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Dr. Xiomar Gómez
Universidad de León (Spain)

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Research Keywords & Expertise

0 Anaerobic Digestion
0 Energy Efficiency
0 waste valorisation
0 biological processes
0 Fermentation engineering

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Anaerobic Digestion
biological processes
Energy Efficiency

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Review
Published: 14 August 2021 in Environments
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High-solid and solid-state anaerobic digestion are technologies capable of achieving high reactor productivity. The high organic load admissible for this type of configuration makes these technologies an ideal ally in the conversion of waste into bioenergy. However, there are still several factors associated with these technologies that result in low performance. The economic model based on a linear approach is unsustainable, and changes leading to the development of a low-carbon model with a high degree of circularity are necessary. Digestion technology may represent a key driver leading these changes but it is undeniable that the profitability of these plants needs to be increased. In the present review, the digestion process under high-solid-content configurations is analyzed and the different strategies for increasing reactor productivity that have been studied in recent years are described. Percolating reactor configurations and the use of low-cost adsorbents, nanoparticles and micro-aeration seem the most suitable approaches to increase volumetric production and reduce initial capital investment costs.

ACS Style

Marcos Ellacuriaga; José García Cascallana; Rubén González; Xiomar Gómez. High-Solid Anaerobic Digestion: Reviewing Strategies for Increasing Reactor Performance. Environments 2021, 8, 80 .

AMA Style

Marcos Ellacuriaga, José García Cascallana, Rubén González, Xiomar Gómez. High-Solid Anaerobic Digestion: Reviewing Strategies for Increasing Reactor Performance. Environments. 2021; 8 (8):80.

Chicago/Turabian Style

Marcos Ellacuriaga; José García Cascallana; Rubén González; Xiomar Gómez. 2021. "High-Solid Anaerobic Digestion: Reviewing Strategies for Increasing Reactor Performance." Environments 8, no. 8: 80.

Journal article
Published: 29 April 2021 in Fuels
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Anaerobic digestion is traditionally used for treating organic materials. This allows the valorization of biogas and recycling of nutrients thanks to the land application of digestates. However, although this technology offers a multitude of advantages, it is still far from playing a relevant role in the energy market and from having significant participation in decarbonizing the economy. Biogas can be submitted to upgrading processes to reach methane content close to that of natural gas and therefore be compatible with many of its industrial applications. However, the high installation and operating costs of these treatment plants are the main constraints for the application of this technology in many countries. There is an urgent need of increasing reactor productivity, biogas yields, and operating at greater throughput without compromising digestion stability. Working at organic solid contents greater than 20% and enhancing hydrolysis and biogas yields to allow retention times to be around 15 days would lead to a significant decrease in reactor volume and therefore in initial capital investments. Anaerobic digestion should be considered as one of the key components in a new economy model characterized by an increase in the degree of circularity. The present manuscript reviews the digestion process analyzing the main parameters associated with digestion performance. The novelty of this manuscript is based on the link established between operating reactor conditions, optimizing treatment capacity, and reducing operating costs that would lead to unlocking the potential of biogas to promote bioenergy production, sustainable agronomic practices, and the integration of this technology into the energy grid.

ACS Style

Marcos Ellacuriaga; José García-Cascallana; Xiomar Gómez. Biogas Production from Organic Wastes: Integrating Concepts of Circular Economy. Fuels 2021, 2, 144 -167.

AMA Style

Marcos Ellacuriaga, José García-Cascallana, Xiomar Gómez. Biogas Production from Organic Wastes: Integrating Concepts of Circular Economy. Fuels. 2021; 2 (2):144-167.

Chicago/Turabian Style

Marcos Ellacuriaga; José García-Cascallana; Xiomar Gómez. 2021. "Biogas Production from Organic Wastes: Integrating Concepts of Circular Economy." Fuels 2, no. 2: 144-167.

Review
Published: 25 January 2021 in Entropy
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Anaerobic digestion is a well-known technology with wide application in the treatment of high-strength organic wastes. The economic feasibility of this type of installation is usually attained thanks to the availability of fiscal incentives. In this review, an analysis of the different factors associated with this biological treatment and a description of alternatives available in literature for increasing performance of the process were provided. The possible integration of this process into a biorefinery as a way for producing energy and chemical products from the conversion of wastes and biomass also analyzed. The future outlook of anaerobic digestion will be closely linked to circular economy principles. Therefore, this technology should be properly integrated into any production system where energy can be recovered from organics. Digestion can play a major role in any transformation process where by-products need further stabilization or it can be the central core of any waste treatment process, modifying the current scheme by a concatenation of several activities with the aim of increasing the efficiency of the conversion. Thus, current plants dedicated to the treatment of wastewaters, animal manures, or food wastes can become specialized centers for producing bio-energy and green chemicals. However, high installation costs, feedstock dispersion and market distortions were recognized as the main parameters negatively affecting these alternatives.

ACS Style

Cristián Sevillano; Alby Pesantes; Elizabeth Peña Carpio; Elia Martínez; Xiomar Gómez. Anaerobic Digestion for Producing Renewable Energy—The Evolution of This Technology in a New Uncertain Scenario. Entropy 2021, 23, 145 .

