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1.
N Biotechnol ; 84: 77-84, 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-39357797

ABSTRACT

The extensive production of olive mill solid waste (OMSW) from olive oil industry in the Mediterranean basin claims effective treatments and valorization strategies. This study aims to elucidate the potential of anaerobic digestion (AD) and anaerobic fermentation (AF) to convert pre-treated OMSW into biogas (CH4) and volatile fatty acids (VFA), respectively. The two thermal treatment conditions (65 °C and 180 °C) that are being implemented in the industry that manages the OMSW were tested. Comparing the two treatments aims to demonstrate the influence on the AD process of the degree of solubilization and degradation of the metabolites produced from the same substrate. AD of OMSW treated at low-temperature (65 °C) exhibited similar methane yields (195 ± 8 mL CH4/g volatile solid (VS)) to raw OMSW. AD of the solid phase (SP) after high-temperature treatment with acid addition at 180 °C resulted in methane yields comparable to raw OMSW while the liquid phase (LP) exhibited low methane yields (85 ± 10 mL CH4/g VS). Nevertheless, LP/180 °C exhibited the highest VFA bioconversion at 27.6 %, compared to less than 10 % for SP/180 ºC, SP/65 °C, and raw OMSW. The VFA profile showed notable variations with thermal treatment temperatures. Propionic acid dominated at SP/65 °C, while acetic acid became the primary VFA at 180 °C. Furthermore, significant degradation rates of phenolic compounds and furans were observed during the final day of both anaerobic processes. Overall, these findings suggest that AD is more suitable for raw OMSW, treated at low temperature and SP at high temperature, while AF offers a promising alternative for high-temperature-treated LP.

2.
Heliyon ; 10(19): e38472, 2024 Oct 15.
Article in English | MEDLINE | ID: mdl-39397928

ABSTRACT

Anaerobic digestion (AD) is one of the most extensively accepted processes for organic waste cleanup, and production of both bioenergy and organic fertilizer. Numerous mathematical models have been conceived for modeling the anaerobic process. In this study, a new modified dynamic mathematical model for the simulation of the biochemical and physicochemical processes involved in the AD process for biogas production was proposed. The model was validated, and a sensitivity analysis based on the OAT approach (one-at-a-time) was carried out as a screening technique to identify the most sensitive parameters. The model was developed by updating the bio-chemical framework and including more details concerning the physico-chemical process. The fraction XP was incorporated into the model as a particulate inert product arising from biomass decay (inoculum). New components were included to distinguish between the substrate and inoculum, and a surface-based kinetics was used to model the substrate disintegration. Additionally, the sulfate reduction process and hydrogen sulfide production have been included. The model was validated using data extracted from the literature. The model's ability to generate accurate predictions was testified using statistical metrics. The model exhibited excellent performance in forecasting the parameters related to the biogas process, with measurements falling within a reasonable error margin. The relative absolute error (rAE) and root mean square error (RMSE) were both less than 5 %, indicating a high ability of the current model in comparison with the literature. Additionally, the scatter index (SI) was below 10 %, and the Nash-Sutcliffe efficiency (NES) approached one, which affirms the model's accuracy and reliability. Finally, the model was applied to investigate the performances of the AD of food waste (FW). The findings of this study support the robustness of the developed model and its applicability as a virtual platform to evaluate the efficiency of the AD treatment and to forecast biogas production and its quality, CO2 emission, and energy potential across various organic solid waste types.

3.
Article in English | MEDLINE | ID: mdl-39390829

ABSTRACT

Industrialization and globalization have increased the demand for petroleum products that has increased a load on natural energy resources. The escalating fossil fuel utilization has resulted in surpassing the Earth's capacity to absorb greenhouse gases, necessitating the exploration of sustainable bioenergy alternatives to mitigate emissions. Biofuels, derived from algae, offer promising solutions to alleviate fossil fuel dependency. Algae, often regarded as third-generation biofuels, present numerous advantages owing to their high biomass production rates. While algae have been utilized for their bioactive compounds, their capability as biomass for the production of biofuel has gained traction among researchers. Various biofuels such as bio-hydrogen, bio-methane, bio-ethanol, bio-oil, and bio-butanol can be derived from algae through diverse processes like fermentation, photolysis, pyrolysis, and transesterification. Despite the enormous commercial potential of algae-derived biofuels, challenges such as high cultivation costs persist. However, leveraging the utilization of algae byproducts could improve economic viability of biofuel production. Moreover, algae derived biofuels offer environmental sustainability, cost-effectiveness, and waste reduction benefits, promising novel opportunities for a more sustainable energy future.

