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.

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.

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.

Biodegradation of PAH and DEHP micro-pollutants in mesophilic and thermophilic anaerobic sewage sludge digestion

2006 ◽  
Vol 53 (8) ◽  
pp. 99-107 ◽  
Author(s):  
T. Benabdallah El-Hadj ◽  
J. Dosta ◽  
J. Mata-Álvarez
Keyword(s):  
Anaerobic Digestion ◽  
Wastewater Treatment Plants ◽  
Economic Cost ◽  
Process Efficiency ◽  
Sludge Digestion ◽  
Thermophilic Conditions ◽  
Polycyclic Aromatic ◽  
Positive Effect ◽  
Process Product ◽  
Micro Pollutants

Anaerobic digestion for the treatment of sludge in wastewater treatment plants has been reported to produce a low organic loaded effluent with an acceptable economic cost. But in the last years, new regulations and the increasing sludge production invite us to find an alternative and/or to improve the process efficiency. Moreover, the use of the effluent as fertilizer in agriculture imposes more restrictions on digestion process product and its micropollutant contents to protect the environment. In this study, a performance of the anaerobic digestion under mesophilic and thermophilic conditions at different hydraulic retention times (HRT) is assessed and the removal efficiencies of two important compounds or family compounds (Polycyclic Aromatic Hydrocarbons, PAH, and Di-2-(Ethyl-Hexyl)-Phthalate, DEHP) are evaluated. A positive effect of thermophilic temperature was observed on both micropollutants' biodegradation. However, HRT effect also had an important role for DEHP and low molecular weighted PAH removal.

scholarly journals Biogas Potential from the Anaerobic Digestion of Potato Peels: Process Performance and Kinetics Evaluation

Energies ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 2311 ◽  
Author(s):  
Spyridon Achinas ◽  
Yu Li ◽  
Vasileios Achinas ◽  
Gerrit Jan Willem Euverink
Keyword(s):  
Anaerobic Digestion ◽  
Energy Recovery ◽  
Biogas Production ◽  
Combined Treatment ◽  
Methane Yield ◽  
Cow Manure ◽  
Potato Peel ◽  
Potato Peels ◽  
The Impact ◽  
Kinetics Of

This article intends to promote the usage of potato peels as efficient substrate for the anaerobic digestion process for energy recovery and waste abatement. This study examined the performance of anaerobic digestion of potato peels in different inoculum-to-substrate ratios. In addition, the impact of combined treatment with cow manure and pretreatment of potato peels was examined. It was found that co-digestion of potato peel waste and cow manure yielded up to 237.4 mL CH4/g VSadded, whereas the maximum methane yield from the mono-digestion of potato peels was 217.8 mL CH4/g VSadded. Comparing the co-digestion to mono-digestion of potato peels, co-digestion in PPW/CM ratio of 60:40 increased the methane yield by 10%. In addition, grinding and acid hydrolysis applied to potato peels were positively effective in increasing the methane amount reaching 260.3 and 283.4 mL CH4/g VSadded respectively. Likewise, compared to untreated potato peels, pretreatment led to an elevation of the methane amount by 9% and 17% respectively and alleviated the kinetics of biogas production.

Ammonia influence in anaerobic digestion of OFMSW

2009 ◽  
Vol 59 (6) ◽  
pp. 1153-1158 ◽  
Author(s):  
T. Benabdallah El Hadj ◽  
S. Astals ◽  
A. Galí ◽  
S. Mace ◽  
J. Mata-Álvarez
Keyword(s):  
Anaerobic Digestion ◽  
Competitive Inhibition ◽  
Biogas Production ◽  
Gompertz Model ◽  
Ammonia Concentration ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Municipal Solid Wastes ◽  
Methane Generation ◽  
Thermophilic Conditions

The anaerobic digestion of the organic fraction of municipal solid wastes is taking increasing importance in the recent years. The main problem of some anaerobic digestion process is the large quantity of ammonia that is released, especially when high solid digestion is implemented. A fraction of the supernatant is treated and the remaining is recirculated to maintain the reactor in the optimum solids concentration. The question arising is if this recirculation stream should also be treated to improve biogas production. However, when doing the latter the quantity of ammonia inside the reactor increases too which could lead to inhibit the reactor operation. In this paper it appears that not only free ammonia affects the methanogenic fermentation but also ammonium ion concentration. Biogas production profiles are estimated using the Gompertz model. On the other hand, inhibition constants are fitted using a non-competitive inhibition model equation Thus, 50% inhibition of biomethane production was observed at level of 215 and 468 mg NH3_N/L under mesophilic and thermophilic conditions. However, the methane generation under mesophilic and thermophilic conditions was reduced by 50% when ammonium ion reach concentrations of 3,860 and 5,600 mg NH4+_N/L respectively. Under mesophilic conditions, pH higher than 7 impacted the methanogens bacteria negatively. This threshold pH limit, is variable under thermophilic conditions, depending on the total ammonia concentration.

