Anaerobic Biogas Research Articles

A Low-Cost IoT System Based on the ESP32 Microcontroller for Efficient Monitoring of a Pilot Anaerobic Biogas Reactor

A pilot anaerobic bioreactor requires near-daily monitoring and frequent maintenance. This study aimed to upgrade a pilot bioreactor into a low-cost IoT device via ESP32 microcontrollers. The methodology was based on remote data acquisition and online monitoring of various parameters towards assessing the anaerobic digestion performance. A semi-continuous tank bioreactor with a 60 L total volume was initially inoculated mainly with livestock manure and fed daily with a mixture of glucose, gelatin, and oleic acid, supplemented with a basic anaerobic medium. Under steady-state conditions, the organic loading rate was 2 g VS LR−1 d−1. Sensors for pH, temperature, REDOX potential, and ammonium concentration, along with devices measuring biogas volume and methane content, were integrated and validated against analytical methods. Biogas production was recorded accurately, enabling the early detection of production declines through ex-situ data analysis. Methane concentration variance was less than 6% compared to gas chromatography, while temperature and pH deviations were 0.15% and 1.67%, respectively. Ammonia ion measurements required frequent recalibration due to larger fluctuations. This IoT-enhanced system effectively demonstrated real-time monitoring of critical bioreactor parameters, with ESP32 enabling advanced control and monitoring capabilities.

Enhancement of anaerobic biogas conversion by Alkali assisted photocatalytic pretreatment of sugarcane bagasse

Enhancement of anaerobic biogas conversion by Alkali assisted photocatalytic pretreatment of sugarcane bagasse

Implementation of sensor fusion for an anaerobic biogas digester using domestic market waste

Implementation of sensor fusion for an anaerobic biogas digester using domestic market waste

Influence of temperature and substrate composition on anaerobic biogas production in a pilot-scale reactor

Influence of temperature and substrate composition on anaerobic biogas production in a pilot-scale reactor

An iterative comprehensive evaluation of pretreatment methods, comparative biomass analysis, and sustainability assessment for optimizing anaerobic biogas production from lignocellulosic biomass

An iterative comprehensive evaluation of pretreatment methods, comparative biomass analysis, and sustainability assessment for optimizing anaerobic biogas production from lignocellulosic biomass

Assessment of the effectiveness of process-induced struvite crystallization process on the recovery of nutrients from high-strength liquid digestate of an anaerobic biogas plant

This study aimed to recover magnesium (Mg2+), ammonium (NH4+) and phosphate (PO43-) as struvite from high-strength liquid digestate (LD) of an anaerobic biogas plant, where poultry manure was processed for biogas production. Effluent quality after the struvite crystallization process was investigated in terms of the change in Mg2+, NH4+ and PO43- concentrations. The change in chemical oxygen demand (COD) concentrations was also investigated to determine whether the struvite formation could help to decrease extremely high initial concentrations in the LD. Results showed that a certain level of Mg2+, NH4+, PO43-, and COD removal occurred under the optimized experimental conditions, leaving an effluent with relatively high residual concentrations. To further reduce the residual concentrations, an attempt was made by performing a secondary struvite crystallization process as a process-induced additional treatment step, which has never been investigated in the literature. The results revealed that an improved quality of effluent was achieved after the process-induced struvite crystallization process as compared to the single-step process. The morphology and the elemental composition of the produced precipitates confirmed by XRD and EDS analysis showed that the structure was typical of struvite crystals. This study clearly demonstrates that the process-induced struvite crystallization process could effectively lessen the adverse environmental impacts arising from the problematic wastes of biogas plants. The cost analysis reveals that low-cost alternative sources of Mg and PO4, such as wastes rich in Mg and/or P content, should be used instead of high purity reagents to improve the economic sustainability of the process.

