Anaerobic digestion of activated sludge, anaerobic granular sludge and cow dung with food waste for enhanced methane production

2017 ◽  
Vol 164 ◽  
pp. 557-566 ◽  
Author(s):  
Rubia Zahid Gaur ◽  
Surindra Suthar
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Food Waste ◽  
Methane Production ◽  
Granular Sludge ◽  
Cow Dung ◽  
Anaerobic Granular Sludge

Identification of mesophilic and thermophilic fermentative species in anaerobic granular sludge

2006 ◽  
Vol 54 (2) ◽  
pp. 19-24 ◽  
Author(s):  
F. Hernon ◽  
C. Forbes ◽  
E. Colleran
Keyword(s):  
Growth Rate ◽  
Anaerobic Digestion ◽  
Molecular Biology ◽  
Food Waste ◽  
Granular Sludge ◽  
Anaerobic Granular Sludge ◽  
Digestion Process ◽  
Fermentative Bacteria ◽  
Landfill Sites ◽  
Rapid Growth Rate

Large quantities of biodegradable food waste in the form of fruit and vegetables are still being deposited in landfill sites in Ireland. The development of an anaerobic digestion process using fermentative species which degrade the carbohydrate-rich waste could divert the food waste from landfills. We identified fermentative species grown on glucose and sucrose at mesophilic and thermophilic temperatures using molecular biology techniques. The dominating fermentative bacteria of the mesophilic sludge were of the Bacteroidetes and Spirochaetes classes. Although both groups of bacteria are typically fermentative their substrate range appears to be limited. The dominating fermentative bacteria in the thermophilic sludge was Thermoanaerobacterium aotearoense of the Clostridia class. The indications are that Thermoanaerobacterium aotearoense may be highly suitable to biodegrade a carbohydrate-rich influent feed due to its possibly very rapid growth rate and also an extensive substrate range.

Anaerobic Co-Digestion of Food Waste and Thermal Pretreated Waste Activated Sludge: Synergetic Effect and Energy Assessment

2021 ◽  
Author(s):  
Jian Zhang ◽  
Peng Gan ◽  
Ru-yi Wang ◽  
Tian Xie ◽  
Yang Liu ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Food Waste ◽  
Methane Production ◽  
Synergetic Effect ◽  
Gompertz Model ◽  
Waste Activated Sludge ◽  
Thermal Pretreatment ◽  
Energy Assessment ◽  
Modified Gompertz Model

Abstract Thermal pretreatment was an effective method to improve the anaerobic digestion of waste activated sludge. However its application in China was still hindered by the high energy demand. In order to balance the energy consumption of sludge thermal pretreatment integrated with anaerobic digestion, food waste was introduced as co-substrate to achieve an energy self-sustainable sludge treatment system. Anaerobic biodegradability test was performed using thermal pretreated sludge and food waste in order to clarify the kinetics and mechanism of co-digestion, especially the synergetic effect on specific methane yield. The prominent synergetic effect was an initial acceleration of cumulative methane production by 20.7- 23.8% observed during the first 15 days, and the cumulative methane production of feedstock can be calculated proportionately from its composition. Between the evaluated models, modified Gompertz model presented a better agreement of the experimental results and it was able to describe the synergetic effect, assessed by the relative deviation between theoretical estimation and the experimental results of co-digestion tests. This feature made modified Gompertz model a suitable tool for methane production prediction of mono- and co-digestion. Energy assessment shown that co-digestion with food waste was a sustainable solution to maintain the integration of thermal pretreatment and anaerobic digestion energy neutral or even positive. Besides, the performance of sludge dewatering was a crucial factor for the energy balance.

scholarly journals Use of extracellular polymer substances as additives for improving biogas yield and digestion performance

2019 ◽  
Author(s):  
Haitong Ma ◽  
Chen Yan Guo ◽  
Ming Wu ◽  
Hui Liu ◽  
Zhiwei Wang ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Suspended Solids ◽  
Granular Sludge ◽  
Average Particle ◽  
Anaerobic Granular Sludge ◽  
Conductive Materials ◽  
Secondary Pollution ◽  
Extracellular Polymer

AbstractTo understand how extracellular polymer substances (EPS) as additives promotes methanogenesis, batch tests of methane production potential in anaerobic reactors with the addition of EPS or not were conducted. Research showed that EPS increased remarkably methane production during anaerobic digestion (36.5% increase compared with the control). EPS enriched functional microorganisms such as Firmicutes, Actinobacteria, Synergistetes, and Chloroflexi. Among them, 8.86% OTUs from the important hydrolysis and acidification phyla, which may be an important reason for the enhanced methanogenic capacity of anaerobic granular sludge. Additionally, EPS also improved the abundance of cytochrome c (c-Cyts), accelerating the direct interspecies electron transfer (DIET) between syntrophic bacteria and methanogens, thus enhancing the methane production. Interestingly, the average particle size, volatile suspended solids/total suspended solids (VSS/TSS) and EPS content of anaerobic granular sludge (AnGS) in the EPS reactor were approximately equal to that of the control reactor during the anaerobic digestion, illustrating that EPS could not affect the physicochemical properties of AnGS. Therefore, these results suggested that EPS mainly played a role in the form of conductive materials in the anaerobic digestion process. Compared with conductive materials, EPS as biomass conductive materials was not only environmentally friendly and economical but also no secondary pollution.ImportanceCompared with the reported conductive materials, EPS has the potential of biodegradation, electron transfer and no significant secondary pollution. Besides, there are few studies on the utilization of EPS resources, especially the effect of EPS as an additive on anaerobic digestion performance. To clarify whether EPS as conductive materials or carbon source promotes methanogenesis. Therefore, in this study, we investigated the influence of EPS as an additive on the methanogenic capacity, physical-chemical properties, microbial community structure and metabolic function of anaerobic granular sludge (AnGS), and preliminarily expatiate the influence mechanism of EPS as an additive on methanogenesis. At the meantime, the research is expected to provide new solutions for the improvement of anaerobic digestion performance and disposal of waste mud.

