursuing the interest of studying interactions between inorganic materials (adsorbents, conductive and others) and anaerobic bacteria, the biological processes were amended with variable amounts of a zeolite type-13X in the range of zeolite/inoculum (in VS) ratios (Z/I) of 0.065–0.26 g g−1. In the batch assays, the presence of the zeolite was beneficial to increase the hydrogen titer by 15–21% with C5 and C6-sugars as compared to the control, and an increase of 27% was observed in the batch fermentation of Sargassum sp. Hydrogen yields also increased by 10–26% with sugars in the presence of the zeolite. The rate of hydrogen production increased linearly with the Z/I ratios in the experiments with C5 and C6-sugars. In the batch assay with Sargassum sp., there was an optimum value of Z/I of 0.13 g g−1 where the H2 production rate observed was the highest, although all values were in a narrow range between 3.21 and 4.19 mmol L−1 day−1. The positive effect of the zeolite was also observed in a continuous high-rate reactor fed with C5 and C6-sugars. The increase of the organic loading rate (OLR) from 8.8 to 17.6 kg m−3 day−1 of COD led to lower hydrogen production rates but, upon zeolite addition (0.26 g g−1 VS inoculum), the hydrogen production increased significantly from 143 to 413 mL L−1 day−1. Interestingly, the presence of zeolite in the continuous operation had a remarkable impact in the microbial community and in the profile of fermentation products. The effect of zeolite could be related to several properties, including the porous structure and the associated surface area available for bacterial adhesion, potential release of trace elements, ion-exchanger capacity or ability to adsorb different compounds (i.e. protons). The observations opens novel perspectives and will stimulate further research not only in biohydrogen production, but broadly in the field of interactions between bacteria and inorganic materials.

Controlling factors for the distribution of typical organic pollutants in the surface sediment of a macrotidal bay

2020 ◽  
Vol 27 (22) ◽  
pp. 28276-28287
Author(s):  
Ning Wang ◽  
Ya Ping Wang ◽  
Xiaoyong Duan ◽  
Jianqiang Wang ◽  
Yongqing Xie ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Surface Sediment ◽  
Controlling Factors

Physical-Chemical and Thermodynamic Analyses of Ethanol Steam Reforming for Hydrogen Production

2006 ◽  
Vol 3 (3) ◽  
pp. 346-350 ◽  
Author(s):  
Antonio Carlos Caetano de Souza ◽  
José Luz-Silveira ◽  
Maria Isabel Sosa
Keyword(s):  
Hydrogen Production ◽  
Steam Reforming ◽  
Production Efficiency ◽  
Physical Chemical ◽  
Steam Reforming Of Ethanol ◽  
Thermodynamic Conditions ◽  
High Production ◽  
Exergetic Analysis ◽  
Global Reaction ◽  
Technical Features

Steam reforming is the most usual method of hydrogen production due to its high production efficiency and technological maturity. The use of ethanol for this purpose is an interesting option because it is a renewable and environmentally friendly fuel. The objective of this article is to present the physical-chemical, thermodynamic, and exergetic analysis of a steam reformer of ethanol, in order to produce 0.7Nm3∕h of hydrogen as feedstock of a 1kW PEMFC. The global reaction of ethanol is considered. Superheated ethanol reacts with steam at high temperatures producing hydrogen and carbon dioxide, depending strongly on the thermodynamic conditions of reforming, as well as on the technical features of the reformer system and catalysts. The thermodynamic analysis shows the feasibility of this reaction in temperatures about 206°C. Below this temperature, the reaction trends to the reactants. The advance degree increases with temperature and decreases with pressure. Optimal temperatures range between 600 and 700°C. However, when the temperature attains 700°C, the reaction stability occurs, that is, the hydrogen production attains the limit. For temperatures above 700°C, the heat use is very high, involving high costs of production due to the higher volume of fuel or electricity used. The optimal pressure is 1atm., e.g., at atmospheric pressure. The exergetic analysis shows that the lower irreversibility is attained for lower pressures. However, the temperature changes do not affect significantly the irreversibilities. This analysis shows that the best thermodynamic conditions for steam reforming of ethanol are the same conditions suggested in the physical-chemical analysis.

Efficient hydrogen gas production from cassava and food waste by a two-step process of dark fermentation and photo-fermentation

2009 ◽  
Vol 33 (10) ◽  
pp. 1458-1463 ◽  
Author(s):  
Wenming Zong ◽  
Ruisong Yu ◽  
Peng Zhang ◽  
Meizhen Fan ◽  
Zhihua Zhou
Keyword(s):  
Food Waste ◽  
Dark Fermentation ◽  
Gas Production ◽  
Hydrogen Gas ◽  
Step Process
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