Biogas Production Performance Research Articles

Life cycle analysis of biogas production from anaerobic digestion of palm oil mill effluent

This study aims to evaluate the cradle-to-gate life cycle environmental performance of biogas production by the anaerobic digestion (AD) of POME. The life cycle assessment (LCA) was performed using the ReCiPe 2016 method and SimaPro 8.5 software. This study emphasizes on global warming (GWP), land use change (LUC) and water consumption (WCP) due to their significant contributions. It was found that the total characterization factor for human health damage by WCP and GWP ranges from 2.49 × 10−8 to 3.36 × 10−3 DALY per m3 of consumption and 1.45 × 10−5 to 1.42 × 10−3 DALY per kg of emission, respectively. The total characterization factor for ecosystem damage by WCP, LUC, and GWP ranges from 6.76 × 10−15 to 2.04 × 10−5 PDF·m2·yr·m−3, 4.92 × 10−8 to 4.78 × 10−6 PDF·m2·yr·m−2, and 1.19 × 10−12 to 4.28 × 10−6 PDF·m2·yr·kg−1, respectively. It can be concluded that waste-derived biogas is a promising technology that can be used to meet the national goals for a sustainable renewable energy. This study can be a starting point to highlight the sustainability of biogas production for a proper waste management and energy recovery in Malaysia context.

Variation of the digester temperature in the annual cycle – using the digester as heat storage

Abstract Regarding digesters, present guidelines assume that the temperature must be kept constant in order to achieve process stability and that there is a drop in gas production between 40 and 50 °C. Nevertheless, observations of full-scale application show that fluctuations in temperature between mesophilic and thermophilic environments is indeed possible without any loss in biogas production performance. This would be particularly favourable because the digester can thus act as a heat storage. In order to validate temperature fluctuations on full-scale digesters the data of two digesters from different wastewater treatment plants (WWTPs) with high temperature fluctuations were analyzed. In addition, chemical oxygen demand (COD) balances for different temperature ranges were conducted in order to evaluate the process stability. The results show that fluctuations between mesophilic and thermophilic conditions can be achieved without a decrease in biogas production. Increasing the temperature above 50 °C leads to an increase in organic acid concentration as described in the literature. Nevertheless, the total concentration of organic acid was still at an uncritical level below 500 mg/L. The COD balance shows no significant difference between 38 °C, 44 °C and 51 °C. The rate of temperature fluctuations per day specifically seems to be a main factor for process stability rather than temperature itself.

Effect of fipronil on biogas production performance during anaerobic digestion of chicken manure and corn straw

Fipronil is a broad-spectrum insecticide that has a good control effect on pests of commercial poultry. Although many studies have reported the environmental fate of fipronil, the influence of residual fipronil in poultry waste on biogas production has not been further explored yet. In this article, an experimental comparative study on anaerobic digestion (AD) of chicken manure (CM) and corn straw (CS) with different fipronil concentrations (FCs) was carried at 8% of total solid (TS) and mid-temperature (35 ± 1)°C. The results showed that fipronil had a significant effect on biogas production during AD of CM and CS. When the FC is at a low level (≤10 mg·kg−1), the biogas production rate is increased and the digestion period was shortened, while higher FC (≥ 20 mg·kg−1) showed an inhibitory effect. During the monitoring of enzyme activity, low FC showed no significant effect on cellulase and saccharase, but the urease activity increased in the early stage. High FC showed inhibition of activity of cellulase and urease, but the saccharase activity was significantly inhibited until FC reached 40 mg·kg−1. This study also confirms that the environment in anaerobic digester is favorable for the degradation of fipronil, and its half-life is about 15.83 days.

High variations of methanogenic microorganisms drive full-scale anaerobic digestion process

Anaerobic digestion is one of the most successful waste management strategies worldwide, wherein microorganisms play an essential role in reducing organic pollutants and producing renewable energy. However, variations of microbial community in full-scale anaerobic digesters, particularly functional groups relevant to biogas production, remain elusive. Here, we examined microbial community in a year-long monthly time series of 3 full-scale anaerobic digesters. We observed substantial diversification in community composition, with only a few abundant OTUs (e.g. Clostridiales, Anaerolineaceae and Methanosaeta) persistently present across different samples. Similarly, there were high variations in relative abundance of methanogenic archaea and methanogenic genes, which were positively correlated (r2 = 0.530, P < 0.001). Variations of methanogens explained 55.7% of biogas producing rates, much higher than the explanatory percentage of environmental parameters (16.4%). Hydrogenotrophic methanogens, especially abundant Methanomicrobiales taxa, were correlated with biogas production performance (r = 0.665, P < 0.001) and nearly all methanogenic genes (0.430 < r < 0.735, P < 0.012). Given that methanogenic archaea or genes are well established for methanogenesis, we conclude that high variations in methanogenic traits (e.g. taxa or genes) are responsible for biogas production variations in full-scale anaerobic digesters.