Effects of thermochemical pretreatment on the anaerobic digestion of waste activated sludge

1997 ◽  
Vol 35 (8) ◽  
pp. 209-215 ◽  
Author(s):  
Shuzo Tanaka ◽  
Toshio Kobayashi ◽  
Ken-ichi Kamiyama ◽  
Ma. Lolita N. Signey Bildan
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Production Rate ◽  
Methane Production ◽  
Waste Activated Sludge ◽  
Batch Experiments ◽  
Industrial Wastewaters ◽  
Thermochemical Pretreatment ◽  
Chemical Heating ◽  
Methane Production Rate

Effects of pretreatment on the anaerobic digestion of waste activated sludge (WAS) were investigated in terms of VSS solubilization and methane production by batch experiments. The methods of pretreatment studied are NaOH addition (chemical), heating (thermal) and heating with NaOH addition (thermochemical) to the domestic WAS and to the combined WAS from domestic, commercial and industrial wastewaters. The thermochemical pretreatment gave the best result among three methods in the combined WAS, i.e., the VSS was solubilized by 40-50% and the methane production increased by more than 200% over the control when the WAS was heated at 130°C for 5 minutes with the dose 0.3 g NaOH/g VSS. In the domestic WAS, the VSS solubilization rate was 70-80% but the increase of the methane production was about 30% after thermochemically pretreated. The domestic WAS consists of 41% protein, 25% lipid and 14% carbohydrate on COD basis, and the solubilization rate of protein, which is the largest constituent of the WAS, was 63% in the thermochemical pretreatment. Although the effect of the thermochemical pretreatment on the methane production was higher to the combined WAS than to the domestic WAS, the methane production rate was 21.9 ml CH4/g VSSWAS·day in the domestic WAS and 12.8 ml CH4/g VSSWAS·day in the combined WAS.

Improving methane production and anaerobic digestion stability of food waste by extracting lipids and mixing it with sewage sludge

2017 ◽  
Vol 244 ◽  
pp. 996-1005 ◽  
Author(s):  
Dalal E. Algapani ◽  
Jing Wang ◽  
Wei Qiao ◽  
Min Su ◽  
Andrea Goglio ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Food Waste ◽  
Methane Production

scholarly journals Thermophilic Alkaline Fermentation Followed by Mesophilic Anaerobic Digestion for Efficient Hydrogen and Methane Production from Waste-Activated Sludge: Dynamics of Bacterial Pathogens as Revealed by the Combination of Metagenomic and Quantitative PCR Analyses

2018 ◽  
Vol 84 (6) ◽  
Author(s):  
Jingjing Wan ◽  
Yuhang Jing ◽  
Yue Rao ◽  
Shicheng Zhang ◽  
Gang Luo
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Quantitative Pcr ◽  
Methane Production ◽  
Bacterial Pathogens ◽  
Methane Yield ◽  
Metagenomic Analysis ◽  
Waste Activated Sludge ◽  
Hydrogen Yield

ABSTRACT Thermophilic alkaline fermentation followed by mesophilic anaerobic digestion (TM) for hydrogen and methane production from waste-activated sludge (WAS) was investigated. The TM process was also compared to a process with mesophilic alkaline fermentation followed by a mesophilic anaerobic digestion (MM) and one-stage mesophilic anaerobic digestion (M) process. The results showed that both hydrogen yield (74.5 ml H 2 /g volatile solids [VS]) and methane yield (150.7 ml CH 4 /g VS) in the TM process were higher than those (6.7 ml H 2 /g VS and 127.8 ml CH 4 /g VS, respectively) in the MM process. The lowest methane yield (101.2 ml CH 4 /g VS) was obtained with the M process. Taxonomic results obtained from metagenomic analysis showed that different microbial community compositions were established in the hydrogen reactors of the TM and MM processes, which also significantly changed the microbial community compositions in the following methane reactors compared to that with the M process. The dynamics of bacterial pathogens were also evaluated. For the TM process, the reduced diversity and total abundance of bacterial pathogens in WAS were observed in the hydrogen reactor and were further reduced in the methane reactor, as revealed by metagenomic analysis. The results also showed not all bacterial pathogens were reduced in the reactors. For example, Collinsella aerofaciens was enriched in the hydrogen reactor, which was also confirmed by quantitative PCR (qPCR) analysis. The study further showed that qPCR was more sensitive for detecting bacterial pathogens than metagenomic analysis. Although there were some differences in the relative abundances of bacterial pathogens calculated by metagenomic and qPCR approaches, both approaches demonstrated that the TM process was more efficient for the removal of bacterial pathogens than the MM and M processes. IMPORTANCE This study developed an efficient process for bioenergy (H 2 and CH 4 ) production from WAS and elucidates the dynamics of bacterial pathogens in the process, which is important for the utilization and safe application of WAS. The study also made an attempt to combine metagenomic and qPCR analyses to reveal the dynamics of bacterial pathogens in anaerobic processes, which could overcome the limitations of each method and provide new insights regarding bacterial pathogens in environmental samples.

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