The Experts below are selected from a list of 30405 Experts worldwide ranked by ideXlab platform
Irini Angelidaki - One of the best experts on this subject based on the ideXlab platform.
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performance and microbial community analysis of the Anaerobic Reactor with coke oven gas biomethanation and in situ biogas upgrading
Bioresource Technology, 2013Co-Authors: Wen Wang, Qi Zhou, Irini AngelidakiAbstract:A new method for simultaneous coke oven gas (COG) biomethanation and in situ biogas upgrading in Anaerobic Reactor was developed in this study. The simulated coke oven gas (SCOG) (92% H2 and 8% CO) was injected directly into the Anaerobic Reactor treating sewage sludge through hollow fiber membrane (HFM). With pH control at 8.0, the added H2 and CO were fully consumed and no negative effects on the Anaerobic degradation of sewage sludge were observed. The maximum CH4 content in the biogas was 99%. The addition of SCOG resulted in enrichment and dominance of homoacetogenetic genus Treponema and hydrogenotrophic genus Methanoculleus in the liquid, which indicated that H2 were converted to methane by both direct (hydrogenotrophic methanogenesis) and indirect (homoacetogenesis+aceticlastic methanogenesis) pathways in the liquid. However, the aceticlasitic genus Methanosaeta was dominant for archaea in the biofilm on the HFM, which indicated indirect (homoacetogenesis+aceticlastic methanogenesis) H2 conversion pathway on the biofilm.
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Hollow fiber membrane based H_2 diffusion for efficient in situ biogas upgrading in an Anaerobic Reactor
Applied Microbiology and Biotechnology, 2013Co-Authors: Irini AngelidakiAbstract:Bubbleless gas transfer through a hollow fiber membrane (HFM) module was used to supply H_2 to an Anaerobic Reactor for in situ biogas upgrading, and it creates a novel system that could achieve a CH_4 content higher than 90 % in the biogas. The increase of CH_4 content and pH, and the decrease of bicarbonate concentration were related with the increase of the H_2 flow rate. The CH_4 content increased from 78.4 % to 90.2 % with the increase of the H_2 flow rate from 930 to 1,440 ml/(l day), while the pH in the Reactor remained below 8.0. An even higher CH_4 content (96.1 %) was achieved when the H_2 flow rate was increased to 1,760 ml/(l day); however, the pH increased to around 8.3 due to bicarbonate consumption which hampered the Anaerobic process. The biofilm formed on the HFM was found not to be beneficial for the process since it increased the resistance of H_2 diffusion to the liquid. The study also demonstrated that the biofilm formed on the membrane only contributed 22–36 % to the H_2 consumption, while most of the H_2 was consumed by the microorganisms in the liquid phase.
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integrated biogas upgrading and hydrogen utilization in an Anaerobic Reactor containing enriched hydrogenotrophic methanogenic culture
Biotechnology and Bioengineering, 2012Co-Authors: Irini AngelidakiAbstract:Biogas produced by Anaerobic digestion, is mainly used in a gas motor for heat and electricity production. However, after removal of CO2, biogas can be upgraded to natural gas quality, giving more utilization possibilities, such as utilization as autogas, or distant utilization by using the existing natural gas grid. The current study presents a new biological method for biogas upgrading in a separate biogas Reactor, containing enriched hydrogenotrophic methanogens and fed with biogas and hydrogen. Both mesophilic- and thermophilic Anaerobic cultures were enriched to convert CO2 to CH4 by addition of H2. Enrichment at thermophilic temperature (55°C) resulted in CO2 and H2 bioconversion rate of 320 mL CH4/(gVSS h), which was more than 60% higher than that under mesophilic temperature (37°C). Different dominant species were found at mesophilic- and thermophilic-enriched cultures, as revealed by PCR–DGGE. Nonetheless, they all belonged to the order Methanobacteriales, which can mediate hydrogenotrophic methanogenesis. Biogas upgrading was then tested in a thermophilic Anaerobic Reactor under various operation conditions. By continuous addition of hydrogen in the biogas Reactor, high degree of biogas upgrading was achieved. The produced biogas had a CH4 content, around 95% at steady-state, at gas (mixture of biogas and hydrogen) injection rate of 6 L/(L day). The increase of gas injection rate to 12 L/(L day) resulted in the decrease of CH4 content to around 90%. Further study showed that by decreasing the gas–liquid mass transfer by increasing the stirring speed of the mixture the CH4 content was increased to around 95%. Finally, the CH4 content around 90% was achieved in this study with the gas injection rate as high as 24 L/(L day). Biotechnol. Bioeng. 2012; 109: 2729–2736. © 2012 Wiley Periodicals, Inc.
