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Methane production

Yue Rao, Jingjing Wan, Yafeng Liu, Irini Angelidaki, Shicheng Zhang, Yalei Zhang, Gang Luo
The present study proposed and demonstrated a novel process for the bioconversion of syngas (mainly CO and H2 ) to valuable volatile fatty acids (VFA) by integrating with mesophilic alkaline fermentation of waste activated sludge (WAS). The results showed that although pH 9 was suitable for VFA production from WAS, 62.5% of the consumed CO was converted to methane due to the presence of hydrogenogenic pathway for CO conversion. The increase of pH from 9 to 9.5 inhibited the methane production from CO because of the possible presence of only acetogenic pathway for CO conversion...
April 11, 2018: Water Research
Yang Zhuo, Yun Han, Qiliang Qu, Yuqin Cao, Dangcong Peng, Yuyou Li
The feasibility of ammonia pre-separation during the thermal-alkaline pretreatment (TAP) of waste activated sludge was evaluated to mitigate ammonia inhibition during high solid anaerobic digestion (HSAD). The results showed that the TAP increased the organics hydrolysis rate as much as 77% compared to the thermal hydrolysis pretreatment (THP). The production and separation of the ammonia during the TAP exhibited a linear relationship with the hydrolysis of organics and the Emerson model. The pre-separation ratio of the free ammonia nitrogen exceeded 98...
March 27, 2018: Water Research
Jay A Kroll, Benjamin Normann Frandsen, Henrik Grum Kjaergaard, Veronica Vaida
The reaction of electronically excited triplet state sulfur dioxide (3 SO2 ) with water was investigated both theoretically and experimentally. The quantum chemical calculations find that the reaction leads to the formation of hydroxyl radical (OH) and hydroxysulfinyl radical (HOSO) via a low energy barrier pathway. Experimentally the formation of OH was monitored via its reaction with methane, which itself is relatively unreactive with 3 SO2 , making it a suitable probe of OH production from the reaction of 3 SO2 and water...
April 17, 2018: Journal of Physical Chemistry. A
Paul Andrew Christensen, Zeinab T A W Mashhadani, Abd Halim Bin Md Ali, Michael A Carroll, Philip A Martin
This paper reports in-situ Fourier Transform Infra Red (FTIR) spectroscopic studies on the non-thermal plasma reaction of isopropyl alcohol in dinitrogen at Macor (a ceramic containing oxides of Al, Mg and Si) and the analogous thermally-driven process. Whilst isopropyl alcohol did not react at the Macor at temperatures up to 600°C, the study of the non-thermal plasma-driven process at the ceramic led to unexpected chemistry hitherto not observed, primarily the reaction of IPA in dinitrogen at short timescales to produce methane, HCN, acetone and "cold" CO at ca...
April 17, 2018: Journal of Physical Chemistry. A
Jiazheng Ren, Alex Chinghuan Lee, Kai Cheng, Ming Li, Yongsheng Chen
Dry reforming of methane converts two greenhouse gases to syngas, and Ni catalysts are commonly used for this reaction. A major catalyst deactivation mechanism is carbon deposition. Although numerous kinetic modelling works have been done on carbon formation, there were only scarce attempts to measure carbon deposition kinetics under relevant (but not real) conditions due to technical difficulties. Here we report first successful measurements of the kinetics under real reaction conditions. This was made possible by a novel algorithm we have developed...
April 17, 2018: Chemphyschem: a European Journal of Chemical Physics and Physical Chemistry
Lan Mi, Bin Yang, Xialu Hu, Yang Luo, Jianxin Liu, Zhongtang Yu, Jiakun Wang
The rumen and the hindgut represent two different fermentation organs in herbivorous mammals, with the former producing much more methane than the latter. The objective of this study was to elucidate the microbial underpinning of such differential methane outputs between these two digestive organs. Methane production was measured from 5 adult sheep and 15 adult rabbits, both of which were placed in open-circuit respiratory chambers and fed the same diet (alfalfa hay). The sheep produced more methane than the rabbits per unit of metabolic body weight, digestible neutral detergent fiber, and acid detergent fiber...
2018: Frontiers in Microbiology
N Zamorano-López, P Moñino, L Borrás, D Aguado, R Barat, J Ferrer, A Seco
Notorious changes in microbial communities were observed during and after the joint treatment of wastewater with Food Waste (FW) in an Anaerobic Membrane Bioreactor (AnMBR) plant. The microbial population was analysed by high-throughput sequencing of the 16S rRNA gene and dominance of Chloroflexi, Firmicutes, Synergistetes and Proteobacteria phyla was found. The relative abundance of these potential hydrolytic phyla increased as a higher fraction of FW was jointly treated. Moreover, whereas Specific Methanogenic Activity (SMA) rose from 10 to 51 mL CH4 g-1 VS, Methanosarcinales order increased from 34...
