scholarly journals Evaluation of biohydrogen production potential of sugarcane bagasse using activated sludge in a dark fermentation process

2016 ◽  
Author(s):  
◽  
Karen Reddy
Keyword(s):  
South Africa ◽  
Sewage Sludge ◽  
Hydrogen Production ◽  
Activated Sludge ◽  
Sugarcane Bagasse ◽  
Magnetite Nanoparticles ◽  
Fermentation Process ◽  
Dark Fermentation ◽  
Hydrogenase Gene ◽  
Pre Treatment

Anaerobic dark fermentation is an efficient biological process to produce hydrogen from waste material. In South Africa, this technology has not been explored adequately to extract energy from biological wastes. Within the KwaZulu Natal region of South Africa, the sugar industry is a prominent venture that produces mass quantities of sugarcane bagasse amongst other waste products. This by-product can be an ideal source of substrate for biohydrogen generation. In this study, sugarcane bagasse was used as the main substrate for biohydrogen production by anaerobic fermentation using sewage sludge as the inoculum. Different pre-treatment methods were employed to maximize the release of fermentable sugars from the lignocellulosic biomass. Among the different pre-treatment methods employed, the maximum sugar yield (294.4 mg/g) was achieved with 0.25% H2SO4 for 60 minutes at 121°C. Prior to inoculation, the sewage sludge was also subjected to thermal pre-treatment to eliminate methanogens. Thermal pre-treatment of inoculum sludge for 30 min was effective in eliminating methanogens. Fluorescence in situ hybridization was used to positively identify the hydrogen producing bacteria present before and after treatment. The pre-treated substrate and inoculum was integrated into a dark fermentation process to further optimize the effect of pH, substrate to biomass, iron and magnetite nanoparticles on hydrogen production. The maximum hydrogen production (1.2 mol/mol glucose) was achieved at a pH range of 5-6, a substrate to biomass ratio of 3.5, and iron and magnetite nanoparticle concentration of 200 mg/L. Microbial analysis using quantitative polymerase chain reaction has confirmed the dominance of Clostridium spp. in the reactor. The highest hydrogenase gene activity (number of copies of hydrogenase gene expression/ng DNA) was recorded in the reactor supplemented with magnetite nanoparticles with lowest being in the raw sludge. There was a direct positive correlation between the hydrogenase gene copy number and the hydrogen yield obtained at different reactor conditions. Scanning electron microscopy was a useful to visually analyse the interaction of microorganisms with activated sludge. This study highlights the significance of anaerobic microorganisms from waste sludge being able to utilize agricultural waste material to produce biohydrogen which could be further scaled up for continuous hydrogen production. In addition, statistical tools used to predict the possible sugar (Design of experiments) and hydrogen yields (Gompertz model) produced would be helpful in saving time during full-scale operation of biohydrogen producing reactors.

scholarly journals Enhancement of biohydrogen production from the aquatic weed Pistia stratiotes through a dark fermentation process

2019 ◽  
Author(s):  
◽  
Nonsikelelo Precios Mthethwa
Keyword(s):  
Hydrogen Production ◽  
Fermentation Process ◽  
Dark Fermentation ◽  
Biohydrogen Production ◽  
Pistia Stratiotes ◽  
Aquatic Weed ◽  
Operational Conditions ◽  
Bacillus Spp ◽  
Pre Treatment ◽  
Clostridium Spp

