A simplified model to simulate bioaugmented anaerobic digestion of lignocellulosic biomass: Biogas production efficiency related to microbiological data

2019 ◽  
Vol 691 ◽  
pp. 885-895 ◽  
Author(s):  
Alberto Ferraro ◽  
Giulia Massini ◽  
Valentina Mazzurco Miritana ◽  
Antonella Signorini ◽  
Marco Race ◽  
...  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Karol Postawa ◽  
Jerzy Szczygieł ◽  
Marek Kułażyński

Abstract Background Increasing the efficiency of the biogas production process is possible by modifying the technological installations of the biogas plant. In this study, specific solutions based on a mathematical model that lead to favorable results were proposed. Three configurations were considered: classical anaerobic digestion (AD) and its two modifications, two-phase AD (TPAD) and autogenerative high-pressure digestion (AHPD). The model has been validated based on measurements from a biogas plant located in Poland. Afterward, the TPAD and AHPD concepts were numerically tested for the same volume and feeding conditions. Results The TPAD system increased the overall biogas production from 9.06 to 9.59%, depending on the feedstock composition, while the content of methane was slightly lower in the whole production chain. On the other hand, the AHPD provided the best purity of the produced fuel, in which a methane content value of 82.13% was reached. At the same time, the overpressure leads to a decrease of around 7.5% in the volumetric production efficiency. The study indicated that the dilution of maize silage with pig manure, instead of water, can have significant benefits in the selected configurations. The content of pig slurry strengthens the impact of the selected process modifications—in the first case, by increasing the production efficiency, and in the second, by improving the methane content in the biogas. Conclusions The proposed mathematical model of the AD process proved to be a valuable tool for the description and design of biogas plant. The analysis shows that the overall impact of the presented process modifications is mutually opposite. The feedstock composition has a moderate and unsteady impact on the production profile, in the tested modifications. The dilution with pig manure, instead of water, leads to a slightly better efficiency in the classical configuration. For the TPAD process, the trend is very similar, but the AHPD biogas plant indicates a reverse tendency. Overall, the recommendation from this article is to use the AHPD concept if the composition of the biogas is the most important. In the case in which the performance is the most important factor, it is favorable to use the TPAD configuration.


Catalysts ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 539 ◽  
Author(s):  
Renfei Li ◽  
Wenbing Tan ◽  
Xinyu Zhao ◽  
Qiuling Dang ◽  
Qidao Song ◽  
...  

Wood waste generated during the tree felling and processing is a rich, green, and renewable lignocellulosic biomass. However, an effective method to apply wood waste in anaerobic digestion is lacking. The high carbon to nitrogen (C/N) ratio and rich lignin content of wood waste are the major limiting factors for high biogas production. NaOH pre-treatment for lignocellulosic biomass is a promising approach to weaken the adverse effect of complex crystalline cellulosic structure on biogas production in anaerobic digestion, and the synergistic integration of lignocellulosic biomass with low C/N ratio biomass in anaerobic digestion is a logical option to balance the excessive C/N ratio. Here, we assessed the improvement of methane production of wood waste in anaerobic digestion by NaOH pretreatment, co-digestion technique, and their combination. The results showed that the methane yield of the single digestion of wood waste was increased by 38.5% after NaOH pretreatment compared with the untreated wood waste. The methane production of the co-digestion of wood waste and pig manure was higher than that of the single digestion of wood waste and had nonsignificant difference with the single-digestion of pig manure. The methane yield of the co-digestion of wood waste pretreated with NaOH and pig manure was increased by 75.8% than that of the untreated wood waste. The findings indicated that wood waste as a sustainable biomass source has considerable potential to achieve high biogas production in anaerobic digestion.


Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 133 ◽  
Author(s):  
Shiwei Wang ◽  
Fang Ma ◽  
Weiwei Ma ◽  
Ping Wang ◽  
Guang Zhao ◽  
...  

In this study, the influence of temperature on biogas production efficiency and the microbial community structure was investigated in a two-phase anaerobic digestion reactor for co-digestion of cow manure and corn straw. The results illustrated that the contents of solluted chemical oxygen demand (SCOD) and volatile fatty acid (VFA) in the acidogenic phase and biogas production in the methanogenic phase maintained relatively higher levels at temperatures ranging from 35–25 °C. The methane content of biogas production could be maintained higher than 50% at temperatures above 25 °C. The microbial community structure analysis indicated that the dominant functional bacteria were Acinetobacter, Acetitomaculum, and Bacillus in the acidogenic phase and Cenarchaeum in the methanogenic phase at 35–25 °C. However, the performances of the acidogenic phase and the methanogenic phase could be significantly decreased at a lower temperature of 20 °C, and microbial activity was inhibited obviously. Accordingly, a low temperature was adverse for the performance of the acidogenic and methanogenic phases, while moderate temperatures above 25 °C were more conducive to high biogas production efficiency.