4.
Bioresour Technol ; 413: 131534, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39326538

ABSTRACT

This work explores the impact of static magnetic field (SMF) intensity on biomethane production from anaerobic digestion (AD) of sewage sludge. Two different SMF intensities (20 mT and 1.5 T) were applied to magnetize the sludge destined to the AD process. The magnetic pretreatment at 20 mT was particularly effective, as it increased biomethane production by 12.7 % compared to the control test. On the contrary, exposing the sludge to 1.5 T adversely affected biomethane production, resulting in a 15.1 % decrease. The positive correlation observed between low-intensity SMF exposure and enhanced biomethane yield, in contrast to the inhibitory effect of high-intensity SMF, suggests the existence of an optimal intensity threshold within the lower range for maximizing methane production. The impact of magnetic pretreatment on the anaerobic microbial community was investigated through high-throughput sequencing analysis of magnetized sludge samples. This approach enabled the identification of specific shifts in microbial populations associated with SMF exposure, thereby elucidating the role of SMF in modulating key microbial communities for the AD process. The findings of this study provide insights into the potential mechanisms underlying these responses and underscore the potential of SMF application for improving the anaerobic valorization of sewage sludge.

5.
Environ Monit Assess ; 196(10): 988, 2024 Sep 30.
Article in English | MEDLINE | ID: mdl-39349837

ABSTRACT

The forecasted global population growth is poised to create a greater exigency for livestock-derived food production, leading to a significant waste generation from the industrial-scale livestock operations, which necessitates to develop sustainable waste management solutions. The heightened demand for livestock and dairy products has driven a surge in cow waste (CW) production. While CW is typically used as organic fertilizer or solid fuel, improper disposal poses potential environmental hazards. Anaerobic digestion and composting transform CW into valuable products, such as biofuels and organic fertilizers, with the potential for electricity and heat generation, biochar production, and advanced friction materials. The CW contains essential inorganic and organic compounds vital for plant functions, including lignin, cellulose, hemicellulose, nitrogen, and minerals such as potassium, sulfur, iron, magnesium, copper, cobalt, and manganese. Additionally, the rich microbial diversity in cow dung drives the production of bioenergy carriers like biomethane and biohydrogen, promoting cost-effective energy generation and environmental sustainability. This review employs bibliometric analysis to explore the latest trends in CW applications, with a particular focus on innovative applications such as cellulose extraction, biochar production, microbial fuel cells, and nanoparticle synthesis. It further evaluates the environmental impacts of these technologies and assesses their potential to advance sustainable and cleaner frontiers in the valorization of CW.


Subject(s)
Manure , Animals , Cattle , Waste Management/methods , Fertilizers , Biofuels
6.
Bioresour Technol ; 413: 131421, 2024 Sep 02.
Article in English | MEDLINE | ID: mdl-39233186

ABSTRACT

Anaerobic digestion (AD) is an environmentally friendly technology that simultaneously stabilizes biowaste and produces biogas. Conventional AD faces challenges such as inadequate substrate degradation and low methane purity. Pressure-centric regulation serves as an AD optimization strategy that can enhance the digestion efficiency and generate higher-energy-value biogas. However, limited reviews have been undertaken to focus on this technology. This review is designed to discuss innovations in ex-situ high-pressure pretreatment and in-situ high-pressure anaerobic digestion (HPAD) processes. Moreover, comprehensive understandings on the intrinsic mechanisms of HPAD are critically examined, including physicochemical reaction principles and microbial responses. The constraints currently curtailing these technologies and potential mitigation strategies are also scrutinized. Additionally, current knowledge gaps and future research directions on mechanisms, model fitting, and engineering practices are presented. Overall, this work highlights the feasibility of pressure-centric regulated AD and provides novel insights to overcome existing technical barriers in its application.