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.

scholarly journals Limiting factors for anaerobic digestion of olive mill wastewater blends under mesophilic and thermophilic conditions

2018 ◽  
Vol 49 (2) ◽  
pp. 130-137
Author(s):  
Demetrio Antonio Zema ◽  
Giovanni Zappia ◽  
Souraya Benalia ◽  
Giuseppe Zimbalatti ◽  
Enzo Perri ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Volatile Fatty Acids ◽  
Biogas Production ◽  
Olive Mill Wastewater ◽  
Limiting Factors ◽  
Citrus Peel ◽  
Thermophilic Conditions ◽  
High Concentrations ◽  
Olive Mill

Experimental trials of anaerobic digestion of olive mill wastewater (OMW) blended with other agro-industrial by-products were carried out to evaluate biogas production and sensitivity of the process to inhibiting compounds. Blends containing different percentages of OMW, digested liquid manure, and citrus peel were subjected to a batch anaerobic digestion process under both mesophilic and thermophilic conditions. The results showed that blends with percentages of OMW higher than 20% (v/v) had low methane yields due high concentrations of polyphenols (PPs) and/or volatile fatty acids (concentrations above 0.8 g kg–1 and 2.4 g L–1, respectively). The addition of other substrates such as citrus peel may have induced synergic inhibiting effects of PPs and essential oils (EO) on microbial growth. Thermophilic processes were more sensitive to these inhibiting compounds than mesophilic processes. The results of this study suggest that reducing PPs and EO concentrations in blends subject to anaerobic digestion below the inhibiting concentrations of 0.6 g L–1 and 0.5 g kg–1, respectively, is suitable. Additionally, it is advisable to maintain the volatile fatty acids content below 2 g L–1 to avoid its evident toxic effects on the growth of microorganisms in biochemical processes.

scholarly journals Effect of Mechanical Pre-Treatment of the Agricultural Substrates on Yield of Biogas and Kinetics of Anaerobic Digestion

2018 ◽  
Vol 10 (10) ◽  
pp. 3669 ◽  
Author(s):  
Józef Szlachta ◽  
Hubert Prask ◽  
Małgorzata Fugol ◽  
Adam Luberański
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Gompertz Model ◽  
Model Parameters ◽  
Production Potential ◽  
Pre Treatment ◽  
Sorghum Silage ◽  
Kinetics Of ◽  
Degree Of Fragmentation ◽  
Modified Gompertz Model

The effect of mechanical pre-treatment of nine different agricultural substrates minced to particle sizes of 1.5 mm, 5 mm and 10 mm on biogas and methane yields and fermentation kinetics was investigated. The results showed, that for five of the nine tested substrates (grass, Progas rye, Palazzo rye, tall wheatgrass, beet), a higher biogas production was obtained for the degree of fragmentation of 10 mm compared to fragmentation of 5 mm and 1.5 mm. For fragmentation of 5 mm, the highest biogas production was achieved for sorghum silage, Atletico maize and Cannavaro maize—649.80, 735.59 and 671.83 Nm3/Mg VS, respectively. However, for the degree of fragmentation of 1.5 mm, the highest biogas production (510.43 Nm3/Mg volatile solid (VS)) was obtained with Topinambur silage. The modified Gompertz model fitted well the kinetics of anaerobic digestion of substrates and show a significant dependence of the model parameters Hmax (biogas production potential) and Rmax (maximum rate of biogas production) on the degree of substrate fragmentation.

Performance, Microbial Community Analysis and Fertilizer Value of Anaerobic Co-digestion of Cattle Manure with Waste Kitchen Oil

2019 ◽  
Vol 35 (2) ◽  
pp. 239-248 ◽  
Author(s):  
Ricardo Galbiatti Sandoval Nogueira ◽  
Teng Teeh Lim ◽  
Haoqi Wang ◽  
Paulo Henrique Mazza Rodrigues
Keyword(s):  
Anaerobic Digestion ◽  
Hydraulic Retention Time ◽  
Biogas Production ◽  
Preliminary Test ◽  
Community Analysis ◽  
Cattle Manure ◽  
Microbial Community Analysis ◽  
Fertilizer Value ◽  
Replication Control ◽  
Mesophilic Conditions

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.

Energy self-sufficient sewage wastewater treatment plants: is optimized anaerobic sludge digestion the key?

2013 ◽  
Vol 68 (8) ◽  
pp. 1739-1744 ◽  
Author(s):  
P. Jenicek ◽  
J. Kutil ◽  
O. Benes ◽  
V. Todt ◽  
J. Zabranska ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Energy Consumption ◽  
Anaerobic Digestion ◽  
Biogas Production ◽  
Treatment Plant ◽  
Anaerobic Sludge ◽  
Waste Activated Sludge ◽  
Sludge Digestion ◽  
Anaerobic Sludge Digestion ◽  
Standard Energy

The anaerobic digestion of primary and waste activated sludge generates biogas that can be converted into energy to power the operation of a sewage wastewater treatment plant (WWTP). But can the biogas generated by anaerobic sludge digestion ever completely satisfy the electricity requirements of a WWTP with ‘standard’ energy consumption (i.e. industrial pollution not treated, no external organic substrate added)? With this question in mind, we optimized biogas production at Prague's Central Wastewater Treatment Plant in the following ways: enhanced primary sludge separation; thickened waste activated sludge; implemented a lysate centrifuge; increased operational temperature; improved digester mixing. With these optimizations, biogas production increased significantly to 12.5 m3 per population equivalent per year. In turn, this led to an equally significant increase in specific energy production from approximately 15 to 23.5 kWh per population equivalent per year. We compared these full-scale results with those obtained from WWTPs that are already energy self-sufficient, but have exceptionally low energy consumption. Both our results and our analysis suggest that, with the correct optimization of anaerobic digestion technology, even WWTPs with ‘standard’ energy consumption can either attain or come close to attaining energy self-sufficiency.

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