April 13, 2018: Journal of Environmental Management
Ying Li, Lianhua Li, Yongming Sun, Zhenhong Yuan
To investigate whether bioaugmentation could improve the digestion performance of high C/N ratio feedstock without co-digestion with nitrogen-rich substrate, different forms of enriched methanogenic culture were introduced to the continuous feed digesters. The performance efficiency of bioaugmentation on digestion improvement was compared. The effect of bioaugmentation on microbial community composition was revealed as well. Results demonstrated that routine bioaugmentation with liquid culture (containing the microbes and the medium remains) showed the best performance, with the organic loading rate (OLR), methane percentage, volumetric methane production (VMP) and volatile solid methane production (VSMP) higher at 1...
April 5, 2018: Bioresource Technology
Peyman Mahmoodi, Keikhosro Karimi, Mohammad J Taherzadeh
Organic fraction of municipal solid waste (OFMSW) is dominated by carbohydrates, including starch-based and lignocellulosic materials. The OFMSW was hydrothermally pretreated at 100-160 °C for 0-60 min, and then assessed for enzymatic ethanol production, followed by biogas production from the stillage. The highest glucose yield of 520 g/Kg of dry OFMSW, corresponding to 131% increase compared to that of the untreated OFMSW, was obtained after the pretreatment and enzymatic hydrolysis. Through ethanolic fermentation by an inhibitory tolerant fungus, Mucor indicus, 191...
April 6, 2018: Bioresource Technology
Damien P Debecker, Solène Le Bras, Cédric Boissière, Alexandra Chaumonnot, Clément Sanchez
Aerosol processing is long known and implemented industrially to obtain various types of divided materials and nanomaterials. The atomisation of a liquid solution or suspension produces a mist of aerosol droplets which can then be transformed via a diversity of processes including spray-drying, spray pyrolysis, flame spray pyrolysis, thermal decomposition, micronisation, gas atomisation, etc. The attractive technical features of these aerosol processes make them highly interesting for the continuous, large scale, and tailored production of heterogeneous catalysts...
April 16, 2018: Chemical Society Reviews
Dong Li, Yi Ran, Lin Chen, Qin Cao, Zhidong Li, Xiaofeng Liu
Effective process monitoring and instability diagnosis are important for stable anaerobic digestion (AD) of vegetable waste (VW). In order to evaluate the performance of thermophilic digestion of VW, to make early diagnosis for instability after organic overload, and to reveal the dynamics of microbial community under different running states, thermophilic AD of VW was carried out under improved organic loading rates (OLR) of 0.5-2.5 g volatile solid (VS)/(L ∙ d) in this study. Gaseous parameters including volumetric methane production rate (VMPR), CH4 , CO2 , and H2 concentrations, and liquid parameters including pH, oxidation-reduction potential, volatile fatty acid (VFA), and total alkalinity (TA), bicarbonate alkalinity (BA), intermediate alkalinity (IA), and ammonia, were monitored...
April 10, 2018: Water Research
Peter B McMahon, Judith C Thomas, John T Crawford, Mark M Dornblaser, Andrew G Hunt
Site-specific and regional analysis of time-series hydrologic and geochemical data collected from 15 monitoring wells in the Piceance Basin indicated that a leaking gas well contaminated shallow groundwater with thermogenic methane. The gas well was drilled in 1956 and plugged and abandoned in 1990. Chemical and isotopic data showed the thermogenic methane was not from mixing of gas-rich formation water with shallow groundwater or natural migration of a free-gas phase. Water-level and methane-isotopic data, and video logs from a deep monitoring well, indicated that a shale confining layer ~125m below the zone of contamination was an effective barrier to upward migration of water and gas...
April 10, 2018: Science of the Total Environment
Seth N Lyman, Marc L Mansfield
Solid or sludgy hydrocarbon waste is a byproduct of oil and gas exploration and production. One commonly-used method of disposing of this waste is landfarming. Landfarming involves spreading hydrocarbon waste on soils, tilling it into the soil, and allowing it to biodegrade. We used a dynamic flux chamber to measure fluxes of methane, a suite of 54 non-methane hydrocarbons, and light alcohols from an active and a remediated landfarm in eastern Utah, U.S.A. Fluxes from the remediated landfarm were not different from a PTFE sheet or from undisturbed soils in the region...