7.
J Hazard Mater ; 480: 135801, 2024 Sep 10.
Article in English | MEDLINE | ID: mdl-39270585

ABSTRACT

This research aims to investigate the influence of sulfate on the performance of microbial electrolysis cell-assisted anaerobic digester (MEC-AD) across varying sulfate conditions, including no sulfate and reduced COD/sulfate ratios from 20 to 1. The principal results indicate a gradual decline in methane yield in the MEC-AD from 78.7 ± 2.3 % under no sulfate conditions to 56.2 ± 2.0 % at a COD/sulfate ratio of 1, contrasting with a more substantial decrease in the control reactor (69.9 ± 3.6 % to 32.8 ± 1.5 %). The MEC-AD reactor exhibits heightened resilience to sulfide toxicity, showcasing higher specific methanogenic activities. Key findings suggest that the MEC-AD reactor maintains lower free sulfide concentrations, attributed to its higher pH and potential anodic sulfide oxidation. Additionally, the study reveals the promotion of syntrophic partnerships in the MEC-AD reactor, particularly between sulfate-reducing bacteria (SRB) such as Desulfovibrio, Desulfomicrobium, and Desulfobulbus, and other microbial groups, including hydrogenotrophic methanogens and electroactive bacteria. The integration of these mechanisms highlights the MEC-AD reactor's ability to effectively mitigate sulfate-induced challenges and enhance overall anaerobic digestion performance. This study presents a significant step forward in the development of resilient anaerobic digestion systems capable of efficiently handling sulfate stress.

8.
Waste Manag Res ; 42(10): 889-900, 2024 Oct.
Article in English | MEDLINE | ID: mdl-39331361

ABSTRACT

This article investigates the pivotal role of non-hazardous waste landfills in achieving greenhouse gas (GHG) reduction objectives within the European Union (EU).1 This study leverages the experience of key stakeholders in the European landfilling, assesses the efficacy of 'best-in-class' landfill installations, evaluates their potential impact on GHG reduction, and offers concrete recommendations for operators and policymakers. 'Best-in-class' landfills exceed the commonly accepted best practices by implementing all the following practices: (1) an anticipated capture system during the operating phase, (2) prompt installation of the final cover and capture system, with use of an impermeable cover, (3) operated as bioreactor, keeping optimal humidity, (4) adequate maintenance and reporting, (5) recovery of captured gas and (6) treatment of residual methane emissions throughout the waste decomposition process. The main finding is that switching from the actual mix of practices to 'best in class' practices would reduce by ~21 MtCO2eq (-36%) the emissions due to the degradation of waste landfilled between 2024 and 2035, compared to the 'business-as-usual scenario', while also providing a renewable energy source, bringing potential avoided emissions and energy sovereignty. The findings underscore that in addition to implementing the organics diversion and waste reduction targets of the EU, adopting 'best-in class' landfill practices has the potential to bolster energy recovery, mitigate emissions and stimulate biomethane production, thereby advancing the EU environmental goals.


Subject(s)
European Union , Greenhouse Gases , Waste Disposal Facilities , Greenhouse Gases/analysis , Methane/analysis , Waste Management/methods , Refuse Disposal/methods , Air Pollution/prevention & control , Environmental Policy , Air Pollutants/analysis
9.
Waste Manag ; 189: 114-126, 2024 Dec 01.
Article in English | MEDLINE | ID: mdl-39182277