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simultaneous hydrogen utilization and in situ biogas upgrading in an Anaerobic Reactor
Biotechnology and Bioengineering, 2012Co-Authors: Gang Luo, Qi Zhou, Sara Johansson, Kanokwan Boe, Li Xie, Irini AngelidakiAbstract:The possibility of converting hydrogen to methane and simultaneous upgrading of biogas was investigated in both batch tests and fully mixed biogas Reactor, simultaneously fed with manure and hydrogen. Batch experiments showed that hydrogen could be converted to methane by hydrogenotrophic methanogenesis with conversion of more than 90% of the consumed hydrogen to methane. The hydrogen consumption rates were affected by both P(H₂) (hydrogen partial pressure) and mixing intensity. Inhibition of propionate and butyrate degradation by hydrogen (1 atm) was only observed under high mixing intensity (shaking speed 300 rpm). Continuous addition of hydrogen (flow rate of 28.6 mL/(L/h)) to an Anaerobic Reactor fed with manure, showed that more than 80% of the hydrogen was utilized. The propionate and butyrate level in the Reactor was not significantly affected by the hydrogen addition. The methane production rate of the Reactor with H₂ addition was 22% higher, compared to the control Reactor only fed with manure. The CO₂ content in the produced biogas was only 15%, while it was 38% in the control Reactor. However, the addition of hydrogen resulted in increase of pH (from 8.0 to 8.3) due to the consumption of bicarbonate, which subsequently caused slight inhibition of methanogenesis.
Qaisar Mahmood - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous sulfide and nitrate removal in Anaerobic Reactor under shock loading.
Bioresource Technology, 2009Co-Authors: Cai Jing, Zheng Ping, Qaisar MahmoodAbstract:The performance of Anaerobic Reactor for simultaneous sulfide and nitrate removal under substrate shock loading was studied. The response to the shock loading could be divided into three stages i.e. disturbance, inertial and recovery periods. The effect of the shock loading was directly proportional to the intensity of the shock loads. The Reactor performance was stable at a relatively lower intensity (1.5 times shock load), while it was considerably affected by higher intensity (higher than 2.0 times shock load). Nevertheless, the Reactor performance recovered from disturbances at all the tested shock loads. The effluent sulfide-sulfur concentration was found as sensitive parameter, which increased up to 18 times of that at steady state; it could be used as an indicator of the Reactor's performance.
Wen Wang - One of the best experts on this subject based on the ideXlab platform.
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performance and microbial community analysis of the Anaerobic Reactor with coke oven gas biomethanation and in situ biogas upgrading
Bioresource Technology, 2013Co-Authors: Wen Wang, Qi Zhou, Irini AngelidakiAbstract:A new method for simultaneous coke oven gas (COG) biomethanation and in situ biogas upgrading in Anaerobic Reactor was developed in this study. The simulated coke oven gas (SCOG) (92% H2 and 8% CO) was injected directly into the Anaerobic Reactor treating sewage sludge through hollow fiber membrane (HFM). With pH control at 8.0, the added H2 and CO were fully consumed and no negative effects on the Anaerobic degradation of sewage sludge were observed. The maximum CH4 content in the biogas was 99%. The addition of SCOG resulted in enrichment and dominance of homoacetogenetic genus Treponema and hydrogenotrophic genus Methanoculleus in the liquid, which indicated that H2 were converted to methane by both direct (hydrogenotrophic methanogenesis) and indirect (homoacetogenesis+aceticlastic methanogenesis) pathways in the liquid. However, the aceticlasitic genus Methanosaeta was dominant for archaea in the biofilm on the HFM, which indicated indirect (homoacetogenesis+aceticlastic methanogenesis) H2 conversion pathway on the biofilm.
Qi Zhou - One of the best experts on this subject based on the ideXlab platform.