Evaluation of Biogas Production Performance During the Anaerobic Digestion of Lipids with Four or More Double Bonds

The purpose of this study was to investigate the influence of the feed to microorganism ratio (F/M ratio) on the biogas production during the high-efficiency anaerobic digestion of lipids, where 50% of lipids contained four or more double bonds. Biochemical methane potential tests were performed at five different F/M ratios, 0.2, 0.4, 0.6, 0.8, and 1.0, under mesophilic conditions. The biogas production patterns, lag-phase, total volatile fatty acids to volatile solid ratio (VFA/VS ratio), and time required for 90% biogas production (T90) were used to evaluate biogas production based on the biochemical methane potential tests. Biogas production started after 4 days of digestion in all the digesters. The biogas production pattern at an F/M ratio of 1.0 was observed to be different to that previously reported. The methane content was in the stabilized range of more than 50% at all F/M ratios. The T90 was reduced at F/M ratios lower than 0.6. The lag-phase of anaerobic digestion of lipid with four or more double bonds could be reduced by using an F/M ratio lower than 0.6 and an initial VFA/VS ratio lower than 11%.

Biogas Production by Co-Digestion of Canteen Food Waste and Domestic Wastewater under Organic Loading Rate and Temperature Optimization

The objective of this study was to characterize biogas production performance from the co-digestion of food waste and domestic wastewater under mesophilic (35 ± 1 °C) and thermophilic (55 ± 1 °C) conditions. The food waste used as a co-substrate in this study was collected from a main canteen at the Hatyai campus of Prince of Songkla University, Songkhla Province, Thailand. The optimum co-digestion ratio and temperature conditions in a batch experiment were selected for a semi-continuous experiment. Organic loading rates (OLRs) of 0.66, 0.33, and 0.22 g volatile solid (VS) L−1 d−1 were investigated in a semi-continuous experiment by continuously stirring a tank reactor (CSTR) for biogas production. The highest biomethane potential (BMP, 0.78 ml CH4 mg−1 VS removal) was achieved with a ratio of food waste to domestic wastewater of 10:90 w/v at a mesophilic temperature. An OLR of 0.22 g VS L−1 d−1 of co-digestion yielded positive biogas production and organic removal. The findings of this study illustrate how biogas production can be used for operating feed conditions and control for anaerobic co-digestion of domestic wastewater and food waste from a university canteen.

Volatile fatty acids and biogas recovery using thermophilic anaerobic membrane distillation bioreactor for wastewater reclamation

The effects of bioreactor temperatures and salinities of an anaerobic membrane distillation bioreactor (anMDBR) on the permeation performance and their potential recovery of bioresources were fully examined in this study. To the best of our knowledge, this is the first study of a lab-scale anMDBR process utilizing sub-merged hollow fiber membranes. The hybrid system utilizing both membrane distillation (MD) and anaerobic bioreactors achieved 99.99% inorganic salt rejection regardless the operation temperatures and high initial flux from (2–4 L m−2 h−1) at 45–65 °C. However, after 7-day operation, the flux dropped by 16–50% proportional to the bioreactor temperatures. It was found that the effects of bioreactor temperatures had strong impacts on both the permeation performance and fouling behavior while salinity had insignificant effect. A compact non-porous fouling layer was observed on the membrane surface from the bioreactor operated at 65 °C while only a few depositions was found on the membrane from 45 °C bioreactor. In the present study, the optimal anMDBR temperature was found to be 45 °C, showing a balanced biogas production and membrane permeation performance including less fouling formation. At this bioreactor temperature (45 °C), the biogas yield was 0.14 L/g CODremoval, while maintaining a methane recovery of 42% in the biogas, similar recovery to those at bioreactor temperatures of 55 and 65 °C. The potential recovery of volatile fatty acids made anMDBR a more economically efficient system, in addition to its lower operation cost and smaller footprint compared with most other technologies for on-site wastewater treatment.

