Biogas Production Process Research Articles

Food Waste Management for Biogas Production in the Context of Sustainable Development

In the context of increasing pressure regarding the sustainable utilization of food waste in a circular economy, one of the trends is their biological transformation, through anaerobic digestion, into biogas as a renewable source of energy. We presented the physical-chemical properties of the main categories of food waste from different sources: dairy, meat, and poultry, fish, fruit and vegetable, cereal and bakery, brewing and winery industries, and others. Due to the high organic load, the presence of a multitude of nutrients, and an insignificant amount of inhibitors, food waste can be successfully used in the biogas production process in co-digestion with other materials. Physical (mechanical and thermal), chemical (alkali, acid, and oxidative), and biological (enzymatic, bacterial, and fungal) techniques have been widely used for pretreatment of different substrate types, including food waste. These pretreatments facilitate the degradation of pretreated food waste during anaerobic digestion and thus lead to an enhancement in biogas production. The purpose of this study is to review the situation of food waste generated in the food industry and to formulate the main trends of progress in the use of this waste in the anaerobic digestion process.

Sustainable Valorization of Four Types of Fruit Peel Waste for Biogas Recovery and Use of Digestate for Radish (Raphanus sativus L. cv. Pusa Himani) Cultivation

Food waste has become a challenging global issue due to its inefficient management, particularly in low and middle-income countries. Among food waste items, fruit peel waste (FPW) is generated in enormous quantities, especially from juice vendors, resulting in arduous tasks for waste management personnel and authorities. However, considering the nutrient and digestible content of organic wastes, in this study four types of FPW (pineapple: PA; sweet lemon: SL; kinnow: KN; and pomegranate: PG) were investigated for their potential use within biogas production, using conventional and electro-assisted anaerobic reactors (CAR and EAR). In addition, the FPW digestate obtained after the biogas production experiments was considered as a soil bio-fertilizer under radish (Raphanussativus L. cv. Pusa Himani) cultivation. In the results, all four types of FPW had digestible organic fractions, as revealed from physicochemical and proximate analysis. However, PA-based FPW yielded the maximum biogas (1422.76 ± 3.10 mL/62.21 ± 0.13% CH4) using the EAR system, compared to all other FPW. Overall, the decreasing order of biogas yield obtained from FPW was observed as PA > PG > SL > KN. The kinetic analysis of the biogas production process showed that the modified Gompertz model best fitted in terms of coefficient of determination (R2 > 0.99) to predict cumulative biogas production (y), lag phase (λ), and specific biogas production rate (µm). Moreover, fertilizer application of spent FPW digestate obtained after biogas production significantly improved the arable soil properties (p < 0.05). Further, KN-based FPW digestate mixing showed maximum improvement in radish plant height (36.50 ± 0.82 cm), plant spread (70.80 ± 3.79 cm2), number of leaves (16.12 ± 0.05), fresh weight of leaves (158.08 ± 2.85 g/plant), fruit yield (140.10 ± 2.13 g/plant), and fruit length (25.05 ± 0.15 cm). Thus, this study suggests an efficient method of FPW management through biogas and crop production.

Changes in Stabile Organic Carbon in Differently Managed Fluvisol Treated by Two Types of Anaerobic Digestate

Biogas and anaerobic digestion has begun to be considered an important renewable and sustainable energy source. The sustainable development of the anaerobic digestion process depends largely on the ability to manage large amounts of by-products generated during the biogas production process. We hypothesized that the use of digestate increases the accumulation of C in stable forms. We supposed that the effect of digestate on soil depends on the land-use system, leading to different stratifications of C. The main task of our research was to ascertain changes in the amount of stabile organic carbon (SOCstabile) in digestate-treated soils. Two field experiments were performed using the same design in 2019–2020. We studied the fertilization effects of digestate on Fluvisol. Fertilization: control; separated liquid digestate 85 kg ha−1 N and 170 kg ha−1 170 N; separated solid digestate 85 kg ha−1 N and 170 kg ha−1 N. A randomized experimental design with three field replicates was used. In terms of carbon stabilization in Fluvisol, soil used for grassland showed an advantage over the arable soil. The study showed that digestate, especially solid digestate, contributes to C accumulation and stabilization in the soil.

