Feedstock For Energy Production Research Articles

Copper nanoclusters: Selective CO2 to methane conversion beyond 1 A/cm²

Carbon dioxide offers a unique opportunity as a feedstock for energy production through electrocatalysis. Methane production holds promise for its widespread applications and market demand. However, commercial viability faces challenges of low selectivity, current density, and high applied potential. Efforts to improve methane selectivity while suppressing multi-carbon products, e.g., ethylene, often involve lower alkalinity electrolytes. However, it reduces current density due to increased ohmic resistance without significant gains in the reaction yield. This study utilizes quantum mechanics computations to design a nano-cluster copper catalyst that redirects the reaction pathway from ethylene towards methane, even under alkaline conditions. We achieved a Faradaic efficiency (FE) of 85 %, a current density of 1.5 A/cm2, and stability of over 10 hours solely by controlling particle size in copper catalysts. This work paves the way to overcoming current limitations in electrocatalytic methane production and holds broader implications for advancing sustainable CO2 utilization in energy systems.

Comprehensive Characterization of Kukui Nuts as Feedstock for Energy Production in Hawaii.

Fuel properties of oil-bearing kukui (Aleurites moluccana) nuts, a commonly found crop in Hawaii and tropical Pacific regions, were comprehensively studied to evaluate their potential for bioenergy production. Proximate and ultimate analyses, heating value, and elemental composition of the seed, shell, and de-oiled seed cake were determined across five sampling locations in Hawaii. The aged and freshly harvested kukui seeds were found to have similar oil contents, ranging from 61 to 64%wt. Aged seeds, however, have 2 orders of magnitude greater free fatty acids than those freshly harvested (50% vs 0.4%). The nitrogen content of the de-oiled kukui seed cake was found to be comparable to that of the soybean cake. Aging of kukui seeds can decrease the flashpoint temperature and increase the liquid-solid phase transition temperatures of kukui oil obtained. Mg and Ca are the major ash-forming elements present in the kukui shells, >80%wt of all metal elements detected, which may reduce deposition problems for thermochemical conversion in comparison with hazelnut, walnut, and almond shells. The study also revealed that kukui oil has similar characteristics to canola, indicating that it is well-suited for biofuel production.

Sustainable Valorisation of Animal Manures via Thermochemical Conversion Technologies: An Inclusive Review on Recent Trends

PurposeWith its substantial CO2eq emissions, the agricultural sector is a significant greenhouse gas (GHG) emitter. Animal manure alone contributes 16% of the total agricultural emissions. With a rapidly increasing demand for animal-based protein, animal wastes are expected to rise if sustainable manure management practices are not implemented. Manures have the potential to be treated to generate valuable products (biofertiliser and biocrude) or feedstock for energy production. Thermochemical conversion technologies such as pyrolysis, combustion, supercritical gasification (SCWG), etc., have demonstrated their potential in manure management and valorisation. This study provides a broader overview of these technologies and envisages future manure valorisation trends.MethodsThe paper presents a state-of-the-art review of manure valorisation. Characterisation of manure, modelling and optimisation of thermochemical conversion technologies along with life cycle anaalysis (LCA) are also reviewed.ResultsThe literature review highlighted that the thermochemical conversion technologies can generate bio-oils, syngas, H2, biofuels, heat, and biochar as carbon-free fertiliser. The reported calorific value of the produced bio-oil was in the range of 26 MJ/kg to 32 MJ/kg. However, thermochemical conversion technologies are yet to be commercialised. The major challenges associated with the scale-up of manure derived feedstocks are relatively high moisture and ash content, lower calorific value and higher concentration of impurities (N, Cl, and S). LCA studies conclude that gasification presents a sustainable option for manure valorisation as it is economical with modest environmental threats.Significance of StudyThis review briefly states the current challenges faced in manure management and presents the case for a sustainable valorisation of animal manures using thermochemical technologies. The economic, environmental and societal advantages of these technologies are presented in order to promote the scientific and industrial development of the subject in the academic and research community.ConclusionsThermochemical conversion technologies are promising for manure valorisation for energy and nutrient recovery. However, their commercialisation viability needs wide-ranging evaluations such as techno-economics, life-cycle analysis, technology take-up and identification of stakeholders. There should be clear-cut policies to support such technologies. It should be advocated amongst communities and industries, which necessitates marketing by the governments to secure a clean energy future for the planet.Graphical

