Biohydrogen Production Using Anaerobic Fermentation at Various pH Values

2012 ◽  
Vol 512-515 ◽  
pp. 570-574
Author(s):  
Ying Chen ◽  
Kai Liu ◽  
Qing Gu ◽  
Min Liu
Keyword(s):  
Hydrogen Production ◽  
Propionic Acid ◽  
Acid Production ◽  
Production Efficiency ◽  
Ph Value ◽  
Anaerobic Fermentation ◽  
Removal Rate ◽  
Clean Energy ◽  
Brown Sugar ◽  
Ph Values

Hydrogen production with waste water can reduce pollution and produce clean energy at the same time. Hydrogen production is affected by many factors. In this experiment, with automatic fermentor, hydrogen and acid production, as well as organic removal rates from brown sugar wastewater by anaerobic cultures at various pH values, are studied. Results showed that the highest hydrogen production efficiency could be achieved when the pH value was maintained at 6.0. The maximum hydrogen production was 61.1mlH2/(g.VSS.d), and COD removal rate reached up to 33.8%, relatively higher than other pH values. The acid production was significantly improved under the condition of pH=4.5. However, the composition of VFAs was similar at the different pH values. The amount of acetic acid and butyric acid was account for about 90% of the final liquor products, and only a little propionic acid has being detected. The TOC removal rate in the system under different pH conditions are increase with pH value, but all below 10%. As the reaction proceeds, the propionic acid accumulation were also observed, higher pH could decrease the producing rate of it.

The Influence of Hydrogen Concentration in Sparging Gas on Hydrogen Production and Consumption via Anaerobic Fermentation

2017 ◽  
Vol 60 (3) ◽  
pp. 607-612
Author(s):  
Yuanyuan Wang ◽  
Leigang Li ◽  
Chao Wu ◽  
Zeyin Zhao ◽  
Liang Meng
Keyword(s):  
Hydrogen Production ◽  
Partial Pressure ◽  
Production Rate ◽  
Propionic Acid ◽  
Butyric Acid ◽  
Acid Production ◽  
Anaerobic Fermentation ◽  
Hydrogen Partial Pressure ◽  
Production And Consumption ◽  
Metabolic Products

Abstract. The main problem of hydrogen production via anaerobic fermentation is the very low production rate due to severe hydrogen-consuming reactions. Hydrogen partial pressure is a major factor influencing reactions of hydrogen production and consumption. To study the influence of H2 concentration on hydrogen production and consumption, H2 was mixed with N2 at initial concentrations of 20%, 40%, 60%, 80%, and 100% to sparge the fermentation broth. The results showed that H2 concentration had significant influence on these reactions, changing the pathway of glucose hydrolysis and acidification. With increasing H2 concentration in the sparging gas, the pathway of glucose acidogenesis hydrolysis transferred from mixed acid production (propionic acid and butyric acid) to propionic acid production. When the H2 concentration was 20% and the N2 concentration was 80%, the production rates of propionic acid and butyric acid were highest (0.76 and 0.41 mmol mmol-1 glucose consumed d-1, respectively) and accounted for 100% of total soluble metabolic products. When the H2 concentration in the sparging gas was more than 40%, the production rates of propionic acid and butyric acid decreased, and glucose degradation was inhibited. In addition, due to propionic acid type fermentation and high hydrogen partial pressure, acetogenesis was not feasible thermodynamically, resulting in a low production rate of H2 during the whole fermentation process. When the initial H2 concentration in the sparging gas was 40%, the production rate of H2 was highest, (0.42 mol mol-1 glucose consumed d-1). In addition, the theoretical production rate of H2 calculated from the production of soluble metabolic products was less than the actual value. This resulted from the co-existence of homoacetogenesis and acetic acid oxidation due to the bidirectionality of homoacetogens, establishing a new symbiotic relationship. Keywords: Anaerobic fermentation, Hydrogen consumption, Hydrogen partial pressure, Hydrogen production, Sparging.