Biogas as a Source of Energy and its Production from Kitchen Waste

This research was conducted to determine the efficiency of biogas generation from kitchen garbage and to present the various biogas production processes. The anaerobic digestion of kitchen waste produces a valuable energy resource, and the activity-based laboratory approach was applied for this purpose. The anaerobic breakdown is a microbiological process that produces biogas, mainly composed of methane and carbon dioxide. Biogas can be utilized as a source of energy and for a variety of other purposes. On the other hand, any potential applications require knowledge and information on the composition and quantity of components in the biogas produced. Sodium hydroxide must be added to maintain alkalinity and pH in the digester. The cow dung slurry, as well as kitchen garbage, were added to this reactor. This mixed Inoculum was combined to produce biogas in a small-scale activity. The production of biogas and methane from starch-rich and sugary material is determined on a small scale using simple digesters.

OPTIMALISASI BIOGAS DARI KOTORAN SAPI DENGAN PENAMBAHAN BAHAN ORGANIK DARI LIMBAH PERTANIAN DAN PASAR

Cow farm waste is one type of raw material that is commonly used in biogas formation technology. According to 1 Wahyuni (2013), a cow can produce fresh waste between 20 to 29 kg/day. According to 2 Kaharudin and Sukmawati (2010), biogas on a household scale with a number of livestock of 2-4 cows or a supply of dung of approximately 25 kg/day is sufficient to use a reactor tube with a capacity of 2500-5000 liters which can produce biogas equivalent to 2 liters of oil. land/day and is able to meet the energy needs of one rural household with 6 family members. The higher the organic matter content in biogas technology, in a suitable environment, the biogas production will increase. This causes the need for the addition of mixed organic matter so that biogas production is maximized. The type of organic material used is a very important factor. Grass, rice straw or vegetable waste can be used as a source of organic matter in the biogas production process.

Design of an integrated membrane system to produce dairy by‐product from waste processing

SummaryMembrane technology is used in different applications. In this work, a whey‐based product with a final protein content of 16% has been formulated from Scotta – the last waste of the dairy industry – by cross‐flow ultrafiltration (UF) membrane followed by vacuum evaporation (EV). Until now, Scotta was only revalorized in conjunction with whey and into the biogas production process. It was never revalorized as food in the food supply chain. UF and EV processes led to an overall water amount removed from the whey of 84.9%. A vertical configuration of the polyethersulfone (PES) hollow‐fibre membrane was used in the OUT‐to‐IN structure. At 1.50 bar of pressure with 120 min of time interval, higher permeate flow decay has been obtained with a further reduction of the microbiological environments. A combination of intermediate and standard blocking seems to happen in all membranes, but concentration polarisation (CP) may be neglected for membranes with high fibres. The best EV operating conditions have been obtained at ten bars, with 37°C of the heating bath and 2.5 h of time, further preventing microorganism formation and protein denaturation. For future applications of Scotta revalorized in a food, it would be interesting to investigate the use of the multistage methods of membrane and evaporators to obtain a low specific energy consumption and to reduce costs further.