Municipal solid waste: A potential source of clean energy for Khartoum State in Sudan

Sudan is a large African country with a land area of 1.882 million km2 and a population of 43 million people. The country has a fast-growing population, consistent migration from rural to urban areas, raised per-capita demand for power and fuels, and falling fossil-fuel production. Additional baseload or on-demand energy sources are needed to supply the Nile Valley system. The increasing silting of the different hydroelectricity dams is a problem for the future availability of hydroelectricity generation. Non-recyclable combustible municipal solid waste and other urban organic waste streams can be used to provide low-emission baseload electricity and a cost-effective supply of heat for industry. These wastes, which have the potential to be used as feedstocks for energy production, have already been gathered together in enormous quantities. The current landfill disposal method is becoming increasingly expensive, and it leads to several negative environmental impacts, such as methane emissions and air and water pollution. This research looks at how the non-recyclable combustible fraction of waste collected in Khartoum State can be used to generate considerable amounts of energy and industrial heat while reducing the greenhouse gas (GHG) emissions. This might be accomplished by employing and adopting efficient technologies that are extensively used elsewhere in the globe, as well as securing the additional benefits of more permanent jobs, fewer fossil fuel imports, and improved national resource security for Sudan.

Limiting silicon supply alters lignin content and structures of sorghum seedling cell walls

Sorghum has been recognized as a promising energy crop. The composition and structure of lignin in the cell wall are important factors that affect the quality of plant biomass as a bioenergy feedstock. Silicon (Si) supply may affect the lignin content and structure, as both Si and lignin are possibly involved in plant mechanical strength. However, our understanding regarding the interaction between Si and lignin in sorghum is limited. Therefore, in this study, we analyzed the lignin in the cell walls of sorghum seedlings cultured hydroponically with or without Si supplementation. Limiting the Si supply significantly increased the thioglycolic acid lignin content and thioacidolysis-derived syringyl/guaiacyl monomer ratio. At least part of the modification may be attributable to the change in gene expression, as suggested by the upregulation of phenylpropanoid biosynthesis-related genes under −Si conditions. The cell walls of the −Si plants had a higher mechanical strength and calorific value than those of the +Si plants. These results provide some insights into the enhancement of the value of sorghum biomass as a feedstock for energy production by limiting Si uptake.

Techno-economic Analysis and Life-Cycle Analysis of Renewable Diesel Fuels Produced with Waste Feedstocks

Wet waste feedstocks represent an important category of resources that could be utilized to produce biofuels. Diversion of the wet waste resources from going through conventional waste management practices to utilization as feedstocks for energy production also benefits from avoided cost and pollutant emissions of waste management and disposal. This study investigates the economic and environmental implications of producing bioblendstocks for mixing controlled compression ignition engines from two waste-to-fuel pathways: hydroprocessed esters and fatty acids (HEFA) from yellow grease and swine manure hydrothermal liquefaction (HTL) followed by biocrude upgrading. Detailed process models were developed for both pathways, which informed the techno-economic analysis and life-cycle analysis. Conventional swine manure management practice was also modeled in detail as the business-as-usual scenario for the swine manure HTL pathway. The estimated minimum fuel selling prices were $1.22/gasoline liter equivalent (GLE) and $0.94/GLE for the yellow grease to HEFA and swine manure HTL pathways, respectively. The life-cycle greenhouse gas (GHG) emissions of the two pathways were 11.2 and −33.3 g of CO2e/MJ, respectively, for the yellow grease to HEFA and swine manure HTL pathways. The credits of avoided emissions from conventional swine manure management were the main reason for the negative GHG emissions of the swine manure HTL pathway. The marginal GHG emissions abatement costs were estimated to be $116–$270/tonne CO2e and $5–$103/tonne CO2e for the yellow grease HEFA and swine manure HTL pathways, respectively, for a diesel price ranging between $0.5/GLE and $0.9/GLE. Since the yellow grease HEFA pathway is already commercialized, it can benefit from the $200/tonne carbon credit in the California Low Carbon Fuel Standard market, which could help the yellow grease HEFA pathway to achieve near-zero marginal GHG emissions abatement cost.