AMA Style

Cristián Sevillano, Alby Pesantes, Elizabeth Peña Carpio, Elia Martínez, Xiomar Gómez. Anaerobic Digestion for Producing Renewable Energy—The Evolution of This Technology in a New Uncertain Scenario. Entropy. 2021; 23 (2):145.

Chicago/Turabian Style

Cristián Sevillano; Alby Pesantes; Elizabeth Peña Carpio; Elia Martínez; Xiomar Gómez. 2021. "Anaerobic Digestion for Producing Renewable Energy—The Evolution of This Technology in a New Uncertain Scenario." Entropy 23, no. 2: 145.

Journal article
Published: 21 January 2021 in Applied Sciences
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An evaluation of the energy and economic performance of thermal hydrolysis technologies is carried out on a theoretical basis. The wastewater treatment plant (WWTP) of Burgos (Spain) was the base scenario of this evaluation. Energy and mass balances were established considering the registered data of primary and secondary thickened sludge in the WWTP for 2011 to 2016. These balances were analysed considering five different scenarios, taking as Scenario 1, the plant operating with conventional mesophilic digestion. The scenarios considered commercially available technologies. The best results were obtained when hydrolysis was applied to digested sludge and sludge from the Solidstream® process. These two scenarios showed the best performance regarding volatile solid removal and lower demand for live steam, achieving a higher amount of biogas available for valorisation using combined heat and power (CHP) units. The main advantage of the hydrolysis process is the decrease in the volume of digesters and the amount of dewatered sludge needing final disposal. The Solidstream® process allowed a 35% increase in biogas available for engines and a 23% increase in electricity production.

ACS Style

José García-Cascallana; Xiomar Gómez; E. Judith Martinez. Thermal Hydrolysis of Sewage Sludge: A Case Study of a WWTP in Burgos, Spain. Applied Sciences 2021, 11, 964 .

AMA Style

José García-Cascallana, Xiomar Gómez, E. Judith Martinez. Thermal Hydrolysis of Sewage Sludge: A Case Study of a WWTP in Burgos, Spain. Applied Sciences. 2021; 11 (3):964.

Chicago/Turabian Style

José García-Cascallana; Xiomar Gómez; E. Judith Martinez. 2021. "Thermal Hydrolysis of Sewage Sludge: A Case Study of a WWTP in Burgos, Spain." Applied Sciences 11, no. 3: 964.

Journal article
Published: 16 November 2020 in Energies
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Wine lees have a great potential to obtain clean energy in the form of biogas through anaerobic digestion due to their high organic load. However, wine lees are a complex substrate and may likely give rise to instabilities leading to failure of the biological process. This work analysed the digestion of wine lees using two different approaches. First, electro-oxidation was applied as pre-treatment using boron-doped diamond-based electrodes. The voltage was 25 V and different treatment times were tested (ranging from 0.08 to 1.5 h) at 25 °C. Anaerobic digestion of wine lees was evaluated in batch tests to investigate the effect of electro-oxidation on biogas yield. Electro-oxidation exhibited a significant positive effect on biogas production increasing its value up to 330 L kg−1 of volatile solids after 1.5 h of treatment, compared to 180 L kg−1 of volatile solids measured from raw wine lees. As a second approach, the addition of biochar to the anaerobic digestion of wine lees was investigated; in the experimental conditions considered in the present study, the addition of biochar did not show any positive effect on anaerobic digestion performance.

ACS Style

Cristian Bernabé Arenas Sevillano; Marco Chiappero; Xiomar Gomez; Silvia Fiore; E. Judith Martínez. Improving the Anaerobic Digestion of Wine-Industry Liquid Wastes: Treatment by Electro-Oxidation and Use of Biochar as an Additive. Energies 2020, 13, 5971 .

AMA Style

Cristian Bernabé Arenas Sevillano, Marco Chiappero, Xiomar Gomez, Silvia Fiore, E. Judith Martínez. Improving the Anaerobic Digestion of Wine-Industry Liquid Wastes: Treatment by Electro-Oxidation and Use of Biochar as an Additive. Energies. 2020; 13 (22):5971.

Chicago/Turabian Style

Cristian Bernabé Arenas Sevillano; Marco Chiappero; Xiomar Gomez; Silvia Fiore; E. Judith Martínez. 2020. "Improving the Anaerobic Digestion of Wine-Industry Liquid Wastes: Treatment by Electro-Oxidation and Use of Biochar as an Additive." Energies 13, no. 22: 5971.