Co-Fermentation of Microalgae Biomass and Miscanthus × giganteus Silage—Assessment of the Substrate, Biogas Production and Digestate Characteristics

The development of a sustainable bioenergy market is currently largely fueled by energy crops, whose ever-increasing production competes with the global food and feed supply. Consequently, non-food crops need to be considered as alternatives for energy biomass production. Such alternatives include microalgal biomass, as well as energy crops grown on non-agricultural land. The aim of the present study was to evaluate how co-digestion of microalgal biomass with giant miscanthus silage affects feedstock properties, the biogas production process, biogas yields, methane fractions and the digestate profile. Combining giant miscanthus silage with microbial biomass was found to produce better C/N ratios than using either substrate alone. The highest biogas and methane production rates—628.00 ± 20.05 cm3/gVS and 3045.56 ± 274.06 cm3 CH4/d—were obtained with 40% microalgae in the feedstock. In all variants, the bulk of the microbial community consisted of bacteria (EUB338) and archaea (ARC915).

Environmental assessment of a two-stage high pressure anaerobic digestion process and biological upgrading as alternative processes for biomethane production

Biomethane plays a key role in achieving decarbonization and sustainable development goals. According to the objectives that arise, choosing the most suitable production system allows optimization of production, thereby reducing CO2 emissions. In this study, three biomethane production scenario life cycle assessments were compared to determine which would maintain the lowest CO2 emissions. Conventional anaerobic digestion and an innovative process called two-stage high pressure anaerobic digestion were considered. These methods were combined with two upgrading processes: water scrubbing and biological upgrading. Cattle manure and sugar beets were used as substrates for the process. Emissions were 805.6 gCO2eq/m3CH4 for the traditional biogas production process combined with water scrubbing and 450.3 gCO2eq/m3CH4 for the two-stage anaerobic digestion process combined with biological upgrading. Furthermore, the analysis demonstrated that these values would be reduced by 29.5 % and 48.0 % if electrical energy were produced using only renewable energy sources.

Integrating biogas in regional energy systems to achieve near-zero carbon emissions

Recent years have witnessed an increasing proliferation of biomass technologies since biomass is recognized as a natural carbon-neutral fuel. Existing studies have paid extensive attention to the concept and modeling of zero-carbon energy systems or buildings. However, few studies have explored the multi-energy coupling method and techno-economic evaluation of biomass to achieve near-zero carbon systems. Therefore, we propose an optimal sizing framework for integrating waste-to-biogas in regional energy systems to achieve near-zero carbon emissions. To establish energy balance between supply and demand and regional self-sufficiency, biomass is added to the existing natural gas energy framework. Biomass produces biogas through anaerobic digestion reactions, and the biogas output can be constructed as an analytical function related to the anaerobic reaction environment temperature and reactant volume. Furthermore, this paper constructs a planning model with the goal of minimizing the investment and operating costs of biomass, solar and storage, respecting carbon emission constraints induced by local electricity and gas energy flows. The impact of carbon emission regulations on the investment of each component of the energy system is determined using a sensitivity analysis of carbon emissions. To solve the nonlinearity issues of the biogas production function, we propose a convexification method based on least squares fitting. Case studies based on realistic datasets demonstrate that, under the constraints of carbon emissions, the integration of biogas can significantly improve the supply adequacy of the energy system, reduce investment costs by up to 77.07%, and carbon emission reduction intensity is 5.11 kg CO2 kg-1 Biogas, all while lowering the Levelized Cost of Energy (LCOE). In comparison to prior research, the model provided in this paper more accurately portrays the biogas production process, lowers the system investment cost and LCOE, and emphasizes the benefits of biomass.

Is anaerobic co-digestion the missing link to integrate sugarcane biorefinery?

This study evaluated the potential of energy generation from anaerobic co-digestion (AcD) of vinasse and hemicelluloses hydrolysate within the context of an integrated 1G-2G sugarcane biorefinery as a mean to ensure its technical, economic and environmental feasibility. Environmental impact indexes for 2G ethanol and biogas production process, such as carbon footprint, which varied from 12.3 to 50.02 g CO2/MJ and reduction of greenhouse gas (GHG) emissions (from 42.7 to 85.9%), were obtained in all scenarios. Economic indicators showed the unviability of 1G-2G sugarcane mill integration adopting AcD of wastes, considering technologies for 2G ethanol production in view of their high capital and operational costs (pretreatment). However, by fixing the experimental methane yield at 0.245 Nm3 kg COD−1r which has been obtained for two-stage anaerobic systems and by considering the use of 50% of bagasse surplus for biogas production, it was possible to achieve internal rate of return (IRR), return on investment (ROI) and payback period of 21.8%, 59.50% and 10.55 years respectively. Moreover, when experimental methane yield is increased in 10% in such scenario, it was possible to achieve internal rate of return (IRR), return on investment (ROI) and payback period of 26%,89.05% and 5.36 years, respectively.

