scholarly journals Mesophilic and Thermophilic Anaerobic Digestion of Organic Fraction Separated during Mechanical Heat Treatment of Municipal Waste

2020 ◽  
Vol 10 (7) ◽  
pp. 2412
Author(s):  
Slawomir Kasinski
Keyword(s):  
Anaerobic Digestion ◽  
Fermentation Process ◽  
Biogas Production ◽  
Municipal Waste ◽  
Organic Fraction ◽  
Thermophilic Anaerobic Digestion ◽  
Volatile Solids ◽  
Thermophilic Conditions ◽  
Potential Impact ◽  
Mesophilic Conditions

The objective of this study was to investigate the effect of process temperature on semi-continuous anaerobic digestion of the organic fraction separated during autoclaving of municipal waste. Tests were carried out in reactors with full mixing. Biogas production was higher in thermophilic conditions than in mesophilic conditions (0.92 L/g volatile solids at 55 °C vs. 0.42 L/g volatile solids at 37 °C, respectively). The resulting methane yields were 0.25-0.32 L CH4/g VS and 0.56–0.70 L CH4/g VS in mesophilic and thermophilic conditions, respectively. In both variants, the methane share was over 70% v/v. This work also discusses the potential impact of Maillard compounds on the efficiency of the fermentation process, which were probably produced during the process of autoclaving of municipal waste. These results indicate that, after autoclaving, the organic fraction of municipal waste can be an effective substrate for anaerobic digestion in thermophilic conditions.

Anaerobic digestion of mixed microalgae cultivated in secondary effluent under mesophilic and thermophilic conditions

2015 ◽  
Vol 72 (8) ◽  
pp. 1398-1403 ◽  
Author(s):  
Glenda Cea-Barcia ◽  
Gloria Moreno ◽  
Germán Buitrón
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Incubation Temperature ◽  
Secondary Effluent ◽  
Microalgae Culture ◽  
Batch Tests ◽  
Volatile Solids ◽  
Thermophilic Conditions ◽  
Maximum Production Rate ◽  
Mesophilic Conditions

The anaerobic digestion of mixed indigenous microalgae, grown in a secondary effluent, was evaluated in batch tests at mesophilic (35°C) and thermophilic (50°C) conditions. Under mesophilic conditions, specific methane production varied from 178 to 207 mL CH4/g volatile solids (VS) and the maximum production rate varied from 8.8 to 26.1 mL CH4/(gVS day), depending on the type of microalgae culture. Lower methane parameters were observed in those cultures where Scenedesmus represents more than 95% of the microalge. The culture with the lowest digestion performances under mesophilic conditions was studied under thermophilic conditions. The increase in the incubation temperature significantly increased the specific methane production (390 mL CH4/g VS) and rate (26.0 mL CH4/(gVS day)). However, under thermophilic conditions a lag period of 30 days was observed.

Relative kinetics of anaerobic digestion under thermophilic and mesophilic conditions

2011 ◽  
Vol 64 (4) ◽  
pp. 848-853 ◽  
Author(s):  
H. Ge ◽  
P. D. Jensen ◽  
D. J. Batstone
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Hydrolysis Rate ◽  
Fermentation Products ◽  
Promising Alternative ◽  
Sludge Digestion ◽  
Increase Glucose Uptake ◽  
Thermophilic Conditions ◽  
Kinetics Of ◽  
Mesophilic Conditions