Techno-economic and environmental impact assessment of biogas production and fertiliser recovery from pelagic Sargassum: A biorefinery concept for Barbados

Pelagic Sargassum inundation of coastlines across the North Atlantic is an ongoing challenge but presents new opportunities for value-added resource recovery. This study assessed the techno-economic feasibility and environmental impact of utilising these invasive brown seaweed, and food waste as feedstock for energy production and fertiliser recovery in Barbados. The biorefinery concept evaluated was designed with hydrothermal pretreatment (HTP) and anaerobic digestion (AD) technologies. Financial analyses of four varied feedstock and process scenarios (S1-S4) established a linear relationship between profitability and the sale of products (electricity and fertiliser). In all cases, simple sale of power generated to the national grid resulted in a negative cash flow and required the introduction of fertiliser sales to achieve positive cash flows. Moreover, the net loss in the electricity only scenarios exceeded that of the landfill disposal, the present operation employed on the island for Sargassum management. The addition of the solid digestate to the revenue stream increased the profit margin and financial attractiveness of the process. Maximum income generation could be attained through 100% supply of the digestate to international markets. However, this approach provides zero support to local food security. The preferred option involves the 50/50 split utilisation of the solid digestate in local and international agricultural practice. While HTP is energy-intensive technology, the recirculation of waste heat generated by a combined heat and power unit for HTP reduced the input energy demand. It also lowered the potential environmental impact by more than 10-fold, relative to landfill disposal. Recycling of the liquid digestate also reduced the fresh water demand and its associated costs. Despite the promising results, process scale-up and commercialisation remain a main challenge, primarily due to the seasonality and variability of Sargassum seaweed for continuous bioprocessing.

Generation of Sustainable Energy from Agro‐Residues through Thermal Pretreatment for Developing Nations: A Review

Biomass is among the common resources in developing countries that could alleviate fuel, energy, and environmental problems. This is due to the abundance of biomass as feedstock for energy production in this region. Though, there are some challenges and limitations to their practical use. This includes low energy densities, high volatile content, low calorific value, etc. Herein, some research works on generation of sustainable energy from agro‐residues through thermal pretreatment (TP) for developing nations are reviewed. The review is carried out using articles available on the ScienceDirect database. TP is normally carried out between the temperature range of 200 and 1300 °C – torrefaction (200–300 °C), carbonization (450–550 °C), pyrolysis (350–700 °C), and gasification (800–1300 °C). The heating rate significantly influences the TP output. The Char yield and calorific value increase with torrefaction temperature (TT), whereas the volatile yield decreases. TT does not have a significant effect on char composition. The effect of temperature on char production is more significant compared with residence time (RT). Some developmental possibilities exist in biomass utilization, especially for developing countries via TP: generation of employment, provision of a cleaner environment, economic diversification, and reduction of the poverty level, among other potential opportunities.

Characterization of the woody biomass feedstock potential resulting from California\u2019s drought

Regional tree die-off events generate large quantities of standing dead wood, raising concern over catastrophic wildfire and other hazards. Governmental responses to tree die-off have often focused on incentivizing biomass energy production that utilizes standing dead trees removed for safety concerns. However, the full distribution of potential woody bioenergy feedstock after tree die-off has not been evaluated due to the complexities of surveying and precisely measuring large forested areas. In this paper, we present a novel method for estimating standing dead biomass at a fine spatial resolution that combines aerial survey data with forest structure maps. Using this method, we quantify biomass generated by the unprecedented tree die-off that occurred in California following a 4-year drought and widespread pest outbreaks. The results are used to estimate feasibly recoverable feedstock for energy production. We find that approximately 95.1 million bone-dry tons (BDT) of dead biomass resulted from 2012–2017 mortality, with a lower bound of 26.2 million BDT. In other words, of the aboveground live tree biomass in 2012, ~1.3–4.8% died by 2017. Of the standing dead biomass, 29% meets minimum constraints for potential cost-effective bioenergy feedstock. This proportion drops to as low as 15% in the most affected areas due to terrain slope, wilderness status, and other factors, highlighting the need to complement disposal via biomass energy with other strategies to mitigate the risks of the tree mortality crisis, which is likely to only become more severe over time due to climate change.