The Comparison of Hydrogen Production Capacity with Two Substrates by Anaerobic Fermentation

2012 ◽  
Vol 512-515 ◽  
pp. 1529-1532
Author(s):  
Chen Guang Wang ◽  
Zhan Qing Wang ◽  
Su Ying Zhou ◽  
Xiao Mei Wang ◽  
Guo Cai Zhang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Propionic Acid ◽  
Anaerobic Fermentation ◽  
Production Capacity ◽  
Continuous Stirred Tank Reactor ◽  
Brown Sugar ◽  
Mixed Acid ◽  
Acid Type ◽  
Large Scope ◽  
Main Components

The experiment took a continuous stirred tank reactor as a reacting device, which based on molasses wastewater and brown sugar wastewater as the fermentation substrate. We studied the hydrogen production capacity with the two different substrates under the anaerobic fermentation. The results showed that the maximum hydrogen production yield were 0.99 L/d (molasses as the substrate) and 1.95L/d (brown sugar as the substrate), respectively, with the hydraulic retention time (HRT) of 6.2 h, temperature of (35 ± 1) °C and the reactor substrate concentration of 3000 mg COD/L. At the same time, the liquid end components were changed in a large scope. During the first 28 days, acetic acid and propionic acid were the main components, when molasses was replaced by brown sugar as the substrate, the percentages of propionic acid and butyrate acid decreased significantly from 25.7%, 15.4% to 11.8%, 9.47%, respectively. And the fermentation type was transformed from the mixed-acid-type fermentation to the more stable ethanol-type fermentation.

scholarly journals Evaluation of fermentation quality of brewers' grains ensiled in combination with malt sprouts and chemical conservation additive

2008 ◽  
Vol 56 (5) ◽  
pp. 227-234
Author(s):  
Ivo Vyskočil ◽  
Petr Doležal ◽  
Jan Doležal ◽  
Václav Pyrochta ◽  
Libor Kalhotka
Keyword(s):  
Propionic Acid ◽  
Acid Production ◽  
Fermentation Process ◽  
Ph Value ◽  
Lactic Acid Production ◽  
Acetic Acid Production ◽  
Chemical Additive ◽  
Fermentation Quality ◽  
Malt Sprout

The aim of the work was to evaluate the effect of addition of humidity absorbent (malt sprouts) and chemical conservation additive on fermentation process quality of brewer grains’ silage. Chemical conservation additive was based on formic acid, propionic acid, benzoic acid and ammonium formate content. In a model experiment the fresh brewer grains were used. A dry matter (DM) content of brewer grains was 187.4 g / kg. Six treatments with three repetitions per treatment were prepared. The treatments A1, A2 and A3 were not supplied by humidity absorbent. Treatment A1 was a control treatment without any additive. The treatments A2 and A3 were supplied by chemical conservation additive in a dose of 3 L per tonne and 6 L per tonne, respectively. The treatments B1, B2 and B3 were supplied by malt sprouts to reach DM content of conserved matter on level 320–350 g / kg. Moreover the treatments B2 and B3 were supplied by chemical additive with its dose 3 and 6 L per tonne. Model silages were evaluated after 8 months of conservation at average laboratory temperature 26–28  °C, from each treatment were the final laboratory samples taken and analyzed. During conservation of treatments B1, B2 and B3 were no drain recognized. From A1 treatment drained 1300 ml of waste fluid that is 145 L per tonne of conserved matter. That was significant (P < 0.01) the malt sprouts addition support the lactic acid production and eliminate acetic acid production. There was no propionic acid or butyric acid detected in silages with malt sprouts event in these silages were analyzed higher (P < 0.01) concentration of ammoniac. Chemical additive supplementation improved (P < 0.01) the pH value and water leach acidity. The results show the malt sprout addition eliminates waste fluid drain and improves fermentation process. The higher concentration of chemical additive (6 l / t) inhibited the fermentation process in our model experiment.

