Search

This work assesses a chemical plant for the conversion of biogas into negative emission "emerald hydrogen" via electrified reforming and CO 2 separation. Electrification of the reformer allows for enhanced syngas production, compact reactor designs and flexible operation, thanks to the avoidance of combustion and heat transfer through pressure walls. The integration of the process with solar and wind power generation has been assessed by part-load process simulations and plant sizing and operation optimization through yearly simulations with hourly discretization. Different European locations with different wind and solar availabilities were assessed considering (i) short- and long-term cost scenarios for renewables and battery technologies and (ii) different plant size (from 390 to 3900 Nm3/h of biogas capacity). The overarching scope of the paper is to calculate the cost of the produced hydrogen and the economic value of flexibility for plants installed in different locations, under different cost scenarios. At design load, the assessed process consumes 17.7 kWh of electricity per kg H2 and retains 96% of the biogas chemical energy in the produced hydrogen. Additionally, 76% of the biogenic carbon is recovered as high-purity liquid CO 2 , achieving up to −9 kg CO2 /kg H2 negative emissions. When powered with 95% of renewable energy, hydrogen production cost ranges from 2.5 to 2.9 €/kg for a long-term REN cost scenario and large-scale flexible plant to 5.9–7.1 €/kg for a short-term REN cost scenario and small-scale inflexible plants. For small-scale plants, flexibility allows to reduce the hydrogen production cost by 11–16% with respect to the inflexible plant in the short-term renewables cost scenario and by 1–4% in the long-term cost scenario. For large-scale plants, the adoption of a flexible plant leads to a reduction of 17–23% of the hydrogen cost in the short-term scenario and of 6–22% in the long-term scenario. Operational flexibility of electrified reforming allows reducing the cost of negative-emission bio-hydrogen by 1–23%, depending on location and cost scenario. [Display omitted] • Process engineering study with off-design model. • Economic optimization of flexible process with PV, wind, BESS and gas storages. • 17.7 kWh/kg H2 of electric consumption and up to −9 kg CO2 /kg H2 negative emissions. • H 2 cost of 2.5–6.2 €/kg depending on location, REN cost scenario and plant capacity. • Flexibility reduces H 2 cost by 1–23% depending on location and REN cost scenario. [ABSTRACT FROM AUTHOR]

The USA has committed to cutting its emissions of methane, an extremely potent greenhouse gas, by at least 30% by 2030 (‘30 × 30’). This is part of the Global Methane Pledge, signed by 155 countries, to keep global warming within 1.5 °C and thereby to forestall the disastrous effects of ‘runaway climate change’. It will be a major challenge for the USA to reach 30 × 30 and there is no consensus on how to do so. This paper provides a concrete, data‐driven roadmap to indicate how to reach 30 × 30 feasibly, focusing on two enormous sources of methane emissions: organic waste and oil and gas production. It calculates that building approximately 4700 anaerobic digesters (ADs) to process food waste and animal manure would cost about $74.2 billion in capital expenditure (capex) and cut 13.6% of total US methane emissions per year. On average, each project would take roughly 2–6 years to build. Of the various methane mitigation measures analyzed in the oil and gas sectors, the most impactful would be full compliance with the US Environmental Protection Agency's (EPA's) revised New Source Performance Standards (NSPS) for oil and gas production by 2029. This would cut 17.5% of total US methane emissions annually, at a cumulative capex of $20.7 billion from 2024 to 2029. Together, the 13.6% cut from food waste and manure ADs and the 17.5% cut from full NSPS compliance would amount to a 31.5% reduction, exceeding the 30 × 30 goal. Greater clarity from the federal government on funding eligibility and additional incentives would accelerate the buildout of ADs. [ABSTRACT FROM AUTHOR]

Anaerobic fermentation (AF) can effectively dispose of kitchen waste (KW) without the shortcomings of traditional methods such as incineration and sanitary landfill. However, KW has a high organic content, which easily leads to acidification and ammonia inhibition during digestion. To mitigate this issue, anaerobic co-digestion (AnCoD) with other substrates helps to adjust the carbon to nitrogen ratio (C/N) and enhance the stability of the reaction system. The hydrolysis of substrate is the rate-determining step in AF, prompting the adoption of necessary pretreatment methods to accelerate substrate hydrolysis. Among physical, chemical, and enzymatic pretreatments, the latter is more efficient. And the enzymatic pretreatment does not need additional equipment or reagents. Therefore, coupling enzyme treatment before AnCoD received more attention. In this review, we conduct a comparative analysis of the biogas production efficiency of enzymatic pretreatment against other pretreatment methods. The challenges and strategies concerning enzymatic pretreatment coupled with AnCoD system were discussed. Finally, the pilot-scale study and industrial application for KW co-digestion are also analyzed. [ABSTRACT FROM AUTHOR]

The industrial sector of Pakistan is currently facing severe load-shedding, which ultimately affects its unit production. The greater dependency on conventional energy resources (Thermal, Nuclear, etc.) results in higher production costs and environmental pollution. A sustainable, cost-effective, and environment-friendly solution can help the industrial growth of Pakistan. This article proposes an optimal hybrid energy system (HES) for the industrial sector of Pakistan to overcome the mentioned challenges. The proposed HES is developed in HOMER Pro. Three different energy cases (Case I: Existing energy system including a utility grid and diesel generator, Case II: On-grid Biogas system, and Case III: On-grid PV system with batteries) are considered for the Gourmet food Industry in the Sundar Industrial estate, Pakistan. The Load profile of the selected site was calculated through on-site visits and data provided by the designated utility grid feeder. The analysis shows that Case III is more effective than other cases, indicating reduced Net Present Cost (NPC), Cost of Energy (COE), and Operating Cost (OC) to $ 19.2 million, $0.034/kWh, and $ 573,371/year respectively. Moreover, the On-grid PV system with batteries (Case III) provides an environmentally friendly solution by reducing 63.82% by and 62.22% . Comparing the sensitivity analysis for various grid sell-back prices ($0/kWh, $0.043/kWh, $0.061/kWh, and $0.09/kWh), Case III is more cost-effective than Case II. The revenue generation in Case III is $128,499.41/yr, considering the supply of excess electricity into nearby small industrial loads at $0.065/kWh, this indicates that installing optimal HES in industries will not only help in overall cost reduction but also support in mitigating environmental pollution and load shedding. [ABSTRACT FROM AUTHOR]

Biogas is a type of biomass energy source, primarily composed of methane and carbon dioxide. It is generated through the controlled anaerobic digestion of manure or other organic residues. As a cleaner alternative to conventional fuels, fully purified biogas can produce approximately 36.68 MJ/m3 of en.ergy. As the separation of CO2/CH4 in biogas became an important part of the energy industry, we used membrane separation technique to study its separation methods. At first, 3,3′‐dihydroxy‐4,4′‐diamino‐biphenyl (HAB) and 4,4′‐(hexafluoroisopropylidene)diphthalic anhydride (6FDA) were polymerized by open‐loop as polyamide acid macromolecules. Then it was divided into two research routes. One was condensation to polyimide (PI) membranes directly and then thermal rearrangement (TR); the other one was ionic liquid (IL) added before condensation and thermal rearrangement. Through adjusting the thermal rearrangement temperature, different modified polyimide membranes were obtained and tested their separation performance of CO2/CH4. For the result of the test, the best one, membrane HAB‐6FDA‐IL‐TR400, could reach a good separation performance as PCO2 = 403.80 Barrer, αCO2/CH4 = 82.35. It was beyond the Robeson's 2019 upper limit and proved that the modification by IL and thermal rearrangement was benefit for the separation performance of polyimide membranes. [ABSTRACT FROM AUTHOR]