Valorizacija ljuske suncokretova nakon konvekcijskog sušenja sjemenka za proizvodnju čvrstog goriva

Since the initial moisture content in sunflower seeds after the harvest is rather high, seeds must be processed by convection drying so that their quality can be maintained for as long as possible a period of time. Sunflower is an oilseed crop, which can be used both as food and as a feedstock for energy production. The aim of this paper is to determine the influence of the convection drying process (at 60 °C, 80 °C and 100 °C) on energy characteristics of seeds of four sunflower hybrids (Apolon, NK Brio, PR 63 A 90 and PR 63 D 82), which by their characteristics belong to early and medium-early hybrids. It will also be determined if the energy used in the drying process can be recovered through utilisation of energy from husk. On the basis of the obtained results, the changes in energy characteristics were identified, namely, the content of non-combustible matters (water, ash, coke, fixed carbon and nitrogen) and of combustible matters (carbon, sulphur, hydrogen, oxygen, volatile matter), as well as higher and lower heating values of sunflower seeds. The resulting data prove that convection drying of sunflower husk has a positive influence on its energy characteristics.

Evaluation of Croatian agricultural solid biomass energy potential

Agricultural solid biomass has been widely recognized as an important source of renewable energy with huge production potential. The utilisation of agricultural solid biomass as feedstock for energy production is continuously growing all over Europe. As shown in the current country's balance of energy production and consumption, Croatia is highly dependent on imported fossil fuels. The aim of this paper is to determine the available agricultural solid biomass and its energy potential in Croatia. The quantity and energy potential of solid biomass refer to post-harvest residues, pruning residues, agro-industrial solid waste and biomass from Miscanthus energy crop. In relation to potentially available agricultural biomass, three scenarios have been developed (progressive – S1, optimistic - S2, and conservative – S3) of introducing solid biomass in the renewable energy production sector. On the basis of these scenarios, it can be concluded that in Croatia the following quantities of agricultural biomass are available: 3050.3 t (S1); 1441.8 t (S2); and 733.68 t (S3). These quantities give energy potential of 51.14 PJ (S1), 24.06 PJ (S2), and 12.18 PJ (S3) respectively.

Technoeconomic and Policy Drivers of Project Performance for Bioenergy Alternatives Using Biomass from Beetle-Killed Trees

As a result of widespread mortality from beetle infestation in the forests of the western United States, there are substantial stocks of biomass suitable as a feedstock for energy production. This study explored the financial viability of four production pathway scenarios for the conversion of beetle-killed pine to bioenergy and bioproducts in the Rocky Mountains. Monte Carlo simulation using data obtained from planned and existing projects was used to account for uncertainty in key technoeconomic variables and to provide distributions of project net present value (NPV), as well as for sensitivity analysis of key economic and production variables. Over a 20-year project period, results for base case scenarios reveal mean NPV ranging from a low of −$8.3 million for electric power production to a high of $76.0 million for liquid biofuel with a biochar co-product. However, under simulation, all scenarios had conditions resulting in both positive and negative NPV. NPV ranged from −$74.5 million to $51.4 million for electric power, and from −$21.6 million to $246.3 million for liquid biofuels. The potential effects of economic trends and public policies that aim to promote renewable energy and biomass utilization are discussed for each production pathway. Because the factors that most strongly affect financial viability differ across projects, the likely effects of particular types of policies are also shown to vary substantially.

Straw preservation reduced total N2O emissions from a sugarcane field

AbstractPost‐harvest biomass can be used as feedstock for energy production and alter N2O emissions from the soil, which is among the main issues determining bioethanol sustainability. To assess the effects of sugarcane straw return on gas emissions, we established a field experiment in which 0, 50, 75 or 100% (0, 5.65, 8.47 and 11.30 Mg/ha dry biomass, respectively) of the crop residues (straw) was left in the field during the first two ratoon crops. As fertilizer is applied in bands to sugarcane, we also investigated the contribution of different positions to the N2O emissions within the field. There was an interactive effect between straw and inorganic fertilizer, leading to a nonlinear effect of crop residues on the fertilizer emission factor (EF). However, straw consistently reduced N2O emissions from the field, acting mainly in the unfertilized areas in the field (P < 0.05). We observed that considering the typical EF used in the literature, the N2O‐N emissions attributed to fertilizer ranged from 0.19 to 0.79 kg/ha, while the total emissions ranged from 3.3 to 5.2 kg/ha, from the highest amount of straw to the lowest. We conclude that overall, the fertilizer EF is not as relevant as the total emissions, based on this and other studies. Consequently, management practices might be more effective in improving the GHG balance than changing inorganic fertilizer use. We conclude that keeping up to 11 Mg/ha of straw with a large C:N ratio (>100:1) on site might increase sugarcane production sustainability by reducing the greenhouse gas emissions from the field.