The Potential of Sustainable Biogas Production from Macroalgae in Indonesia

Indonesia is the second world’s major macroalgae producer after China, contributing to 28% of the global macroalgae production. Indonesia increased its macroalgae farming output from less than 4 million tons in 2010 to over 9.9 million tons in 2019. It is expected to continue rising to 13 million tons by 2024. The contribution of macroalgal products is quite significant, 60.7% of the total national aquaculture production. To achieve sustainable energy development goals in many developing countries, including Indonesia, biomass to energy technology such as the production of biogas form macroalgae has been considered one of the best options. Therefore, we aim to investigate the potential application of biomass to energy technology via the production of biogas from macroalgae as an alternative source of local power generation. Indonesia’s energy mix and several issues regarding macroalgae production are comprehensively reviewed. Additionally, we also discussed the process of macroalgal biogas production.

Study on biogas production from corn straw pretreated by compound microorganisms

The pretreated corn straw is pretreated by Fomes fomentarius, Trichoderma adaptatum and the compound microbial agent of Fomes fomentarius and Trichoderma adaptatum under the same conditions. Then biogas was produced by anaerobic fermentation of pretreated straw. According to the experimental results, it has been found that the straw pretreatment with complex microorganisms can not only promote the process of straw anaerobic fermentation biogas production, but also improve the gas production and gas production efficiency, among which the compound microbial agent pretreatment shows the best effect. Compared with the untreated straw, the degradation of lignin and cellulose in straw pretreated with compound microbial agent is much higher, and the lignin content is decreased from 16.6% to 6.8%, and the cellulose content is decreased from 32.3% to 19.8%. Besides, the gas production of compound microbial agent pretreatment has increased by 14.86%, the gas production time is 6 d earlier, the gas production peak is 17 d earlier, the volume gas production rate reaches 2.008 mL/(mL⋅d), and the gas production rate of raw materials reaches 526.66 mL/g. The straw pretreatment with only Fomes fomentarius also has a good effect. However, the effect of straw pretreatment by Trichoderma adaptatum is poor, which has indicated that straw pretreatment by lignin-degrading strain plays an important role in improving the anaerobic fermentation efficiency of straw.

Determining optimal parameters using Taguchi’s design of experiments (DOE) for improving the quality of biogas generation process

The use of an anaerobic process of biogas production depends on various parameters. Increasing the methane (CH4) production percentage is a critical task in an anaerobic process. In the present investigation, the role of the four most common process parameters are temperature, pH value, solid concentration, and C/N ratio optimized for two responses i.e. biogas production and higher methane percentage. A Taguchi Design of Experiment (DOE) methodology was used to investigate and analyze the effects of different parameters using an L9 orthogonal array. The investigation results for both responses showed that solid concentration had a higher contribution of 65.37% and 73.37% for biogas production and methane percentage respectively. The second rank responsible parameter for both the responses is pH having the same contribution of 18%. the initial pH and rotation speed of the process was the most effective parameters for comparison with others. While the other factors’ temperature and C/N ratio contribution are 15.54% and 0.13% for biogas production and 3.48% and 4.25% for methane percentage. Biogas production and methane percentage model found with correlation percentage (r2) 0.98 and 0.92 respectively which is agreeable. The confirmation test results with Taguchi’s model show errors of 7.46% and 2.43% for biogas and methane production percentages respectively.