This paper presents a bibliometric review on biogas reforming for the production of sustainable aviation fuel. The central themes are catalyst stability and syngas H 2 /CO ratio. It begins with a summary of bibliometric data, literature trends, and most productive agents. Followed by citation analysis on dry reforming (DR) and steam reforming (SR), including internal reforming in fuel cells. Then, a statistical exploration of literature data on reforming in nickel catalysts, followed by the thermodynamic effects of temperature, pressure, and H 2 O/CH 4 ratio. For Sustainable Aviation Fuel (SAF) production, steam reforming appears as the best option. The biggest gaps in the biogas reforming literature are kinetic studies and pressure effect assessments, for scale-up. [Display omitted] • Steam reforming syngas is most appropriate for Sustainable Aviation Fuel production. • Dry reforming values CO 2 but still presents major challenges to industrial implementation. • Biogas reforming literature is poor in studies of the effect of pressure, and reaction kinetics. • Nickel loads have negative correlation with catalyst activity. The H 2 O concentration, with the conversion and H 2 /CO ratio. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Textile waste is becoming among the most polluting waste in the world, discarded mostly in landfills. Valorizing textile waste via anaerobic digestion (AD) helps conserve resources, reduce environmental impact, and foster a circular economy. Although several reviews have discussed textile waste AD, there is a lack of detailed understanding of the challenges encountered during textile waste AD. Therefore, the goal of this review is to focus on challenges encountered and possible solutions for those challenges for biogas and fertilizer conversion via AD. Potential strategies include chemical, biological, and thermal pretreatments that significantly increase the digestion process. Co‐digestion of natural textile waste, cotton, and wool with carbon and nitrogen‐rich substrates improves AD efficiency by twofold. Moreover, separating polyester from polycotton and textile dye removal via solvent and advanced oxidation processes significantly increases methane yield compared with untreated textile waste. This review can aid in analyzing suitable methods to optimize the biogas production of textile waste via AD. [ABSTRACT FROM AUTHOR]

The amount of biomass production each year is huge, and microwave-assisted pyrolysis of biomass to obtain biogas, bio-oil, and biochar is a promising method. In this study, silicon carbide (SiC) was selected as the microwave absorber, and the effects of microwave power (400, 450, 500, 550 and 600 W), reactor chamber volume (100, 150, 200, 250, and 300 W), and the mass ratio of SiC and corn straw (0, 0.25, 0.5, 0.75, and 1) on the heating performances of corn straw particles were investigated and presented in this study. When the microwave power increased from 400 to 600 W, the average heating rate of corn straw particles increased from 23.06 ℃ /min to 101.46 ℃ /min, and that of mixture particles of corn straw and SiC increased from 87.00 ℃ /min to 236.88 ℃/min. When the reactor chamber volume increased from 100 to 300 mL, the average heating rate of corn straw particles decreased from 38.21 ℃/min to 22.54 ℃/min, and that of mixture particles of corn straw and SiC decreased from 98.84 ℃/min to 76.01 ℃/min. When the mass ratio of SiC and corn straw increased from 0 to 1, the average heating rate of mixture particles of corn straw and SiC increased from 101.46 ℃/min to 236.88 ℃/min. Some formulae with R2 values ranged from 0.971 to 0.998 were proposed to determine the transient temperatures of corn straw particles and mixture particles of corn straw and SiC. [ABSTRACT FROM AUTHOR]

Water hyacinth is one of the most significant sources of biomass in tropical regions that can be used to create biogas. This strategy aims to improve the sustainability, precise energy content, and ease of transport of the original biofuel feedstock, as well as to extract gases. An experimental investigation on the biomethanation of water hyacinth took place in a semi-batch digester. Temperature, stirring speed, and catalyst concentration all have an impact on the rate of biogas production. The catalyst has been discovered to primarily boost the rate of biogas production from water hyacinth (Eichhornia crassipes). As the catalyst is used here to boost up the biomethanation reaction, the effect of the catalyst on different kinetic parameters is investigated. The key conclusions of the research indicate that the maximum value of acidogenic cell mass concentration is 0.13 kg/m3d while the minimum value of methanogenic cell mass concentration is 0.014 kg/m3d at 50 ppm catalyst concentration. Moreover, the maximum specific growth rate of the entire process increases as the catalyst concentration rises, reaching a maximum level of 0.312 d−1 at a 50 ppm catalyst concentration. This is proof that using a catalyst can expedite the biomethanation process. As the catalyst concentration increases, so does the overall biomass concentration. Since it increases the precision of the parameter estimates, the simultaneous estimation of the parameters is a crucial part of the estimation process. [ABSTRACT FROM AUTHOR]

The article discusses the utilization of biogas technology to supply energy for urban buildings and rural households. It highlights the benefits of integrating biogas facilities with buildings, such as recycling organic waste and reducing greenhouse gas emissions. Biogas can provide clean and cost-effective energy, acting as an alternative to traditional fossil fuels. In rural areas, biogas can replace biomass fuels, improving indoor air quality and reducing deforestation. However, the article also acknowledges potential risks associated with biogas production, such as fire and explosion hazards, toxic gases, and odour issues. It emphasizes the importance of implementing safety measures and proper system design to prevent accidents and protect public health. [Extracted from the article]

Biogas plays a significant part in replacing solid biomass and fossil fuels for cooking. However, the implementation of appropriate policies to promote the development of biogas plants is hindered by a lack of adequate assessment of the biogas potential in Nepal. Thus, we estimate the potential of biogas production at the district level of Nepal from available waste biomass, including livestock manure, agricultural residues, and organic fraction of municipal solid waste (OFMSW). Our estimates show the theoretical potential of biogas production from livestock manure of 1890 million m3 year−1, agricultural residues of 2290 million m3 year−1, and OFMSW of 234 million m3 year−1. The total biogas production is 4412 million m3 year−1, equivalent to 153 million liquefied petroleum gas (LPG) cylinders yearly. Using this biogas potential to replace LPG and solid biomass for cooking could result in avoided CO2, CO, and PM2.5 emissions of 6.3 million tons year−1, 0.4 million tons year−1, and 0.04 million tons year−1, respectively. Our findings suggest that the Terai districts of Morang, Sunsari, Saptari, and Banke, as well as the Hilly districts of Kavrepalanchok, Dhading, and Nuwakot, have a significant amount of biogas‐producing potential. Utilising this potential could also contribute to achieving several Sustainable Development Goals and a clean cooking energy transition in Nepal. For this, governments need careful planning, designing, policy support, and facilitation on bio‐resource management and utilisation at the local level. [ABSTRACT FROM AUTHOR]