Renewable materials as feedstock for energy production and other applications

Renewable materials as feedstock for energy production and other applications

Energy potential of sugarcane biomass: an application of optimal location modeling

Bagasse and trash (leaves left in the field), two sugarcane processing byproducts, are underexploited resources that can be used to provide energy. In Brazil, the development of this readily available lignocellulose biomass as feedstock for energy production would diversify the country’s energy matrix and increase its energy security. This study is intended to identify and quantify the energy potential of sugarcane biomass in the forms of bagasse and trash, determine the optimal allocation of these byproducts as energy producers, and identify advantageous locations for biomass electrical generation and cellulosic ethanol production in Brazil’s Centre-South. Two scenarios were created and analyzed using a model built to evaluate the potential economic value of sugarcane bagasse and trash from the perspective of energy output. The scenarios incorporate alternative input mixes, plant locations, and time frames. Scenario 1 is designed to define the optimal allocation of bagasse and trash from the 2013/14 harvest season while Scenario 2 is designed to define the optimal allocation of this biomass from 2021 thru 2025. Using Scenario 1 parameters, cellulosic ethanol production was not advised and a negligible number of new or expanded generation facilities were recommended. Interestingly, there was found to be potential for the production of almost twice as much exportable electricity, 40,000 GWh, as was actually produced. Using Scenario 2 parameters, it was found that annual profit maximization would come from the production of approximately 9 mn m3 of cellulosic ethanol from 68 new refinery facilities and that 36,000 GWh of exportable electricity should be generated.

Effects of a ladle furnace slag added to soil on morpho-physiological and biochemical parameters of Amaranthus paniculatus L. plants

Industrial slag from steelwork activities is considered a by-product by the EU legislation and it can be used for civil construction. In this work, an experiment in a greenhouse was conducted over a 6-week period to investigate the effect of soil enrichment with ladle furnace slag on morpho-physiological parameters of Amaranthus paniculatus L. plants. Results showed that the addition of 5% (w/w) slag to soil did not alter the plant growth, highlighting a high tolerance to this slag concentration. Contrarily, plants cultivated in a soil with 10% (w/w) slag showed a marked reduction both in growth and biometric parameters. Moreover, plants grown on a slag-rich soil (20% w/w) highlighted a very low survival rate. This behaviour was confirmed by the biochemical and physiological investigations on chlorophyll a and b content, gas exchange and chlorophyll fluorescence analyses. Metal(loid)s determination showed the accumulation of Ni, Se, Sn, As, Sb and Cd in 10% slag-treated plants, while revealed an increase in Ni, Cd, As and Pb in 5% slag-treated plants. Results are discussed highlighting the profitability of the cultivation of Amaranthus plants on slag enriched soil, as this plant species is largely used both as feedstock for energy production and for environmental restoration.

Environmental impact of cereal straw management: An on-farm assessment

This work assessed the environmental impact of cereal straw end-practices at farm gate and highlighted the best on-farm scenario. A sample of cereal farms located in Apulia Region, in Southern Italy, was investigated through a survey questionnaire. Straw incorporation in the soil, straw burning and baling, were the three practices considered. In the light of the ever-growing demand of straw for energy feedstock production, we discussed two scenarios, namely the status quo and the demand pulled scenarios, each one with a different mix of the three straw end-practices. Following farmer's intentions, in the demand pulled scenario a high percentage of straw was baled while reducing straw incorporation; straw burning practice was not eliminated because it allows farmers to prepare the soil for cultivation. Sensitivity analysis tested different wheat and straw allocation methods (economic vs mass and cereal unit allocation). The environmental impact of alternative straw end-practices and scenarios was assessed by means of an attributional Life Cycle Assessment. Straw incorporation resulted the best environmental practice. Scenarios had quite similar impacts for 8 out of 11 impact categories, but the demand pulled scenario was less impacting than the status quo on global warming, human toxicity, and photochemical oxidation impact categories. These results allow us to conclude that the perspective of selling the straw on the local market for energy production is a better solution compared to the current situation.

