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1
Phuong, Nguyen Le. "STUDY ON CO-FERMENTATION OF COW DUNG AND GIANT DIRT IN SEMI-CONTINUOUS ANAEROBIC DIGESTER". Vietnam Journal of Science and Technology 54, n. 2A (19 marzo 2018): 287. http://dx.doi.org/10.15625/2525-2518/54/2a/11943.
Testo completoAbstract (sommario):
Study on co-fermentation of cow dung (CD) and giant dirt (GD - Pistia stratiotes L.) in semi-continuous anaerobic digester aims to test biogas quantity and quality by time. Three mixing rates counted based on ODM of each material were chosen: 100 %CD, 50 %CD + 50 %GD, and 100 %GD. The experiments were set up in laboratory conditions with two types of digesters: one-stage digesters and two-stage digesters (triplicate for each treatment). After 80 days, the biogas produced from the one-stage digesters was not significantly different to the two-stage digesters with similar input material. The highest production of biogas came from digesters of 100 %GD - 235.8 L for the one-stage and 240.3 L for the two-stages. The medium production came from digesters of 50 %CD + 50 %GD - 127.8 L for the one-stage and 118.4 L for the two-stages. After one month, the percentage of CH4 was high enough for burning and almost giant dirt was digested that limited of a blockage inside the digesters. The results showed that co-fermentation of GD and CD is an alternative for livestock raising households to produce biogas for energy purpose.
2
Pradip B. Acharya, Pradip, e Prateek Shilpkar. "Solanum tuberosum Supplementation for Biogas Production". Current World Environment 10, n. 1 (30 aprile 2015): 285–87. http://dx.doi.org/10.12944/cwe.10.1.35.
Testo completoAbstract (sommario):
Production of biogas using animal dung is well documented. Nutritional supplement enhances microbial activity and ultimately results in increase biogas production. Solanum tuberosum (potato) is a vegetable crop grown in most parts of world. It is a rich source of carbohydrate starch and many minerals. Present experiment was conducted in 5L capacity glass digester bottles filled with mixture of buffalo dung and water at 5.3% total solids. A total of six sets were prepared, three as control and three as test. Control sets were fed daily with buffalo dung water mixture throughout the period of experimentation, i.e. 80 days, whereas in test, from 51st day onward digesters were filled with mixture of dung and boiled potato with water. Feed was added daily in the amount of 120mL upto 80 days from beginning. On first day 12 mL fresh digested biogas slurry from running biogas plant was also added in all the digesters as inoculum. From 41th day onward biogas production was recorded by water displacement method and compared. Results reveal that in test digesters addition of potato shows an immediate and long lasting effect and increases biogas production between 90.48 and 192.86% higher than control sets.
3
Wang, Yan, e Shan Shan Zhang. "The Investigation Based on Heating with Biomass Energy for Biogas Digesters Winter Gas Production Technology in Cold Regions". Advanced Materials Research 1008-1009 (agosto 2014): 107–10. http://dx.doi.org/10.4028/www.scientific.net/amr.1008-1009.107.
Testo completoAbstract (sommario):
The average temperature is low in cold regions; therefore, under natural conditions, the gas production is more unlikely to be successful. When temperature drops below 6 °C in the biogas digester, it stops producing gas. By aiming household biogas digesters as subjects, from the test materials, experimental methods, experimental test results and economic analysis, this experiment studied the feasibility of heating with biomass energy for biogas digester to accomplish the digesters gas production in winter in in cold regions.
4
Li, Qian, Jingjing Wang, Xiaoyang Wang e Yubin Wang. "The Impact of Training on Beef Cattle Farmers’ Installation of Biogas Digesters". Energies 15, n. 9 (21 aprile 2022): 3039. http://dx.doi.org/10.3390/en15093039.
Testo completoAbstract (sommario):
Anaerobic digestion is one of the leading ways to manage livestock manure for energy production and move towards the target of carbon neutrality in the agricultural sector. Based on field survey data from China, a binary probit model and the propensity score matching method are employed to empirically examine the impact of agricultural training on livestock farmers’ installation of biogas digesters to manage livestock manure. The survey results show that beef cattle farmers in our study area are reluctant to install biogas digesters and the actual installation ratio of farmers is much lower than that that is willing to install. On the contrary, the beef cattle farmers are enthusiastic to participate in training (e.g., policy-oriented, technology-oriented, and field-based) related to sustainable farming practices. Regression results suggest that training can effectively promote the installation of biogas digesters, and with the increase of training intensity, the probability to install biogas digesters increases. We further find three other factors that affect farmers’ installation of biogas digesters: the education level of a farmer, which is one of the most important factors positively affecting the installation of biogas digesters; longer farming experience of a farmer, which can significantly promote biogas digester installation; and the farther away a farm is from town/urban centers, which means the more likely it is that the farmer will install biogas digesters. Policy implications are discussed.
5
Syed Sabeer Ali, S. N., R. Omar, H. Che Man, A. I. Md Idris e H. A. Tajuddin. "Foaming Tendency in Anaerobic Digestion of Wastewater Inoculated with Anaerobic Sludge and Cow Manure: Effect of Protein Concentration". IOP Conference Series: Materials Science and Engineering 1257, n. 1 (1 ottobre 2022): 012043. http://dx.doi.org/10.1088/1757-899x/1257/1/012043.
Testo completoAbstract (sommario):
Abstract Foaming has impacted the digestion process causing severe process failures. The basis of foaming is often unclear due to multiple foaming compounds in a single system. This study aims to elucidate the effect of protein concentration on foaming in anaerobic sludge and cow manure (CM) digesters inoculated with synthetic wastewater as a substrate. Gelatine was used to alter the protein concentration in the digesters. The foaming tendency, biogas production, protein, and chemical oxygen demand (COD) removal were measured to comprehend the findings. The results show that the foaming tendency increased with protein concentration in anaerobic sludge digesters. It also had the highest biogas production. There was no evident process inhibition observed in the anaerobic sludge digester, even at higher protein and COD concentrations. For CM digester, the foaming tendency and biogas production increased to 9 g/L; however, the biogas production decreased with increased substrate protein concentration, indicating process inhibition. The results indicate that the biogas production, foaming tendency, COD and protein removal increased steadily for both digesters. However, the trend decreased for CM digester at increased protein concentrations. This study also concluded that protein creates foaming when inoculated with anaerobic sludge and CM even at low substrate protein concentration.
6
Shang, Y., B. R. Johnson e R. Sieger. "Application of the IWA Anaerobic Digestion Model (ADM1) for simulating full-scale anaerobic sewage sludge digestion". Water Science and Technology 52, n. 1-2 (1 luglio 2005): 487–92. http://dx.doi.org/10.2166/wst.2005.0557.
Testo completoAbstract (sommario):
A steady-state implementation of the IWA Anaerobic Digestion Model No. 1 (ADM1) has been applied to the anaerobic digesters in two wastewater treatment plants. The two plants have a wastewater treatment capacity of 76,000 and 820,000 m3/day, respectively, with approximately 12 and 205 dry metric tons sludge fed to digesters per day. The main purpose of this study is to compare the ADM1 model results with full-scale anaerobic digestion performance. For both plants, the prediction of the steady-state ADM1 implementation using the suggested physico-chemical and biochemical parameter values was able to reflect the results from the actual digester operations to a reasonable degree of accuracy on all parameters. The predicted total solids (TS) and volatile solids (VS) concentration in the digested biosolids, as well as the digester volatile solids destruction (VSD), biogas production and biogas yield are within 10% of the actual digester data. This study demonstrated that the ADM1 is a powerful tool for predicting the steady-state behaviour of anaerobic digesters treating sewage sludges. In addition, it showed that the use of a whole wastewater treatment plant simulator for fractionating the digester influent into the ADM1 input parameters was successful.
7
Kamarád, Luděk, Stefan Pohn, Günther Bochmann e Michael Harasek. "Determination of mixing quality in biogas plant digesters using tracer tests and computational fluid dynamics". Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 61, n. 5 (2013): 1269–78. http://dx.doi.org/10.11118/actaun201361051269.