Chapter
Published: 09 October 2020 in Biofuel and Biorefinery Technologies
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The conversion of biomass is full of challenges requiring multiples steps for attaining high efficiencies in the transformation of this material for producing valuable goods and chemicals. There exist several biological processes capable of generating different fuels and green chemicals; however, their efficiency may be too low associated with the need of biomass pre-treatments or the maturity of these technologies may be at an early stage requiring for the development of pilot-scale experiences to get an insight on their performance under different conditions and for assessing their behaviour during extended periods. Some technical aspects are still in need of deep research to consider their implications in a global economic balance when the integration into multiple phases is proposed. Technologies for the production of fuels and the valorisation of the variety of side streams are reviewed in this chapter giving an approximation of the several possibilities of integrating these biological alternatives considering the production of ethanol, butanol, biodiesel and biogas along with the production of hydrogen. A cascade approach for applying a diversity of valorisation stages has been studied taking into account the use of different side streams for coupling biological and thermal processes in an attempt to increase process yields and reduce operating costs. The integration of anaerobic digestion and fermentative hydrogen production for the valorisation of cellulosic biomass into different processes as ethanol and biodiesel production has been assessed.

ACS Style

José Francisco González-Álvarez; Judith González-Arias; Cristian B. Arenas; Xiomar Gómez. Bioconversion and Biorefineries: Recent Advances and Applications. Biofuel and Biorefinery Technologies 2020, 185 -227.

AMA Style

José Francisco González-Álvarez, Judith González-Arias, Cristian B. Arenas, Xiomar Gómez. Bioconversion and Biorefineries: Recent Advances and Applications. Biofuel and Biorefinery Technologies. 2020; ():185-227.

Chicago/Turabian Style

José Francisco González-Álvarez; Judith González-Arias; Cristian B. Arenas; Xiomar Gómez. 2020. "Bioconversion and Biorefineries: Recent Advances and Applications." Biofuel and Biorefinery Technologies , no. : 185-227.

Journal article
Published: 29 September 2020 in Environments
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This manuscript deals with the detailed design of a small digestion prototype intended as a commercial unit fully operational to cover the demand for decentralized treatment of wastes. These plants are highly affected by the complex nature of wastes giving rise to different operating problems that should be considered in detail. This paper describes the design and start-up strategy of a small-scale digestion plant with a volume of 8 m3 designed to operate with a hydrolysis pretreatment unit. The plant was designed to treat fruit and vegetable wastes as substrates derived from a local processing food factory. The performance of the plant during fed-batch operation was reported. The strategy of inoculating the reactor only to a third of its original volume and subsequently increasing the volume of the reactor by using the fed-batch mode was inadequate. The acid pH of the feeding substrate resulted in the application of a low organic loading rate with a volumetric variation of just 19.7 L/d. The performance of the plant was evaluated at non-steady state conditions and resulted in excessive destruction of volatile solids due to the low nitrogen content of the feeding substrate. The prototype reported a specific methane production of 232 L/kg volatile solids despite the low feeding rate supplemented.

ACS Style

Rubén González; Daniel Blanco; Judith González-Arias; José García-Cascallana; Xiomar Gómez. Description of a Decentralized Small Scale Digester for Treating Organic Wastes. Environments 2020, 7, 78 .

AMA Style

Rubén González, Daniel Blanco, Judith González-Arias, José García-Cascallana, Xiomar Gómez. Description of a Decentralized Small Scale Digester for Treating Organic Wastes. Environments. 2020; 7 (10):78.

Chicago/Turabian Style

Rubén González; Daniel Blanco; Judith González-Arias; José García-Cascallana; Xiomar Gómez. 2020. "Description of a Decentralized Small Scale Digester for Treating Organic Wastes." Environments 7, no. 10: 78.

Journal article
Published: 03 September 2020 in Waste Management
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The performance of a small-scale prototype digestion plant (7.2 m3 working volume) intended for decentralised operation was evaluated considering energy efficiency and technical suitability for biogas valorisation in producing electrical and thermal energy. The digester operated in recirculation mode to enhance organic matter conversion and improve volatile solid degradation. An energy assessment of the process assumed the incorporation of a combined heat and power (CHP) unit. The coefficient of overall performance of the plant for electrical energy (COPel) was 0.95 — this values was estimated at an electrical efficiency of 22.5% and represents the ratio between energy production and consumption — for a methane yield of 360 L/kg VS and an organic loading rate (OLR) of 1.06 g VS/L d. This parameter was slightly lower than the unit thus indicating that the micro-plant was close to attaining self-sufficiency regarding electrical energy use. The temperature increase of the feed to process conditions supposed a significant amount of thermal energy which highly compromised the efficiency when operating at low organic load, thus accounting for more than 80% of the total energy demand of the installation. When the energy assessment of the process was performed at higher OLR of 2.7 g VS/ L d, the resulting COPel value was1.68, demonstrating the feasibility of this configuration for decentralised digestion.

ACS Style

Rubén González; Jesus Ernesto Hernández; Xiomar Gómez; Richard Smith; Judith González Arias; Elia Judith Martínez; Daniel Blanco. Performance evaluation of a small-scale digester for achieving decentralised management of waste. Waste Management 2020, 118, 99 -109.

AMA Style

Rubén González, Jesus Ernesto Hernández, Xiomar Gómez, Richard Smith, Judith González Arias, Elia Judith Martínez, Daniel Blanco. Performance evaluation of a small-scale digester for achieving decentralised management of waste. Waste Management. 2020; 118 ():99-109.