ABSTRACT

This study optimized the anaerobic digestion (AD) of separated collected organic fractions of municipal solid waste (OFMSW) to produce energy and digestate as biofertilizer. Due to OFMSW's partial recalcitrance to degradation, enzymatic (UPP2, MCPS, USC4, USE2, A. niger) and physical (mechanical blending, heating, hydrodynamic cavitation) pre-treatments were tested. Experimental and modeling approaches were used to compare AD performance regarding energy sustainability and digestate quality. Digestate was separated into solid and liquid fractions, and then chemically and physically characterized by investigating the nutrient release mechanisms. Principal Component Analysis was applied, equally weighing energy and digestate productions. Unlike previous studies focusing only on biogas, this study evaluated the effects of pre-treatments on both biogas and digestate production, viewing AD as a biorefinery process for urban waste valorization. Results showed that all pre-treatments were energetically sustainable, but enzymatic pre-treatments yielded digestates richer in nutrients (increase of 80% N, 200% P and 150% K as compared to OFMSW) and with greater organic matter degradation compared to physical pre-treatments. The liquid fraction of digestate from enzymatic pre-treatments had higher nutrient concentrations, while those from physical pre-treatments had more balanced nutrient content, making them more suitable for fertigation.


Subject(s)
Biofuels , Refuse Disposal , Solid Waste , Anaerobiosis , Biofuels/analysis , Solid Waste/analysis , Refuse Disposal/methods , Agriculture/methods , Bioreactors
10.
Environ Sci Pollut Res Int ; 31(38): 49935-49984, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39090294

ABSTRACT

Biohythane, a balanced mixture comprising bioH2 (biohydrogen) and bioCH4 (biomethane) produced through anaerobic digestion, is gaining recognition as a promising energy source for the future. This article provides a comprehensive overview of biohythane production, covering production mechanisms, microbial diversity, and process parameters. It also explores different feedstock options, bioreactor designs, and scalability challenges, along with techno-economic and environmental assessments. Additionally, the article discusses the integration of biohythane into waste management systems and examines future prospects for enhancing production efficiency and applicability. This review serves as a valuable resource for researchers, engineers, and policymakers interested in advancing biohythane production as a sustainable and renewable energy solution.


Subject(s)
Bioreactors , Anaerobiosis , Biofuels , Waste Management/methods , Methane
11.
Bioresour Technol ; 412: 131395, 2024 Nov.
Article in English | MEDLINE | ID: mdl-39216699

ABSTRACT

The increasing production of industrial solid waste requires better disposal solutions. Porous hollow microspheres (PHM) are small inorganic materials with high surface area and adsorption capacity, but their potential for use in anaerobic digestion (AD) has not been explored. With PHM as additive, the effects of different industrial solid wastes (waste glass, steel slag, and fly ash) with different loadings (2 %-8 %), respectively, on the AD of corn straw were investigated in this study. The results showed that PHM could supplement trace elements and promote biofilm formation, which effectively shortened the lag period (25.00-60.87 %) and increased the methane yield (4.75 %-16.28 %). The 2 % PHM loading based on steel slag gave the highest methane yield (300.16 NmL/g VSadd). Microbial and PICRUSt2 analyses indicated that PHM enriched hydrolytic and acidogenic bacteria, increased the abundance of methanogenesis-related enzyme genes. This study provides a theoretical basis for the comprehensive utilization of coupled industrial and agricultural wastes.


Subject(s)
Industrial Waste , Methane , Microspheres , Zea mays , Zea mays/chemistry , Methane/metabolism , Porosity , Anaerobiosis , Biofuels , Biofilms
12.
Molecules ; 29(15)2024 Jul 25.
Article in English | MEDLINE | ID: mdl-39124898

ABSTRACT

By allowing coal to be converted by microorganisms into products like methane, hydrogen, methanol, ethanol, and other products, current coal deposits can be used effectively, cleanly, and sustainably. The intricacies of in situ microbial coal degradation must be understood in order to develop innovative energy production strategies and economically viable industrial microbial mining. This review covers various forms of conversion (such as the use of MECoM, which converts coal into hydrogen), stresses, and in situ use. There is ongoing discussion regarding the effectiveness of field-scale pilot testing when translated to commercial production. Assessing the applicability and long-term viability of MECoM technology will require addressing these knowledge gaps. Developing suitable nutrition plans and utilizing lab-generated data in the field are examples of this. Also, we recommend directions for future study to maximize methane production from coal. Microbial coal conversion technology needs to be successful in order to be resolved and to be a viable, sustainable energy source.