Testo completoAbstract (sommario):
The total electricity demand of investigated biogas plants (BGP) makes up 7–8 % of the total electricity produced. Nearly 40 % of this energy is consumed just for mixing in digesters and the energy demand for mixing in some biogas plants can be even higher. Therefore, optimal mixing in anaerobic digesters is a basic condition for efficient plant operation and biogas production. The use of problematic substrates (e.g. grass silage or other fibrous substrates), installation of unsuitable mixing systems or inconvenient mixing intervals may lead to mixing problems. Knowledge about mixing in biogas digesters is still insufficient, so the objective of this study was to fill the information gaps in the literature by determining the minimal retention time of substrates fed into anaerobic digesters and to describe substrate distribution and washing out rates from investigated digesters. Two full-scale biogas plant digesters (2000 m3 and 1500 m3) using different mixing systems and substrates were investigated. To characterize the substrate distribution, lithium hydroxide monohydrate solutions were used for tracer tests at concentrations of 47.1 mg Li+ / kg TS and 46.6 mg Li+ / kg TS in digester. The tracer concentration in the digester effluents was measured during two hydraulic retention times and compared. Although the tracer was detected in the digester effluent at nearly the same time in both cases, the tracer tests showed very different distribution curves. The tracer concentration in effluent B grew much slower than in effluent A and no significant short circuiting streams were detected. Although the data calculated by computational fluid dynamics methods (CFD) showed a very good agreement with the full scale results, full comparison was not possible.
8
A, Adewumi, Lasisi K. H, Akinmusere O. K, Ojo A. O e Babatola J. O. "COMPARATIVE STUDY OF ELECTROLYSIS-ENHANCED ANAEROBIC DIGESTION OF THREE SOLUBLE SOLID WASTES FOR BIOGAS PRODUCTION". INDONESIAN JOURNAL OF URBAN AND ENVIRONMENTAL TECHNOLOGY 4, n. 1 (11 ottobre 2020): 11. http://dx.doi.org/10.25105/urbanenvirotech.v4i1.8004.
Testo completoAbstract (sommario):
<p><strong>Aim</strong>: A comparative study of biogas production from three soluble solid wastes was conducted under anaerobic conditions by subjecting each waste to both conventional and electrolyzed digesters. <strong>Methodology and Results</strong>: Varying weight of each of the waste was mixed thoroughly with water and fed into five digesters. Three of these digesters were electrolytically-enhanced while the other two were not. The digestion of each of the wastes was monitored for 40 days at an ambient temperature ranging from 24 to 35oC. In all the digesters, biogas production started on the day 2, and attained maximum value on day 14 to17. Biogas production ended on the day 34 and 35 in digester 1a, 1b, 2a and 2b with production ending earliest in digester 3 containing wastewater on day 19. The highest biogas was produced in digester 2b containing electrolyzed digester loaded with poultry droppings) with a cumulative volume percentage of 91.41 as compared to its conventional state with a cumulative volume percentage of 85.19 and both states of the cow dung waste with cumulative volume percentages of 77.26 and 71.64 respectively. The least production occurred in digester 3 with a cumulative volume percentage of 4.59. <strong>Conclusion, significance and impact study</strong>: It is therefore concluded that poultry droppings has the greatest potentials for the generation of biogas as compared to cow dung in conventional and electrolyzed state and wastewater.</p>
9
Harrison, Ogala, e Ige Ayodeji Rapheal. "Biogas production from blends of fonio husk and donkey dung via anaerobic digestion for sustainable development". International Journal of Advanced Chemistry 9, n. 1 (25 dicembre 2020): 1. http://dx.doi.org/10.14419/ijac.v9i1.31254.
Testo completoAbstract (sommario):
There is growing public concern over potential impact on environmental quality caused by animal wastes. Anaerobic digestion, a biological conversion process can be used to obtain energy from biologicall wastes. This study explored the production of biogas from co-digestion of fonio hus and donkey dung using anaerobic biological conversion. The digesters were labeled as; digester A –Fonio husk only, digester B - donkey dung only, digester C – Fonio husk (300g) and Donkey Dung (200g), digester D – Fonio husk (200g) and donkey dung (300g). Proximate analysis of the substrates before and after digestion were determined such as total solids (TS), volatile solid, carbon content, nitrogen content, ash content, etc., and pH before and after digestion process. The biogas produced during this period was collected by water displacement method and subsequently measured. The results showed that Fonio husk in bio-digesters A and B gave a cumulative average biogas volume of 4972 ml and 5222 ml (week 3) while pig dung in bio-digesters C and D gave a cumulative average biogas volume of 5564 ml and 5978 respectively (week 3) within three weeks of fermentation. The digester is capable of producing 0.007m at average working temperature of 320C. Digester D produces higher volume of biogas as a result of improved nutrient provide by donkey dung as shown in the results obtained from the proximate analysis and has the best neutral pH, there was a reduction in the startup time.
10
Loughrin, John, Stacy Antle, Karamat Sistani e Nanh Lovanh. "In Situ Acoustic Treatment of Anaerobic Digesters to Improve Biogas Yields". Environments 7, n. 2 (8 febbraio 2020): 11. http://dx.doi.org/10.3390/environments7020011.
Testo completoAbstract (sommario):
Sound has the potential to increase biogas yields and enhance wastewater degradation in anaerobic digesters. To assess this potential, two pilot-scale digestion systems were operated, with one exposed to sound at less than 10 kHz and with one acting as a control. Sounds used were sine waves, broadband noise, and orchestral compositions. Weekly biogas production from sound-treated digesters was 18,900 L, more than twice that of the control digester. The sound-treated digesters were primarily exposed to orchestral compositions, because this made cavitational events easier to identify and because harmonic and amplitude shifts in music seem to induce more cavitation. Background recordings from the sound-treated digester were louder and had more cavitational events than those of the control digester, which we ascribe to enhanced microbial growth and the resulting accelerated sludge breakdown. Acoustic cavitation, vibrational energy imparted to wastewater and sludge, and mixing due to a release of bubbles from the sludge may all act in concert to accelerate wastewater degradation and boost biogas production.
11
Singh, Buta, Kornél L. Kovács, Zoltán Bagi, József Nyári, Gábor L. Szepesi, Máté Petrik, Zoltán Siménfalvi e Zoltán Szamosi. "Enhancing Efficiency of Anaerobic Digestion by Optimization of Mixing Regimes Using Helical Ribbon Impeller". Fermentation 7, n. 4 (1 novembre 2021): 251. http://dx.doi.org/10.3390/fermentation7040251.
Testo completoAbstract (sommario):
The appropriate mixing system and approach to effective management can provide favorable conditions for the highly sensitive microbial community, which can ensure process stability and efficiency in an anaerobic digester. In this study, the effect of mixing intensity on biogas production in a lab-scale anaerobic digester has been investigated experimentally and via modeling. Considering high mixing efficiency and unique feature of producing axial flow, helical ribbon (HR) impeller is used for mixing the slurry in this experiment under various conditions. Three parallel digesters were analyzed under identical operating conditions for comparative study and high accuracy. Effects of different mixing speeds (10, 30, and 67 rpm for 5 min h−1) on biogas production rate were determined in 5-L lab-scale digesters. The results demonstrated 15–18% higher biogas production at higher mixing speed (67 rpm) as compared to 10 rpm and 30 rpm and the results proved statistically significant (p < 0.05). Biogas production at 10, 30, and 67 rpm were 45.6, 48.6, and 52.5 L, respectively. Higher VFA concentrations (7.67 g L−1) were recorded at lower mixing intensity but there was no significant difference in pH and ammonia at different speeds whereas the better mixing efficiency at higher speeds was also the main reason for increase in biogas production. Furthermore, model simulation calculations revealed the reduction of dead zones and better homogeneous mixing at higher mixing speeds. Reduction of dead zones from 18% at 10 rpm to 2% at 67 rpm was observed, which can be the major factor in significant difference in biogas production rates at various mixing intensities. Optimization of digester and impeller geometry should be a prime focus to scale-up digesters and to optimize mixing in full-scale digesters.
12
Jegede, Abiodun O., Grietje Zeeman e Harry Bruning. "Effect of Mixing Regimes on Cow Manure Digestion in Impeller Mixed, Unmixed and Chinese Dome Digesters". Energies 12, n. 13 (2 luglio 2019): 2540. http://dx.doi.org/10.3390/en12132540.