Food waste (FW) biotransformation into bioenergy has garnered a lot of scientific interest as a way to address the energy crisis and trash disposal issues. FW is converted into biogas, a gaseous combination of biomethane and carbon dioxide. In order to valorize FW, anaerobic digestion (AD) with combined pretreatment (hydrothermal (HT) and ultrasonic (US)) is used as a potential method. Three digesters were investigated: the control (unpretreated), HT(121°C) + US, and HT(134°C) + US, respectively. Based on changes in the combined pretreatment conditions, the paper assessed the methane productivity. Furthermore, kinetic modeling was evaluated with six kinetic models. The results show that the HT pretreatment at 121°C combined with US improves the volatile solid (VS) removal to 73 ± 5% and the methane yield to 529.7 ± 11 NmL/gVS. Both the Transference model and the first order have the greatest fits in terms of R2, and they also have the best fits in terms of relative errors, and methane production rate, respectively. The combined pretreatment has a positive impact on increasing methane yield as well as stabilizing the anaerobic digestion process. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: During this energy transition, research is being done to develop sustainable ways to support the shift to a decarbonized energy and production system. These ways include using renewable energy sources to promote circularity in products, green technologies, and safer procedures. Anaerobic digestion of palm oil mill effluent is a beneficial process for generating biogas, while the waste can also be utilized as fertilizer. The biogas can be further refined into biomethane, a valuable resource commonly used in transportation and power generation. The objective of this study is to examine the enhancement of biogas from Palm oil mill effluent and the elimination of sludge nutrients by utilizing microalgae Chlorella vulgaris. The microalgae will be cultivated in a modified photobioreactor to enhance the capture of carbon dioxide. METHODS: The study utilized anaerobic batch reactor digesters. A modified photobioreactor, consisting of two columns separated by a membrane, was developed for the technological advancement of biogas upgrading, specifically for carbon dioxide capture and biogas upgrading. A technological gap in biogas upgrade technology innovation is filled by the improved photobioreactor. To optimize the bio-fixation of carbon dioxide from flue gas, it is essential to carefully select a suitable strain of microalgae that possesses both a strong ability to absorb carbon dioxide and a high tolerance to varying concentrations of this gas. By choosing the right strain, the efficiency of carbon dioxide removal can be significantly enhanced. Since Chlorella vulgaris microalgae have demonstrated this potential, they were chosen for this investigation. Microalgae also play a role in removing nutrients contained in the sludge. FINDINGS: Numerous chemical and biological methods have been used to upgrade biogas. Results of biological upgrading of biogas from palm oil mill effluent have been reported, with carbon dioxide removal reaching 89 percent until the methane concentration of the biogas is upgraded to 84 percent. The highest biomass of 1,835 grams per liter was achieved by culturing the microalgae Chlorella vulgaris in laboratory-scale photobioreactors. In this study, the application of 15 percent volume per volume biogas with an optical density of 0.4 was found to be optimal for the growth of the microalgae. The cultivation period lasted for 14 days. The peak biomass production was observed due to the achievement of a remarkable 98 volume per volume efficiency in carbon dioxide removal, which subsequently led to a significant rise in methane content, reaching 60 percent. The enhanced biogas achieved a peak methane content of 98 percent, indicating a significant improvement in quality. CONCLUSION: The findings of this study, conducted using a modified photobioreactor, indicate that Chlorella vulgaris demonstrated high efficacy in the removal of carbon dioxide, with a rate of up to 90 percent. Additionally, it exhibited remarkable performance in upgrading biogas derived from palm oil mill effluent, achieving a conversion rate of up to 98 percent. The optical density of microalgae at 0.4 played a crucial role in these processes. Furthermore, Chlorella vulgaris showcased its ability to effectively eliminate nutrient nitrogen, reaching a removal rate of 90 percent at an optical density of 0.2. Moreover, it demonstrated a phosphate removal rate of 80 percent at an optical density of 0.4. [ABSTRACT FROM AUTHOR]

This study investigates the production of waste tire pyrolyzed oil on a laboratory scale and its potential use as a fuel along with biogas and hydrogen in a variable-speed transportation engine. The pyrolyzed oil, obtained from waste tire pieces through a lab-scale plant, undergoes distillation and is blended with diesel fuel in a 20% ratio. This blended fuel is supplied to a multi-cylinder variable-speed transportation engine, either alongside biogas or HHO separately or both combined, at fixed flow rates with air passage through a premixing device (venturi). This study aimed to assess engine combustion characteristics such as in-cylinder pressure and heat release rate; performance parameters, including brake thermal efficiency (BTE) and brake-specific fuel consumption (BSFC), as well as emissions of hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOx). The results indicate that using pyrolyzed oil in unmodified diesel engines reduces combustion characteristics and performancewhile increasing HC and NOx emissions and decreasing CO emissions. In addition, supplying biogas and the fuel mixture further deteriorates combustion and performance, while increases HC and CO emissions, and reduces NOx emissions. The focus of the present research is to evaluate the impact of adding green hydrogen (HHO) gas to a pyrolyzed oil fuel mixture and a biogas-led fuel mixture in a compression ignition (CI) engine. The results indicate that the addition of hydrogen enhances combustion characteristics, engine performance and reduces emissions, except for NOx. Specifically, there is an increase in cylinder peak pressure and HRR by around 6–10% range, improvement in BTE by 16–20% and BSFC by 5–7%, along with a decrease in HC and CO emissions by 13–16% and 11–13%, respectively. However, there is an increase in NOx emissions of 6–9%. In essence, the addition of green hydrogen enhances engine performance and reduces emissions in waste tire-derived pyrolyzed oil and biogas blends, indicating a viable path for sustainable transportation fuel. • Pyrolyzed tire oil blended with diesel fuel (20%) tested in variable-speed engines. • Adding biogas to the fuel blend worsens performance and increases HC and CO emissions. • Green hydrogen (HHO) improves combustion and performance in the fuel blend. • HHO addition increases cylinder peak pressure and heat release rate by 6–10%. • HHO addition enhances BTE by 16–20% and reduces HC and CO emissions by 13–16% and 11–13%, respectively. [ABSTRACT FROM AUTHOR]

This critical review examines the potential of household biogas technology in Africa, focusing on biogas production and techno‐economic feasibility studies. The review highlights the benefits of biogas technology, including renewable energy generation, waste management, and improved public health. A significant portion of Africa's rural population, approximately 60%, grapples with limited access to reliable power sources. The study analyzes various biogas production systems, including anaerobic digesters and biomass gasifiers, and evaluates their economic viability in different African contexts. The review identifies key factors influencing the adoption of household biogas technology, including policy and regulatory frameworks, financing mechanisms, and public awareness. Biogas production stands out as one of the promising renewable energy sources. However, it also discusses the challenges and limitations of implementing this technology on a continental scale. The study analyzes various biogas production systems, including anaerobic digesters and biomass gasifiers, and evaluates their economic viability in different African contexts. The review identifies key factors influencing the adoption of household biogas technology, including policy and regulatory frameworks, financing mechanisms, and public awareness. The study concludes by recommending strategies for scaling up biogas technology in Africa, including capacity building, technology transfer, and innovative financing models. The review aims to provide a comprehensive resource for researchers, policymakers, and practitioners working towards sustainable energy solutions in Africa. [ABSTRACT FROM AUTHOR]

AbstractIn this study, the impact of cobalt iron oxide(CoFe2O4) on the anaerobic digestion (AD) of food waste (FW) was investigated including the variations in pH, VFAs, ORP, Fe2+/Fe3+ concentrations, SCOD, dehydrogenase activity, methane production and microbial community structure. The results showed that CoFe2O4 had a positive effect on the anaerobic digestion of food waste. CoFe2O4 could promote the release of SCOD, increase the dehydrogenase concentration and reduce ORP resulting in an increase of methane production. At a CoFe2O4 concentration of 200 mg/L, the cumulative methane production reached to 414.75 mL/(gVS) which was increased by 79.1% compared to the control group(231.59 mL/(gVS)). Meanwhile, the variation of microbial community showed that CoFe2O4 could increase the relative abundance of Methanobacterium and the methane production pathway in the AD was shifted from acetoclastic to hydrogenotrophic. [ABSTRACT FROM AUTHOR]

Driven by environmental and economic considerations, this study explores the viability of utilizing coconut juice residues (CJRs), a byproduct from coconut milk production, as a carbon source for bacterial cellulose (BC) synthesis in the form of a versatile bio-membrane. This work investigates the use of optimization modeling as a tool to find the optimal conditions for BC cultivation in consideration of waste minimization and resource sustainability. Optimization efforts focused on three parameters, including pH (4–6), cultivation temperature (20–30 °C), and time (6–10 days) using Design Expert (DE) V.13. The maximum yield of 9.31% (g/g) was achieved when the cultivation took place at the optimal conditions (pH 6, 30 °C, and 8 days). This approach aligns with circular economy principles, contributing to sustainable resource management and environmental impact reduction. The experimental and predicted optimal conditions from DE V.13 were in good agreement, validating the study's outcomes. The predictive model gave the correlations of the optimal conditions in response to the highest yield and maximum eco-efficiency. The use of prediction modeling resulted in a useful tool for forecasting and obtaining guidelines that can assist other researchers in calculating optimal conditions for a desired yield. Acetylation of the BC resulted in cellulose acetate (CA) membranes. The CA membrane exhibited the potential to separate CO2 from a CH4/CO2 mixed gas with a CO2 selectivity of 1.315 in a membrane separation. The promising gas separation results could be further explored to be utilized in biogas purification applications. [ABSTRACT FROM AUTHOR]