Peningkatan Produktivitas Dengan Metode Green Productivity Pada PT. Bangun Tenera Riau Desa Pantai Raja Kabupaten Kampar

PT Bangun Tenera Riau is a company engaged in the processing of oil palm fresh fruit bunches, located in Pantai Raja Village, Perhentian Raja District, Kampar Regency, Riau Province. The problem faced by PT Bangun Tenera Riau is that the company has not maximally utilized the by-products produced in the form of waste. This research aims to improve the production process by selecting alternative solutions to increase and enhance the initial green productivity index value so that productivity can increase and the impact on the environment can be reduced. The method used in this research is the green productivity method. Based on the environmental performance indicator (EPI) calculation, it is known that the value of biological oxygen demand (BOD) liquid waste has a deviation of -0.63% and an EPI value of -0.16 which exceeds the waste quality standard based on Kep-51 / MENLH / 1995 so that it is necessary to improve the quality of waste through alternative solutions. The alternative solution chosen is an anaerobic biogas reactor and rotating biological contactor (RBC) used to improve waste quality and company productivity. The study's results using the green productivity method obtained an average final total productivity of 1.31 with the initial value of the average productivity in each month being 1.17. The productivity value of the company increased by 0.21 with the efficiency of improving the quality of waste by BOD by 96.81% and converting liquid waste into biogas which is beneficial to the community

Study on preliminary economic availability of electric energy use from drying bed sludge by biogas from anaerobic digestion and incineration in Brazil

This study aimed to analyze electrical energy generation derived from anaerobic biogas digestion and the incineration of drying bed sludge (DBS) from an Upflow Anaerobic Sludge Blanket (UASB) reactor using samples from a Wastewater Treatment Plant in Itajubá, Minas Gerais, Brazil. Some data including Automatic Methane Potential Test System (AMPTS II) were obtained from Moni Silva et al. (2021). An experimental apparatus comprised of a biodigester and gasometer was elaborated to conduct quali-quantitative evaluation of DBS biogas generation. Economic analysis was conducted on the Thermal Power Plant (TPP) electrical generation system, powered by biogas with data from i. experimental apparatus, and ii. AMTPS, as well as an incineration power plant. Greenhouse Gas (GHG) emission reductions were assessed. The results demonstrate that TPP from biogas with biodigestion without temperature control (experimental apparatus) was not economically feasible, even when considering ICMS tax exemptions; nonetheless, it would be capable of mitigating GHG emissions. Biodigestion with temperature control enabled TPP projects economic viability with payback in 20 years (178.67 kW, 9% IRR) considering a minimum population of 3,000,000 inhabitants. In all cases, the ICMS taxation reduces project feasibility.

Effects of Substrate and Processing Conditions on Nematode Suppressiveness of Anaerobic Biogas Digestates

Biogas digestates produced from anaerobically processed food or dairy manure have demonstrated some potential to suppress different pathogens and pests. In this study, digestates from these two substrates processed mesophilically (20 to 40°C) or thermophilically (>40°C) were compared for their nematode-suppressive potential. In bioassays, the suppressive potential of Heterodera schachtii or Meloidogyne incognita was tested at different amendment rates. Testing was expanded to field microplot experiments with M. incognita and greenhouse tests with Pratylenchus vulnus. In the bioassay with H. schachtii, fewer nematodes penetrated radish roots after amendment with thermophilic than with mesophilic digestates. Root penetration was lowest after treatment with digestates of food waste and thermophilic dairy manure at the highest rate. In a watermelon bioassay with M. incognita, nematode-induced galling and egg mass production were reduced after amendment with food waste digestates compared with manure digestates and after thermophilic compared with mesophilic digestates in the case of egg masses. In a greenhouse experiment with peach rootstock ‘Nemaguard’, the numbers of P. vulnus in roots were diminished after amendment with digestates at the highest rate. In microplot experiments with bell peppers, plants initially were more vigorous after amendment with thermophilic digestates than after mesophilic digestate additions. This effect was transient and was no longer measurable at harvest. In summary, food waste digestates, especially those that were thermophilically produced, had nematode suppressive and plant growth-improving properties. These effects were not long lasting and probably need additional mitigation for practical utility. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Life cycle assessment of environmental impacts for two-stage anaerobic biogas plant between commercial and pilot scales