Testo completoAbstract (sommario):
This study examines the effect of mixing on the performance of anaerobic digestion of cow manure in Chinese dome digesters (CDDs) at ambient temperatures (27–32 °C) in comparison with impeller mixed digesters (STRs) and unmixed digesters (UMDs) at the laboratory scale. The CDD is a type of household digester used in rural and pre-urban areas of developing countries for cooking. They are mixed by hydraulic variation during gas production and gas use. Six digesters (two of each type) were operated at two different influent total solids (TS) concentration, at a hydraulic retention time (HRT) of 30 days for 319 days. The STRs were mixed at 55 rpm, 10 min/hour; the unmixed digesters were not mixed, and the Chinese dome digesters were mixed once a day releasing the stored biogas under pressure. The reactors exhibited different specific biogas production and treatment efficiencies at steady state conditions. The STR 1 exhibited the highest methane (CH4) production and treatment efficiency (volatile solid (VS) reduction), followed by STR 2. The CDDs performed better (10% more methane) than the UMDs, but less (approx. 8%) compared to STRs. The mixing regime via hydraulic variation in the CDD was limited despite a higher volumetric biogas rate and therefore requires optimization.
13
Dohoo, Carolyn, Judith Read Guernsey, Kimberley Critchley e John VanLeeuwen. "Pilot Study on the Impact of Biogas as a Fuel Source on Respiratory Health of Women on Rural Kenyan Smallholder Dairy Farms". Journal of Environmental and Public Health 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/636298.
Testo completoAbstract (sommario):
Biomass burning in indoor environments has been highlighted as a major cause of respiratory morbidity for women and children in low-income countries. Inexpensive technological innovations which reduce such exposures are needed. This study evaluated the impact of low tech compost digesters, which generate biogas for cooking, versus traditional fuel sources on the respiratory health of nonsmoking Kenyan farmwomen. Women from 31 farms with biogas digesters were compared to age-matched women from 31 biomass-reliant farms, in June 2010. Only 43% of the biogas group reported any breathing problems, compared to 71% in the referent group (P=0.03). Referent women self-reported higher rates of shortness of breath (52% versus 30%), difficulty breathing (42% versus 23%), and chest pain while breathing (35% versus 17%) during the last 6 months (P=0.09to 0.12) compared to biogas women. Biogas women demonstrated slightly better spirometry results but differences were not statistically significant, likely due to limited latency between biogas digester installation and spirometry testing. Most biogas women reported improved personal respiratory health (87%) and improved children’s health (72%) since biogas digester installation. These findings suggest that using biogas in cookhouses improves respiratory symptoms but long-term impacts on lung function are unclear.
14
Mao, T., e K. Y. Show. "Performance of high-rate sludge digesters fed with sonicated sludge". Water Science and Technology 54, n. 9 (1 novembre 2006): 27–33. http://dx.doi.org/10.2166/wst.2006.798.
Testo completoAbstract (sommario):
A major limitation of anaerobic sludge digestion is the long hydraulic retention time (HRT) required for satisfactory stabilization which results in large digester size. This study explored a possibility of operating digesters at shortened HRTs by sonication pretreatment of secondary sludges. Four identical digesters designated D1, D2, D3 and D4 were fed with untreated and sludge sonicated at densities of 0.18 W/ml, 0.33 W/ml and 0.52 W/ml, respectively. All digesters were operated at three HRTs of 8-day, 4-day and 2-day. Comparing with the control digester (D1), total solids removal efficiencies improved by 12–19%, 17–36% and 20–39% in digesters D2, D3 and D4, respectively. The volatile solids removal was also increased by 11–21%, 17–33% and 19–36% in the respective digesters. The improved solids degradation corresponded with increase in biogas production by 1.4–2.5, 1.9–3.0 and 1.6–3.1 times, respectively. Increase in methane composition by 2–17% was also noted in all digesters fed with sonicated sludge. An analysis indicated that sonication pretreatment could enhance degradation of carbon, nitrogen and sulfur substances in the digestion. The study suggested that sonication of sludge is a possible pretreatment to shorten the digester operating HRT with improvement in solids degradation, biogas production and methane content. It can be deduced that to maintain a consistent solids loading at a desire performance, sludge digester with smaller size can be designed.
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Nekhubvi, Vhutshilo, e David Tinarwo. "Long-term temperature measurement: Biogas digesters fermenting slurry". Journal of Energy in Southern Africa 28, n. 3 (22 settembre 2017): 99. http://dx.doi.org/10.17159/2413-3051/2017/v28i3a1437.
Testo completoAbstract (sommario):
This paper reports the results of the temperature profile of the unheated and unstirred continuous fermenting bio-slurry in a fixed-dome Deenbandhu 2000 model. The digester is a brick-built system of bulk size 6 m3. The digester was monitored for eight months, measuring internal bio-slurry temperature. A K-type nickel chromium-nickel temperature sensor with a sensitivity of approximately 41 µV and response time of 0.8s in liquids was positioned at the centre of the digester to measure the slurry temperature. The sensor was connected to the data logger and programmed to record temperature readings every second for the entire study period. The study results reported give a clear indication about the reaction of bio-slurry temperature in the digester at a local level, particularly for the eight months’ period, which covered all seasons. The calculated values of the daily average temperature reveal that the digester was operating within the range of psychrophilic 10.32 and mesophilic 28.80 , although it sometimes operated at 35 and above during certain hours in summer. This study is useful for anaerobic digestion processes for biogas production. The results obtained can be used as a basis to estimate the amount of heat required to raise the temperature of digesters to reach an optimum temperature of mesophilic digesters.
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Catyanadika, Putra Endi. "OPTIMASI LOKASI INSTALASI DIGESTER BIOGAS SKALA KOMUNITAS DESA PUDAK WETAN PONOROGO". Forum Agribisnis 10, n. 2 (8 settembre 2020): 106–17. http://dx.doi.org/10.29244/fagb.10.2.106-117.
Testo completoAbstract (sommario):
Community-scale biogas digester would become an alternative that reduces the cost of constructing biogas facilities. However, it is important to identify ideal locations of digesters to optimize distribution process of biogas input materials to digester facilities. This research aims to determine optimal locations of digester using geospatial kernel density analysis by calculating the biogas raw material using the total mass of the solid waste, which is applied on cowshed locations of Sumber Rejeki Dairy Cooperation in Pudak Wetan, Ponorogo. The results of the analysis have found nine ideal locations which community scale biogas digester facilities can be built by considering the density of the total mass of the solid waste and the proximity of the cowsheds on the research location.
17
Lindorfer, H., R. Braun e R. Kirchmayr. "Self-heating of anaerobic digesters using energy crops". Water Science and Technology 53, n. 8 (1 aprile 2006): 159–66. http://dx.doi.org/10.2166/wst.2006.246.
Testo completoAbstract (sommario):
With the increasing application of energy crops in agricultural biogas plants and increasing digester volumes, the phenomenon of self-heating in anaerobic digesters appeared in some cases. Until now this development was just known from aerobic systems. To obtain an idea of the thermodynamics inside an anaerobic digester, a detailed analysis of all heat fluxes in a full-scale agricultural biogas plant was carried out. Several experiments were realised to quantify the influences of different internal and external energy sources. To estimate the impact of self-heating in anaerobic systems, data of other full-scale agricultural biogas plants in Austria were collected. Alternatives to the cooling of the digesters are discussed based on individual experiences of several plants. A connection between carbohydrate-rich substrates, especially with high starch contents, and the self-heating could be shown. From the results it can be assumed that the anaerobic digestion of most energy crops is exothermic, which is in contrast to the current thermodynamic belief.
18
Alkhalidi, Ammar, Mohamad K. Khawaja, Khaled A. Amer, Audai S. Nawafleh e Mohammad A. Al-Safadi. "Portable Biogas Digesters for Domestic Use in Jordanian Villages". Recycling 4, n. 2 (16 maggio 2019): 21. http://dx.doi.org/10.3390/recycling4020021.