Aquatic weeds are well known for their fast growth rate and high carbohydrate content that can be easily hydrolysed into fermentable sugars. This study was aimed at the utilization of an indigenous aquatic weed, Pistia stratiotes for biohydrogen production through the dark fermentation process. Characterization of the biomass, effect of pre–treatment methods on biomass hydrolysis, effect of reactor operational conditions and type of inoculum on enhancing hydrogen production potential of P. stratiotes was assessed. Physical and chemical pre–treatments were employed on P. stratiotes biomass to increase digestibility and to achieve high conversion rates of fermentable sugars. The highest sugar yield of 139± 0.8 mg/g was obtained when the oven dried biomass was subjected to H2SO4 (2.5%) pre– treatment followed by autoclaving at 121°C for 30 min. Biohydrogen production under different operational conditions was thereafter optimized using One–factor–at–a–time (OFAT) batch experiments in 120 mL serum bottles. A maximum hydrogen yield (HY) of 2.46 ± 0.14 mol-H2/mol-glucose (3.51 ± 0.20 mg-H2/g-dry weight) and 2.75 ± 0.07 mL h-1 hydrogen production rate was observed under optimized conditions (pH 5.5, Temp 35°C, S/X: 1.0 g-COD/g-VSS and HRT 8 h). The organic mass balance (92 – 96%) and electron– equivalent balance (92 – 98%) further indicated the reliability of the obtained fermentation data. Assessment of microbial activity was achieved using molecular techniques such as quantitative polymerase chain reaction (qPCR) targeting both 16s rRNA (of Clostridium spp., Bacillus spp., and Enterobacter spp.) and the functional hydrogenase gene (hydA). The highest gene activity of hydrogenase was noted at pH of 5.5 with 2.53×104 copies/ng-DNA compared to low pH: 4.5 (6.95 × 103 copies/ng-DNA) and high pH: 8.5 (7.77×103 copies/ng- DNA). A similar trend was also observed for the species containing a highly active hydrogenase (i.e. Clostridium spp., Bacillus spp., and Enterobacter spp.). During the optimum reactor conditions, three hydrogen producing bacterial strains Bacillus cereus and Enterobacter cloacae were successfully isolated. These isolates were used as inoculums for the pure culture studies and achieved HYs of 2.2, 1.10 and 1.97 mol-H2/mol-glucose respectively under optimized fermentation conditions. However, the thermally treated mixed culture displayed a marginally higher HY (2.46 mol-H2/mol-glucose) compared to the pure culture used alone. Furthermore, the cost estimation indicated a potential and economically feasible for biotransformation of P. stratiotes to hydrogen energy. In conclusion, the results from this study has revealed the potential of employing P. stratiotes biomass for biohydrogen production. The results also indicated the importance of employing suitable pre–treatment methods, operating conditions as well as inoculum types for enhanced hydrogen production using P. stratiotes.

Enhanced bio-energy recovery in a two-stage hydrogen/methane fermentation process

2009 ◽  
Vol 59 (11) ◽  
pp. 2137-2143 ◽  
Author(s):  
M. J. Lee ◽  
J. H. Song ◽  
S. J. Hwang
Keyword(s):  
Hydrogen Production ◽  
Fermentation Process ◽  
Continuous Production ◽  
Strong Acid ◽  
Treatment Method ◽  
Engineering System ◽  
Production Rates ◽  
Two Stage ◽  
Methane Fermentation ◽  
Pre Treatment

A two-stage hydrogen/methane fermentation process has emerged as a feasible engineering system to recover bio-energy from wastewater. Hydrogen-producing bacteria (HPB) generate hydrogen from readily available carbohydrates, and organic acids produced during the hydrogen fermentation step can be degraded to generate methane in the following step. Three strong acids, HCl, H2SO4, and HNO3, were tested to determine the appropriate pre-treatment method for enhanced hydrogen production. The hydrogen production rates of 230, 290, and 20 L/kg-glucose/day was observed for the sludge treated with HCl, H2SO4, and HNO3, respectively, indicating that the acid pre-treatment using either HCl or H2SO4 resulted in a significant increase in hydrogen production. The fluorescent in situ hybridization method indicated that the acid pre-treatment selectively enriched HPB including Clostridium sp. of cluster I from inoculum sludge. After hydrogen fermentation was terminated, the sludge was introduced to a methane fermentation reactor. This experiment showed methane production rates of 100, 30, and 13 L/kg-glucose/day for the sludge pre-treated with HCl, H2SO4, and HNO3, respectively, implying that both sulfate and nitrate inhibited the activity of methane-producing bacteria. Consequently, the acid pre-treatment might be a feasible option to enhance biogas recovery in the two-stage fermentation process, and HCl was selected as the optimal strong acid for the enrichment of HPB and the continuous production of methane.

scholarly journals Thermophilic Dark Fermentation of Sewage Sludge for Biohydrogen Production - Influence of pH

2018 ◽  
Vol 20 (3) ◽  
pp. 564-571
Keyword(s):  
Sewage Sludge ◽  
Hydrogen Production ◽  
Waste Water Treatment ◽  
Dark Fermentation ◽  
Biohydrogen Production ◽  
Pure Hydrogen ◽  
Constant Ph ◽  
Initial Ph ◽  
Sludge Waste ◽  
Almost All