Organic Acid Production by Propionibacterium shermanii: Effect of pH, Temperature and Vitamin-Nitrogen Source

1997 ◽  
Vol 52 (3-4) ◽  
pp. 193-196 ◽  
Author(s):  
A. Quesada-Chanto ◽  
A . G. Schroeder ◽  
A. C. Schmid-Meyer ◽  
J. A. López ◽  
M. M. Silveira ◽  
...  
Keyword(s):  
Nitrogen Source ◽  
Propionic Acid ◽  
Yeast Extract ◽  
Acid Production ◽  
Ph Value ◽  
Corn Steep Liquor ◽  
Organic Acid Production ◽  
Propionibacterium Shermanii ◽  
Difco Yeast Extract ◽  
Steep Liquor

Abstract Production of propionic acid by Propionibacterium shermanii CDB 10014 was enhanced by a pH value of 6.5 and by temperatures in the range 35-37 °C. Depending on the type of yeast extract, succinic acid can be produced in higher proportions, with decreasing propionic acid yields. With respect to propionic acid production, Difco yeast extract has shown the best results when yeast extract preparations from other different suppliers were compared. To replace yeast extract by a cheaper vitamin-nitrogen source, corn-steep liquor was tested. A complete depletion of glucose was achieved, yielding a final propionic acid concentration of over 35 g/l. These results are even better than those obtained with Difco yeast extract and suggest the possibility of an economical process based on corn-steep liquor.

The Study on Anaerobic Fermentative Biological Hydrogen Production with Organic Wastes

2010 ◽  
Vol 113-116 ◽  
pp. 1476-1480
Author(s):  
Xiao Ye Liu ◽  
Yi Sun ◽  
Jian Yu Yang ◽  
Yong Feng Li
Keyword(s):  
Ph Value ◽  
Biogas Production ◽  
Removal Rate ◽  
Maximum Yield ◽  
Liquid Product ◽  
Oxygen Demand ◽  
H2 Production ◽  
Hydrogen Yield ◽  
Continuous Stirred Tank Reactor ◽  
Brown Sugar

This papre discussed the ability of H2-production and wastewater treatment, a continuous stirred tank reactor (CSTR)using a synthesized substrate with brown sugar wastewater was conducted to investigate the hydrogen yield, fermentation type of biohydrogen production, and the chemical oxygen demand (COD) removal rate, respectively. The results show that when the pH value was 4.0～4.5, OLR was 24.5kg/(m3•d), oxidation-reduction potential was -350～-450mv, temperature was 34.0°C～36.0°C, hydraulic retention time was 6h～8h, the maximum yield of biogas production reached 20L/d and the maximum content of hydrogen is 70%. Detection of the end liquid product, ethanol and acetic acid are main, they are 70% ~90% of the total liquid product, so that is called ethanol-type fermentation.

Preparation of Xonotlite Whiskers from Carbide Slag

2010 ◽  
Vol 434-435 ◽  
pp. 787-789
Author(s):  
Fei Liu ◽  
Ling Ke Zeng ◽  
Jian Xin Cao ◽  
Qian Lin ◽  
Jing Li
Keyword(s):  
Ph Value ◽  
Raw Materials ◽  
Removal Rate ◽  
Hydrothermal Conditions ◽  
Hydrothermal Route ◽  
Synthesis Conditions ◽  
Ph Values ◽  
Carbide Slag ◽  
Xrd Techniques ◽  
First Time

Carbide slag was used as raw materials for the first time to prepare xonontlite whiskers via a hydrothermal route without special instruments and synthesis conditions. And the effect of pH value of emulsion of carbide slag and hydrothermal conditions on removal rate of impurities, morphology and crystallinity of synthesized xonotlite whiskers were explored using ICP, SEM and XRD techniques. The results indicated that the carbide slag after purification could be used to prepare xonotlite whiskers, and different pH values of emulsion of carbide slag had great impact on the removal rate of impurities and morphology of xonotlite whiskers. Xonotlite whiskers with 20-40 μm in length and 100-500 nm in diameter were hydrothermally synthesized at 230 °C for 15 h with using silicic acid as kiesel material.