Testo completoAbstract (sommario):
Essential energy needs are not always met in poor and rural areas of developing counties; therefore, natural energy sources are necessary to mitigate this problem. Rural areas inhabitants utilize methane as a replacement for cooking gas to reduce their gas bill. Methane gas can be produced from a biogas digester; however, operating a large digester in a densely populated village in Jordan can be challenging due to inefficient village waste management systems. On the other hand, using a small-scale portable biogas digester to generate biogas could overcome these problems. In this work, three biogas digester feedstocks for a small portable biogas digester from natural sources available in Jordanian villages such as human and animal waste were designed and evaluated. The three feedstocks are food waste, human waste, and a mixture of human and food waste. The parameters tested were the digester size and the biogas production. The results showed that the best digester for portable application was that which digested a mixture of human and food waste; for a five-member family, this type of digester provided 115% of the family’s cooking gas requirements with a digester volume of 0.54 m3. This design, while applicable for a typical rural Jordanian family, can also be utilized globally.
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Pradana, Hendra Andiananta. "ANAEROBIC DIGESTER VARIATION FOR BIOGAS PRODUCTION ON COFFEE WASTEWATER TREATMENT". Jurnal Teknik Pertanian Lampung (Journal of Agricultural Engineering) 8, n. 3 (30 settembre 2019): 164. http://dx.doi.org/10.23960/jtep-l.v8i3.164-174.
Testo completoAbstract (sommario):
Wet coffee processing methods will produce waste water containing organic matter. The high content of organic matter can be utilized as biogas through the anaerobic process. Biogas becomes renewable energy source. Anaerobic digesters construction can affect removal process of wastewater pollution and biogas quantity. The research aim’s was determine the performance biogas production of digester construction on conventional digester, CSTR and UASB from coffee waste water. The conventional digester worked without temperature control system, a UASB digester, and CSTR digester worked with temperature control system. Biomass volume was about 5 L with 35 days incubation time. The research result showed variation of biogas production on each digester. Based on the feeding variations, UASB has a stable performance with 83.57 ml/day of average biogas production. It has also highest remediation efficiency of COD, BOD and C/N with 85.00±0.34 %, 84.40%± 5.66 and 97.78± 0.57.
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Oktavitri, Nur Indradewi, Wahyu Budi Pratiwi, Indah Purnamasari, Mufrihatul Hayati, Mega Rosita Fitrianingtyas e Semma Hadinnata. "Anaerobic Digestion of Slaughterhouse Wastewater: CO2 Capture of Biogas Using Chlorella vulgaris". Indonesian Journal of Chemistry 19, n. 1 (29 gennaio 2019): 1. http://dx.doi.org/10.22146/ijc.25129.
Testo completoAbstract (sommario):
Biogas quality from anaerobic digester influenced the combustion of biogas. A high percentage of CO2 in biogas indicates the low quality of biogas. Abatement of CO2 using microalgae, such as Chlorella vulgaris could enhance the quality of biogas. The aim of this research was to observe the ability of C. vulgaris on CO2 removal from slaughterhouse wastewater biogas. In this research, two anaerobic digesters were provided with the different condition of biogas collector bag. The first digester was combined with only biogas collector bag, while another digester was combined with C. Vulgaris. Slaughterhouse wastewater volume in each digester was 3.5 L. Observation time was 15 days and the samples were collected for every 5 days. The result showed that anaerobic digester was able to remove 63% of COD. Biogas composition of slaughterhouse wastewater after incubation for 15 days was 52.70% of air, 46.85% of CH4and 0.45% of CO2. C. Vulgaris enhanced CO2 removal from biogas up to 7%. The density of C. vulgaris decreased to 51 cell/mL. The biogas composition was probably influenced by the density of C. vulgaris.
21
Zikakis, D., J. Chauzy, I. Droubogianni e A. Georgakopoulos. "Why applying THP on waste activated sludge makes sense: Psyttalia – Athens case study". Water Practice and Technology 14, n. 4 (14 novembre 2019): 921–30. http://dx.doi.org/10.2166/wpt.2019.078.
Testo completoAbstract (sommario):
Abstract In order to improve the energy footprint of Psyttalia wastewater treatment plant (WWTP) in Athens, the application of a thermal hydrolysis process (THP) was preferred to the option of constructing additional digesters. Since August 2015, approximately half of the generated waste activated sludge (WAS) has been treated by a Cambi B6-4 system, while the thickened primary sludge (PS) is by-passing the THP and is mixed with the hydrolysed WAS before entering the 4 digesters. The 4 other conventional digesters have treated the remaining sludge. The dewaterability of the mixed digested sludge has significantly been improved from 22% dry solids (DS) before THP installation, up to 31% DS after THP installation. This is providing substantial reduction of energy use and cost savings at the sludge drying plant of Psyttalia. In addition, biogas generation and digester efficiency (VSR) have been increased.
22
Banks, Charles J., Michael Chesshire e Anne Stringfellow. "A pilot-scale comparison of mesophilic and thermophilic digestion of source segregated domestic food waste". Water Science and Technology 58, n. 7 (1 ottobre 2008): 1475–81. http://dx.doi.org/10.2166/wst.2008.513.
Testo completoAbstract (sommario):
Source segregated food waste was collected from domestic properties and its composition determined together with the average weight produced per household, which was 2.91 kg per week. The waste was fed over a trial period lasting 58 weeks to an identical pair of 1.5 m3 anaerobic digesters, one at a mesophilic (36.5°C) and the other at a thermophilic temperature (56°C). The digesters were monitored daily for gas production, solids destruction and regularly for digestate characteristics including alkalinity, pH, volatile fatty acid (VFA) and ammonia concentrations. Both digesters showed high VFA and ammonia concentrations but in the mesophilic digester the pH remained stable at around 7.4, buffered by a high alkalinity of 13,000 mg l−1; whereas in the thermophilic digester VFA levels reached 45,000 mg l−1 causing a drop in pH and digester instability. In the mesophilic digester volatile solids (VS) destruction and specific gas yield were favourable, with 67% of the organic solids being converted to biogas at a methane content of 58% giving a biogas yield of 0.63 m3 kg−1 VSadded. Digestion under thermophilic conditions showed potentially better VS destruction at 70% VS and a biogas yield of 0.67 m3 kg−1 VSadded, but the shifts in alkalinity and the high VFA concentrations required a reduced loading to be applied. The maximum beneficial loading that could be achieved in the mesophilic digester was 4.0 kg VS m−3 d−1.
23
Kayode Latinwo, Ganiyu, e Samuel Enahoro Agarry. "Modelling the Kinetics of Biogas Production from Mesophilic Anaerobic Co-Digestion of Cow Dung with Plantain Peels". International Journal of Renewable Energy Development 4, n. 1 (15 febbraio 2015): 55–63. http://dx.doi.org/10.14710/ijred.4.1.55-63.
Testo completoAbstract (sommario):
This work investigated the effect of plantain peels as co-substrate in the anaerobic digestion of cow dung for efficient and high biogas production. The biogas experiments were carried out in two different 5 L anaerobic digesters and incubated for 40 days at ambient mesophilic temperatures (28 oC to 34 °C). The results showed that co-digestion of cow dung with plantain peels as co-substrate reduced start-up time for biogas generation and increased biogas yield by 18% as compared to cow dung alone. Peak biogas production was obtained for both digesters at pH of 6.7 and 6.9 as well as temperature of 29 and 30oC, respectively. Modelling study revealed that exponential plot simulated better in both ascending and descending limb than the linear plot the biogas production rates in biogas production from cow dung co-digested with plantain peels and cow dung alone, respectively. Logistic growth model and modified Gompertz plot showed better correlation of cumulative biogas production than exponential rise to maximum plot. These results show that biogas production can be enhanced efficiently through co-digestion process.
24
Wasajja, Henry, Saqr A. A. Al-Muraisy, Antonella L. Piaggio, Pamela Ceron-Chafla, Purushothaman Vellayani Aravind, Henri Spanjers, Jules B. van Lier e Ralph E. F. Lindeboom. "Improvement of Biogas Quality and Quantity for Small-Scale Biogas-Electricity Generation Application in off-Grid Settings: A Field-Based Study". Energies 14, n. 11 (26 maggio 2021): 3088. http://dx.doi.org/10.3390/en14113088.