With several advantages over the conventional mesophilic anaerobic digestion, such as better sludge quality and higher biogas production, thermophilic anaerobic digestion is regarded as a promising alternative for sludge digestion. Primary and activated sludges are complex materials, and historically, analysis of kinetics has been largely on whole sludge, without analysis of individual components. This paper analyses relative digestion kinetics of pure substrates designed to target main stages of sludge digestion under thermophilic and mesophilic conditions. Hydrolysis rate of cellulose was significantly influenced by temperature with hydrolysis coefficients of – at 55 °C (0.7 ± 0.1 day−1), 60 °C (0.8 ± 0.2 day−1), 65 °C (1.1 ± 0.2 day−1) and 70 °C (1.2 ± 0.2 day−1) over 38 °C (0.4 ± 0.1 day−1). This strongly follows the Arrhenius relationship, with an activation energy (EA) of 31 ± 4 kJ mol−1, corresponding to an increase of 1.5x for each 10 °C of temperature increase. Glucose uptake was rapid with a wide variety of fermentation products detected under mesophilic conditions, while uptake was slower under thermophilic conditions with acetate and propionate being dominant products. Propionate acetogenesis and acetate-utilizing methanogenesis kinetics were not influenced by temperatures. Hydrolysis is widely regarded as a rate-limiting step in sludge digestion, thus improvements in hydrolysis rates as measured during this study have the potential for significant improvements in overall apparent sludge digestion rates.

Comparison Between Thermophilic and Mesophilic Anaerobic Digestion of Sewage Sludge Coming from Urban Wastewater Treatment Plants

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2409-2412 ◽  
Author(s):  
F. Cecchi ◽  
P. Pavan ◽  
A. Musacco ◽  
J. Mata-Alvarez ◽  
C. Sans
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Biogas Production ◽  
Feed Flow Rate ◽  
Organic Fraction ◽  
Urban Wastewater ◽  
Stability Parameters ◽  
Thermophilic Conditions ◽  
Urban Wastewater Treatment

Yields of anaerobic digestion (AD) of sewage sludge carried out at mesophilic and thermophilic conditions at the optimum hydraulic retention times (HRT) found for the semi-dry AD of the mechanically selected organic fraction of municipal solid waste (OFMSW) (15 and 12 days, respectively) are compared. Due to the characteristics of the sludge used in thermophilic conditions (partially stabilized) the specific biogas production was lower. However, stability parameters show a secure process. Based on experience gained digesting OFMSW and hypothesizing a similar ratio between yields at mesophilic and thermophilic conditions, an economic analysis has been carried out. It shows that the increased biogas production is large enough to compensate the additional consumption to heat the feed flow rate to 55°C instead to 35°C.

scholarly journals Pilot Plant Data Assessment in Anaerobic Digestion of Organic Fraction of Municipal Waste Solids

Processes ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 54 ◽  
Author(s):  
Massimo Migliori ◽  
Enrico Catizzone ◽  
Girolamo Giordano ◽  
Adolfo Le Pera ◽  
Miriam Sellaro ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Continuous Process ◽  
Solid Content ◽  
Municipal Waste ◽  
Slight Reduction ◽  
Organic Fraction ◽  
Municipal Solid Wastes ◽  
Dry Process

In this paper, a preliminary study of anaerobic digestion of organic fraction of municipal solid wastes (OFMSW) in presented with the aim to compare the performances of both wet- and dry-type reactors. The treatment of OFMSW via anaerobic digestion (AD) producing biogas is a process that is receiving a growing interest because two different needs can be coupled: the request of sustainable municipal waste treatments and increasing demand renewable energy. This paper aims to offer experimental results comparing batch test and continuous experimental reactors under different conditions of humidity and solid content. Results show that both the investigated configurations may be used for converting OFMSW into a high quality biogas and that the increase of dry matter in the continuous process still allows to achieve significant biogas production rates. A slight reduction of the methane content was observed (less than 5% relative) that can be also related to the change in the level of volatile fatty acids. These results are very promising in supporting the possibility of operating an industrial scale plant with a dry-process without affecting the system performance.

scholarly journals Temperature Effects on Methanogenesis and Sulfidogenesis during Anaerobic Digestion of Sulfur-Rich Macroalgal Biomass in Sequencing Batch Reactors

2019 ◽  
Vol 7 (12) ◽  
pp. 682 ◽  
Author(s):  
Jung ◽  
Kim ◽  
Lee
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Suppressive Effect ◽  
Microbial Reduction ◽  
Organic Loading Rate ◽  
Batch Reactors ◽  
Sulfate Reducing ◽  
Macroalgal Biomass ◽  
Thermophilic Conditions ◽  
Mesophilic Conditions