April 13, 2018: Journal of the Air & Waste Management Association
Mary J Espina, C M Sabbir Ahmed, Angelina Bernardini, Ekundayo Adeleke, Zeinab Yadegari, Prakash Arelli, Vince Pantalone, Ali Taheri
Soybean is an important oil-producing crop in the Fabaceae family and there are increasing demands for soybean oil and other soybean products. Genetic improvement of soybean is needed to increase its production. In order to provide genetic diversity and resources for identifying important genes, a new ethyl methane sulfonate (EMS) mutagenized soybean population was generated using the newly released germplasm, JTN-5203 (maturity group V). Treatment of soybean seeds with 60 mM EMS concentration was found to be suitable for inducing mutation...
2018: Frontiers in Plant Science
Z X He, J Y Qiao, Q X Yan, Z L Tan, M Wang
Methane produced from formate is one of the important methanogensis pathways in the rumen. However, quantitative information of CH4 production from formate has been rarely reported. The aim of this study was to characterize the conversion rate (CR) of formic acid into CH4 and CO2 by rumen microorganisms. Ground lucerne hay was incubated with buffered ruminal fluid for 6, 12, 24 and 48 h. Before the incubation, 13C-labeled H13COOH was also supplied into the incubation bottle at a dose of 0, 1.5, 2.2 or 2.9 mg/g of DM substrate...
April 12, 2018: Animal: An International Journal of Animal Bioscience
Sung Sill Lee, Do Hyung Kim, Shin Ja Lee, Da Som Oh, Il Dong Lee, Jun Sik Eom, Ha Young Park, Sung Ho Choi
Objective: This study was conducted to evaluate the effects of additional levels of Rhus succedanea extracts on in vitro ruminal fermentation and microbial growth. Methods: Two ruminally-fistulated steer consuming 600 g/kg timothy and 400 g/kg cracked corn-based concentrate with free access to water and mineral block were used as rumen fluid donors. In vitro batch fermentation supplied by the timothy as a substrate was conducted for up to 72 h with Rhus succedanea extracts which was dosed to achieve final concentrations of 0, 10, 30, 50, 70, and 90 mg/L, respectively...
April 12, 2018: Asian-Australasian Journal of Animal Sciences
Hongliang Wang, Shikun Zhu, Bo Qu, Yu Zhang, Bin Fan
Anaerobic treatment is the core technology for resource and energy recovery from source-separated domestic bio-wastes. The higher efficiency of an improved upflow solid reactor (IUSR) designed in this study was demonstrated in the treatment of concentrated black water and kitchen waste. The highest methane production of 48L/person/day was achieved at the hydraulic retention time (HRT) of 7days, while the other measures of performance at the HRT of 8.3days were better than at the HRT of 7 or 10days, achieving a methane production of 43L/person/day, removal of total chemical oxygen demand (TCOD) of 89%, removal of soluble chemical oxygen demand (SCOD) of 92%, and conversion of chemical oxygen demand (COD) to methane of 71%...
April 2018: Journal of Environmental Sciences (China)
Rania Mona Alqaralleh, Kevin Kennedy, Robert Delatolla
This paper investigates the feasibility and advantages of using a dual-stage hyper-thermophilic/thermophilic semi-continuous reactor system for the co-digestion of Thickened Waste Activated Sludge (TWAS) and Fat, Oil and Grease (FOG) to produce biogas in high quantity and quality. The performance of the dual-stage hyper-thermophilic (70°C)/thermophilic (55°C) anaerobic co-digestion system is evaluated and compared to the performance of a single-stage thermophilic (55°C) reactor that was used to co-digest the same FOG-TWAS mixtures...
April 5, 2018: Journal of Environmental Management
Ashley J Ansari, Faisal I Hai, William E Price, Huu H Ngo, Wenshan Guo, Long D Nghiem
This study assessed the performance and key challenges associated with the integration of forward osmosis (FO) and anaerobic digestion for wastewater treatment and resource recovery. Using a thin film composite polyamide FO membrane, maximising the pre-concentration factor (i.e. system water recovery) resulted in the enrichment of organics and salinity in wastewater. Biomethane potential evaluation indicated that methane production increased correspondingly with the FO pre-concentration factor due to the organic retention in the feed solution...
March 30, 2018: Bioresource Technology
Y Arij, S Fatihah, A R Rakmi
The anaerobic treatment of leachate from a municipal waste transfer station in Malaysia was tested using a pilot scale anaerobic biofilm digester system that was operated under HRT sequence of 30-day, 25-day, 20-day and 10-day for 163 days under mesophilic conditions. Despite the leachate's complex characteristics, the system showed great performance given its maximum COD, BOD5 and total phosphorus removal efficiencies of 98 ± 1%, 99 ± 1% and 92 ± 9% respectively. The system was stable throughout its operation and showed optimal average values for the monitored parameters such as pH (7...
March 30, 2018: Bioresource Technology
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