Testo completoAbstract (sommario):
Small-scale electrical power generation (<100 kW) from biogas plants to provide off-grid electricity is of growing interest. Currently, gas engines are used to meet this demand. Alternatively, more efficient small-scale solid oxide fuel cells (SOFCs) can be used to enhance electricity generation from small-scale biogas plants. Most electricity generators require a constant gas supply and high gas quality in terms of absence of impurities like H2S. Therefore, to efficiently use the biogas from existing decentralized anaerobic digesters for electricity production, higher quality and stable biogas flow must be guaranteed. The installation of a biogas upgrading and buffer system could be considered; however, the cost implication could be high at a small scale as compared to locally available alternatives such as co-digestion and improved digester operation. Therefore, this study initially describes relevant literature related to feedstock pre-treatment, co-digestion and user operational practices of small-scale digesters, which theoretically could lead to major improvements of anaerobic digestion process efficiency. The theoretical preamble is then coupled to the results of a field study, which demonstrated that many locally available resources and user practices constitute frugal innovations with potential to improve biogas quality and digester performance in off-grid settings.
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Osei-Marfo, M., E. Awuah e N. K. de Vries. "Biogas technology diffusion and shortfalls in the central and greater Accra regions of Ghana". Water Practice and Technology 13, n. 4 (1 dicembre 2018): 932–46. http://dx.doi.org/10.2166/wpt.2018.100.
Testo completoAbstract (sommario):
Abstract The current status of biogas technology in Ghana, a developing country, was explored focusing on factors affecting dissemination of the technology and the associated challenges. Data collection was by personal interview and physical observations, and was conducted between July and October 2017. Non-probabilistic sampling procedures were used to select 61 respondents from 162 users, while 54 digesters were selected from 120 digester sites. The findings revealed that: initial installation and maintenance costs appear high; the needs of most biogas users had not been fully met, thus, they were only partially satisfied with the outcome of the technology; and 21% of the biogas service providers were engineers and 79% from other disciplines (plumbers, masons, carpenters, and graduates from arts, social sciences, business, etc.). These factors affect technology diffusion. In addition, bottlenecks for more intense use of biogas technology that need to be addressed include lack of government subsidies or financial support, poor or unstandardized digester design, lack of gas production, lack of follow-up, lack of maintenance, lack of monitoring, and market value for bio-fertiliser (digestate). It is recommended that financial institutions support individuals and institutions with soft loans to acquire biogas digesters/plants, and that a regulatory body be formed for the activities of biogas service providers in developing countries.
26
Nawir, Herman, Muhammad Ruswandi Djalal e Apollo Apollo. "Pemanfaatan Limbah Eceng Gondok Sebagai Energi Biogas Dengan Menggunakan Digester". JEEE-U (Journal of Electrical and Electronic Engineering-UMSIDA) 2, n. 2 (27 novembre 2018): 56. http://dx.doi.org/10.21070/jeee-u.v2i2.1582.
Testo completoAbstract (sommario):
Biogas is an alternative energy in the form of gas formed from the process of fermentation of organic materials. One of the most abundant organic materials is water hyacinth. This research aims to design the tool that will be used to process water hyacinth so that it can produce biogas energy. The main components of the equipment made consist of digester, water trap, gas container, and gas stove, each made 3 appliances. The experiment was conducted using 3 pieces of digester where each digester was filled with 10kg of water hyacinth and different starter. Digester A uses a 0.5 liter EM4 starter mixed with 4.5 liters of water. Digester B using starter 5 kg of cow dung mixed with water 3 liters. And digester C using starter 5 kg of cow dung mixed with 0.5 liters EM4 and 4, 5 liters of water. Then see the development of biogas during the fermentation process (35 days). From the results of this study can be obtained biogas pressure, temperature, acidity (pH) and the duration of the flame generated by the means of producing biogas using this digester and can be applied to the stove. The pressure change produced by digester C is greater than the pressure generated from digesters A and B. The temperature changes produced in digester C are greater than the temperature produced by digesters A and B. The initial pH value of mixing for digester A is pH 6.3, digester B with pH 7.5 and digester C with pH 5.5. The pH value after biogas was produced for digester A with pH 7.5, digester B with pH 7.5 and digester C with pH 7.6. This corresponds to a good pH for the growth of biogas-forming microbes, ranging from 6.4 to 7.8. The fire generated on the blue flame test, with the total length of the flame for each digester is 54 minutes 46 seconds.
27
TAHRI, Ahmed, e Slimane KALLOUM. "Energy Recovery by Production of Electricity from Anaerobic Digestion of Organic Waste in the Saharan Environment". Algerian Journal of Renewable Energy and Sustainable Development 03, n. 01 (15 giugno 2021): 63–73. http://dx.doi.org/10.46657/ajresd.2021.3.1.7.
Testo completoAbstract (sommario):
Anaerobic digestion is a natural process of transforming organic matter into energy by methanogenic bacteria. This process is performed in the digesters in the absence of oxygen, they produce biogas composed mainly of methane (CH4) which is a combustible natural gas we can used in everyday life. In this work, we produced biogas using a continuous digester with a capacity of 4m3 and after the biogas purification; we used methane produced to run the generator to produce electricity. The results are very encouraging, where we have to produce electricity and cover the daily needs of the Algerian individual in electricity using 1m3 of biogas from our digester
28
Rajendran, Karthik, Solmaz Aslanzadeh e Mohammad J. Taherzadeh. "Household Biogas Digesters—A Review". Energies 5, n. 8 (8 agosto 2012): 2911–42. http://dx.doi.org/10.3390/en5082911.
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29
Danmallam, Aisha, E. B. Agbaji, N. C. Nwokem, U. Sani e C. O. Nwokem. "PLANT EXTRACT ADDITION FOR IMPROVED METHANE POTENTIAL OF TUBER PEEL". FUDMA JOURNAL OF SCIENCES 4, n. 2 (6 ottobre 2020): 699–703. http://dx.doi.org/10.33003/fjs-2020-0402-434.
Testo completoAbstract (sommario):
The percentage yield of methane in biogas ranges from 40 – 70 %, which is relatively low when compared to natural gas whose methane composition is about 90 %. Improving the methane yield will increase the efficiency of the biogas to some extent. As a result, the use of plant additives is employed to improve the methane gas yield of the biogas produced. Methane gas production from starch-rich tuber peel was investigated at laboratory scale using a batch anaerobic digester of two litres working volume at mesophilic temperature. The digesters were fed with slurry of dry tuber peel and operated for sixty (60) days. Initially, 42 % methane production was recorded. The effect of the volume (100, 300 and 500 cm3) of aqueous extracts of soya, neem and water hyacinth on methane gas yield was also studied. An increase in methane production over the control was recorded in all the digesters. Significantly higher levels of methane gas production were observed in the digesters to which 500 cm3 of aqueous extract was added with the neem extracts recording the highest.
30
Sindall, R., J. Bridgeman e C. Carliell-Marquet. "Velocity gradient as a tool to characterise the link between mixing and biogas production in anaerobic waste digesters". Water Science and Technology 67, n. 12 (1 giugno 2013): 2800–2806. http://dx.doi.org/10.2166/wst.2013.206.
Testo completoAbstract (sommario):
Whilst the importance of mixing in anaerobic digesters to enhance process performance and gas production is well recognised, the specific effects of mixing regime on biogas production are not clear. Here, the velocity gradient is used to demonstrate the importance of minimally mixed zones in a digester, with computational fluid dynamics (CFD) models indicating that 20–85% of a laboratory-scale digester experiences local velocity gradients of less than 10 s−1, dependent on mixing speed. Experimental results indicate that there is a threshold above which increased mixing speed (and hence velocity gradient) becomes counter-productive and biogas production falls. The effects of minimal mixing on digester microbiology are considered with the creation or destruction of localised pockets of high acetate concentration providing a possible explanation for the velocity gradient threshold. The identification of this threshold represents a valuable contribution to the understanding of the effects of mixing on gas production in anaerobic digesters.
31
Tinajero, A., e A. Noyola. "Increasing microbial activity in thermophilic anaerobic digestion of physicochemical sludge". Water Science and Technology 54, n. 2 (1 luglio 2006): 245–51. http://dx.doi.org/10.2166/wst.2006.512.