Biogas Production from Water Hyacinth (Eichhornia Crassipes): The Effect of F/M Ratio

Distribution of water hyacinth (Eichhornia crassipes), generally considered as a water weed, that has been a problem which can harm the environment, irrigation system, and agriculture. However water hyacinth can be used in biogas production because it has large enough amount of hemicellulose contents. The purpose of this study was to know the effect of F/M ratio to biogas production from water hyacinth waste with Liquid Anaerobic Digestion (LAD) method. A series of laboratory experiments using biodigester were performed in batch anaerobic operation at room temperature. F/M ratio that used in each reactor was 39.76, 20.03, 13.32, and 10.01. Degradation process was done in 60 days. The result showed that F/M ratio effects to the biogas production. The best performance of biogas production from this research will be obtained if F/M ratio is in the range of 10.01-20.03 (correspond to 25%-50% of rumen fluid) with water hyacinth as the main substrate.

The Effect of C/N Ratio and Type of Microbes Sludge to Biogas Production: Combination of Tapioca Industrial Wastewater and Tofu Industrial Wastewater

Biogas will be produced from a single organic substrate and controlled the ratio of carbon nitrogen by added inorganic nitrogen substances. The study has been tried to combine substrates from industrial tapioca industrial wastewater with tofu industrial wastewater. The experiments were carried out in batch anaerobic digesters with a C/N ratio range of 20 - 30 and variation of microbial sludge from cow rumen, anaerobic sludge of tofu wastewater treatment plant (WWTP) and anaerobic sludge of tapioca WWTP. The ratio of C/N in the range of 20-30 didn’t significant effect on the volume of biogas production. The microbial from cow rumen gives the best biogas production performance. Biogas yield is 2,199 liter per kg COD.

Modeling of biogas production from cattle manure with co-digestion of different organic wastes using an artificial neural network

The present study utilizes an artificial neural network (ANN) as an estimation model of biogas production from laboratory-scale up-flow anaerobic sludge blanket (UASB) reactors treating cattle manure with co-digestion of different organic wastes. It can be estimated depending on working days, influent chemical oxygen demand, influent pH, influent alkalinity, influent ammonia, influent total phosphorus, hydraulic retention time, waste adding ratio, pretreatment and additive waste sorts. The suitable architecture of an ANN for use in biogas prediction consists of 10 input factors, tangent sigmoid transfer function (tansig) at the four hidden layer neurons and a linear transfer function (purelin) at the output layer neuron. The R 2 was found to equal 0.89, 0.79 and 0.75 in the training, validation and testing steps, respectively. ANN estimation modeling can effectively predict the biogas production performance of laboratory-scale UASB reactors. These results indicate that biogas production was optimized to occur in the 20–30% addition range with different organic wastes.

Effects of coffee processing residues on anaerobic microorganisms and corresponding digestion performance

The objective of this study was to delineate the effects of different coffee processing residues on the anaerobic microbes and corresponding digestion performance. The results elucidated that mucilage-rich feed enhanced the accumulation of methanogens, which consequently led to better digestion performance of biogas production. Fifty percent more methane and up to 3 times more net energy (heat and electricity) output were achieved by the digestion of the mucilage-rich feed (M3). The microbial community and statistical analyses further elucidated that different residues in the feed had significant impact on microbial distribution and correspondingly influenced the digestion performance.

Linkage of kinetic parameters with process parameters and operational conditions during anaerobic digestion

Kinetic characteristics play an important role in anaerobic digestion system for representing biogas production performance, however, its relationship with anaerobic digestion process parameters (i. e., volatile fatty acids, total ammonia nitrogen, pH and total alkalinity) and operational conditions remains poorly understood. To illustrate the linkage of kinetic parameters with process parameters and swine manure content and initial pH, and the effects of swine manure content and initial pH on anaerobic digestion performance, substrate properties, accumulative biogas production, specific biogas production rate and process parameters were analyzed under different treatments. Additionally, the effects of swine manure and initial pH on hydrolysis constant, lag phase, biogas production potential and the maximum biogas production rate were investigated. The results revealed that volatile solid and C:N ratio were significantly decreased with swine manure content increased which were considered as operational conditions with initial pH following the linkage illustration. Furthermore, accumulative biogas production, biogas production rate, final pH, total ammonia nitrogen and hydrolysis constant were increased with swine manure content and initial pH increased, while volatile fatty acids and lag phase showed the opposite trend. The results showed that these operational conditions significantly influenced process parameters and kinetic parameters, with close correlations were observed. Lag phase closely correlated with VFA which was closely correlated with C:N ratio. Therefore, C:N ratio impacted kinetic parameters via effecting VFA, while initial pH directly influenced kinetic parameters. Meanwhile, the correlation of kinetic parameters with C:N ratio was stronger than initial pH. Therefore, C:N ratio should be an indicator for estimating process performance, time the bacteria's acclimatization to the new environment and biogas production. Taken together, these findings provide a scientific theory for estimating anaerobic digestion performance.