Chicago/Turabian Style

Rubén González; Jesus Ernesto Hernández; Xiomar Gómez; Richard Smith; Judith González Arias; Elia Judith Martínez; Daniel Blanco. 2020. "Performance evaluation of a small-scale digester for achieving decentralised management of waste." Waste Management 118, no. : 99-109.

Article
Published: 31 July 2020 in Environmental Monitoring and Assessment
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Changes in consumer demand due to preferences for a healthier lifestyle have led to a new market offering fruit and salad products ready to eat. This affects the agro-industrial sector and the characteristic of waste streams generated having the organic fraction higher quality and representing a new opportunity of valorisation. This study experimentally evaluated the digestion of wastes derived from the fourth range product sector. It was also proposed the use of this digestate as a fermentation medium for producing plant growth-promoting cultures. Three digestion scenarios were studied: Scenario 1 considered biogas valorisation using a combined heat and power (CHP) unit. Scenario 2 featured biogas upgrading to be used as vehicle fuel. Finally, scenario 3 evaluated the transport of waste materials to the digestion plant by a network of pipes and pumps directly from the production chain. All three scenarios included the land application of a biostimulator based on the production of a plant growth-promoting culture derived from digestate. Life cycle analysis and life cycle costing were used to determine potential environmental impacts and costs over a lifetime of 25 years. The study showed that scenario 1 was the most favourable option for valorising this type of waste, although the economic assessment resulted in negative values for all three alternatives.

ACS Style

Rubén González; José Guillermo Rosas; Daniel Blanco; Richard Smith; Elia Judith Martínez; Raquel Pastor-Bueis; Xiomar Gómez. Anaerobic digestion of fourth range fruit and vegetable products: comparison of three different scenarios for its valorisation by life cycle assessment and life cycle costing. Environmental Monitoring and Assessment 2020, 192, 1 -19.

AMA Style

Rubén González, José Guillermo Rosas, Daniel Blanco, Richard Smith, Elia Judith Martínez, Raquel Pastor-Bueis, Xiomar Gómez. Anaerobic digestion of fourth range fruit and vegetable products: comparison of three different scenarios for its valorisation by life cycle assessment and life cycle costing. Environmental Monitoring and Assessment. 2020; 192 (8):1-19.

Chicago/Turabian Style

Rubén González; José Guillermo Rosas; Daniel Blanco; Richard Smith; Elia Judith Martínez; Raquel Pastor-Bueis; Xiomar Gómez. 2020. "Anaerobic digestion of fourth range fruit and vegetable products: comparison of three different scenarios for its valorisation by life cycle assessment and life cycle costing." Environmental Monitoring and Assessment 192, no. 8: 1-19.

Journal article
Published: 24 June 2020 in C
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Anaerobic digestion is an established technological option for the treatment of agricultural residues and livestock wastes beneficially producing renewable energy and digestate as biofertilizer. This technology also has significant potential for becoming an essential component of biorefineries for valorizing lignocellulosic biomass due to its great versatility in assimilating a wide spectrum of carbonaceous materials. The integration of anaerobic digestion and pyrolysis of its digestates for enhanced waste treatment was studied. A theoretical analysis was performed for three scenarios based on the thermal needs of the process: The treatment of swine manure (scenario 1), co-digestion with crop wastes (scenario 2), and addition of residual glycerine (scenario 3). The selected plant design basis was to produce biochar and electricity via combined heat and power units. For electricity production, the best performing scenario was scenario 3 (producing three times more electricity than scenario 1), with scenario 2 resulting in the highest production of biochar (double the biochar production and 1.7 times more electricity than scenario 1), but being highly penalized by the great thermal demand associated with digestate dewatering. Sensitivity analysis was performed using a central composite design, predominantly to evaluate the bio-oil yield and its high heating value, as well as digestate dewatering. Results demonstrated the effect of these parameters on electricity production and on the global thermal demand of the plant. The main significant factor was the solid content attained in the dewatering process, which excessively penalized the global process for values lower than 25% TS.

ACS Style

Rubén González; Judith González; José G. Rosas; Richard Smith; Xiomar Gómez. Biochar and Energy Production: Valorizing Swine Manure through Coupling Co-Digestion and Pyrolysis. C 2020, 6, 43 .

AMA Style

Rubén González, Judith González, José G. Rosas, Richard Smith, Xiomar Gómez. Biochar and Energy Production: Valorizing Swine Manure through Coupling Co-Digestion and Pyrolysis. C. 2020; 6 (2):43.

Chicago/Turabian Style

Rubén González; Judith González; José G. Rosas; Richard Smith; Xiomar Gómez. 2020. "Biochar and Energy Production: Valorizing Swine Manure through Coupling Co-Digestion and Pyrolysis." C 6, no. 2: 43.