Testo completoAbstract (sommario):
Two thermophilic lab-scale reactors of 5 L were operated on a daily fed basis. Digester T1 received raw sludge (control) and digester T2 was fed with raw sludge plus metallic micronutrients and a bacilli additive. Raw sludge was obtained from a municipal chemically enhanced primary treatment plant. The effect of additives was clear on methane production, since on day 50, digester T2 produced 900 ml more methane than T1, an increase of 64%. On day 80, T2 reached twice the production of biogas of T1. Volatile solid removal (% VSR) in T2 increased to 29%; while T1 achieved only 15%. Acetic acid concentration in T2 diminished to 100 mg/L, which related to the higher biogas production. Based on the Mexican biosolids standard, the digested sludge reached Class A biosolids, in both digesters: fecal coliforms were reduced to less than 1000 MPN/gTS; Salmonella spp was totally eliminated and helminth egg counts were lower than one viable egg per gram of total solids.
32
Tseng, D. W. S., e M. A. Connor. "The effect of disc submergence level on the performance of a laboratory-scale anaerobic rotating biological contactor: implications for digester design and modelling". Water Science and Technology 30, n. 12 (1 dicembre 1994): 357–65. http://dx.doi.org/10.2166/wst.1994.0635.
Testo completoAbstract (sommario):
A hypothesis was advanced that an anaerobic rotating biological contactor (AnRBC) digester, if operated with its discs half rather than fully submerged, should show an enhanced capability to withstand shock loads. Laboratory-scale AnRBC digesters were constructed and their performance under 50% and 100% disc submergence conditions compared. In all cases, under otherwise comparable conditions the performance in the 50% disc submergence mode was better. From measurements, including biogas hydrogen concentration, pH and propionic acid content of the digester liquid, it was concluded that it was the markedly better hydrogen stripping capability of the digester operated with discs only half submerged that accounted for its superior performance. Implications for design and modelling of digesters are discussed. It is concluded that current models of anaerobic digester systems need to reflect more accurately the actual hydrodynamic conditions in digesters if good predictions of digester performance under dynamic conditions are to be realised.
33
Norouzi, Omid, e Animesh Dutta. "The Current Status and Future Potential of Biogas Production from Canada’s Organic Fraction Municipal Solid Waste". Energies 15, n. 2 (10 gennaio 2022): 475. http://dx.doi.org/10.3390/en15020475.
Testo completoAbstract (sommario):
With the implementation of new policies supporting renewable natural gas production from organic wastes, Canada began replacing traditional disposal methods with highly integrated biogas production strategies. Herein, data from published papers, Canadian Biogas Association, Canada’s national statistical agency, and energy companies’ websites were gathered to gain insight into the current status of anaerobic digestion plants in recovering energy and resource from organic wastes. The availability of materials prepared for recycling by companies and local waste management organizations and existing infrastructures for municipal solid waste management were examined. Governmental incentives and discouragements in Canada and world anaerobic digestion leaders regarding organic fraction municipal solid waste management were comprehensively reviewed to identify the opportunities for developing large-scale anaerobic digestion in Canada. A range of anaerobic digestion facilities, including water resource recovery facilities, standalone digesters, and on-farm digesters throughout Ontario, were compared in terms of digestion type, digester volume, feedstock (s), and electricity capacity to better understand the current role of biogas plants in this province. Finally, technology perspectives, solutions, and roadmaps were discussed to shape the future in terms of organic fraction municipal solid waste management. The findings suggested that the biogas industry growth in Canada relies on provincial energy and waste management policies, advanced technologies for diverting organic waste from landfills, improving biogas yield using existing pretreatment methods, and educating farmers regarding digester operations.
34
Page, D. I., K. L. Hickey, R. Narula, A. L. Main e S. J. Grimberg. "Modeling anaerobic digestion of dairy manure using the IWA Anaerobic Digestion Model no. 1 (ADM1)". Water Science and Technology 58, n. 3 (1 agosto 2008): 689–95. http://dx.doi.org/10.2166/wst.2008.678.
Testo completoAbstract (sommario):
The Anaerobic Digestion Model No. 1 (ADM1) can be used to describe treatment of dairy manure once manure characteristics have been incorporated in the model. In this paper a parameter set is presented that can be used with ADM1 for simulation of dairy manure digester performance. Model results have been verified with bench-scale experiments and reported data from full-scale systems. Model predictions fit experimental data best for biogas composition and digester effluent COD. Simulated biogas productions were inconsistent with measurements from three different digesters. The model overpredicted acetogenesis, resulting in higher simulated than observed acetate concentrations. However, total volatile acid concentrations were simulated reasonably well. The model consistently predicted higher inorganic nitrogen than measured or reported results, indicating a need for further research in that area. The presented model and associated parameter set can be used to simulate and optimize the performance of full-scale dairy manure digesters.
35
MS, Nanang Apriandi, Lily Maysari Angraini e Nurul Qomariyah. "Optimalisasi Pengelolaan Limbah Tahu Menjadi Biogas Menuju Desa Mandiri Energi". Unram Journal of Community Service 2, n. 1 (29 marzo 2021): 29–32. http://dx.doi.org/10.29303/ujcs.v2i1.25.
Testo completoAbstract (sommario):
Optimization of tofu waste management in Danger Village masbagik kemacatan East Lombok district has been done. Danger village is a village that focuses its economic sector on home indutrsi tofu making. Almost 50% of the total population in the village is involved in this field. Tofu waste, both solid waste and liquid waste, which was initially only disposed of and caused a foul smell, has now been optimally processed into biogas. This new energy source can be used by citizens as fuel for production. The purpose of this activity aims to improve the skills of citizens designing and building household-scale digesters in order to optimize the management of waste tofu into biogas. The method of activity used is focus discussion group to need assement problems that exist in the citizens, and then transfer biogas technology by providing assistance to citizens as partners ranging from digester making to slury management of biogas waste. The result of this activity is the establishment of household-scale digesters in partners and increased understanding of partners related to the use of waste tofu both solid and liquid to become biogas and the realization of the concept of energy independent villages
36
Nogueira, Ricardo Galbiatti Sandoval, Teng Teeh Lim, Haoqi Wang e Paulo Henrique Mazza Rodrigues. "Performance, Microbial Community Analysis and Fertilizer Value of Anaerobic Co-digestion of Cattle Manure with Waste Kitchen Oil". Applied Engineering in Agriculture 35, n. 2 (2019): 239–48. http://dx.doi.org/10.13031/aea.13023.
Testo completoAbstract (sommario):
Abstract. Co-digestion trials of beef cattle manure and waste kitchen oil (WKO) were conducted to evaluate potential increase of biogas production for a local beef farm anaerobic digester. The trials were conducted using laboratory-scale, semi-continuously loaded digesters under mesophilic conditions, with 21-day hydraulic retention time (HRT). In a preliminary test, WKO was added at 0%, 0.5%, 1.0%, 1.5%, and 2.0% by volume, each with replicate digesters (n=2), except for the 0% level, which had one digester (n=1). Methane (CH4) yield per week increased linearly with WKO levels. Populations of bacteriodetes decreased, while clostridiales and synergistales increased with the WKO levels. A second test was conducted using treatments with more replication: control (n=3), and 1.0% (n=3) and 2% (n=3) WKO levels. Methane yields of the 1.0% and 2.0% WKO levels were 79.1% and 203% higher than the control, respectively. Addition of WKO have resulted in changes of the metagenomics of the digesters. Populations of clostridiales increased, while bacteroidales and euryarchaeota methanomicrobia YC-E6 decreased with the WKO levels. The findings confirm adding low amounts (1% and 2%) of WKO as co-digestion feedstock can be an effective way to increase CH4 yield for beef operation anaerobic digestion, especially when there are available feedstock nearby. Keywords: Anaerobic digestion, Biogas, Methane, Semi-continuous digesters.
37
Eboibi, B. E., K. O. Adiotomre, F. Onobrudu e E. Osioh. "Anaerobic Digestion of Cassava (Manihot Esculenta) Waste: Effects of Inoculum on Biogas Production Rate". Nigerian Journal of Environmental Sciences and Technology 4, n. 2 (ottobre 2020): 411–20. http://dx.doi.org/10.36263/nijest.2020.02.0226.