13.
ChemSusChem ; 17(19): e202400779, 2024 Oct 07.
Article in English | MEDLINE | ID: mdl-38958605

ABSTRACT

Biogas offers significant benefits as a renewable energy source, contributing to decarbonization, waste management, and economic development. This comprehensive review examines the historical, technological, economic, and global aspects of biomethane production, focusing on the key players such as China, the European Union, and North America, and associated opportunities and challenges as well as future prospects from an Australia perspective. The review begins with an introduction to biogas, detailing its composition, feedstock sources, historical development, and anaerobic digestion (AD) process. Subsequently, it delves into major biomethane production technologies, including physicochemical absorption, high-pressure water scrubbing (HPWS), amine scrubbing (AS), pressure swing adsorption (PSA), membrane permeation/separation (MP), and other technologies including organic solvent scrubbing and cryogenic separation. The study also discusses general guidelines of techno-economic assessments (TEAs) regarding biomethane production, outlining the methodologies, inventory analysis, environmental life cycle assessment (LCA), and estimated production costs. Challenges and opportunities of biogas utilization in Australia are explored, highlighting and referencing global projections, polarization in production approaches, circularity in waste management, and specific considerations for Australia. The review concludes discussing future perspectives for biomethane, emphasizing the importance of technological advancements, policy support, and investment in realizing its full potential for sustainable energy and waste management solutions.


Subject(s)
Biofuels , Methane , Biofuels/economics , Methane/chemistry
14.
Heliyon ; 10(12): e33401, 2024 Jun 30.
Article in English | MEDLINE | ID: mdl-39027437

ABSTRACT

Examining the case of Lithuania, this study comparatively analyzed five perennial grass-legume mixtures in terms of biomethane production. Every mixture was divided into two parts: long (during the fifth year or beyond) and short (during the first four years) time periods. The analysis includes three types of perennial bell grass: Timothy, P. Ryegrass, C. Cocksfoot, and one legume grass Red clover. With this study, we aimed to evaluate how perennial grass-legume mixtures can promote biomethane uptake in Lithuania. Through analyzing the efficiency and consequences of government subsidy measures, this study aimed to address the question of how governmental assistance can promote the growth of the biomethane industry, specifically focusing on the utilization of perennial grass-legume mixtures. This study used seven financial indicators, including subsiding policy, in order to gain a deeper understanding of mixtures for biomethane production. The analysis revealed that the best mixtures for biomethane production with subsidies were the second (Red clover 35 % + Timothy 45 % + Ryegrass 20 % grass mixture) and fourth scenarios (Red clover 55 % + Ryegrass 45 % grass mixture). The first (Red clover 35 %. + Timothy 25 % + Ryegrass 20 % + Cocksfoot 20 % grass mixture), third (Red clover 55 % + Timothy 45 % grass mixture), and fifth scenarios (Red clover 55 % + Cocksfoot 45 % grass mixture) had the smallest positive effects. The results showed that, in Lithuania, in order to encourage farmers to produce biomethane, subsidy policies are needed. Incentives for engaging with this activity are necessary, as the income earned does not cover the costs incurred; unfortunately, biomethane production is unprofitable without subsidy. As such, our recommendation is to develop a long-term subsidy policy to promote biomethane production, focusing on the effectiveness, particularly in the Lithuanian context, of utilizing mixtures of perennial grasses. Further research and policy interventions are needed to address the opportunities associated with scaling synergy between perennial energy cops and environmental sustainability in bioenergy crop cultivation.

15.
Environ Sci Pollut Res Int ; 31(37): 49560-49573, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39080174

ABSTRACT

Anaerobic and membrane technologies are a promising combination to decrease the energy consumption associated with wastewater treatment, allowing the recovery of resources: organic matter as biomethane, nutrient assimilation by microalgae and reclaimed water. In this study, domestic wastewater was treated using a combination of an upflow anaerobic sludge blanket sludge reactor (UASB) and a membrane photobioreactor (MPBR). The outdoor facilities were operated continuously for three months under unfavourable environmental conditions such as lack of temperature control, winter season with lower solar irradiation and lower daylight hours which was a challenge for the present work, not previously described. The energetic valorisation of the organic matter present in the wastewater by biomethane produced in the UASB would contribute to reducing overall facilities' energy requirements. The ultrafiltration (UF) membrane facilitated the harvesting of biomass, operating at 10 L·h-1·m-2 during the experimental period. Although the main contribution to fouling was irreversible, chemical cleanings were not necessary due to effective fouling control, which prevented the final TMP from exceeding 25 kPa. In addition, microalgae-bacterial consortium developed without prior inoculation were harvested from the MPBR using membrane assistance. The obtained biomass was also successfully tested as a biostimulant for corn germination/growth, as well as a biopesticide against Rhizoctonia solani and Fusarium oxysporum.