Research article
Published: 08 June 2020 in Environmental Science and Pollution Research
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The coupling of biological and thermal technologies allows for the complete conversion of wastes into energy and biochar eliminating the problem of sludge disposal. The valorisation of fatty residues as co-substrate in a mesophilic digester of a wastewater treatment plant was studied considering an integrated approach of co-digestion and pyrolysis. Four digested samples obtained from co-digestion of sewage sludge and butcher’s fat waste were studied by thermogravimetric analysis. The activation energy corresponding to the sludge pyrolysis was calculated by a non-isothermal kinetic. Arrhenius activation energy was lower for the pyrolysis of a digested grease sample (92 kJ mol−1 obtained by OFW and 86 kJ mol−1 obtained by Vyazovkin) than for the pyrolysis of sewage sludge and its blends (164–190 kJ mol−1 obtained by OFW and 162–190 kJ mol−1 obtained by Vyazovkin). The analysis of the integrated approach of anaerobic co-digestion and pyrolysis of digestates demonstrated that the addition of 3% (w/v) of fat to the feeding sludge results in a 25% increase in the electricity obtained from biogas (if a combined heat and power unit is considered for biogas valorisation) and increasing the fat content to 15% allows for covering all thermal needs for drying of digestate and more than doubles (2.4 times) the electricity production when the scenario of digestion and pyrolysis is contemplated.

ACS Style

Judith González-Arias; María Victoria Gil; Ramón Ángel Fernández; Elia Judith Martínez; Camino Fernández; George Papaharalabos; Xiomar Gómez. Integrating anaerobic digestion and pyrolysis for treating digestates derived from sewage sludge and fat wastes. Environmental Science and Pollution Research 2020, 27, 32603 -32614.

AMA Style

Judith González-Arias, María Victoria Gil, Ramón Ángel Fernández, Elia Judith Martínez, Camino Fernández, George Papaharalabos, Xiomar Gómez. Integrating anaerobic digestion and pyrolysis for treating digestates derived from sewage sludge and fat wastes. Environmental Science and Pollution Research. 2020; 27 (26):32603-32614.

Chicago/Turabian Style

Judith González-Arias; María Victoria Gil; Ramón Ángel Fernández; Elia Judith Martínez; Camino Fernández; George Papaharalabos; Xiomar Gómez. 2020. "Integrating anaerobic digestion and pyrolysis for treating digestates derived from sewage sludge and fat wastes." Environmental Science and Pollution Research 27, no. 26: 32603-32614.

Original article
Published: 06 March 2020 in Biomass Conversion and Biorefinery
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The large cost of components used in microbial electrolysis cell (MEC) reactors represents an important limitation that is delaying the commercial implementation of this technology. In this work, we explore the feasibility of using pyrolysed almond shells (PAS) as a material for producing low-cost anodes for use in MEC systems. This was done by comparing the microbial populations that developed on the surface of PAS bioanodes with those present on the carbon felt (CF) bioanodes traditionally used in MECs. Raw almond shells were pyrolysed at three different temperatures, obtaining the best conductive material at the highest temperature (1000 °C). The behaviour of this material was then verified using a single-chamber cell. Subsequently, the main test was carried out using two-chamber cells and the microbial populations extant on each of the bioanodes were analysed. High-throughput sequencing of the 16S rRNA gene for eubacterial populations was carried out in order to compare the microbial communities attached to each type of electrode. The microbial populations on each electrode were also quantified by real-time polymerase chain reaction (real-time PCR) to determine the amount of bacteria capable of growing on the electrodes’ surface. The results indicated that the newly developed PAS bioanodes possess a biofilm similar to those found on the surface of traditional CF electrodes.

ACS Style

Cristian Arenas; Ana Sotres; Raúl M. Alonso; Judith González-Arias; Antonio Morán; Xiomar Gómez. Pyrolysed almond shells used as electrodes in microbial electrolysis cell. Biomass Conversion and Biorefinery 2020, 1 -9.

AMA Style

Cristian Arenas, Ana Sotres, Raúl M. Alonso, Judith González-Arias, Antonio Morán, Xiomar Gómez. Pyrolysed almond shells used as electrodes in microbial electrolysis cell. Biomass Conversion and Biorefinery. 2020; ():1-9.

Chicago/Turabian Style

Cristian Arenas; Ana Sotres; Raúl M. Alonso; Judith González-Arias; Antonio Morán; Xiomar Gómez. 2020. "Pyrolysed almond shells used as electrodes in microbial electrolysis cell." Biomass Conversion and Biorefinery , no. : 1-9.

Original paper
Published: 04 November 2019 in Waste and Biomass Valorization
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The feasibility of coupling the anaerobic digestion of pig manure and co-pyrolysis of its digestate with milk thistle as lignocellulosic biomass was studied. Kinetic analysis was performed along with an evaluation of energy recovery attained from a combined approach Pig slurry was digested under mesophilic semi-continuous conditions. Digestate was dried and submitted to thermogravimetric analysis under inert atmosphere along with milk thistle samples. Kinetic evaluation was carried out using non-isothermal methods. Assessment of the energy obtained from the combined digestion and pyrolysis process was performed. Digestion resulted in a yield of 308.5 ± 18.2 mL CH4/g VS. The evaluation of co-pyrolysis of mixtures at different contents of milk thistle showed no interactions between the two materials during pyrolysis. The energy need associated with thermal drying of digestate was 476 MJ/m3 of pig slurry. Co-pyrolysis of lignocellulosic biomass and digestate [25% content of digestate (w/w)] resulted in a lower char production, associated with the lower ash content of the former. The extra supply of energy needed for thermal drying of the digestate might be obtained from co-pyrolysis with biomass. This approach presented an energy recovery of about 29.4%

ACS Style

Judith González Arias; C. Fernández; J. G. Rosas; Maria Pilar Bernal; R. Clemente; M. E. Sánchez; X. Gómez. Integrating Anaerobic Digestion of Pig Slurry and Thermal Valorisation of Biomass. Waste and Biomass Valorization 2019, 11, 6125 -6137.