Testo completoAbstract (sommario):
In this paper, cow manure fluid was used as inoculums to investigate biogas production rate from anaerobic digestion of cassava peel at mesophilic temperature (280C). The anaerobic experiment was conducted using six batch digesters (D1, D2, D3, D4, D5 and D6) each of 20L capacity for 40-day hydraulic retention. Each digester, was loaded with 5kg of cassava peel (CP) and 0%, 10%, 20%, 30%, 40% and 50% of inoculum to CP. Hashimoto model was used to obtain the digestion kinetic parameters. The results of the study showed that inoculums influenced the rate of biogas production, showing variations in biogas production, correlation coefficient (R2) and in first-order decay constant (k). The average cumulative biogas production was in the range of ~2358 to 4010ml/kgVS for 10% to 50% inoculum. The R2 and k for D1 was 0.959 and 0.359 D1 (without inoculum), 0.990 and 0.371 for D2 (10% inoculum) and 0.991 and 0.371 for D3 (20% inoculum), 0.951 and 0.356 for D4 (30% inoculum), 0.992 and 0.372 for D5 (40% inoculum), and 0.990 and 0.371 was obtained for D6 loaded with 50% inoculum. Despite variation in biogas yields from different inoculums, biogas production obtained from anaerobic digesters loaded with inoculums were still lower compared with that without inoculum.
38
Yusuf, M. O. L., A. Debora e D. E. Ogheneruona. "Ambient temperature kinetic assessment of biogas production from co-digestion of horse and cow dung". Research in Agricultural Engineering 57, No. 3 (22 settembre 2011): 97–104. http://dx.doi.org/10.17221/25/2010-rae.
Testo completoAbstract (sommario):
Biogas production from 5 batch digesters containing varying ratio of mix of horse and cow dung was studied for a period of 30 days at ambient temperature. It was observed that biogas production was optimized when horse and cow dung were mixed in a ratio of 3:1. The modified Gompertz equation was used to adequately describe the cumulative biogas production from these digesters. In addition, a modified first order model was developed to assess the kinetics of the biodegradation process. It was observed that the rates of substrate biodegradability and of removal of the biodegradable fractions of the substrate could be obtained by plotting 1/t (ln(dyt/dt)) against the inverse of time of digestion. This modified first order model also showed that the digester containing horse dung and cow dung in the ratio of 3:1 had the highest short term anaerobic biodegradability index (STABI) of 3.96 at room temperature.
39
Shrestha, Ankita, Mieke C. A. A. van-Eerten Jansen e Bishnu Acharya. "Biodegradation of Bioplastic Using Anaerobic Digestion at Retention Time as per Industrial Biogas Plant and International Norms". Sustainability 12, n. 10 (21 maggio 2020): 4231. http://dx.doi.org/10.3390/su12104231.
Testo completoAbstract (sommario):
Bioplastics are gaining interest as an alternative to fossil-based plastics. In addition, biodegradable bioplastics may yield biogas after their use, giving an additional benefit. However, the biodegradability time in international norms (35 days) far exceeds processing times in anaerobic digestion facilities (21 days). As the bioplastic packaging does not indicate the actual biodegradability, it is important to understand the time required to biodegrade bioplastic if it ends up in the anaerobic digestion facility along with other organic waste. For this work, cellulose bioplastic film and polylactic acid (PLA) coffee capsules were digested anaerobically at 55 ℃ for 21 days and 35 days, which are the retention times for industrial digestors and as set by international norms, respectively. Different sizes of bioplastics were examined for this work. Bioplastic film produced more biogas than bioplastic coffee capsules. The biodegradability of bioplastic was calculated based on theoretical biogas production. With an increase in retention time, biogas production, as well as biodegradability of bioplastic, increased. The biodegradability was less than 50% at the end of 35 days for both bioplastics, suggesting that complete degradation was not achieved, and thus, the bioplastic would not be suitable for use in biogas digesters currently in use.
40
Bala, B. K., e M. M. Hossain. "Economics of biogas digesters in Bangladesh". Energy 17, n. 10 (ottobre 1992): 939–44. http://dx.doi.org/10.1016/0360-5442(92)90042-x.
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Nielsen, Anders Michael, Knud Villy Christensen e Henrik Bjarne Møller. "Inline NH3 removal from biogas digesters". Biomass and Bioenergy 50 (marzo 2013): 10–18. http://dx.doi.org/10.1016/j.biombioe.2012.06.041.
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42
Gaida, D., C. Wolf, C. Meyer, A. Stuhlsatz, J. Lippel, T. Bäck, M. Bongards e S. McLoone. "State estimation for anaerobic digesters using the ADM1". Water Science and Technology 66, n. 5 (1 settembre 2012): 1088–95. http://dx.doi.org/10.2166/wst.2012.286.
Testo completoAbstract (sommario):
The optimization of full-scale biogas plant operation is of great importance to make biomass a competitive source of renewable energy. The implementation of innovative control and optimization algorithms, such as Nonlinear Model Predictive Control, requires an online estimation of operating states of biogas plants. This state estimation allows for optimal control and operating decisions according to the actual state of a plant. In this paper such a state estimator is developed using a calibrated simulation model of a full-scale biogas plant, which is based on the Anaerobic Digestion Model No.1. The use of advanced pattern recognition methods shows that model states can be predicted from basic online measurements such as biogas production, CH4 and CO2 content in the biogas, pH value and substrate feed volume of known substrates. The machine learning methods used are trained and evaluated using synthetic data created with the biogas plant model simulating over a wide range of possible plant operating regions. Results show that the operating state vector of the modelled anaerobic digestion process can be predicted with an overall accuracy of about 90%. This facilitates the application of state-based optimization and control algorithms on full-scale biogas plants and therefore fosters the production of eco-friendly energy from biomass.
43
Li, Bai, Xue Zhi Zhou e Wang Yan. "Experimental Study on Using Solar to Improve Producing Methane in Northeast China". Advanced Materials Research 953-954 (giugno 2014): 132–35. http://dx.doi.org/10.4028/www.scientific.net/amr.953-954.132.
Testo completoAbstract (sommario):
It presents a new idea of producing methane with solar heating. In order to improve the temperature and promote production of methane, providing the run situation of solar digesters on every stage with the heat-transfer content and the temperature of digesters is shown in this article. It indicates that in this experimental study, according to processing and analysis the experimental data, it’s beneficial to improve the rates of biogas production, and it solve the problem of digester and safe operation in winter in the northeast of China.
44
Alferes, J., J. L. García-Heras, E. Roca, C. García e I. Irizar. "Integration of equalisation tanks within control strategies for anaerobic reactors. Validation based on ADM1 simulations." Water Science and Technology 57, n. 5 (1 aprile 2008): 747–52. http://dx.doi.org/10.2166/wst.2008.104.
Testo completoAbstract (sommario):
The combination of equalisation tanks and anaerobic digesters represents a typical design scenario within the treatment of industrial wastewaters. In this context, if the hydraulic capacity of the equalisation tanks is effectively handled, significant improvements in the performance of anaerobic digesters can be achieved in terms of process stability and biogas production. This paper presents a rule-based control strategy for anaerobic reactors with the objective of maximising in the long-term the net production of biogas. The control algorithm combines real-time information about the state of the anaerobic digester with on-line measurements about the wastewater volume of the equalisation tank in order to set permanently the appropriate production of biogas. Such a strategy guarantees a continuous influent flow so that emptying and overflowing episodes in the equalisation tank can be prevented. Aiming at a further full-scale implementation, only reliable and cost-effective on-line instrumentation has been considered within the control architecture. The performance of the proposed control approach has been validated for an anaerobic hybrid configuration (AHR) by simulation using the IWA ADM1 model.
45
Wriege-Bechtold, A., M. Barjenbruch, C. Sieker, A. Peter-Fröhlich, B. Heinzmann e B. Lengemann. "Production of energy by co-fermentation with contents from fat separators". Journal of Water and Climate Change 1, n. 4 (1 dicembre 2010): 251–57. http://dx.doi.org/10.2166/wcc.2010.105.
Testo completoAbstract (sommario):
It is possible to use co-fermentation to increase biogas production considerably in digesters with free capacity. Also, the energy production increases by increasing biogas production. Many co-substrates such as energy crops, biodegradable waste from the food industry, restaurants and public parks, etc. are on the market. Water consumption is decreasing because of population movement and a decreasing population size because of a drop in the birth rate. Therefore, capacities in digesters will increase and new uses for this capacity are needed. Co-fermentation could be one solution. Useful co-substrates should be identified by material characteristics. It is important to assess suitability of materials for fermentation in small-scale tests, and to gain experience particularly with regard to the handling, the compatibility of the biocoenosis in the digester and the effects of returning effluent to the activated sludge process. A test period with fat separator contents has started at the wastewater treatment plant, Waßmannsdorf, Germany. Biogas production and methane content increased compared to the reference cascade without co-substrate input.