The energy sector is essential in the transition to a more sustainable future, and renewable energies will play a key role in achieving this. It is also a sector in which the circular economy presents an opportunity for the utilisation of other resources and residual energy flows. This study examines the environmental and social performance of innovative energy technologies (which contribute to the circularity of resources) implemented in a demonstrator site in Luleå (Sweden). The demo-site collected excess heat from a data centre to cogenerate energy, combining the waste heat with fuel cells that use biogas derived from waste, meeting part of its electrical demand and supplying thermal energy to an existing district heating network. Following a cradle-to-gate approach, an environmental and a social life cycle assessment were developed to compare two scenarios: a baseline scenario reflecting current energy supply methods and the WEDISTRICT scenario, which considers the application of different renewable and circular technologies. The findings indicate that transitioning to renewable energy sources significantly reduces environmental impacts in seven of the eight assessed impact categories. Specifically, the study showed a 48% reduction in climate change impact per kWh generated. Additionally, the WEDISTRICT scenario, accounting for avoided burdens, prevented 0.21 kg CO2 eq per kWh auto-consumed. From the social perspective, the WEDISTRICT scenario demonstrated improvement in employment conditions within the worker and local community categories, product satisfaction within the society category, and fair competition within the value chain category. Projects like WEDISTRICT demonstrate the circularity options of the energy sector, the utilisation of resources and residual energy flows, and that these lead to environmental and social improvements throughout the entire life cycle, not just during the operation phase. [ABSTRACT FROM AUTHOR]

[Display omitted] • Biofilters (BFs) can remove significant VMS loads from gas. • Low toluene concentrations (315–635 mg m−3) improved VMS removal. • Majority (87.7%) of VMS and toluene removal occurred in the initial BF section. • Toluene shaped microbial population, boosting VMS-degrading microorganisms. • Results underscore BF potential to reduce VMS concentration, requiring optimization. The removal of volatile methyl siloxanes (VMS) from landfill biogas is crucial for clean energy utilization. VMS are usually found together with aromatic compounds in landfill biogas of which toluene is the major representative. In the present study, two biofilters (BFs) packed with either woodchips and compost (WC) or perlite (PER) were used to study the (co–) removal of octamethyltrisiloxane (L3) and octamethylcyclotetrasiloxane (D4) from gas in presence and absence of toluene, used as a representative aromatic compound. The presence of low inlet toluene concentrations (315 ± 19 – 635 ± 80 mg toluene m-3) enhanced the VMS elimination capacity (EC) in both BFs by a factor of 1.8 to 12.6. The highest removal efficiencies for D4 (57.1 ± 1.1 %; EC = 0.12 ± 0.01 gD4 m-3 h-1) and L3 (52.0 ± 0.6 %; EC = 0.23 ± 0.01 gL3 m-3 h-1) were observed in the BF packed with WC. The first section of the BFs (EBRT = 9 min), where toluene was (almost) completely removed, accounted for the majority (87.7 ± 0.6 %) of the total VMS removal. Microbial analysis revealed the impact of VMS and toluene in the activated sludge, showing a clear selection for certain genera in samples influenced by VMS in the presence (X 2) or absence (X 1) of toluene, such as Pseudomonas (X 1 = 0.91 and X 2 = 12.0 %), Sphingobium (X 1 = 0.09 and X 2 = 4.04 %), Rhodococcus (X 1 = 0.42 and X 2 = 3.91 %), and Bacillus (X 1 = 7.15 and X 2 = 3.84 %). The significant maximum EC values obtained by the BFs (0.58 gVMS m-3 h-1) hold notable significance in a combined system framework as they could enhance the longevity of traditional physicochemical methods to remove VMS like activated carbon in diverse environmental scenarios. [ABSTRACT FROM AUTHOR]

Experimental investigations of hydrogenated biogas deflagration, considering varying carbon dioxide percentages (0%, 10%, 20%, and 30%) and the addition of hydrogen at two different percentages (5% and 10%), were carried out within a constant cylindrical combustion chamber, across three equivalence ratio (ER = 0.8, 1, 1.2). The aim was to explore the potential for recycling CO 2 in biogas applications. Analysis of the experimentally recorded pressure profile allowed the calculation of crucial parameters, including the net heat release rate (N H R R) and the deflagration index (K G). The study's results highlight the effect of CO 2 concentration in biogas on combustion efficiency compared to CH 4 /air combustion. It was found that an increase in the CO 2 volume fraction in biogas leads to a reduction in the net heat release rate (N H R R) , especially in stoichiometric and rich mixtures. This finding is significant as it provides insights into the combustion dynamics of biogas with varying CO 2 levels, contributing to the understanding of biogas combustion efficiency under different conditions. Under lean conditions (Φ = 0.8), combustion tests were unsuccessful. However, the injection of 5% H2 proved sufficient to enhance the reactivity of lean mixtures and promote flame propagation. The findings indicate superior performance of biogas-hydrogenated mixtures compared to stoichiometric and rich mixtures of CH 4 /air combustion. Nonetheless, the addition of hydrogen increased the deflagration index, an important parameter for managing explosion risks. This nuanced understanding contributes valuable insights into optimizing the removal of CO 2 from biogas and combustion processes involving hydrogenated biogas, with implications for both efficiency and safety considerations. • The geometric configuration of the CVCC cylinder significantly influences the dynamics of combustion. • Interactions between the front flame and side walls intensify heat dissipation within the CVCC. • Elevated CO2 levels within biogas significantly alter the reactivity of biogas/air mixtures. • Enhancing B73 with a 5% concentration of H2 effectively boosts its fuel reactivity. • High amounts of H2 have the potential to increase the deflagration index, raising safety considerations. [ABSTRACT FROM AUTHOR]

The article discusses the current problem of energy utilization of municipal solid waste, most of which is currently buried in landfills. An assessment of greenhouse gas emissions from these anthropogenic objects is provided. It is noted that a promising direction for utilization of landfill biogas is the production of biohydrogen. The authors present the results of laboratory studies on the production of biomethane from organic waste with its further conversion into biohydrogen. Using the example of a large landfill for municipal solid waste, a possible geo-ecological effect is shown by reducing greenhouse gas emissions during the energy utilization of biogas. [ABSTRACT FROM AUTHOR]

This article presents the genome sequence of a strain of Methylomonas sp. AM2-LC, a methanotrophic bacterial species found in a Finnish lake. Methanotrophic bacteria are important for reducing methane emissions and have potential for biotechnological applications. The genome sequence can be used for comparative analysis and understanding the metabolic capabilities of methanotrophs. The article also discusses the isolation and DNA extraction process, as well as bioinformatic services provided by a sequencing facility. The document is a list of references related to methanotrophic bacteria, providing a comprehensive overview of current research in the field. It includes references to three scientific articles that cover microbial variant detection, methane-dependent mineral reduction, and the discovery of a new type of methanotroph. These articles are valuable resources for library patrons conducting research in microbiology. [Extracted from the article]