AMA Style

Judith González Arias, C. Fernández, J. G. Rosas, Maria Pilar Bernal, R. Clemente, M. E. Sánchez, X. Gómez. Integrating Anaerobic Digestion of Pig Slurry and Thermal Valorisation of Biomass. Waste and Biomass Valorization. 2019; 11 (11):6125-6137.

Chicago/Turabian Style

Judith González Arias; C. Fernández; J. G. Rosas; Maria Pilar Bernal; R. Clemente; M. E. Sánchez; X. Gómez. 2019. "Integrating Anaerobic Digestion of Pig Slurry and Thermal Valorisation of Biomass." Waste and Biomass Valorization 11, no. 11: 6125-6137.

Journal article
Published: 30 March 2019 in Energies
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The effect of hydrogen pulse addition on digestion performance of sewage sludge was evaluated as a means for studying the increase in efficiency of methane production. Microbial communities were also evaluated to get an insight of the changes caused by the operational modifications of the digester. An energy evaluation of this alternative was performed considering the theoretical process of coupling bioelectrochemical systems (BES) for the treatment of wastewater along with hydrogen production and the subsequent anaerobic digestion. The addition of hydrogen to sewage sludge digestion resulted in an increase of 12% in biogas production over the control (1353 mL CH4 d−1 at an injection flow rate of 1938 mL H2 d−1). The liquid phase of the sludge reactor and the H2 supplemented one did not show significant differences, thus indicating that the application of hydrogen as the co-substrate was not detrimental. High-throughput sequencing analysis showed slight changes in archaeal relative abundance after hydrogen addition, whereas eubacterial community structure and composition revealed noteworthy shifts. The mass and energy balance indicated that the amount of hydrogen obtained from a hypothetical BES can be assimilated in the sludge digester, improving biogas production, but this configuration was not capable of covering all energy needs under the proposed scenario.

ACS Style

Elia Judith Martínez; Ana Sotres; Cristián B. Arenas; Daniel Blanco; Olegario Martínez; Xiomar Gómez. Improving Anaerobic Digestion of Sewage Sludge by Hydrogen Addition: Analysis of Microbial Populations and Process Performance. Energies 2019, 12, 1228 .

AMA Style

Elia Judith Martínez, Ana Sotres, Cristián B. Arenas, Daniel Blanco, Olegario Martínez, Xiomar Gómez. Improving Anaerobic Digestion of Sewage Sludge by Hydrogen Addition: Analysis of Microbial Populations and Process Performance. Energies. 2019; 12 (7):1228.

Chicago/Turabian Style

Elia Judith Martínez; Ana Sotres; Cristián B. Arenas; Daniel Blanco; Olegario Martínez; Xiomar Gómez. 2019. "Improving Anaerobic Digestion of Sewage Sludge by Hydrogen Addition: Analysis of Microbial Populations and Process Performance." Energies 12, no. 7: 1228.

Chapter
Published: 11 January 2019 in Biofuel and Biorefinery Technologies
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Bio-hydrogen is generated by renewable feedstocks from biological, chemical, thermochemical and photolytic methods. Biological methods such as dark fermentation have been suggested as a feasible alternative to produce this gas and obtain a sustainable energy source. Bio-hydrogen is not a primary energy source, but it is compatible with electrochemical and combustion processes for energy conversion; this gas can be stored, transported and utilised to fulfil energy needs, and it also contributes to minimise carbon-based emissions reducing environmental pollution and climate change. In the present manuscript, a review is performed about the state of the art of the dark fermentation process and its integration with other processes in an attempt to increase the efficiency of substrate conversion. The two-stage configurations studied involve the bioprocesses for hydrogen production and waste treatment by coupling the dark fermentation process with an alternative biological route such as anaerobic digestion, microbial electrochemical systems or photo-fermentation to promote an efficient stabilisation and use of the organic matter.

ACS Style

E. Judith Martínez; Daniel Blanco; Xiomar Gómez. Two-Stage Process to Enhance Bio-hydrogen Production. Biofuel and Biorefinery Technologies 2019, 149 -179.

AMA Style

E. Judith Martínez, Daniel Blanco, Xiomar Gómez. Two-Stage Process to Enhance Bio-hydrogen Production. Biofuel and Biorefinery Technologies. 2019; ():149-179.

Chicago/Turabian Style

E. Judith Martínez; Daniel Blanco; Xiomar Gómez. 2019. "Two-Stage Process to Enhance Bio-hydrogen Production." Biofuel and Biorefinery Technologies , no. : 149-179.