Methanogenesis and sulfidogenesis, the major microbial reduction reactions occurring in the anaerobic digestion (AD) process, compete for common substrates. Therefore, the balance between methanogenic and sulfidogenic activities is important for efficient biogas production. In this study, changes in methanogenic and sulfidogenic performances in response to changes in organic loading rate (OLR) were examined in two digesters treating sulfur-rich macroalgal waste under mesophilic and thermophilic conditions, respectively. Both methanogenesis and sulfidogenesis were largely suppressed under thermophilic relative to mesophilic conditions, regardless of OLR. However, the suppressive effect was even more significant for sulfidogenesis, which may suggest an option for H2S control. The reactor microbial communities developed totally differently according to reactor temperature, with the abundance of both methanogens and sulfate-reducing bacteria being significantly higher under mesophilic conditions. In both reactors, sulfidogenic activity increased with increasing OLR. The findings of this study help to understand how temperature affects sulfidogenesis and methanogenesis during AD.

Partial stream digestion of residual municipal solid waste

2008 ◽  
Vol 57 (7) ◽  
pp. 1073-1077 ◽  
Author(s):  
L. De Baere
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Biogas Production ◽  
Municipal Waste ◽  
Organic Fraction ◽  
Partial Digestion ◽  
Sludge Cake ◽  
Dry Fermentation

Anaerobic digestion of residual municipal solid waste (MSW) has become more important than the digestion of source separated biowaste. More than 52% of the capacity available in Europe was designed for digestion of residual municipal waste by the end of 2006, while this was only 13% in 1998. Partial digestion of residual waste organics, by which only a part of the organics is digested, has been implemented to reduce the need for dewatering and subsequent wastewater treatment. The digestate coming from part of the organics is immediately mixed with the non-digested organic fraction. This organic fraction is drier and still contains a lot of energy which can be used to dry the digestate during the aerobic composting of the mixture of digested and undigested organics. Such a MBT-plant has been operating for over a year whereby 2/3 of the organics (including sludge cake) are digested (25,000 t/year) and mixed after digestion with the remaining 1/3 of the organics. Biogas production averages 125.7 Nm2 per ton fed and contained 56.2% of methane. The mixture of digestate and non-digested organics is aerated in tunnels during 4 to 6 weeks. The stabilized endproduct is landfilled, meeting the stringent German standards for inert landfills. By using a dry fermentation able to produce a digestate at 35% solids, there is no need for dewatering the digestate so that no wastewater is produced.

scholarly journals Effect of co-digestion of food waste and cow dung on biogas yield

2020 ◽  
Vol 181 ◽  
pp. 01005
Author(s):  
Makhura Emmanuel Pax ◽  
Edison Muzenda ◽  
Tumeletso Lekgoba
Keyword(s):  
Anaerobic Digestion ◽  
Moisture Content ◽  
Food Waste ◽  
Biogas Production ◽  
Cow Dung ◽  
Mixing Ratio ◽  
Total Solids ◽  
Biogas Yield ◽  
Volatile Solids ◽  
Thermophilic Conditions

This paper aims at finding the effect of co-digestion of cow dung and food waste on total biogas yield. Biogas production was improved through co-digestion of cow dung and food waste (FW) containing a small fraction of inoculum under mesophilic temperature (37ºC) over a retention time of 24 days. Co-digestion ratios of 1:1, 2:1 and 3:1 for cowdung/foodwaste were used for the study on anaerobic digestion on the co digested matter. Tests were carried out starting with the preparation of substrates, substrate characterization to determine the moisture content (MC), total solids (TS), volatile solids (VS) and ultimately batch anaerobic digestion experiments under thermophilic conditions (370C). The moisture content, volatile solids and total solids for food waste were 78, 22 and 90.7% respectively while the characteristics for cow dung were 67.2, 32.8 and 96.0 % respectively. From the study, a mixing ratio of cow dung: food waste of 1:2 was found to be the optimum substrate mixture for biogas production at 25595.7 Nml. The accumulated gas volumes of 18756.6, 14042.5, 13940.8 and 13839.1 Nml were recorded for cow dung: food waste ratios of 2:1, 1:1, 1:3 and 3:1 respectively. For a co-digestion containing more of the food waste than cow dung, a higher volume of biogas is produce.