Energy sources are critical in the industrial sector, particularly as population growth intensifies the pressure on industries to scale up production to meet increasing demands. Integrating renewable energy sources such as biomass, biogas, and photovoltaic systems in the palm oil production process can be considered a pivotal strategy for mitigating carbon emissions. However, load fluctuations due to mill size and insufficient supply of biogas and photovoltaic are significant challenges in energy management for the palm oil industry. Adopting renewable energy solutions is hindered by process disturbances and climatic variability caused by weather, ambient temperature, relative humidity, and solar radiation. These factors pose constraints on the implementation of renewable energy solutions. Therefore, this study aims to fill the gap in terms of renewable energy management within the palm oil industry by applying reinforcement learning to achieve effective energy management and reduce carbon emissions under five climatic scenarios. The result shows that reinforcement learning effectively combines renewable energy sources to generate electricity and steam while efficiently managing energy storage without exceeding predefined levels. Additionally, deploying a photovoltaic system contributes to energy savings from biomass and biogas of 2.9% and reduces average daily carbon dioxide emissions by 3137 kg. The proposed method has proved beneficial across all climate scenarios for energy savings and emission reduction. [ABSTRACT FROM AUTHOR]

Background: Environmental pollution is a public health problem in Niger Delta, Nigeria. Therefore, the aims of the present study were to: identify the major fresh biowastes in Bayelsa State, Niger Delta; quantify the biogas yields from mono-digestion and co-digestion of identified biowastes; determine the first day of biogas production during hydraulic retention time; assess pH variations during anaerobic digestion; and evaluate biogas flame colours. Methods: Fifteen communities in Bayelsa State were randomly selected, and on-the-spot assessment and quantification of the biowastes found in each community were carried out daily per week. Mono-digestion of 20 kg of each biowaste and co-digestion of 10 kg of animal waste with 10 kg of plant waste were carried out respectively under anaerobic conditions. Cumulative biogas yield and pH were measured using a pH meter and weighing scale respectively. Biogas flame colours during combustion were visually assessed. Results: Exactly 120.61 metric ton of fresh biowastes was found to be generated per week in Bayelsa State, Niger Delta. Industrial biowastes were the highest [47.6 tonnes, (39.46%)], followed by abattoir biowastes [33 tonnes (27%)], market and roadside sellers biowastes [25.5 tonnes (21.14%)], and farm biowastes [14.51 (12.03%)]. Biogas yields (kg) were: 0, 0, 0, 0, 0, 17, 14, 2, 18, 16, 17, 15 and 1 kg for palm oil mill effluent (POME), orange fruit waste (OFW), pineapple peels (PP), plantain peels, cassava mill effluent (CME), rumen digesta (RD), cow dung, sewage, PP-RD, plantain peels-cow dung, POME-rumen digesta, OFW-cow dung, and CME-sewage respectively. The first day of biogas production for RD, cow dung, sewage, PP-RD, plantain peels-cow dung, POME-RD, OFW-cow dung, and CME-sewage was on the 6th, 32nd. 56th, 1st, 26th, 18th, 25th, and 60th day of hydraulic retention time respectively. A dominant blue flame colour mixed reddish yellow or orange flames were found during biogas combustion. A slight increase in pH was found in all the biodigester media. Conclusions: In the present study, a variety of biowastes yielding various quantities and qualities of biogas were identified in Bayelsa State, Niger Delta. The study's findings have provided evidence-based data that might be explored as a road map and catalyst for policy creation against inadequate biowaste management and as sustainable alternatives to the expensive liquefied petroleum gas. The potential of current research study to be scaled up for commercial use is implicated in the present study. [ABSTRACT FROM AUTHOR]

Second- and third-generation biorefineries enable the sustainable management of biomasses within the framework of circular economy principles. This approach aims to minimize waste biomass while generating high-value molecules and bio-energy, such as biogas. Biogas production is achieved via anaerobic digestion, a process where microorganisms metabolize organic compounds in the absence of oxygen to primarily produce CO2 and CH4. The efficiency of this process is closely linked to the composition of the biomass and, sometimes, characteristics of the initial matrix can impede the process. To address these challenges, various pretreatments are employed to enhance digestion efficiency and mitigate issues associated with biomass complexity. However, the implementation of pretreatments can be energy-intensive and costly. The extraction of valuable molecules from biomass for various applications can represent a form of pretreatment. This extraction process selectively removes recalcitrant molecules such as lignin and cellulose, which can hinder biodegradation, thereby adding new value to the biomass. These extracted molecules not only contribute to improved anaerobic digestion efficiency but also offer potential economic benefits by serving as valuable inputs across diverse industrial sectors. This article presents a detailed state of the art of the most widespread biomass pretreatments and specifies when biomass is pretreated to improve the biogas yield and, in contrast, when it is treated to extract high-added-value products. Finally, in order to define if the same treatment can be simultaneously applied for both goals, an experimental section was dedicated to the production of biogas from untreated olive mill wastewater and the same biomass after being freeze-dried and after the extraction of polyphenols and flavonoids. The use of pretreated biomass effectively improved the biogas production yield: the untreated olive mill wastewater led to the production of 147 mL of biogas, while after freeze-drying and after polyphenols/flavonoids extraction, the production was, respectively, equal to 169 mL and 268 mL of biogas. [ABSTRACT FROM AUTHOR]

The present study analyzed the effect of temperature, pH, pre-treatment and mixing ratio on the anaerobic digestion process. The parameters during the anaerobic co-digestion of cow manure and food waste were then optimized using the Taguchi experimental design method. ANOVA was carried out to find the significant parameters which influence biogas production. Experimental tests were carried out at laboratory-scale reactors kept at different temperatures (28 °C, 35 °C, and 50 °C). The specific methanogenic performance (SMP) during anaerobic digestion at higher temperatures was characterized with the analysis of acetate, propionate, butyrate, hydrogen, glucose, and formate, and was validated with the literature. The improvement of biogas production with different pre-treatments, i.e., ultrasonic, autoclave, and microwave techniques, was also analyzed. The results showed that the reactor that was maintained at 35 °C showed the highest biogas production, while the reactor that was maintained at a lower temperature (28 °C) produced the lower volume of biogas. As the retention time increases, the amount of biogas production increases. Methanogenic activities of microorganisms were reduced at higher temperature conditions (65 °C). Biogas production increased by 28.1%, 20.23%, and 13.27% when the substrates were treated with ultrasonic, autoclave, and microwave, respectively, compared to the untreated substrate. The optimized condition for the highest biogas production during anaerobic co-digestion of food waste and cow manure is a temperature of 35 °C, a pH of 7 and a mixing ratio (CM:FW = 1.5:0.5). ANOVA showed that temperature is the most important input parameter affecting biogas production, followed by mixing ratio. [ABSTRACT FROM AUTHOR]

This study proposes a combination system consisting of a biogas dry reforming reactor and a solid oxide fuel cell (SOFC). Since biogas dry reforming is an endothermic reaction, this study adopted a membrane reactor operated due to the non-equilibrium state with H2 separation from the reaction space. This study aimed to clarify the performance of the Ni/Cr/Ru catalyst using a biogas dry reforming membrane reactor. Additionally, this study also undertook a comparison of the performance of the Ni/Cr/Ru catalyst with that of the Ni/Cr catalyst. The impact of operation temperature, the molar ratio of CH4:CO2, the differential pressure between the reaction chamber and the sweep chamber, and the introduction of a sweep gas on the performance of the biogas dry reforming membrane reactor using a Pd/Cu membrane and a Ni/Cr/Ru catalyst was examined. The concentration of H2 using the Ni/Cr/Ru catalyst was greater than that using the Ni/Cr catalyst by 2871 ppmV for the molar ratio of CH4:CO2 = 1.5:1 at the reaction temperature of 600 °C and the differential pressure of 0 MPa without a sweep gas in particular. Under this condition, CH4 conversion, H2 yield, and thermal efficiency were 67.4%, 1.77 × 10−2%, and 0.241%, respectively. [ABSTRACT FROM AUTHOR]