Biogas Production Enhancement through Chicken Manure Co-Digestion with Pig Fat

Chicken manure and pig fat are found abundantly around the globe, and there is a challenge to get rid of them. This waste has considerable energy potential to be recovered into fuel, but extracting this energy from some by-products, especially fat, isn’t an easy task. When anaerobic digestion technology stepped to the level of anaerobic co-digestion, the utilisation of hardly degradable waste became feasible. Our research was conducted on anaerobic co-digestion of chicken manure as the primary substrate with pig fat as a fat reach supplement in a semi-continuous mode at different organic load rates. The influence of fat waste on the process of biogas production from chicken manure and the composition of the obtained products was determined using an organic load rate of 3.0–4.5 kg VS·(m3·day)−1. A sturdy and continuously growing biogas production was observed at all organic load rates, implying the synergetic effect on chicken manure and pig fat co-digestion. The highest specific methane yield, 441.3 ± 7.6 L·kg VS−1, was observed at an organic load rate of 4.5 kg VS·(m3·day)−1. The research results showed that co-digestion of chicken manure with pig fat is an appropriate measure for fat utilisation and contributes to the increase in biogas yield, methane concentration, and overall methane yield at investigated organic load rates.

Neglected effect of transportation on the property of municipal biowaste and the subsequent biomethane potential

Long-distance transportation of municipal biowaste can influence its physio-chemical characteristics and the subsequent anaerobic digestion (AD) performance. However, the effect of whole transportation processes on the characteristics of municipal biowaste from upstream source separation/collection to downstream storage remains poorly documented. To this end, this study presented the relevant work by sampling in practical conditions. Results showed that transportation led to a high hydrolysis rate of 33.4%–35.5%, and an acidification rate of 15.8%–17.3%. Simultaneously, lactic acid was produced to a concentration of 18.1 g/L, occupying approximately 20% of dissolved organic carbon. Furthermore, the highest cumulative CH4 production was observed at the samples of source separation/collection (398 ± 52–519 ± 117 mL/gVS for FW, 276 ± 51–332 ± 41 mL/gVS for KW), and then accompanied by a decrease (299 ± 31 mL/gVS for FW and 285 ± 39 mL/gVS for KW) after downstream storage. The results indicated that the subsequent anaerobic digestion would be inclined to appear perturbation caused by the lactic acidification of the initial feed and it is imperative to avoid further conversion of lactic acid to propionic acid, which could provide vital guideline reference for the optimization of biogas production process. Moreover, the lactic acid-rich property also highlights other value-added pathways for the resource recovery of municipal biowaste.

Pengembangan ternak Ruminansia terintegrasi di Desa Koto Simandolak Kabupaten Kuantan Singingi: Pemanfaatan kotoran ternak untuk biogas dan pupuk organik

Kuantan Singingi Regency is one of the ruminant-producing districts in Riau Province. Koto Simandolak Village, located in Benai District, Kuantan Singingi Regency, the majority of the people work as farmers. Generally, farmers in Koto Simandolak Village cultivate livestock traditionally, namely by releasing them to the wild. This condition causes several problems including livestock manure, pollution of the village environment, and conflicts with residents. This problem can be solved if the farmer wants to keep the cattle. By holding cattle, the manure will be collected directly in the cage. Animal manure can be processed and used in biogas and organic fertilizer. The Research and Community Services Team of Universitas Riau saw the potential for utilizing livestock manure waste in Koto Simandolak Village. The Team conducts training and assistance in the installation of biogas reactors as well as training and mentoring in the biogas production process using livestock manure. Another output of biogas production is organic fertilizer. The ultimate goal of this service activity is to increase the income of the target community, namely through increasing livestock production, biogas production, and organic fertilizer production.