Environmental analysis of Spirulina cultivation and biogas production using experimental and simulation approach

Abstract Microalgae is constituted by different compounds, interesting for the production of a wide range of end-products by using different technologies. Many potential possibilities have been developed under the context of a biorefinery. The aim of this work is to evaluate the environmental performance of biogas production from Spirulina ( Arthrospira maxima ) through LCA using experimental and simulation results. For this purpose, kinetic models for batch cultivation and anaerobic digestion (AD) were determined from experimental data. Thus, Monod kinetic model and a first order model describe well microalgal biomass growth and AD, respectively. This model was used to simulate growth of Spirulina in a continuous system by using SuperPro Designer 9.5. Calculated results were compared to continuous experimental ones, obtaining good agreement in all cases. On the other hand, the whole process (cultivation, dewatering and AD of Spirulina biomass) was also simulated and the obtained results (material and energy balances) were used to construct LCA inventory data. Thereafter, environmental impacts were quantified through CML-2001 methodology using software Gabi 6.0. LCA results show that abiotic depletion of fossil resources (ADFR) category presents the highest impact, being biomass cultivation the most important contributor (about 56%). This result is directly related to the high energy consumption required for nutrient production, which also leads to increase remarkably the global warming potential (GWP) category. Main conclusion of the work is that the total/partial substitution of mineral fertilizers as nutrient source is the key to improve the environmental performance of the studied process. In this sense, a potential alternative could be the use of nutrients from wastewater or other wastes.

Effect of Organic Loading Rate on Anaerobic Digestion of Food Waste under Mesophilic and Thermophilic Conditions

This study investigated the effect of organic loading rate (OLR) on anaerobic digestion (AD) of food waste under mesophilic and thermophilic conditions. Results showed that the performance of the AD system was distinctly influenced by temperature and OLR in terms of biogas production, intermediate metabolism, and degradation performance. The optimal OLR under thermophilic condition was 2.5 g of volatile solids (VS)/L/day with methane yield (MY) of 541 mL/g of VSadded. In addition, the optimal OLR under mesophilic condition was 1.5 g of VS/L/day with a MY of 371 mL/g of VSadded. At the same OLR, the MY under thermophilic condition was 33–49% higher than that under mesophilic condition. Under thermophilic condition, steady methane production and degradation efficiency were achieved with considerably high OLR of 7.5 g of VS/L/day. Under mesophilic condition, stability was obtained only when the OLR was controlled below 2.5 g of VS/L/day. Results also revealed that food waste is a highly desirable substrate w...

Feasibility study of a centralized biogas plant performance in a dairy farming area

In this feasibility study, the anaerobic co-digestion of different organic wastes obtained from a dairy farming area in Hokkaido prefecture, Japan was investigated with the objective of building a centralized biogas plant. The daily organic wastes generated from the study area were 210 t/day, comprised of 90% barn wastes and 10% wastewater sludge and feed residue of total mixed ration. The wastes can be categorized into high VS/TS ratio which is easily biodegradable and low VS/TS ratio which is hardly biodegradable. The methane yield of each substrate was investigated in a batch experiment followed by a continuous experiment at mesophilic temperature. Compared to other organic wastes, higher methane production potential were obtained from dairy manures with the highest yield, resulting in 0.19 m3/kgVS, from dairy manure slurry. Moreover, a longer hydrolysis rate constant (7.2 days) was observed with dairy manure slurry rather than beef cattle manure (3.4 days). Due to the mixture of substrates in the continuous experiment, the methane yield increased significantly (0.35 m3/kgVS), reaching almost double of that observed during batch experiments. The average biogas production performance was 39.26 m3 per m3 of added substrate. This illustrates the potential economic viability of the prospective centralized biogas plant.

The Performance of Biogas Production from Pome at Different Temperatures

Indonesia, as the largest palm oil producer in the world, also produces palm oil mill effluent (POME. While the latter is a liquid waste that is hazardous for the environment, with proper processing, it can be a potential energy source. The objective of this study was to study the performance of biogas production from POME at various temperatures. The POME and sludge mixture was fermented, according to the treatment,at 27-28oC, 45oC, and 55oC, with the results showing that methane could thereby be produced by as much as 0.19m3, 0.25 m3, and 0.28 m3, respectively. For each kilogram of Chemical Oxygen Demand (COD) removal, with POME fermentation at room temperature, 45oC, and 55oC, biogas could be produced with methane content of 65.44%, 62.57%, and 59.15%, respectively.