This study presents the detailed life cycle assessment (LCA) of environmental impact potential for two-stage anaerobic biogas plants between commercial and pilot scales. It provides a comprehensive and systematic approach to evaluating the environmental impacts of producing biogas from livestock wastes in several phases: collecting, processing, and production. The commercial biogas plant (C-BP) system is located in Central Taiwan's pig farm, with 1500–2000 pigs a year. The Symnergy (symbiosis bioenergy model) biogas pilot plant (S-BP) is installed in Manado City, Indonesia. The Institute of Green Products, Feng Chia University, designed both C-BP and S-BP systems. The environmental impacts of both systems' gate-to-grave life cycles were assessed and compared using Simapro 9.0.0 software. The pilot-scale biogas plants produce bioenergy from the wastewater of the slaughterhouse. Therefore, 10,950 tonne/year of slurry feedstock flowing into the commercial biogas plant was considered a functional unit equal to 21 times larger than the pilot scale biogas plant. The LCA analyzes the impacts of three processes for feedstock collection, biogas production, and digestate production. It was found that Photochemical Ozone Creation Potential had the highest total impact on C-BP (33%), and Eutrophication had the highest impact on S-BP (33%). Both the biogas production systems of C-BP and S-BP showed very low environmental impacts, and the impacts of C-BP are lower than the S-BP. However, implementing digesters considerably reduced the potential environmental impacts of well manure feedstock handling and fertilizer applications. The LCA analysis among the three individual processes is developed to allow critical points and environmental impacts for local government. Consequently, the LCA report could help establish regional sustainability strategies for the management of livestock wastes by anaerobic two-stage biogas plant from manure.

Enhancement in anaerobic biogas conversion by visible light photocatalytic Pre-treatment of rice husk with indium vanadate decorated titanium dioxide nanocomposite

Production of biogas from crop wastes via the biological route is one of the most demanding and promising technologies for energy generation for sustainable development. The incorporation of photocatalytic pretreatment as a robust catalytic technique has been reported to enhance the overall efficiency of the anaerobic process. Rice husk has been pretreated using Indium Vanadate decorated Titania nanocomposite to enhance its biodegradability for biogas production. Scanning electron microscopy confirmed the deformities and crevices that may support the role of the photocatalytic pretreatment in the subsequent anaerobic degradation process. FT-IR spectroscopy investigated the structural characteristics of pretreated and photolyzed rice husk samples. Gas chromatography was used to quantify the CH4 content of biogas yield after different treatments of rice husk. Photocatalytic pretreatment of rice husk showed 2.8 times higher cumulative biogas production than raw or untreated rice husk. Statistical analysis showed a significant difference between natural and pretreated rice husk biogas yield with a p-value of < 0.01. The results suggest that visible light active photocatalysis is an efficient pretreatment method that can facilitate the microbes to degrade the rigid rice husk for enhanced biogas production via the anaerobic digestion process.

Biomethane Potential in Anaerobic Biodegradation of Commercial Bioplastic Materials

Bioplastics have emerged as a promising alternative to conventional plastics, marketed as environmentally friendly and sustainable materials. They provide a variety of methods for efficient waste management contributing to the goals of the circular economy. At their end-of-life stage, bioplastics can generate added value through aerobic and anaerobic biological treatments (composting or anaerobic digestion). In this study, biomethane potential (BMP) tests were carried out under mesophilic conditions on eight different catering biodegradable plastics available in the market and certified as being biodegradable under industrial composting conditions. Chemical analysis of the biodegradable plastics included elemental analysis, Fourier-transform infrared spectroscopy, and inductively coupled plasma–optical emission spectrometry. Key differences were observed in total solids (TS) and volatile solids (VS) contents between the studied biopolymer products. TS values ranged between 85.00 ± 0.26% (Product 8) and 99.16 ± 0.23% (Product 4), whereas VS content ranged between 64.57 ± 0.25 %wm (Product 6) and 99.14 ± 0.17 %wm (Product 4). Elemental analysis (elements C, H, N, S, and O) was used to estimate the theoretical methane production (ThBMP) of each product. The highest ThBMP (538.6 ± 8.7 NmL/gVS) was observed in Product 4 correlated with the highest C and H contents, while the lowest ThBMP (431.8 ± 6.1 NmL/gVS) was observed in Product 2. Significant differences were recorded between BMP values according to the chemical composition of the polymers. The average of BMP values ranged between 50.4 ± 2.1 NmL/gVS and 437.5 ± 1.0 NmL/gVS. Despite being characterized by the same composition (cellulose/cellulose derivatives and calcium carbonate), Products 2, 3, and 6 revealed significant differences in terms of TS, VS, ThBMP, and BMP. Furthermore, a significant statistical relationship (p &lt; 0.001) was found between time (days) and BMP values of the eight products (R2 = 0.899–0.964) during the initial phase. The study confirmed that cellulose-based materials can convert efficiently under mesophilic conditions into methane, at a relatively short retention time; hence, they can be regarded as a promising material for co-digestion with feedstock in industrial anaerobic biogas plants. In contrast, biodegradation of polylactic acids (PLA) does not occur under mesophilic conditions, and hence, pre-treatment of the polymers is recommended. Moreover, PLA-containing products are highly affected by the presence of other components (e.g., polybutylene adipate terephthalate and cellulose/cellulose derivatives).