Comparative Functional Microbiome Profiling of Various Animal Manures During Their Anaerobic Digestion in Biogas Production Processes

Comparative Functional Microbiome Profiling of Various Animal Manures During Their Anaerobic Digestion in Biogas Production Processes

Effects of Heavy Metal Ions (Fe<sup>3+</sup>, Cu<sup>2+</sup>, Zn<sup>2+</sup> and Cr<sup>3+</sup>) on the Productivity of Biogas and Biomethane Production

It was shown that the concentration of heavy metal ions Fe3+, Cu2+, Cr3+ and Zn2+, which are contained in the fermentation medium, affects the process of biogas production. The aim of this paper was to establish the concentration of ions, which makes it possible to increase the yield of biogas and the methane content in it. The total yield of biogas per unit of dry organic matter, methane and the kinetics of changes in the yield of biogas during fermentation of cattle manure in the presence of different concentrations of metal ions in the anaerobic environment. It was established that the content of Fe3+, Cu2+ is up to 80 mg/dm3, Cr3+ and Zn2+ is up to 50 mg/dm3 in the medium lead to increased methane production by anaerobic association of microorganisms due to the effect on the activity of enzyme systems in comparison with the sample without the addition of metal ions. It was found that the rational concentrations to increase the methane yield in the biogas obtained by fermentation of cattle manure are: Fe3+-20 - 40 mg/dm3, Cu2+-40 - 60 mg/dm3, Cr3+-10 mg/dm3. The increase in the concentration of metal ions above rational values leads to a decrease in the methane content in biogas. It was shown that zinc ions have a positive effect on methane production, but reduce the total biogas yield and, accordingly, the degree of conversion of organic raw materials. Therefore, the rational concentration of Zn2+ in the fermentation medium is 10 mg/dm3.

ELECTION OF CRITERIA FOR ASSESSMENT OF SUSTAINABILITY IN THE DESIGN OF TECHNOLOGICAL SYSTEMS FOR BIOGAS PRODUCTION

One of the most promising renewable energy sources is the production of biogas from waste and its further use. The stability of technological systems for biogas production is described by a set of quantitative indicators that depend on the structure, operation algorithm and stability indicators of individual elements. When developing technological control systems for biogas plants, it is necessary to solve a whole range of tasks related to the processing of initial information for the analysis and synthesis of optimal system options. The aim of the study is to develop a methodology for determining the stability of the automatic control system for biogas production processes as an integral part of the technological system, which makes it possible to formalize quantitative and qualitative characteristics and create an algorithmic and software base for calculations. Since the technological control systems of biogas plants are nonlinear control objects, then to study their operation, linearization is provided within the basic mode, while the mode specified by the optimizer is within the linearization error. Design problems are solved in the presence of analytical dependences of the stability characteristics of the system on the stability characteristics of objects. Considering that the interacting elements of the systems are individual types of equipment and various types of raw materials and energy carriers involved in technological processes, a large number of information materials should be used when operating equipment of biogas plants. When designing a technological system for biogas production for a specific object, it is necessary to create its conditionally complete dynamic model, and using the model, calculate matrices for various operating modes and determine the boundaries of the spectra of eigenvalues and consider options for matching the regulator with the object. Considering approximately the same costs, the preferred option should be considered the option that provides the greatest margin of stability.

ENERGY SAVING OF MODULAR BUILDINGS WITH THE HELP OF BIOGAS TECHNOLOGIES

Ukraine has significant land resources for agriculture and is able to provide its population not only with food but also with raw materials for bioenergy. The article presents a graph of heat capacities and the distribution of heat flows in a bioreactor. The dependences for determining the heat fluxes of flat and cylindrical surfaces are presented. The article outlines the present state of utilization of fallen leaves of trees. The method of utilization by anaerobic fermentation is proposed. The design of bioreactors and the main factors influencing the methane formation process are considered. The methodology for calculating the biogas production process is presented. The productivity of the bioreactor has been determined, depending on the temperature of the raw material and the time of hydraulic resistance