Comparison of hyper-thermophilic–mesophilic two-stage with single-stage mesophilic anaerobic digestion of waste activated sludge: Process performance and microbial community analysis

2016 ◽  
Vol 290 ◽  
pp. 290-301 ◽  
Author(s):  
Li-Jie Wu ◽  
Atsushi Higashimori ◽  
Yu Qin ◽  
Toshimasa Hojo ◽  
Kengo Kubota ◽  
...  
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Community Analysis ◽  
Single Stage ◽  
Microbial Community Analysis ◽  
Waste Activated Sludge ◽  
Process Performance ◽  
Activated Sludge Process ◽  
Two Stage

Oxidative and thermo-oxidative co-treatment with anaerobic digestion of excess municipal sludge

2005 ◽  
Vol 52 (1-2) ◽  
pp. 237-244 ◽  
Author(s):  
J.A. Cacho Rivero ◽  
N. Madhavan ◽  
M.T. Suidan ◽  
P. Ginestet ◽  
J.-M. Audic
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Fecal Coliform ◽  
Single Stage ◽  
Waste Activated Sludge ◽  
Municipal Sludge ◽  
Two Stage ◽  
Two Stages ◽  
Solids Removal

The effect of oxidative and thermo-oxidative co-treatment of excess municipal sludge was investigated. A mixture of primary and waste activated sludge was anaerobically treated using two different configurations: i) two stages and ii) a single stage with recycling. Oxidative or thermo-oxidative co-treatment placed in between the reactor or in the recycle line was studied. A two-stage configuration with no co-treatment served as a control and resulted in 50.1% overall solids removal. Compared to the control, an increase in solids removal of 10.8 and 2.7% was observed when oxidative co-treatment was placed between reactors and in the recycle line respectively. When thermo-oxidative co-treatment was placed between the two stages or in the recycle line an increase in solids removal of 25.1 and 26.9% respectively was observed. The performances of the different configurations were also evaluated with parameters such as COD, TKN, ammonia, and fecal coliform concentration.

Two-stage thermophilic-mesophilic anaerobic digestion of waste activated sludge from a biological nutrient removal plant

2006 ◽  
Vol 53 (8) ◽  
pp. 149-157 ◽  
Author(s):  
S. Watts ◽  
G. Hamilton ◽  
J. Keller
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Nutrient Removal ◽  
Treatment Plant ◽  
Single Stage ◽  
Biological Nutrient Removal ◽  
Waste Activated Sludge ◽  
Two Stage ◽  
Primary Sludge ◽  
Second Stage

A two-stage thermophilic-mesophilic anaerobic digestion pilot-plant was operated solely on waste activated sludge (WAS) from a biological nutrient removal (BNR) plant. The first-stage thermophilic reactor (HRT 2 days) was operated at 47, 54 and 60 °C. The second-stage mesophilic digester (HRT 15 days) was held at a constant temperature of 36–37 °C. For comparison with a single-stage mesophilic process, the mesophilic digester was also operated separately with an HRT of 17 days and temperature of 36–37 °C. The results showed a truly thermophilic stage (60 °C) was essential to achieve good WAS degradation. The lower thermophilic temperatures examined did not offer advantages over single-stage mesophilic treatment in terms of COD and VS removal. At a thermophilic temperature of 60 °C, the plant achieved 35% VS reduction, representing a 46% increase compared to the single-stage mesophilic digester. This is a significant level of degradation which could make such a process viable in situations where there is no primary sludge generated. The fate of the biologically stored phosphorus in this BNR sludge was also investigated. Over 80% of the incoming phosphorus remained bound up with the solids and was not released into solution during the WAS digestion. Therefore only a small fraction of phosphorus would be recycled to the main treatment plant with the dewatering stream.

scholarly journals The feedstock microbiome selectively steers process stability during the anaerobic digestion of waste activated sludge

2019 ◽  
Author(s):  
Cindy Ka Y Law ◽  
Rens De Henau ◽  
Jo De Vrieze
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Methane Production ◽  
Cost Effective ◽  
Organic Loading Rate ◽  
Waste Activated Sludge ◽  
Process Performance ◽  
Process Stability ◽  
Process Disturbances

AbstractStrategies to enhance process performance of anaerobic digestion remain of key importance to achieve further spreading of this technology for integrated resource recovery from organic waste streams. Continuous inoculation of the microbial community in the digester via the feedstock could be such a cost-effective strategy. Here, anaerobic digestion of fresh waste activated sludge (WAS) was compared with sterilized WAS in response to two common process disturbances, i.e., organic overloading and increasing levels of salts, to determine the importance of feedstock inoculation. A pulse in the organic loading rate severely impacted process performance of the digesters fed sterile WAS, with a 92 ± 45 % decrease in methane production, compared to a 42 ± 31 % increase in the digesters fed fresh WAS, relative to methane production before the pulse. Increasing salt pulses did not show a clear difference in process performance between the digesters fed fresh and sterile WAS, and process recovery was obtained even at the highest salt pulse of 25 g Na+ L−1. Feedstock sterilisation strongly impacted the microbial community in the digesters. In conclusion, feedstock inoculation can be considered a cheap, yet, disturbance-specific strategy to enhance process stability in full-scale anaerobic digestion processes.

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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