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performance and microbial community analysis of the Anaerobic Reactor with coke oven gas biomethanation and in situ biogas upgrading
Bioresource Technology, 2013Co-Authors: Wen Wang, Qi Zhou, Irini AngelidakiAbstract:A new method for simultaneous coke oven gas (COG) biomethanation and in situ biogas upgrading in Anaerobic Reactor was developed in this study. The simulated coke oven gas (SCOG) (92% H2 and 8% CO) was injected directly into the Anaerobic Reactor treating sewage sludge through hollow fiber membrane (HFM). With pH control at 8.0, the added H2 and CO were fully consumed and no negative effects on the Anaerobic degradation of sewage sludge were observed. The maximum CH4 content in the biogas was 99%. The addition of SCOG resulted in enrichment and dominance of homoacetogenetic genus Treponema and hydrogenotrophic genus Methanoculleus in the liquid, which indicated that H2 were converted to methane by both direct (hydrogenotrophic methanogenesis) and indirect (homoacetogenesis+aceticlastic methanogenesis) pathways in the liquid. However, the aceticlasitic genus Methanosaeta was dominant for archaea in the biofilm on the HFM, which indicated indirect (homoacetogenesis+aceticlastic methanogenesis) H2 conversion pathway on the biofilm.
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simultaneous hydrogen utilization and in situ biogas upgrading in an Anaerobic Reactor
Biotechnology and Bioengineering, 2012Co-Authors: Gang Luo, Qi Zhou, Sara Johansson, Kanokwan Boe, Li Xie, Irini AngelidakiAbstract:The possibility of converting hydrogen to methane and simultaneous upgrading of biogas was investigated in both batch tests and fully mixed biogas Reactor, simultaneously fed with manure and hydrogen. Batch experiments showed that hydrogen could be converted to methane by hydrogenotrophic methanogenesis with conversion of more than 90% of the consumed hydrogen to methane. The hydrogen consumption rates were affected by both P(H₂) (hydrogen partial pressure) and mixing intensity. Inhibition of propionate and butyrate degradation by hydrogen (1 atm) was only observed under high mixing intensity (shaking speed 300 rpm). Continuous addition of hydrogen (flow rate of 28.6 mL/(L/h)) to an Anaerobic Reactor fed with manure, showed that more than 80% of the hydrogen was utilized. The propionate and butyrate level in the Reactor was not significantly affected by the hydrogen addition. The methane production rate of the Reactor with H₂ addition was 22% higher, compared to the control Reactor only fed with manure. The CO₂ content in the produced biogas was only 15%, while it was 38% in the control Reactor. However, the addition of hydrogen resulted in increase of pH (from 8.0 to 8.3) due to the consumption of bicarbonate, which subsequently caused slight inhibition of methanogenesis.
Cai Jing - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous sulfide and nitrate removal in Anaerobic Reactor under shock loading.
Bioresource Technology, 2009Co-Authors: Cai Jing, Zheng Ping, Qaisar MahmoodAbstract:The performance of Anaerobic Reactor for simultaneous sulfide and nitrate removal under substrate shock loading was studied. The response to the shock loading could be divided into three stages i.e. disturbance, inertial and recovery periods. The effect of the shock loading was directly proportional to the intensity of the shock loads. The Reactor performance was stable at a relatively lower intensity (1.5 times shock load), while it was considerably affected by higher intensity (higher than 2.0 times shock load). Nevertheless, the Reactor performance recovered from disturbances at all the tested shock loads. The effluent sulfide-sulfur concentration was found as sensitive parameter, which increased up to 18 times of that at steady state; it could be used as an indicator of the Reactor's performance.
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The effect of shock loads on performance of Anaerobic Reactor for simultaneous sulfide and nitrate removal
China Environmental Science, 2009Co-Authors: Cai Jing, Zheng PingAbstract:The effect of substrate shock loads on the performance of Anaerobic Reactor for simultaneous sulfide and nitrate removal was evaluated. The response to the shock loads could be divided into disturbance,inertial and recovery periods. The effect of the shock loads on the Reactor was associated with the intensity of the shock loads. The Reactor performance was almost unaffected at lower intensity(1.5 times shock load) ,whereas it was considerably influenced at higher intensity(higher than 2.0 times shock load) . The performance was recoverable from disturbance at all the tested shock loads within 30h(7.5 hydraulic retention time) . The effluent sulfide concentration was a sensitive parameter,which increased up to 18 times of that at steady state;thus it was an important indicator of the Reactor performance.