Towards fair, just and equitable energy ecosystems through smart monitoring of household-scale biogas plants in Kenya

Anaerobic biogas digestors offer a technological solution to facilitate modern, sustainable, and equitable energy access, efficiency, and transition pathways to achieve United Nations Sustainable Development Goal 7 – affordable, reliable, sustainable and modern energy for all. In this paper we create critical evidence, through documenting insights from the Smart Biogas (SB) II project, that contributes to the introduction of (low cost) smart metered biogas energy systems at the household level. Our research objectives were to 1) understand and analyse the lived experience of key SB project stakeholders, and 2) create evidence that can contribute to the widespread adoption of smart biogas meters for household-scale applications.In early 2022 13 semi-structured qualitative interviews were conducted with key SB II project stakeholders (biogas end-users, system specialists, carbon finance professionals, research partners, and general experts). These semi-structured interviews followed a phenomenological approach focusing on the lived experience of study participants. Our results showed that biogas is particularly suited to live monitoring and the SB system unlocks significant benefits to both the end-user and energy supplier. These benefits are realised through improved user experience, unlocking biogas-as-a-service delivery models and seamlessly integrating remote monitoring capabilities for carbon credit programs, as well as identifying a series of future work pathways across these themes. Ultimately, we show the SB meter enables an accessible and low-cost approach to decentralised energy for households across the globe and a potentially scalable pathway to achieve SDG7.

Acid-modified anaerobic biogas residue biochar activates persulfate for phenol degradation: Enhancement of the efficiency and non-radical pathway

The treatment of biogas residue with complex composition from anaerobic bog has gradually become a challenge for energy utilization of solid waste. However, biogas residue rich in cellulose hemicellulose and lignin can be employed to prepare biochar. In this study, biogas residue biochar (HBC800) activated persulfate(PS) was prepared by a two-step method of 800 ℃ calcination and acid modification, which has the characteristics of large specific surface area, rich functional groups. HBC800 had excellent activated PS degradation efficiency of phenol (91.6 %). The effect of common ions was weak and showed good environmental adaptability in groundwater on phenol degradation. Electron Paramagnetic Resonance (EPR) and quenching tests were employed to find that electron transfer and singlet oxygen (1O2) were the main mechanisms for phenol degradation in the HBC800/PS system. This result is mainly attributed to the important role played by surface oxygen-containing functional groups, defects and graphite nitrogen as active sites. HBC800 has good recycling efficiency and practical ability to treat coking wastewater. This study provides an alternative to biogas residue biochar utilization and better support for the closed-loop utilization of agroforestry waste resource.

Solid-State Fermentation of Trichoderma spp.: A New Way to Valorize the Agricultural Digestate and Produce Value-Added Bioproducts.

In this study, the agricultural digestate from anaerobic biogas production mixed with food wastes was used as a substrate to grow Trichoderma reesei RUT-C30 and Trichoderma atroviride Ta13 in solid-state fermentation (SSF) and produce high-value bioproducts, such as bioactive molecules to be used as ingredients for biostimulants. The Trichoderma spp. reached their maximum growth after 6 and 3 SSF days, respectively. Both Trichoderma species were able to produce cellulase, esterase, and citric and malic acids, while T. atroviride also produced gibberellins and oxylipins as shown by ultraperformance liquid chromatography with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) profiling. Experimental evaluation of germination parameters highlighted a significant promotion of tomato seed germination and root elongation induced by T. atroviride crude extracts from SSF. This study suggests an innovative sustainable use of the whole digestate mixed with agro-food waste as a valuable substrate in fungal biorefineries. Here, it has been applied to produce plant growth-promoting fungi and bioactive molecules for sustainable agriculture.