Review
Published: 01 November 2018 in C
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Anaerobic digestion is a well-known technology which has been extensively studied to improve its performance and yield biogas from substrates. The application of different types of pre-treatments has led to an increase in biogas production but also in global energy demand. However, in recent years the use of carbon conductive materials as supplement for this process has been studied resulting in an interesting way for improving the performance of anaerobic digestion without greatly affecting its energy demand. This review offers an introduction to this interesting approach and covers the different experiences performed on the use of carbon conductive materials proposing it as a feasible alternative for the production of energy from biomass, considering also the integration of anaerobic digestion and thermal valorisation.

ACS Style

Judith González; Marta E. Sánchez; Xiomar Gómez. Enhancing Anaerobic Digestion: The Effect of Carbon Conductive Materials. C 2018, 4, 59 .

AMA Style

Judith González, Marta E. Sánchez, Xiomar Gómez. Enhancing Anaerobic Digestion: The Effect of Carbon Conductive Materials. C. 2018; 4 (4):59.

Chicago/Turabian Style

Judith González; Marta E. Sánchez; Xiomar Gómez. 2018. "Enhancing Anaerobic Digestion: The Effect of Carbon Conductive Materials." C 4, no. 4: 59.

Original paper
Published: 06 September 2018 in International Journal of Environmental Science and Technology
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This paper evaluates the technical and economic feasibility of using a steam accumulator in the thermal hydrolysis process for the treatment of sludge. The increase in the efficiency of anaerobic digestion and biogas valorisation through the combined use of heat and power engines was studied based on scenarios from the wastewater treatment plant of the city of Burgos (Spain). These scenarios were evaluated based on the installation of steam accumulation to average the thermal needs of the process. Biogas production was estimated based on the plant’s operating conditions between 2011 and 2016. Results indicated a process enhancement from 33 to 100% due to a better use of exhaust gases. Consequently, increases of 20.0% in the net biogas and 13.1% in electrical energy production were obtained, along with decreases of 66.8% in the thermal power needs and 61.9% in the biogas consumed by the recovery boiler. The economic savings were 98,213 €/year, due to a decrease in the need to purchase electrical energy from the network. The return on investment period was 2 years after introducing a steam accumulator to the process and replacing the boiler with a new, smaller one.

ACS Style

J. García-Cascallana; David Borge-Diez; X. Gómez. Enhancing the efficiency of thermal hydrolysis process in wastewater treatment plants by the use of steam accumulation. International Journal of Environmental Science and Technology 2018, 16, 3403 -3418.

AMA Style

J. García-Cascallana, David Borge-Diez, X. Gómez. Enhancing the efficiency of thermal hydrolysis process in wastewater treatment plants by the use of steam accumulation. International Journal of Environmental Science and Technology. 2018; 16 (7):3403-3418.

Chicago/Turabian Style

J. García-Cascallana; David Borge-Diez; X. Gómez. 2018. "Enhancing the efficiency of thermal hydrolysis process in wastewater treatment plants by the use of steam accumulation." International Journal of Environmental Science and Technology 16, no. 7: 3403-3418.

Journal article
Published: 01 September 2018 in Biochemical Engineering Journal
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In this study, the effects on process performance and changes in microbial populations with the addition of biochar to the anaerobic digestion of sludge and orange peels were evaluated. Biochar had a positive influence in batch digestions, leading to a decrease in the lag phase and an increase in methane yields; this was even more evident for citrus peel wastes, which reached an increase of approximately 33% when 10 g L-1 of biochar was added and 56% when 30 g L-1 was added. Particle size analysis performed for the experiments shows greater surface area available in biochar systems for biomass immobilization. Analysis of the microbial communities by means of 16S rRNA gene pyrosequencing shows that the biochar addition favoured the electro-active microorganisms consortia creating a synthrophic metabolism between eubacterial and archaeal populations, which resulted in an improvement of the anaerobic digestion performance. The codigestion of the mixture under a semicontinuous regimen showed an improvement in methane yields of approximately 60% and at hydraulic retention times of 30–20 days (reaching methane production values above 500 L CH4 kg VS-1 at an OLR of 1.49 kg VS m-3 d-1). The enhancement observe in biochar supplemented fermentations may be explained by the adsorption of inhibitors and the relatively high surface area favoured the adhesion and growth of microorganisms.

ACS Style

E. Judith Martínez; Jose Guillermo Rosas; Ana Sotres; Antonio Moran; Jorge Cara-Jiménez; Marta Elena Sánchez; Xiomar Gómez. Codigestion of sludge and citrus peel wastes: Evaluating the effect of biochar addition on microbial communities. Biochemical Engineering Journal 2018, 137, 314 -325.

AMA Style

E. Judith Martínez, Jose Guillermo Rosas, Ana Sotres, Antonio Moran, Jorge Cara-Jiménez, Marta Elena Sánchez, Xiomar Gómez. Codigestion of sludge and citrus peel wastes: Evaluating the effect of biochar addition on microbial communities. Biochemical Engineering Journal. 2018; 137 ():314-325.