scholarly journals Biochemical Methane Potential of Cork Boiling Wastewater at Different Inoculum to Substrate Ratios

2021 ◽  
Vol 11 (7) ◽  
pp. 3064
Author(s):  
Roberta Mota-Panizio ◽  
Manuel Jesús Hermoso-Orzáez ◽  
Luis Carmo-Calado ◽  
Gonçalo Lourinho ◽  
Paulo Sérgio Duque de Brito
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Organic Substrates ◽  
Biochemical Methane Potential ◽  
Volatile Solids ◽  
Working Volume ◽  
Methane Potential ◽  
Bmp Test ◽  
Cork Industry

The present study evaluates the digestion of cork boiling wastewater (CBW) through a biochemical methane potential (BMP) test. BMP assays were carried out with a working volume of 600 mL at a constant mesophilic temperature (35 °C). The experiment bottles contained CBW and inoculum (digested sludge from a wastewater treatment plant (WWTP)), with a ratio of inoculum/substrate (Ino/CBW) of 1:1 and 2:1 on the basis of volatile solids (VSs); the codigestion with food waste (FW) had a ratio of 2/0.7:0.3 (Ino/CBW:FW) and the codigestion with cow manure (CM) had a ratio of 2/0.5:0.5 (Ino/CBW:CM). Biogas and methane production was proportional to the inoculum substrate ratio (ISR) used. BMP tests have proved to be valuable for inferring the adequacy of anaerobic digestion to treat wastewater from the cork industry. The results indicate that the biomethane potential of CBWs for Ino/CBW ratios 1:1 and 2:1 is very low compared to other organic substrates. For the codigestion tests, the test with the Ino/CBW:CM ratio of 2/0.7:0.3 showed better biomethane yields, being in the expected values. This demonstrated that it is possible to perform the anaerobic digestion (AD) of CBW using a cosubstrate to increase biogas production and biomethane and to improve the quality of the final digestate.

scholarly journals Batch and Semi-Continuous Anaerobic Digestion of Industrial Solid Citrus Waste for the Production of Bioenergy

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 648
Author(s):  
Erik Samuel Rosas-Mendoza ◽  
Andrea Alvarado-Vallejo ◽  
Norma Alejandra Vallejo-Cantú ◽  
Raúl Snell-Castro ◽  
Sergio Martínez-Hernández ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
Continuous Mode ◽  
Citrus Industry ◽  
Batch Mode ◽  
Volatile Solids ◽  
Working Volume ◽  
Plant Level ◽  
Citrus Waste ◽  
Mesophilic Conditions

The aim of this paper is to describe a study of the anaerobic digestion of industrial citrus solid waste (ISCW) in both batch and semi-continuous modes for the production of bioenergy without the elimination of D-limonene. The study was conducted at the pilot plant level in an anaerobic reactor with a working volume of 220 L under mesophilic conditions of 35 ± 2 °C. Cattle manure (CM) was used as the inoculum. Three batches were studied. The first batch had a CM/ISCW ratio of 90/10, and Batches 2 and 3 had CM/ISCW ratios of 80/20 and 70/30, respectively. In the semi-continuous mode an OLR of approximately 8 g total chemical oxygen demand (COD)/Ld (4.43 gVS/Ld) was used. The results showed that 49%, 44%, and 60% of volatile solids were removed in the batch mode, and 35% was removed in the semi-continuous mode. In the batch mode, 0.322, 0.382, and 0.316 LCH4 were obtained at STP/gVSremoved. A total of 24.4 L/d (34% methane) was measured in the semi-continuous mode. Bioenergy potentials of 3.97, 5.66, and 8.79 kWh were obtained for the respective batches, and 0.09 kWh was calculated in the semi-continuous mode. The citrus industry could produce 37 GWh per season. A ton of processed oranges has a bioenergy potential of 162 kWh, which is equivalent to 49 kWh of available electricity ($3.90).

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