Improvement of gaseous bioenergy production from spent coffee grounds Co-digestion with pulp wastewater by physical/chemical pretreatments

Two steps of hydrolysis and anaerobic biogas production processes was investigated in this study. In the first step, subcritical water (SBW) hydrolysis and chemical (acid/alkali) pretreatments were carried out to enhance hydrolysis efficiency by obtaining and analyzing the total volatile fatty acids (TVFA), chemical oxygen demand (COD), and total sugar productions from spent coffee grounds (SCG) hydrolysate. The subcritical water (SBW) hydrolysis under the condition of temperature 150 °C for 30 min can greatly improve the organic matter breakdown and reached the COD concentration of 1010 g/L which was 30% higher than the untreated raw SCG. For chemical pretreatments, it was found that the alkaline hydrolysis of SCG resulted in the greatest total sugar concentration of 181 g/L whereas the operation conditions were 2.0 M NaOH at 60 °C for 1 h. The peak of TVFA concentration 3725 mg/L was found at the acid hydrolysis of SCG with 1.0 M H2SO4 acid, 60 °C for 1 h. The optimal biomethane yield of 115 mL/g COD was obtained when 1.0 M H2SO4 acid hydrolysate co-digestion with pulp wastewater which increase methane yield production 8 times of raw pulp wastewater. The pretreatment process was confirmed in this study can significant improve the converting of the biowastes to bioenergy efficiency.

Application fuzzy DEMATEL methodology to investigate some technical parameters of biochemical methane potential (BMP) test produced vegetable waste anaerobic biogas.

As the transition to renewable energy systems is accelerating, anaerobic digestion, which is one of the methods of energy recovery from organic substrates, continues to be studied with great interest by scientists. Anaerobic digestion research and applications are mostly carried out with biochemical methane potential (BMP) tests to decide the methane potency of sewage sludge, energy crops, and organic wastes. Unlike long and costly continually reactor experiments, actually, BMP tests are cumulative and can be performed with a relatively low investment of materials, technical labor, and also time. For the BMP to give accurate results, the effect of all the tools and technical parameters used in the implementation of the BMP should be well understood. In such situations, it is very useful to apply fuzzy logic methods in multi-criteria decision-making stages when more than one parameter changes at the same time. Therefore, in this study, fifteen parameters were determined and analyzed with the fuzzy DEMATEL (decision-making trial and evaluation laboratory) method to understand the cause-effect mechanism of the technical parameters of BMP. As a result of these analyses, it was seen that the material of the reactor (ri-cj value of 0.55), the particle size (ri-cj value of 0.43), the effect of mixing (ri-cj value of 0.32), and the amount of the total solids (TSA) (ri-cj value of 0.25) had a high effect in the causal sense. It was observed that the first-order parameter (material of reactor) was 27% stronger than the second-order (the particle size) parameter in terms of causality. Likewise, the second-order parameter is 34% stronger than the third-order parameter (the effect of mixing) in terms of cause effect. In addition, it was understood that the most effective parameters in the mechanism of effect were pH (ri + cj value of 3.41), C/N ratio (ri + cj value of 3.26), and temperature (ri + cj value of 3.07), respectively. Besides, high methane yield is seen in mesophilic conditions. The average cumulative biogas yield of the reactor is 282.1 NmL/g VS. The highest percentage of methane formed in the biogas occurred on the 21st day. Briefly, this study is important to provide a facilitating way for researchers working on BMP to understand the cause-effect mechanism of system technical requirements.