<p>This study investigates the usability of sewage sludge, waste from a waste water treatment facility, at the stable thermophilic temperature and different pH conditions in the biohydrogen production by dark fermentation. Without the addition of a pure hydrogen producer and nutrient source, the effect of a different constant pH in the range of pH 4-9 on biohydrogen production using sewage sludge was compared with that of a different initial pH. It was understood from the results that biohydrogen production varies according to the characterization of sewage sludge. In the experiments, the lag time was insignificant (~2h). The maximum hydrogen production was achieved at pH 5 within the first 24-30 hours of fermentation (92894 mL m-3 H2). Therefore, it was determined that the higher digestion efficiencies of the sewage sludge were obtained at pH 5. In general, with the increase in methanogens in the medium, the hydrogen producing ability and hydrogen content of the sewage sludge gradually decreased. Hydrogen production at almost all the pH values after the third day was less than 1000 mL m-3.</p>

Revealing the mechanisms of rhamnolipid enhanced hydrogen production from dark fermentation of waste activated sludge

2022 ◽  
Vol 806 ◽  
pp. 150347
Author(s):  
Xiaoming Li ◽  
Kexin Sui ◽  
Jiamin Zhang ◽  
Xuran Liu ◽  
Qiuxiang Xu ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Activated Sludge ◽  
Dark Fermentation ◽  
Waste Activated Sludge

Calcium peroxide promotes hydrogen production from dark fermentation of waste activated sludge

2019 ◽  
Vol 355 ◽  
pp. 22-32 ◽  
Author(s):  
Dongbo Wang ◽  
Dan Zhang ◽  
Qiuxiang Xu ◽  
Yiwen Liu ◽  
Qilin Wang ◽  
...  
Keyword(s):  
Hydrogen Production ◽  
Activated Sludge ◽  
Dark Fermentation ◽  
Waste Activated Sludge ◽  
Calcium Peroxide

scholarly journals The Influence of Low-Temperature Disintegration on the Co-Fermentation Process of Distillation Residue and Waste-Activated Sludge

Energies ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 482
Author(s):  
Anna Remiszewska-Skwarek ◽  
Ryszard Wierzchnicki ◽  
Otton K. Roubinek ◽  
Archana Kasinath ◽  
Alicja Jeżewska ◽  
...  
Keyword(s):  
Low Temperature ◽  
Activated Sludge ◽  
Fermentation Process ◽  
Biogas Production ◽  
Correlation Coefficients ◽  
Gompertz Model ◽  
Waste Activated Sludge ◽  
Distillation Residue ◽  
Accumulation Curves ◽  
Pre Treatment

Innovative low-temperature disintegration (process temperature 55 °C and oxygen concentration 0.2 mg/dm3) can be an economically rational technology to intensifying energy production from renewable sources. The proposed process can achieve a degree of disintegration—under optimal conditions—of about 50%, which is excellent when compared with other methods of feed pre-treatment. The low-temperature disintegration of distillation residue and waste-activated sludge before the co-fermentation process increased biogas production by 30% and methane production by 65% (over a 26 d duration). The obtained results confirm that the low-temperature disintegration method can be effectively used to pre-prepare this type of feed. At the same time, it was discovered that the Gompertz model can be used to mathematically describe the biogas accumulation curves in the methane co-fermentation processes of the tested feeds (the correlation coefficients were higher than 0.98).

scholarly journals Effect of Thermal Hydrolysis Pretreatment on Solubilization of Primary Sludge and Thickened Waste Activated Sludge (TWAS) During Dark Fermentation Process

2021 ◽  
Author(s):  
Alborz Mahmoudi
Keyword(s):  
Activated Sludge ◽  
Fermentation Process ◽  
Continuous Fermentation ◽  
Reduction Rate ◽  
Treatment Temperature ◽  
Waste Activated Sludge ◽  
Thermal Hydrolysis ◽  
Primary Sludge ◽  
Treated Sample ◽  
Pre Treatment

The objective of this research was to evaluate the effect of thermal hydrolysis pre-treatment on the solubilization of primary sludge (PS) and thickened waste activated sludge (TWAS) through the semi-continuous fermentation process under the mesophilic conditions. For this measure, the inoculum (anaerobic digestate), Primary Sludge (PS) and Thickened waste activated Sludge (TWAS) was subjected to the pre-treatment condition. The pre-treatment temperature ranged from 20°C to170°C. Then both raw and pre-treated sample was introduced the semi-continuous reactors for the fermentation process. The degree of solubilization was achieved 18% for raw (unpretreated sample) and 38% for the pre-treated sample. Moreover, the volatile suspended solids (VSS) reduction rate for the raw and pre-treated sample was 24% and 50% respectively. Additionally, the soluble COD production yield for the raw and pre-treated sample was obtained 247 mg COD/g VSS and 544 mg COD/g VSS correspondingly. Keywords: Fermentation process, Anaerobic digestion, Thermal hydrolysis pretreatment.

Sign in / Sign up

Export Citation Format

Share Document