The production of huge amounts of biogas slurry during livestock breeding has resulted in pressing environmental issues. Although paddy fields can be potential sinks for the disposal of biogas slurry, the impacts of biogas slurry on rice production, grain quality, and relevant environmental risks in the Yangtze Delta region remain unclear. Herein, we conducted a field trial from 2021 to 2023 which involved different gradients of biogas slurry utilization, including CK (no fertilizer), CN (100% chemical nitrogen (N) of 240 kg ha−1), NBS (biogas slurry replacing 50% chemical N), BS1 (replacing 100% chemical N), BS1.5 (replacing 150% chemical N), and BS2 (replacing 200% chemical N). The results showed that there were no significant differences in average rice yields between CN, NBS, BS1.5, and BS2 over the three-year study period, with an average yield of 8283 kg ha−1, and the average yields of BS1 and CK were 7815 kg ha−1 and 6236 kg ha−1, respectively. However, heavy utilization of biogas slurry (BS1.5 and BS2) not only significantly reduced the rice seed-setting rate, the 1000-grain weight, and the processing quality, but also significantly increased the protein, amylose, Cu, and Zn content in rice grains; additionally, higher N losses occurred via surface water and increased NH3 volatilization was observed, finally resulting in lower nitrogen-use efficiency. Meanwhile, moderate utilization of biogas slurry (NBS and BS1) led to better rice quality and nitrogen-use efficiency, lower potential food safety risk, and N loss. Further, compared to BS1, NBS showed higher yield, harvest index, processing quality, gel consistency, palatability scores, and nitrogen-use efficiency, but lower N losses were present. Overall, the NBS treatment balanced the agronomic benefits and environmental risks in the Yangtze River Delta region. In the future, more attention should be paid to food safety and environmental risks when using biogas slurry. [ABSTRACT FROM AUTHOR]

The real implementation of biogas reforming at an industrial scale to obtain interesting products (like hydrogen or syngas) is a developing research field where multidisciplinary teams are continuously adding improvements and innovative technologies. These works can contribute to the proliferation of green technologies where the circular economy and sustainability are key points. To assess the sustainability of these processes, there are different tools like life cycle assessment (LCA), which involves a complete procedure where even small details count to consider a certain technology sustainable or not. The aim of this work was to review works where LCA is applied to different aspects of biogas reforming, focusing on the role of catalysts, which are essential to improve the efficiency of a certain process but can also contribute to its environmental impact. In conclusion, catalysts have an influence on LCA through the improvement of catalytic performance and the impact of their production, whereas other aspects related to biogas or methane reforming could equally affect their catalytic durability or reusability, with a subsequent effect on LCA. Further research about this subject is required, as this is a continuously changing technology with plenty of possibilities, in order to homogenize this research field. [ABSTRACT FROM AUTHOR]

Wastewater treatment plants (WWTPs) contribute to the release of microplastics into the environment. While the removal efficiency of MPs in WWTPs can reach up to 99.9 %, the highest amount of microplastics is retained in the sludge. Anaerobic digestion, one of the most promising and common processes, can help reduce sludge volume and odour, and due to the formation of biogas, mainly consisting of methane (CH4) and carbon dioxide (CO2), can help decrease the operating costs of WWTPs. A test measuring the inhibition of biogas production using the OxiTop® measuring system was employed to determine the effect of added microfibres (MFs) on biogas production. Particles less than 1 mm in size of polyester, polyamide, and polyacrylic, were added to anaerobic sludge at concentrations ranging from 0.05 to 0.10 g l–1 to simulate their effect on biogas production. The yields of CH4 and CO2 produced during anaerobic digestion of the MFs-contaminated sludge were determined. The addition of MFs to sewage sludge affects methane production. The results indicated that the lowest added concentrations of 0.05 g l–1 of MFs promoted methane production, while the presence of 0.1 g l–1 decreased methane production for all types of MFs used. Polyacrylic at 0.1 g l–1 had the most negative effect on methane production (up to 27 %), while polyamide at 0.05 g l–1 reached the highest methane production (up to 25 %). [ABSTRACT FROM AUTHOR]

One of the key guidelines in the European waste management policy is the diversion of waste from landfills, preventing harmful effects on human health and the environment and ensuring that economically valuable waste materials are efficiently recycled and reused through proper management. The organic fraction of municipal waste is abundant and contains biodegradable ingredients such lignocellulose, starch, lipids, pectin, and proteins, making it suitable for biotechnological production. Taking into account that a large amount of organic waste is disposed of in landfills, within this work, the amount of organic waste disposed of in the landfill in Banja Luka was considered. Four simulation model scenarios of the integrated production of bioethanol and biogas are generated, and their process and economic aspects are discussed. In the first two modelled scenarios, the pretreatment conditions (1% sulfuric acid and a different neutralization agent) were varied, while in the other two, the share of the amount of raw material used for the production of bioethanol, i.e., biogas, was varied (split factor: 10–90%). The modelled plant, with a designed capacity of 6 tons/h of organic waste, is a significant bioethanol producer, generating 5,000,000 L/year. The profitability indicators, when examined, revealed that dedicating a portion of the organic municipal waste input exclusively to biogas production leads to decreased process efficiency. Based on the modeled process parameters, ethanol's minimum feasible selling price is $0.6616 per liter, while regarding the composition of organic municipal waste, carbohydrates have the most significant impact on the viability of the process. The developed model represents an excellent basis for further development of this integrated bioprocess in such a way that it can be modified with new process parameters or economic or ecological indicators and used at all levels of bioprocess design. Additionally, the obtained sustainable integrated bioethanol and biogas production plant models could support forthcoming steps in municipal waste management by providing reliable data on the conditions under which the integrated process of bioethanol and biogas production would take place, as well as the technical feasibility and economic profitability of such organic municipal waste utilization. [ABSTRACT FROM AUTHOR]

This research focuses on the impact of pulsed feeding of corn residues on biogas production from pig manure. It also analyzes the properties and microbial diversity in the resulting product. The study highlights the increasing global demand for pork and the resulting environmental challenges, such as effluent management, and suggests that biogas production can be a sustainable solution. The research was conducted at a model farm in Argentina and involved evaluating biogas production and microbial variability at different stages of the pulsed feeding process. The results showed a significant decrease in the chemical and biochemical oxygen demands after the degassing process, indicating a reduction in organic matter. The biogas composition improved with an increase in methane and a reduction in volatile fatty acids. There was also an increase in biogas and methane production and a decrease in methane production lag time, indicating an improvement in anaerobic digestion efficiency. Microbiological analysis revealed a reduction in microbial diversity during pulsed feeding, indicating the adaptation of the microbial community to new conditions. Overall, the study demonstrates the potential of pulsed feeding of corn residues to enhance biogas production from pig manure, with significant implications for effluent management in pork production and sustainable biogas production. [ABSTRACT FROM AUTHOR]

Digitally controlled reactors can optimize biological reactions and process control through a neural network system. This study reports on the design, fabrication, and automation of a laboratory‐scale anaerobic reactor for the management of agrifood byproducts and bioenergy recovery. The process described here can digitally control the operational parameters, which is beneficial for stable methane production. The proposed process comprises the digital measurement of temperature, pH, humidity, biogas volume, and methane composition by integrating the data in a processor module. The proposed automated reactor can assist significantly in controlling and monitoring the anaerobic digestion process, providing decision making during waste management and bioenergy recovery. A case study is described with the application of automated reactors in a pilot‐scale plant, operated with the flow of 8 m3 slaughterhouse wastewater per day and a biogas production of 10 m3 h−1. The automated pilot‐scale process presents many advantages, including a continuous mode of operation and a faster adaptation of the microorganisms to the substrate, improving biogas production. [ABSTRACT FROM AUTHOR]