Co-production of biogas and humic acid using rice straw and pig manure as substrates through solid-state anaerobic fermentation and subsequent aerobic composting

Compared with wet anaerobic digestion, solid-state fermentation possesses many merits such as low water consumption, high biogas yield and low processing cost. In this work, co-producing biogas and humic acid (HA) by two-step solid-state fermentation was innovatively investigated using rice straw and pig manure as materials. The result indicates that C/N ratio, straw particle size, and total solid content (TS%) caused significant effects on the solid-state fermentation process. At the first step for anaerobic biogas fermentation, the optimal fermentation conditions included C/N ratio of 27.5, straw particle size of 0.85 mm and TS% of 25%. The maximal biogas productivity and methane content were up to 0.43 m3/(m3·d) and 64.88%, respectively. This means that biogas production was significantly improved by adjusting C/N ratio during the co-fermentation of rice straw and pig manure. Following, the digested residue was aerobically composted for HA biosynthesis to improve the fertilizer efficiency of the fermented substrate. The optimal aeration rate of 0.75 L/min was obtained, and the volatile solid (VS) degradation rate, HA content, and the germination index (GI) value were up to 19.16%, 100.89 mg/g, and 103.07%, respectively, which indicates that HA biosynthesis and compost maturity were significantly enhanced. Therefore, the co-production of biogas and HA using rice straw and pig manure as fermentation materials was achieved by adopting the two-step solid-state fermentation, and the bioconversion efficiencies of livestock manure and straw were significantly improved.

Integrating metagenomic binning with flux balance analysis to unravel syntrophies in anaerobic CO2 methanation

BackgroundCarbon fixation through biological methanation has emerged as a promising technology to produce renewable energy in the context of the circular economy. The anaerobic digestion microbiome is the fundamental biological system operating biogas upgrading and is paramount in power-to-gas conversion. Carbon dioxide (CO2) methanation is frequently performed by microbiota attached to solid supports generating biofilms. Despite the apparent simplicity of the microbial community involved in biogas upgrading, the dynamics behind most of the interspecies interaction remain obscure. To understand the role of the microbial species in CO2 fixation, the biofilm generated during the biogas upgrading process has been selected as a case study. The present work investigates via genome-centric metagenomics, based on a hybrid Nanopore-Illumina approach the biofilm developed on the diffusion devices of four ex situ biogas upgrading reactors. Moreover, genome-guided metabolic reconstruction and flux balance analysis were used to propose a biological role for the dominant microbes.ResultsThe combined microbiome was composed of 59 species, with five being dominant (> 70% of total abundance); the metagenome-assembled genomes representing these species were refined to reach a high level of completeness. Genome-guided metabolic analysis appointed Firmicutes sp. GSMM966 as the main responsible for biofilm formation. Additionally, species interactions were investigated considering their co-occurrence in 134 samples, and in terms of metabolic exchanges through flux balance simulation in a simplified medium. Some of the most abundant species (e.g., Limnochordia sp. GSMM975) were widespread (~ 67% of tested experiments), while others (e.g., Methanothermobacter wolfeii GSMM957) had a scattered distribution. Genome-scale metabolic models of the microbial community were built with boundary conditions taken from the biochemical data and showed the presence of a flexible interaction network mainly based on hydrogen and carbon dioxide uptake and formate exchange.ConclusionsOur work investigated the interplay between five dominant species within the biofilm and showed their importance in a large spectrum of anaerobic biogas reactor samples. Flux balance analysis provided a deeper insight into the potential syntrophic interaction between species, especially Limnochordia sp. GSMM975 and Methanothermobacter wolfeii GSMM957. Finally, it suggested species interactions to be based on formate and amino acids exchanges.AQaLxbUWFz91qWxiAB1_X5Video

Risk matrix approach of extreme temperature and precipitation for renewable energy systems in Malaysia

Renewable energy is crucial to reducing climate change as it replaces fossil fuel-based energy sources partially. However, renewable energy facilities are highly dependent on climate conditions. There have been few studies in Malaysia focusing on the impacts of extreme temperature and precipitation on energy systems. None of the studies used the risk assessment method to examine the effects. This research aims to study the possible risks associated with common renewable energy systems in Malaysia (solar photovoltaic, anaerobic biogas system, biomass, and hydropower) using a risk matrix approach. The mitigation action plan to reduce extreme weathepact on each energy system will also be presented in this study. Three extreme temperature and precipitation scenarios were used to explore the potential impacts on infrastructures, energy resources, power capacity, and efficiency of solar photovoltaic systems, hydropower, biomass, and biogas power plant. The trend of daily temperature and precipitation in Malaysia from 1970 to 2070 is also presented. By 2070, Malaysia will be experiencing greater change in rainfall, as well as warmer temperatures and more droughts. Results of the study show that biomass is the most vulnerable to extreme temperature and precipitation.