Evaluation of Biogas Production Performance and Dynamics of the Microbial Community in Different Straws.

The development and utilization of crop straw biogas resources can effectively alleviate the shortage of energy, environmental pollution, and other issues. This study performed a continuous batch test at 35°C to assess the methane production potential and volatile organic acid contents using the modified Gompertz equation. Illumina MiSeq platform sequencing, which is a sequencing method based on sequencing-by-synthesis, was used to compare the archaeal community diversity, and denaturing gradient gel electrophoresis (DGGE) was used to analyze the bacterial community diversity in rice straw, dry maize straw, silage maize straw, and tobacco straw. The results showed that cumulative gas production values for silage maize straw, rice straw, dry maize straw, and tobacco straw were 4,870, 4,032.5, 3,907.5, and 3,628.3 ml/g ·VS , respectively, after 24 days. Maximum daily gas production values of silage maize straw and rice straw were 1,025 and 904.17 ml/g ·VS, respectively, followed by tobacco straw and dry maize straw. The methane content of all four kinds of straws was > 60%, particularly that of silage maize straw, which peaked at 67.3%. Biogas production from the four kinds of straw was in the order silage maize straw > rice straw > dry maize straw > tobacco straw, and the values were 1,166.7, 1,048.4, 890, and 637.4 ml/g ·VS, respectively. The microbial community analysis showed that metabolism was mainly carried out by acetate-utilizing methanogens, and that Methanosarcina was the dominant archaeal genus in the four kinds of straw, and the DGGE bands belonged to the phyla Firmicutes, Bacteroidetes, and Chloroflexi. Silage maize is useful for biogas production because it contains four kinds of straw.

Biogas Production Performance of Different Components from Banana Stems

The object of this paper was to provide data for process design and economic feasible analysis of biogas production from banana stems. Fresh banana stems were separated into fiber cells (FC), parenchyma cells (PC), and liquid, and their biochemical methane potential (BMP) was analyzed. The BMP of FC, PC, and liquid were 225.0 ± 17.0 mL/g of total solids (TS), 187.5 ± 12.1 mL/g of TS, and 299.6 ± 12.6 mL/g of chemical oxygen demand (COD), accounting for 56.18, 40.48, and 3.34% of the total methane production of banana stems, respectively. Smashing before squeezing increased the COD of liquid from 1939 to 7464 mg/L, and the percentage of methane production from liquid would increase to 11.96%. Therefore, squeezing before transportation directly or after smashing can be used to both reduce transportation cost and, thus, increase the economic feasibility of biogas production from banana stems.

Evaluation of Mixing Effects on Solid-state Anaerobic Digestion Performance of Dairy Manure and Sawdust Bedding Mixtures

The influence of mixing on biogas production and organic material removal performance of solid state anaerobic digestion of dairy manure and sawdust bedding mixtures was evaluated using 22 L volume lab-scale digesters. After 45 days of anaerobic digestion at 37°C, cumulative methane yield of unmixed test unit (73.1 N·mL/g-VS) was almost 1.3 times of that of mixed one (56.3 N·mL/g-VS). The biodegradable volatile solids removal rate of unmixed test unit was 67%, which was almost 28% greater than mixed one. Our results reveal that unmixed condition is better than mixed one in terms of biogas production and organic material reduction.

Combined Electrochemical and Hypochlorite Pretreatment for Improving Solubilization and Anaerobic Digestion of Waste-Activated Sludge: Effect of Hypochlorite Dosage

The electrochemical (EC) combined with hypochlorite (ClO–) pretreatment has been proven to be effective in improving disintegration of waste-activated sludge (WAS) and enhancing anaerobic digestion recently. The ClO– dosage had a significant impact on the performance of WAS solubilization and biogas production in terms of the disintegration degree (DDCOD), release of proteins (PNs) and polysaccharides (PSs), soluble nitrogen and phosphate, and subsequent anaerobic digestion. The results showed that a higher ClO– dosage was favorable to WAS solubilization and EC–ClO– pretreatment was able to rupture the floc structure and break cells apart. According to batch anaerobic digestion tests, the optimum ClO– dosage for EC–ClO– pretreatment was 0.6% (v/v), with up to 61.1% higher methane production compared to the unpretreated sludge after mesophilic anaerobic digestion for 40 days. Model-based analysis suggested that EC–ClO– pretreatment could enhance the hydrolysis process as well as methane potential. Moreover...