scholarly journals Augmentation of Granular Anaerobic Sludge with Algalytic Bacteria Enhances Methane Production from Microalgal Biomass

Fermentation ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 88 ◽  
Author(s):  
Anna Doloman ◽  
Yehor Pererva ◽  
Michael H. Cortez ◽  
Ronald C. Sims ◽  
Charles D. Miller
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Algal Biomass ◽  
Organic Substrate ◽  
Anaerobic Sludge ◽  
Success Rates ◽  
Metabolic Capacity ◽  
Microalgal Biomass ◽  
Feed Composition

The efficiency of anaerobic digestion relies upon activity of the inoculum converting organic substrate into biogas. Often, metabolic capacity of the inoculum needs to be augmented with new capabilities to accommodate changes in the substrate feed composition. However, bioaugmentation is not a widely used strategy possibly due to the lack of studies demonstrating successful applications. This study describes the bioaugmentation of granular anaerobic sludge digesting mixed algal biomass in batch-scale reactors. The addition of an algalytic bacterial mixture to the granular consortium increased methane yield by 11%. This study also investigated changes in the microbial 16SrRNA composition of the augmented and non-augmented granular inoculum, which demonstrates a significant change in the hydrolytic microbial community. Overall, the studies’ results aim to provide a feasible checklist to assess the success rates of bioaugmentation of anaerobic digestion applications.

Growth of microalgal biomass on supernatant from biosolid dewatering

2013 ◽  
Vol 69 (4) ◽  
pp. 896-902 ◽  
Author(s):  
E. Ficara ◽  
A. Uslenghi ◽  
D. Basilico ◽  
V. Mezzanotte
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Biogas Production ◽  
Treatment Plant ◽  
Biomass Concentration ◽  
Anaerobic Sludge ◽  
Available Nitrogen ◽  
Microalgal Biomass ◽  
Production Values ◽  
Average Specific Growth Rate

The paper reports the results of an experiment to assess the feasibility of including a photobioreactor within the design of a wastewater treatment plant, growing microalgae on the centrate from anaerobic sludge dewatering. The growth of algal biomass would take advantage of the available nitrogen and provide a substrate for biogas production by anaerobic digestion. Tests were carried out by semi-continuously feeding a photobioreactor with a centrate–effluent blend and by increasing the fraction of centrate. The experimental results show that the centrate does not induce any toxicity and, on the contrary, can be well utilized by microalgae, whose average specific growth rate (μ), on centrate as such, was between 0.04 and 0.06 d−1. The maximum biomass concentration in the photobioreactor effluent was 1.6 gSS/L at 10 days HRT (hydraulic retention time). Methane production tests led to biochemical methane production values of 335 ± 39, and 284 ± 68 mL 0°C, 1 atm CH4/g VS for the two tested samples, in agreement with literature values. Settling tests show that the settling capacity of microalgae, although satisfactory, could be effectively improved after mixing with activated sludge, confirming the potential to use the existing primary settler for microalgae thickening in order to feed microalgae for anaerobic digestion with primary/secondary sludge.

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.

scholarly journals Anaerobic biodegradation of cassava wastewater under different temperatures and inoculums

2019 ◽  
Vol 10 (1) ◽  
pp. 65-76
Author(s):  
Miriam Cleide Cavalcante de Amorim ◽  
Paula Tereza De Souza Silva ◽  
Patricia Silva Barbosa ◽  
Nayara Evelyn Montefusco
Keyword(s):  
Anaerobic Digestion ◽  
Methane Production ◽  
Semiarid Region ◽  
Anaerobic Sludge ◽  
Bovine Rumen ◽  
Different Temperatures ◽  
Influence Of Temperature On ◽  
Cassava Wastewater ◽  
Kinetics Of ◽  
Goat Rumen

The production of starch generates, as a by-product, the cassava wastewater (manipueira), which can be treated by anaerobic digestion to provide biogas and minimize its polluting potential. The most commonly utilized biomass in the anaerobic digestion is the anaerobic sludge. The literature presents, as an alternative to sludge, bovine manure and ruminal fluids, being scarce the studies with the cassava wastewater. This research evaluated the influence of temperature on the microbial ability of cattle and goat rumen in anaerobically biodegrading the manipueira in substitution to the anaerobic sludge. The cattle and goat rumen specific methanogenic activities (SMA) were compared with that of the anaerobic sludge. Subsequently, by using the inoculum which had the best SMA results, cassava wastewater biodegradability tests were performed, investigating the kinetics of the organic matter removal and methane production at 32 ° C and 39 ° C. The bovine rumen presented better results in the SMA (0,315 g COD-CH4 g VSS.d-1) and methane production (1,026 mL). The temperature of 32 °C did not influence the activity of bovine ruminal inoculum as the kinetics of the biodegradation of the manipueira did not differ for the evaluated temperatures (0.1799 d-1 at 32°C and 0.1781 d-1 at 39°C). Bovine rumen achieved glucose reduction of 76% and 80% and methane yield of 77% and 79% for the tests at 32°C and 39°C, respectively. It is inferred that this type of inoculum might be used in reactors of anaerobic digestion processes for the treatment of the cassava wastewater at the ambient temperature of the semiarid region.

Attapulgite enhances methane production from anaerobic digestion of pig slurry by changing enzyme activities and microbial community

2020 ◽  
Vol 145 ◽  
pp. 222-232 ◽  
Author(s):  
Yue-gan Liang ◽  
Lu Xu ◽  
Jing Bao ◽  
Kotchikpa Adekunle Firmin ◽  
Wenming Zong
Keyword(s):  
Microbial Community ◽  
Anaerobic Digestion ◽  
Methane Production ◽  
Enzyme Activities ◽  
Pig Slurry
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