46
Kor-Bicakci, Gokce, Emine Ubay-Cokgor e Cigdem Eskicioglu. "Comparative Analysis of Bacterial and Archaeal Community Structure in Microwave Pretreated Thermophilic and Mesophilic Anaerobic Digesters Utilizing Mixed Sludge under Organic Overloading". Water 12, n. 3 (21 marzo 2020): 887. http://dx.doi.org/10.3390/w12030887.
Testo completoAbstract (sommario):
The effects of microwave (MW) pretreatment were investigated by six anaerobic digesters operated under thermophilic and mesophilic conditions at high organic loading rates (4.9–5.7 g volatile solids/L/d). The experiments and analyses were mainly designed to reveal the impact of MW pretreatment and digester temperatures on the process stability and microbial community structure by correlating the composition of microbial populations with volatile fatty acid (VFA) concentrations. A slight shift from biogas production (with a reasonable methane content) to VFA accumulation was observed in the thermophilic digesters, especially in the MW-irradiated reactors. Microbial population structure was assessed using a high-throughput sequencing of 16S rRNA gene on the MiSeq platform. Microbial community structure was slightly affected by different MW pretreatment conditions, while substantially affected by the digester temperature. The phylum Bacteroidetes proliferated in the MW-irradiated mesophilic digesters by resisting high-temperature MW (at 160 °C). Hydrogenotrophic methanogenesis (mostly the genus of Methanothermobacter) was found to be a key route of methane production in the thermophilic digesters, whereas aceticlastic methanogenesis (mostly the genus of Methanosaeta) was the main pathway in the mesophilic digesters.
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Loughrin, John, Stacy Antle, Michael Bryant, Zachary Berry e Nanh Lovanh. "Evaluation of Microaeration and Sound to Increase Biogas Production from Poultry Litter". Environments 7, n. 8 (16 agosto 2020): 62. http://dx.doi.org/10.3390/environments7080062.
Testo completoAbstract (sommario):
Microaeration, wherein small amounts of air are introduced into otherwise anaerobic digesters, has been shown to enhance biogas production. This occurs by fostering the growth of facultatively aerobic bacteria and production of enzymes that enhance the degradation of complex polymers such as cellulose. The treatment of anaerobic digestate with sound at sonic frequencies (<20 kHz) has also been shown to improve biogas production. Microaeration at a rate of 800 mL day−1, treatment with a 1000-Hz sine wave, and combined microaeration/sound were compared to a control digester for the production of biogas and their effect on wastewater quality. Poultry litter from a facility using wood chips as bedding was used as feed. The initial feeding rate was 400 g week−1, and this was slowly increased to a final rate of 2400 g week−1. Compared to the control, sound treatment, aeration, and combined sound/aeration produced 17%, 32%, and 28% more biogas. The aeration alone treatment may have been more effective than combined aeration/sound due to the sound interfering with retention of aeration or the formation of free radicals during cavitation. Digesters treated with sound had the highest concentrations of suspended solids, likely due to cavitation occurring within the sludge and the resulting suspension of fine particles by bubbles.
48
Chiumenti, Pezzuolo, Boscaro e da Borso. "Exploitation of Mowed Grass from Green Areas by Means of Anaerobic Digestion: Effects of Grass Conservation Methods (Drying and Ensiling) on Biogas and Biomethane Yield". Energies 12, n. 17 (22 agosto 2019): 3244. http://dx.doi.org/10.3390/en12173244.
Testo completoAbstract (sommario):
Grass from landscape management or from agricultural practices is currently destined mainly for composting, with the production of a valuable product; however, this process demands energy. Anaerobic digestion, instead, represents an energy-positive process that results in the production of fuel, biogas, and a fertilizer, namely digestate. Previous tests for the evaluation of biogas yield from freshly harvested grass gave promising results. However, for a practical exploitation of this resource, appropriate conservation is necessary in order to enable the daily load of digesters while reducing the loss of organic matter. The present work is focused on the evaluation of biogas and methane yield from dried and ensiled grass (without conditioning) in order to assess eventual biogas potential losses in comparison to digested fresh grass. Tests were performed with grass collected from riverbanks (Veneto, Northern Italy) in batch, lab scale digesters. Dry and ensiled grass showed a good potential for exploitation in the anaerobic digestion process, reaching biogas yields of 565.9 and 573.4 NL∙kgVS−1, respectively. Compared to the biogas yield of 639.7 NL∙kgVS−1 of the fresh grass, the conservation treatment determined yield reductions of 11.5% and 10.4% for dried and ensiled grass, respectively. However, considering the methane yields, conservation treatments showed lower reductions, amounting to 4.8% for dry grass and 0.5% for ensiled grass; presumably the higher concentration of organic acids in ensiled grass determined a higher methane content in biogas and the consequently lower reduction of methane yield.
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Kunetz, Thomas E., Jarek Fink-Finowicki, Steve McGowan e Eric Auerbach. "Development of a comprehensive plan for utilization of digester gas moves towards energy self-sufficiency in Chicago, USA". Water Science and Technology 66, n. 1 (1 luglio 2012): 95–104. http://dx.doi.org/10.2166/wst.2012.132.
Testo completoAbstract (sommario):
The Metropolitan Water Reclamation District (MWRD) of Greater Chicago's Stickney Water Reclamation Plant (SWRP) anaerobically digests approximately 430 dry tons per day (dtpd) (390 dry metric tons per day) of solids and produces 3.4 million ft3/day (96 thousand m3/day) of biogas from the anaerobic digesters, making it one of the largest municipal digester gas complexes in the world. Installation of new treatment processes, as well as future increases in flows and loads to the plant, are expected to significantly increase production of biologically degradable sludge and biogas. This paper presents a comprehensive planning study that was completed to identify and evaluate alternatives for utilization of this biogas. The best, sustainable approach was identified, taking into consideration economics, social impacts, and environmental impacts. The model results indicate that the most economically favorable scenario involves installing a cogeneration facility to produce electricity on-site, and operating it in conjunction with the plant's existing boilers to satisfy the heating needs of the plant. This scenario also provides the greatest reduction in GHG offsets at the power plants.
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Nguyen, Vo Chau Ngan. "Small-scale anaerobic digesters in Vietnam – development and challenges". Journal of Vietnamese Environment 1, n. 1 (3 novembre 2011): 12–18. http://dx.doi.org/10.13141/jve.vol1.no1.pp12-18.
Testo completoAbstract (sommario):
Small-scale anaerobic digesters, known as biogas plants, were applied as an optimal livestock waste treatment as well as biogas supply for cooking and lighting demand for small-scale farmers in Vietnam. Although the biogas technology was introduced for nearly 30 years, the number of the constructed biogas plants is still limited. The current development of biogas plants is far below the real demand on livestock waste treatment that has increased significantly. This paper gives a comprehensive overview on the biogas plant development in Vietnam and attempts to address the challenges and discuss appropriate solutions for the further biogas development.
Mô hìnhlên men yếm khíquy mô nhỏ (được biếtvới tên hầm ủ khí sinh học) đã được ứng dụng hiệu quả trongxử lý chất thải chăn nuôicũng nhưcung cấpnguồn nhiên liệu phục vụ nhu cầu nấu ănvàthắp sáng cho các hộ chăn nuôi nhỏ ở Việt Nam. Mặc dù đã hiện diện gần 30 năm, nhưng số lượng hầm ủ khí sinhhọc vẫn còn hạn chế. Sự gia tăng số lượnghầm ủ khí sinh học chưa theo kịp với nhu cầu về xử lý chất thải chăn nuôi đang ngày càng gia tăng. Bài báo trình bày các chặng đường phát triển của hầm ủ khí sinh học tại Việt Nam, ghi nhận các thách thức trong việcnhân rộng hầm ủ khí sinh họctrong thực tế và thảo luận một sốgiải pháp để phát triển công nghệ khí sinh học.