Subject(s)
Photobioreactors , Waste Disposal, Fluid , Wastewater , Wastewater/chemistry , Anaerobiosis , Waste Disposal, Fluid/methods , Bioreactors , Microalgae , Biomass , Membranes, Artificial
16.
J Environ Manage ; 366: 121860, 2024 Aug.
Article in English | MEDLINE | ID: mdl-39025008

ABSTRACT

The biodegradation of guar gum by microorganisms sourced from coalbeds can result in low-temperature gel breaking, thereby reducing reservoir damage. However, limited attention has been given to the influence of salinity on the synergistic biodegradation of coal and guar gum. In this study, biodegradation experiments of guar gum and lignite were conducted under varying salinity conditions. The primary objective was to investigate the controlling effects and mechanisms of salinity on the synergistic biodegradation of lignite and guar gum. The findings revealed that salinity had an inhibitory effect on the biomethane production from the co-degradation of lignite and guar gum. The biomethane production declined with increasing salinity levels, decreasing from 120.9 mL to 47.3 mL. Even under 20 g/L salt stress conditions, bacteria in coalbeds could effectively break the gel and the viscosity decreased to levels below 5 mPa s. As salinity increased, the removal rate of soluble chemical oxygen demand (SCOD) decreased from 55.63% to 31.17%, and volatile fatty acids (VFAs) accumulated in the digestion system. High salt environment reduces the intensity of each fluorescence peak. Alterations in salinity led to changes in microbial community structure and diversity. Under salt stress, there was an increased relative abundance of Proteiniphilum and Methanobacterium, ensuring the continuity of anaerobic digestion. Hydrogentrophic methanogens exhibited higher salt tolerance compared to acetoclastic methanogens. These findings provide experimental evidence supporting the use of guar gum fracturing fluid in coalbeds with varying salinity levels.


Subject(s)
Biodegradation, Environmental , Galactans , Mannans , Plant Gums , Salinity , Plant Gums/metabolism , Galactans/metabolism , Mannans/metabolism , Coal , Fatty Acids, Volatile/metabolism
17.
Huan Jing Ke Xue ; 45(7): 4352-4360, 2024 Jul 08.
Article in Chinese | MEDLINE | ID: mdl-39022979

ABSTRACT

Food waste is one of the important reservoirs of antibiotic resistance genes (ARGs), and its resource utilization has potential environmental risks. Anaerobic digestion (AD) technology can concurrently achieve resource recovery and ARGs removal, which is one of the popular resource technologies for food waste management. However, the removal efficiency of ARGs during the AD process is limited, and thus the safety of digestate for agricultural use is still questioned. Therefore, how to improve the performance of ARGs removal during the AD process is critical for efficient and environmentally friendly bioconversion of food waste. This study summarized the transmission pathways and mechanisms of ARGs in food waste; discussed the effects of different operation parameters on the transmission of ARGs in food waste during the AD process; described the research progress of exogenous addition of conductive materials, feedstock pretreatment, etc., strategies to enhance the removal of ARGs; and analyzed the migration regularity and removal mechanism of ARGs in food waste during the AD process, which mainly included microbial community structure evolution, mobile genetic element changes, and environmental factor changes. Finally, this study prospected the future improvement of methane yield and ARGs removal in the AD process of food waste based on the existing research.