Anaerobic fermentation of organic solid wastes: volatile fatty acid production and separation

2014 ◽  
Vol 69 (10) ◽  
pp. 2132-2138 ◽  
Author(s):  
H. Yesil ◽  
A. E. Tugtas ◽  
A. Bayrakdar ◽  
B. Calli
Keyword(s):  
Fatty Acid ◽  
Volatile Fatty Acid ◽  
Production Efficiency ◽  
Anaerobic Fermentation ◽  
Fold Increase ◽  
Feed Solution ◽  
Caproic Acid ◽  
Fatty Acid Production ◽  
Ph Values ◽  
Recycle Rate

Anaerobic fermentation of organic municipal solid waste was investigated using a leach-bed reactor (LBR) to assess the volatile fatty acid (VFA) production efficiency. The leachate recycle rate in the LBR affected the VFA composition of the leachate. A six-fold increase in the recycle rate resulted in an increase of the acetic acid fraction of leachate from 24.7 to 43.0%. The separation of VFAs via leachate replacement resulted in higher total VFA production. VFA separation from synthetic VFA mix and leachate of a fermented organic waste was assessed via a counter-current flow polytetrafluoroethylene (PTFE) membrane contactor. Acetic and propionic acid permeation fluxes of 13.12 and 14.21 g/m2.h were obtained at low feed pH values when a synthetic VFA mix was used as a feed solution. The highest selectivity was obtained for caproic acid compared to that of other VFAs when synthetic VFA mix or leachate was used as a feed solution. High pH values and the presence of suspended solids in the leachate adversely affected the permeation rate.

Rapid Start-Up of Ethanol-Type Fermentation in Biological Hydrogen Production Reactor from Molasses Wastewater

2010 ◽  
Vol 113-116 ◽  
pp. 623-631
Author(s):  
Li Ran Yue ◽  
Yong Feng Li ◽  
Wei Han ◽  
Jing Li Xu ◽  
Hong Chen ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Ph Value ◽  
Anaerobic Fermentation ◽  
Oxygen Demand ◽  
Low Ph ◽  
Continuous Stirred Tank Reactor ◽  
Fermentation Products ◽  
Biological Hydrogen Production ◽  
Molasses Wastewater ◽  
Start Up

Research on anaerobic fermentation biohydrogen production from molasses wastewater in a continuous stirred-tank reactor (CSTR) was conducted. Emphasis was focused on the rapid start-up of ethanol-type fermentation in biological hydrogen production reactor. It was found that an initial biomass of 17.71 g/L, temperature of 35°C±1°C, hydraulic retention time (HRT) of 6 h, the reactor could start-up the ethanol-type fermentation at the range of 2000-4000 mg/L and at pH from 3.23 to 4.39 in 12 days with COD (chemical oxygen demand), respectively. The content of hydrogen was 45.77% in the fermentation biogas and the COD removal was 8%. As the hydrogen production system experienced low pH (3.23-4.0), the ethanol-produce bacterial can resume easier compared with other fermentation bacteria which are difficult to restore. In addition, when the pH value ranged from 4.0 to 4.63, the hydrogen production increased with the content of ethanol in liquid fermentation products increased. However, it was detected that the yield of hydrogen decreased with a high content of ethanol in the pH value ranged from 3.23 to 4.0, which demonstrated pH value played the most important role on hydrogen production within low pH.

Removal of Perfluorooctanoate from Water by Polyaluminium Chloride Coagulation

2012 ◽  
Vol 610-613 ◽  
pp. 1784-1788
Author(s):  
Liu Yang ◽  
Li Zhao ◽  
Peng Yu Liu ◽  
Zong Shuo Li ◽  
Qing Chang
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Mixing Time ◽  
Model Solution ◽  
Neutral Solution ◽  
Solution Ph ◽  
Polyaluminum Chloride ◽  
Ph Values ◽  
Coagulation Process ◽  
Slow Mixing

The removal of perfluorooctanoate （PFOA） and turbidity from model solution by coagulation was investigated. A polyaluminum chloride (PACl) was used as a coagulant in the coagulation process. The effects of coagulant dose, slow mixing time, solution pH value and initial turbidity on the removal of both PFOA and turbidity from water were studied. It was found that the removal rate of PFOA in water increase along with the increase in slow mixing time, initial turbidity and PAC dose. The removal rate of PFOA is more effective at the near neutral solution pH values and the high initial turbidity. The removal percents of PFOA exceed 80% at the optimal condition. The removal mechanism was speculated to be the electrostatic interaction and hydrophobic interaction in coagulation process.

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