2018 ◽  
Vol 14 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Zulfah Zulkifli ◽  
Nazaitulshila Rasit ◽  
Noor Azrimi Umor ◽  
Shahrul Ismail

Lignocellulosic material consists of lignin, cellulose and hemicellulose. Converting lignocellulosic biomass such as cow manure (CM) into value-added products provides a potential alternative. Hydrolysis of cellulose and hemicellulose is a limiting step during Anaerobic Digestion (AD) of lignocellulosic biomass. Lignin in lignocellulosic biomass is the barrier for hydrolysis, thus limits the biogas production. In this study, the effect of A.Fumigatus SK1 and Trichoderma sp. on enzymatic pre-treatment of CM was investigated with respect to the biogas production. Three set of anaerobic digestion assays were carried out, with a working volume of 500 mL at 35 ± 2°C and 120 rpm. The first set of fermentation contained untreated CM. The second set of fermentation involved addition of A.Fumigatus SK1, and the last set contained Trichoderma sp. Several analysis were conducted to determine the biomethane potential (BMP), anaerobic biodegradability, reducing sugars concentration and lignin removal of CM before and after pre-treatment. Result showed that, among both evaluated pre-treatment methods, CM treated with Trichoderma sp. gave the highest methane potential with 0.023 LCH4-STP g VS-1 compared to CM treated with A.Fumigatus SK1(0.011 LCH4-STP g VS-1). A good correlation have been found in this study between lignin removal and reducing sugar produced where, the total lignin removal after treated with Trichoderma sp. was 60% followed by 43% after treated with A.Fumigatus SK1.The reducing sugar produced after pre-treated with Trichoderma sp. and A.Fumigatus SK1 was about 9.59 and 4.91 μmol glucose, respectively. These results collectively suggested that CM treated with Trichoderma sp. could be a better pre-treatment method for the higher methane production in anaerobic mono-digestion process.


2018 ◽  
Vol 10 (12) ◽  
pp. 4588 ◽  
Author(s):  
Yanran Fu ◽  
Tao Luo ◽  
Zili Mei ◽  
Jiang Li ◽  
Kun Qiu ◽  
...  

Dry anaerobic digestion technology (DADT) is considered a highly feasible way to treat agricultural straw waste; however, most practical operations are always in low efficiency, due to the poor fluidity behavior and complex lignocellulosic structure of straw, which is not easily decomposed by anaerobic bacteria. Hence, it is necessary to further investigate the operation boundary, in order to increase biogas production efficiency for effective applications. In this paper, typical DADTs are reviewed and their suitability for application in China is analyzed. The advantages and disadvantages of different anaerobic digestion processes are evaluated considering pretreatment, organic loading rate, anaerobic digestion temperature, and homogenization of the feedstock and inoculate. The suitability of the DADTs is evaluated considering the accessibility of straw resources and the convenience of biogas use. It is concluded that batch anaerobic digestion processes would be more suitable for the development of southern China due to the prevalence of small-scale agriculture, while continuous anaerobic digestion would be preferable in the north where large-scale agriculture is common. However, the DADTs discussed here need to broad application in China.


2016 ◽  
Vol 78 (5-6) ◽  
Author(s):  
Hathaikarn Thongpan ◽  
Rachadaporn Thongnan ◽  
Nirattisai Rakmak ◽  
Chairat Siripatana

In this work, both models for batch and continuous anaerobic digestion of palm oil mill effluent were developed based on Monod’s kinetics. Then the authors attempt to understand the effect of wastewater-sludge (WW:S) ratio on the biogas production efficiency in batch digesters. The experiments were carried out at a controlled temperature of 35±0.5 °C. Two series of the experiment were conducted. In the first series, the wastewater-sludge ratios covered 1:1 (add sodium bi-carbonate), 1:1, 1:2 and 2:1. It was found that the ratio of 1:2 gave the highest biogas producing efficiency followed by the ratio 1:1 (add sodium bi-carbonate). At 1:1 ratio, sodium bi-carbonate addition was required to start anaerobic digestion at a workable pH range whereas at 1:2 ratio the initial pH is in the workable range without the need of its addition. However, at the ratio of 2:1 the starting pH was too low to adjust pH economically by adding sodium bi-carbonate. The second series was to confine experiments to a narrower ratio range, namely: 1:1 (add sodium bi-carbonate), 1:1.5, 1:2, 1:2.5. In both sets of experiment, the ratio 1:2 gave the best biogas production potential of 76.62 and 78.52 ml of biogas/g COD removed respectively. In all treatments, the process was able to remove more than 80% of wastewater initial COD. The modified Gompertz equation was used to estimate the maximum specific biogas production rate (MBPR or Rm/S0). It was also found that the ratio of 1:2 gave the best MBPR in both experimental series (26.87 ml biogas/g COD-day). A modified Monod-type Model was also developed to describe the microbial growth, substrate consumption and biogas production in continuous operation. In general, sludge recycle provided active biomass which can use the substrate in the wastewater instantly without significant lag phase or delay. Furthermore, continuous-flow model developed, with parameters estimated from batch experiments, predicted the experimental kinetics of the actual continuous experiments satisfactory.  


2020 ◽  
pp. 11-21
Author(s):  
Uduak U. Ndubuisi-Nnaji ◽  
Utibe A. Ofon ◽  
Ata O. Inyang-Enin ◽  
Georgina N. Ananso

Anaerobic digestion (AD) of lignocellulosic agro-waste such as coconut husk fibre, pineapple floret and banana stem was studied using standard protocols. A combination of physical, chemical and biological Pre-treatment was performed to facilitate the anaerobic digestion process. The experiment was carried out using laboratory-scale batch bioreactors maintained at 44.5 ± 2ºC and retention time of 25 days. Biogas production, pH, total and volatile solids concentrations (TS, VS) were also measured. With a general increase in pH after Pre-treatment of all substrates, biogas yield was significantly improved by 83.1% in all codigestion assays when compared to control (untreated substrates) with highest TS and VS removal rates of 77.7% and 87.2% respectively. In terms process performance, Pre-treatment of single substrate did not significantly improve AD of single substrates (coconut husk fibre/pineapple floret) and biogas production was inhibited in pre-treated banana stem. However, the highest biogas production with corresponding TS and VS removal rates of 78.3% and 92.9% respectively were obtained from untreated banana stem. Codigestion significantly enhanced biogas production that can be utilized for heating and knowledge of appropriate Pre-treatment choice is recommended to improve bioenergy production efficiency during anaerobic digestion.


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