In this study, we investigated the effectiveness of charge charge-enhanced dry impregnation (CEDI) method on a ceria-supported nickel-based catalyst (10Ni/CeO2) used to produce synthesis (syngas) under biogas dry reforming conditions. The CEDI method was used to enhance the electrostatic adsorption of nickel precursor onto the ceria support during dry impregnation (DI), hence charge-enhanced dry impregnation. The other ceria-supported nickel-based catalyst (labelled 10Ni/CeO2-DI) was prepared by the commonly used DI method and used as the reference catalyst. The catalysts were then tested for stability and catalytic performance (biogas conversion and syngas yield) under biogas reforming conditions using CatLab-QGA equipment supplied by Hidden Analytical. The characterisation studies: X-ray diffraction (XRD), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), oxygen temperature programmed oxidation (O2-TPO), temperature programmed reduction (TPR), and H2-chemisorption were performed on the fresh and spent catalysts to gain insight into the influence of the CEDI method on dispersion, nanoparticles size of the active phase, metal-support interaction, bulk composition, and phase composition. The results showed that enhancing electrostatic attraction during the DI method produced 10Ni/CeO2-CEDI with smaller nanoparticles (3.33 nm), improved nickel dispersion from 1.40 to 5.04% and improved metal-support interaction inferred from TPR values increased from 290 to 340 °C. These favourable physicochemical properties had a positive correlation with the improvement in the conversion of model biogas feed and the least coke formation. [ABSTRACT FROM AUTHOR]

Anaerobic digestion plays a significant role in obtaining renewable energy through biogas production, reducing greenhouse gas emissions, helping with waste management, and bringing economic and social benefits. This work aims to examine approaches for the treatment and use of cambuci bagasse, identifying typical problems and proposing solutions concerning the application of the technique, control of operational parameters, management in dry regime conditions, optimization of efficiency, and increased productivity, using anaerobic digestion as a fundamental and central technology. The results showed the potential of electric energy and heat that could be generated by burning the biomass in a CHP system. Also, they presented the respective avoided greenhouse gas emissions in situations where biogas is applied to replace conventional heat or electricity sources. The biogas average production ratio was 102.69 m³/ton of cambuci by-product with a methane composition of around 60% in the 24th to 30th days. The experimental data obtained was subjected to calculations that indicate an electric generation of 202.98 kWh/ton of cambuci biomass and heat generation of 913.40 MJ/ton of cambuci biomass. In this theoretical scenario, for each ton of cambuci, it is possible to produce 913.4 MJ of thermal energy and 202.98 kWh of electric energy, considering the biogas burning into a CHP system. In the analysis of types of substrates regarding growth capacity, it was concluded that the substrate with a 30% dilution of the digested end was the one that showed the best growth of the cultivar's stem, obtaining a CEC of 9.1516 mol/g. [ABSTRACT FROM AUTHOR]

The purification of biogas as a product of anaerobic digestion has gradually become a research focus. In situ hydrogen-assisted biogas purification is an effective way to enhance the reaction rate, but the solubility and mass transfer efficiency of hydrogen are the difficulties that constrain the technology. Thus, four continuous hydrogen injection modes M1: 1 mL/min, M2: 2 mL/min, M3: 5 mL/min, and M4: 10 mL/min and two intermittent hydrogen injection modes A: 4 mL/min (interval 20 min) and B: 6 mL/min (interval 40 min) were designed to explore the effect of different hydrogen injection modes on in situ biogas upgrading of upflow anaerobic sludge bed (UASB) in the research. The results showed that the methane production showed a trend of increasing first and then decreasing in continuous hydrogenation experiment. The CH4 production reached its peak at 86.2% in the M2 stage. In the two batch hydrogenation tests, group A showed better hydrogenation effect with a CH4 production of about 92%, which was 4% higher than that of group B. The hydrogenotrophic methanogens (HMs) in group A archaea community were more effectively enriched, with an abundance of 52.83% of Methanobacterium. The results illustrate that proper hydrogen injection can enhance anaerobic digestion and promote biogas purification, and the effect of short-term intermittent hydrogen injection is more significant. [ABSTRACT FROM AUTHOR]

The purpose of this research was to develop an integrated biorefinery process of solid-state anaerobic digestion (SS-AD) and hydrothermal carbonization (HTC) for the co-production of methane and hydrochar using elephant dung (ED) as substrate. With a leachate recirculation rate of 4 times/day, the SS-AD presented the highest cumulative methane yield of 83.2 ± 1.7 NmL/g volatile solid (VS)added and VS removal efficiency of 53.9 ± 0.3%. In subsequent HTC, the maximum higher heating value (HHV) of 10,078.5 ± 288.5 MJ/ton dry wt. was achieved for the digested ED without leachate recirculation under HTC temperature of 170 °C. In addition, the maximum mass and energy yields were 76.3 ± 0.8% and 84.1 ± 0.3%, respectively. The produced hydrochar had higher HHV compared to the raw digestate. Moreover, the HHV of the hydrochar was higher, and ash content was identical to conventional coal (lignite). An assessment of a full-scale elephant-sanctuary waste management scheme integrating SS-AD and HTC indicates that more than 10,078.5 ± 288.5 MJ of energy and 563.0 ± 5.2 kg dry weight of hydrochar could be recovered per ton dry weight of ED. The developed elephant dung management platform could enhance energy yield from ED while addressing environmental issues. [ABSTRACT FROM AUTHOR]

This study investigates the impact of alkaline pretreatment on the anaerobic digestion of waste activated sludge (WAS) with varying types and total solids (TS) concentrations. Using NaOH, we optimized pretreatment conditions with a pH of 8.5 and a contact time of 2 hours. Our key findings demonstrate that this pretreatment significantly enhances sludge solubilization, evidenced by a notable increase in soluble chemical oxygen demand (SCOD). Specifically, SCOD increased by 57.5% for domestic wastewater (Plant A) and by 12.1% for industrial wastewater (Plant B) at a 0.5% TS concentration. Higher TS concentrations showed similar trends, with improved solubilization and higher methane production rates. Additionally, pretreatment elevated ammonia nitrogen (NH3-N) and phosphorus concentrations, with greater releases at higher TS levels. These improvements resulted in enhanced anaerobic digestibility, higher total solids (TS) and volatile solids (VS) destruction, and increased specific methane production. The study underscores the effectiveness of alkaline pretreatment in optimizing anaerobic digestion processes, offering practical implications for wastewater treatment efficiency. [ABSTRACT FROM AUTHOR]

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista Foco (Interdisciplinary Studies Journal) is the property of Revista Foco and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This review paper analyzes the methodologies adopted to optimize the operational parameters of biogas power plants to enhance biogas production and maintain efficiency. It discusses the influence of various process parameters, such as pH, Organic Loading Rate (OLR), temperature, mixing ratio, Hydraulic Retention Time (HRT), pre-treatment, C/N ratio, inoculation, and seeding, on biogas production. The impact of these parameters varies depending on the operating conditions, leading to instability and process interference issues in the anaerobic digestion process. Numerous studies have been conducted on optimizing biogas power plant processes using techniques such as the Taguchi method and machine learning approaches. This review provides an indepth analysis of the application of Taguchi Design of Experiments (DoE) and grey relational analysis (GRA) in the multi-objective optimization of process parameters in biogas power plants. Additionally, it examines various machine learning methods employed by researchers for process optimization, helping to identify suitable algorithms based on substrate quantity, operating conditions, and the thermophysical parameters of the anaerobic digestion process. [ABSTRACT FROM AUTHOR]