Regional woody biomass supply and economic impacts from harvesting in the southern U.S

Demand for woody biomass from the southern United States (US) is increasing because of its reliability in supply, recent developments in co-firing and biofuel conversion technologies, overseas pellet demand, and the expected economic impacts from reorienting the forestry sector towards energy feedstock production. This research examines the interaction between a set of woody biomass harvesting sources (logging residue, non-merchantable, and merchantable roundwood) and wood types (hardwood, planted softwood, and natural softwood), and the impacts harvest costs have on the extraction of these materials in the southern US. The expected woody biomass availability and its geographic distribution are determined with a cost minimizing linear programming model. The marginal cost of woody biomass supply is determined for different energy production targets, subject to satisfying conventional wood demand. Given derived industry supply curves, the economic impacts of the sector are analyzed using the IMpact analysis for PLANning model (IMPLAN) at the Bureau of Economic Analysis (BEA) level. The results suggest that forest biomass for energy production is projected to be available over a much wider price range with logging, residue, and non-merchantable and merchantable roundwood in these regions. Supply of hardwood and softwood biomass from merchantable roundwood is expected to increase if these materials can be harvested for non-conventional uses. Development of harvesting woody biomass from logging residue, non-merchantable, and merchantable timber has positive effects on local economies, bringing with it employment opportunities to some BEA regions.

Microwave Pyrolysis of the Spruce Sawdust for Producing High Quality Syngas

Currently, a demand for alternative energy sources to replace traditional fossil fuels is growing. Although there are still found new reserves or mining techniques – e.g. Shale gas, searching for new substitute solutions is needed. Waste from the wood processing industry could be serving as a potential feedstock for energy production, e.g. hydrogen.Microwave irradiation is an alternative heating method and has already been successfully applied to biomass pyrolysis. Compared with convectional heating processes where heat is transferred from the surface to the core of the material through conduction driven by temperature gradient, microwaves induce heat at the molecular level by direct conversion of the electromagnetic energy into heat, and therefore, they can provide uniform internal heating for material particles. Microwave pyrolysis promotes the heterogeneous catalytic reaction and produces greater concentration of syngas and hydrogen in the product gas than convectional pyrolysis. In addition, it is easier for a rapid start-up and shut-down.The biomass is mixed with a suitable material which significantly absorbs microwave radiation for generation of intensive heating in the reactor. In our case, the spruce sawdust was mixed with char from previous pyrolysis of spruce sawdust. Char from the pyrolysis of sawdust also contains small amounts of ash (up to 5 %), which includes alkali metals and alkaline earth metals. The presence of such char has a catalytic effect on the pyrolysis process, the cracking of tars and phenolic compounds to the simple gases (H2 and CO).In this work the influence of various parameters of microwave pyrolysis of spruce sawdust (microwave power, particle size, ratio of sawdust and char, pyrolysis duration, etc.) was studied to maximize the yield of hydrogen, or syngas. Experiments were carried out in a conventional microwave oven with power up to 1 kW. The influence of parameters on the quantity of products (gas, liquid and solid), but also the amount of waste water in the liquid condensate were studied.

Biomethanation potential of marine macroalgal Ulva biomass in sequencing batch mode: Changes in process performance and microbial community structure over five cycles

Anaerobic digestion (AD) of Ulva biomass, a promising next-generation feedstock for energy production, was investigated in sequencing batch mode. Over five cycles of operation, the methane yield decreased more than twofold (from 0.15 to 0.07 L/g CODfed), while the organic treatment efficiency (i.e., chemical oxygen demand (COD) removal) remained fairly constant (53.7–61.1%). Such changes in reactor performance were related with structural variations in the microbial community, particularly the bacterial community, with repeated cycles. Methanosaeta- and Methanolinea-related populations were most likely the main aceticlastic and hydrogenotrophic methanogens, respectively, in the reactor. The emergence and prevalence of sulfate-reducing bacteria (SRBs), primarily a Solitalea-related population, most likely resulted in increased consumption of organic substrates for sulfate reduction, rather than methane production, in later cycles. Our observations suggest that the metabolic properties of the reactor changed with the transition of the bacterial community structure over cycles, and the metabolic shift had a negative effect on methanogenesis. The sequencing batch operation strategy applied in this study was not suitable for maximizing methane production from Ulva biomass, although the treatment efficiency was fairly stable. Robust control of SRB activity is necessary for more stable and efficient biomethanation of Ulva biomass in sequencing batch mode.