Chicago/Turabian Style

E. Judith Martínez; Jose Guillermo Rosas; Ana Sotres; Antonio Moran; Jorge Cara-Jiménez; Marta Elena Sánchez; Xiomar Gómez. 2018. "Codigestion of sludge and citrus peel wastes: Evaluating the effect of biochar addition on microbial communities." Biochemical Engineering Journal 137, no. : 314-325.

Research article
Published: 29 June 2018 in Environmental Science and Pollution Research
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The anaerobic digestion process of swine manure was studied when char was used as supplement for improving performance. The use of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was proposed for assessing the organic matter degradation. The assessment on biogas production was carried out using samples of swine manure (SM) supplemented with char in one case and pre-treated by microwave irradiation in the other. This experimental set-up allows for the comparison of the biological degradation observed under these two different configurations and therefore aids in understanding the effect of char particles on the process. Results showed similar performance for both systems, with an average improvement of 39% being obtained in methane production when compared to the single digestion of SM. The analysis of digestate samples by Fourier transform infrared (FTIR) spectroscopy and Py-GC/MS showed improved degradation of proteins, with the Py-GC/MS technique also capable of identifying an increase in microbial-derived material when char was added, therefore highlighting the relevant role of carbon conductive particles on biological systems. Py-GC/MS along with the use of FTIR spectroscopy has proven to be useful tools when evaluating anaerobic digestion.

ACS Style

Xiomar Gómez; William Meredith; Camino Fernández; Mario Sánchez García; Rebeca Diez Antolinez; Jorge Garzón-Santos; Colin Snape. Evaluating the effect of biochar addition on the anaerobic digestion of swine manure: application of Py-GC/MS. Environmental Science and Pollution Research 2018, 25, 25600 -25611.

AMA Style

Xiomar Gómez, William Meredith, Camino Fernández, Mario Sánchez García, Rebeca Diez Antolinez, Jorge Garzón-Santos, Colin Snape. Evaluating the effect of biochar addition on the anaerobic digestion of swine manure: application of Py-GC/MS. Environmental Science and Pollution Research. 2018; 25 (25):25600-25611.

Chicago/Turabian Style

Xiomar Gómez; William Meredith; Camino Fernández; Mario Sánchez García; Rebeca Diez Antolinez; Jorge Garzón-Santos; Colin Snape. 2018. "Evaluating the effect of biochar addition on the anaerobic digestion of swine manure: application of Py-GC/MS." Environmental Science and Pollution Research 25, no. 25: 25600-25611.

Article
Published: 09 June 2018 in Journal of Thermal Analysis and Calorimetry
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Co-digestion of swine manure with glycerine was studied by thermal analysis (TA) and differential scanning calorimetry (DSC). Co-digestion experiments were performed under batch conditions at different organic loadings by increasing the volumetric percentage of glycerine in the mixture. Batch results were used for evaluating the performance of the process under semi-continuous conditions in an attempt to study the characteristics of the digested material. Batch tests demonstrated a successful digestion at a glycerine volumetric addition of 16% (v/v), whilst failure of the semi-continuous digestion process was reported at 8%. The different operating regimes explained the discrepancy in these outcomes, therefore, indicating that results from batch tests should not be directly extrapolated to estimate continuous performance. The addition of glycerine at high percentage negatively affected the digestion under semi-continuous conditions, resulting in the accumulation of volatile fatty acids and high H2S evolution in biogas. These characteristics were accompanied by a decrease in the conversion of the organic matter as reported from the thermal evaluation of digested samples. TA represents a good indicator of the stabilisation attained when evaluating the fate of complex materials during biological transformations. DSC demonstrated to be a superior tool when evaluating the course of digestion and the quality of the organic material obtained. The failure stage (8% glycerine content) reported a mass change of 25.3 ± 0.5% for the complex materials, which represented an increase of 17% when evaluated against the successful digestion at 4% glycerine content. In this same line, when the enthalpy is considered, these complex materials contribute an increase of 22% in the digested sample of the failure stage. This enthalpy value calculated for the complex materials (temperature region of 370–575 °C) greatly aids in assessing degradation. Therefore, the need of a stabilisation stage for co-digestion systems with a high content of readily degradable material was highly recommended.

ACS Style

Rubén González; Richard Smith; D. Blanco; J. Fierro; X. Gómez. Application of thermal analysis for evaluating the effect of glycerine addition on the digestion of swine manure. Journal of Thermal Analysis and Calorimetry 2018, 135, 2277 -2286.

AMA Style

Rubén González, Richard Smith, D. Blanco, J. Fierro, X. Gómez. Application of thermal analysis for evaluating the effect of glycerine addition on the digestion of swine manure. Journal of Thermal Analysis and Calorimetry. 2018; 135 (4):2277-2286.

Chicago/Turabian Style

Rubén González; Richard Smith; D. Blanco; J. Fierro; X. Gómez. 2018. "Application of thermal analysis for evaluating the effect of glycerine addition on the digestion of swine manure." Journal of Thermal Analysis and Calorimetry 135, no. 4: 2277-2286.