This study investigated the integrated valorization of defatted rice bran (DRB) by converting it into lactic acid (LA) and subsequently utilizing the residues from LA production for biomethane generation through anaerobic digestion (AD). Processing 480 kg of DRB resulted in the production of 70 L of pure LA and generated significant waste streams, primarily consisting of 572 kg of decanted hydrolysate pellet (Pellet DEC) and 220 kg of microfiltration retentate (Retentate MF). Exceptionally high methane yields of 374-434 LN kgVS -1 were observed for residues from LA fermentation in biochemical methane potential tests, indicating their high potential for biogas production. During long-term semi-continuous AD, varying organic loading rates (OLRs) from 0.5-2.5 kgVS m-3 d-1 demonstrated feedstock- and OLR-dependent methane production. Reactor failure at higher OLRs was attributed to the accumulation of total ammoniacal nitrogen (TAN). The co-digestion of Pellet DEC and Retentate MF proved to be more resilient, with OLRs up to 2 kgVS m-3 d-1, mitigating TAN inhibition. Methane yields, ranging from 265-334 LN kgVS-1 before reaching inhibitory OLR levels, were higher than those found in the literature. Process integration has emerged as a promising approach because the biogas generated from residues could effectively offset the energy demands of LA production. Supported by life cycle assessment, the integrated processes showed a 67% lower environmental impact at the midpoint and a 71% lower environmental impact at the endpoint, along with an 80% reduction in energy costs compared to the standalone LA production. Results proved a significant enhancement of the sustainability and economic viability of this integrated biorefinery approach. [ABSTRACT FROM AUTHOR]

To reduce and convert biodegradable waste into energy-rich biogas, anaerobic digestion technology is usually employed. Hence, this takes place inside the biogas digester. Studies have revealed that these digesters are designed and constructed using bricks, cement, and metal; often require a large footprint; and are bulky and expensive. The innovation of portable biogas digesters has come into the market to address these challenges. This present review provides an overview of the in-depth and comprehensive information on portable biogas digesters in the literature. Areas covered in the review include the modification of the biogas digester design, the need for a portable biogas digester, recent studies on the factors affecting the performance of portable biogas digesters, and specific assumptions taken into consideration for designing any portable biogas digester. Convincingly, portable biogas digesters appeal to small rural families because of their ease of operation, maintenance, and ability to save space. The material for the construction and comparison of the portable biogas digester with other designs and the economic feasibility of the system were also reviewed. Implications: The full-scale design, fabrication, and utilization of a portable biogas digester are viable but not widely employed compared to other designs. However, there is a lack of readily available information on the portable design of biogas digesters. This review presents various aspects relating to portable biogas digesters and the quality of biogas produced. Therefore, the review suits audiences in energy process design and engineers, energy researchers, academics, and economists. [ABSTRACT FROM AUTHOR]

In a previous study, we demonstrated a change in membrane morphology and gas separation performance by varying the recipe of a casting solution based on polysulfone in a certain solvent system. Although all results were reproducible, all used solvents were harmful and not sustainable. In this study, the solvents tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAc) are replaced by the more sustainable solvents 2-methyl-tetrahydrofuran (2M-THF), N-butyl pyrrolidinone (NBP) and cyclopentyl methyl ether (CPME). The gas permeation performance and, for the first time, morphology of the membranes before and after solvent replacement were determined and compared by single gas permeation measurements and SEM microscopy. It is shown that THF can be replaced by 2M-THF and NBP without decreasing the gas permeation performance. With CPME replacing THF, no membranes were formed. Systems with 2M-THF as a THF alternative showed the best gas permeation results. Permeances for the tested gases oxygen (O2), nitrogen (N2), carbon dioxide (CO2) and methane (CH4) were 5.91 × 10−2, 8.84 × 10−3, 4.00 × 10−1 and 1.00 × 10−2 GPU, respectively. Permselectivities of those membranes for the gas pairs O2/N2, CO2/N2 and CO2/CH4 were 6.7, 38.3 and 34.0, respectively. When also replacing DMAc in the solvent system, no or only porous membranes were obtained, even if the precipitation procedure was adjusted. These findings indicate that a complete replacement of the solvent system without affecting the membrane morphology or gas permeation performance is not possible. By varying the temperature of the precipitation bath, the formation of mechanically stable PSU membranes is possible only if THF is replaced by 2M-THF. [ABSTRACT FROM AUTHOR]

Climate change and the growing demand for energy have prompted research on alternative eco-friendly energy sources. This study focused on the potential for biogas production from water hyacinth and banana peel waste through physicochemical characterization and batch anaerobic digestion tests. The water hyacinth and banana peel samples were dried, ground, and subjected to elemental, proximate, and fiber content analyses. Subsequently, banana peel waste, water hyacinth stems, and leaves were used for batch anaerobic digestion tests in 500 mL glass flask bottles for 21 days under mesophilic conditions in n = 3 trials. Kruskal–Wallis and Dunnett's tests were performed to identify the significance of the differences in biogas yield among the samples. The analyses of the elemental, proximate, and fiber contents of water hyacinth and banana peels revealed that they possess a suitable chemical composition and essential nutrients for the production of high-yield biogas. The biogas yields from water hyacinth leaves, stems, and banana peels were 280.15, 324.79, and 334.82 mL/g VS, respectively. These findings indicate that water hyacinth and banana peel waste have significant potential for biogas production. [ABSTRACT FROM AUTHOR]

The present study pays attention to biogas dry reforming for the purpose of producing H2. It is known that biogas contains approximately 40 vol% CO2, causing a decrease in the efficiency of power generation due to its lower heating value compared to natural gas, i.e., CH4. We suggest a hybrid system composed of a biogas dry reforming membrane reactor and a high-temperature fuel cell, i.e., a solid oxide fuel cell (SOFC). Since biogas dry reforming is an endothermic reaction, we adopt a membrane reactor, controlled by providing a non-equilibrium state via H2 separation from the reaction site. The purpose of the present study is to understand the effect of the thickness of the Pd/Cu membrane on the performance of the biogas dry reforming membrane reactor with a Pd/Cu membrane as well as a Ni/Cr catalyst. The impact of the reaction temperature, the molar ratio of CH4:CO2 and the differential pressure between the reaction chamber and the sweep chamber on the performance of the biogas dry reforming membrane reactor with the Pd/Cu membrane as well as the Ni/Cr catalyst was investigated by changing the thickness of the Pd/Cu membrane. It was revealed that we can obtain the highest concentration of H2, of 122,711 ppmV, for CH4:CO2 = 1:1 at a reaction temperature of 600 °C and a differential pressure of 0 MPa and using a Pd/Cu membrane with a thickness of 40 μm. Under these conditions, it can be concluded that the differential pressure of 0 MPa provides benefits for practical applications, especially since no power for H2 separation is necessary. Therefore, the thermal efficiency is improved, and additional equipment, e.g., a pump, is not necessary for practical applications. [ABSTRACT FROM AUTHOR]

This paper aims to study the performance of solar collectors of various sizes under different weather conditions in different Japanese cities, i.e., Kofu City, Nagoya City and Yamagata City. The heat generated by the solar collector was used to conduct a biogas dry reforming reactor for producing H2 to feed a solid oxide fuel cell (SOFC). This study revealed that the output temperature of a solar collector Tfb in April and July was higher than that in January and October irrespective of city. The optimum length of the absorber (dx) of the collector was 4 m irrespective of city. It was clarified that the Tfb in Yamagata City in January and October, i.e., winter and autumn, is lower than that in Kofu City and especially Nagoya City, which is strongly influenced by the tendency of solar intensity (I), not the velocity of the surrounding air (ua). On the other hand, the Tfb is almost the same in April and July, i.e., spring and summer, irrespective of city. The amount of produced H2 via the biogas dry reforming reactor and the power generated by the SOFC using H2 in spring and summer were higher compared to the other seasons irrespective of city. This study revealed that the highest available household number per month was 4.7, according to the investigation in this study. [ABSTRACT FROM AUTHOR]