Subject(s)
Drug Resistance, Microbial , Anaerobiosis , Drug Resistance, Microbial/genetics , Refuse Disposal/methods , Bioreactors/microbiology , Food , Biodegradation, Environmental , Food Loss and Waste
18.
Bioresour Technol ; 406: 130981, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38879053

ABSTRACT

Biological H2-assisted biogas upgrading has gained significant attention as an environmentally friendly substitute to common physico-chemical upgrading techniques, but is largely limited by the low solubility of H2. This study evaluated the design of a ceramic membrane contactor module for H2 injection. H2 dissolution was maintained at high efficiency by controlling gas supply and sludge recirculation rate, achieving a biogas quality of average 98.8% CH4 during the stable operation phase with a 108% increase in the CH4 production rate. This also outperforms conventional H2 injection using diffuser sparging which could only achieve a biogas quality of 84% CH4 content. Microbial community analysis found high Methanobacterium spp. abundance within the archaea at 95.2% at the end of the operation, allowing the dominance of the hydrogenotrophic methanogenesis pathway for high upgrading efficiencies. The system is a high-performance external membrane connector module coupled to common anaerobic digestion systems for biogas upgrading.


Subject(s)
Biofuels , Ceramics , Hydrogen , Membranes, Artificial , Methane , Ceramics/chemistry , Methane/metabolism , Hydrogen/metabolism , Bioreactors , Sewage/microbiology , Anaerobiosis
19.
Bioresour Technol ; 406: 130987, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38885724

ABSTRACT

Biochar has been proved to improve methane production in high solids anaerobic co-digestion (HS-AcoD) of dewatered sludge (DS) and food waste (FW), but its potential mechanism for simultaneous methane production and phosphorus (P) transformation has not been sufficiently revealed. Results showed that the optimal preparation temperature and dosage of sludge-based biochar were selected as 300 °C and 0.075 g·g-1, respectively. Under this optimized condition, the methane production of the semi-continuous reactor increased by 54%, and the active phosphorus increased by 18%. The functional microorganisms, such as Methanosarcina, hydrogen-producing, sulfate-reducing, and iron-reducing bacteria, were increased. Metabolic pathways associated with sulfate reduction and methanogenesis, especially hydrogenotrophic methanogenesis, were enhanced, which in turn promoted methanogenesis and phosphorus transformation and release. This study provides theoretical support for simultaneously recovery of carbon and phosphorus resources from DS and FW using biochar.


Subject(s)
Bioreactors , Charcoal , Methane , Phosphorus , Sewage , Methane/metabolism , Sewage/microbiology , Charcoal/chemistry , Anaerobiosis , Food , Food Loss and Waste
20.
Int J Biol Macromol ; 274(Pt 2): 133443, 2024 Aug.
Article in English | MEDLINE | ID: mdl-38942405

ABSTRACT

Lignocellulose is an abundant renewable bio-macromolecular complex, which can be used to produce biomethane and other high-value products. The lignin, presents in lignocellulose is typically regarded as an inhibitor of anaerobic digestion. Therefore, it is crucial to develop a novel selective separation strategy to achieve efficient biomethane production and all-component utilization of biomass. Hence, a combination of two-step pretreatment and solid-state anaerobic digestion was employed to enhance the production of biomethane and to generate valuable chemicals from poplar waste. Optimal conditions (4 % acetic acid, 170 °C, and 40 min) resulted in 70.85 % xylan removal, yielding 50.28 % xylo-oligosaccharides. The effect of a strong acid 4-CSA-based novel three-constituent DES on delignification was investigated from 80 °C to 100 °C; the cellulose content of DES pretreated poplar increased from 64.11 % to 80.92 %, and the delignification rate increased from 49.0 % to 90.4 %. However, high delignification of the pretreated poplar (DES-100 and DES-110) led to a rapid accumulation of volatile organic acids during the hydrolysis and acidogenesis stages, resulting in methanogenesis inhibition. The highest biomethane yield of 208 L/kg VS was achieved with DES-80 (49.0 % delignification), representing a 148 % improvement compared over untreated poplar. This approach demonstrates the potential for comprehensive utilization of all components of biomass waste.


Subject(s)
Lignin , Methane , Populus , Lignin/chemistry , Populus/chemistry , Populus/metabolism , Methane/chemistry , Methane/metabolism , Anaerobiosis , Hydrolysis , Oligosaccharides/chemistry , Biomass , Glucuronates/chemistry , Waste Products
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