Modeling de novo granulation of anaerobic sludge

Doloman, Anna; Varghese, Honey; Miller, Charles D.; Flann, Nicholas S.

doi:10.1186/s12918-017-0443-z

Cited by 26 publications

(30 citation statements)

References 62 publications

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“…The "pockets" map well to the ethanol distribution in the granule, as secreted by Clostridium1 cell types ( Figure 2B). Absence of stratification for other cell types is different from the previous simulation of a glucose-fed granule (Doloman et al, 2017) and published laboratory studies (Rocheleau et al, 1999). Smooth diffusion gradient of the formed/consumed solutes can explain such cells distribution ( Figure 2B).…”

Section: Formation Of a Granule On Cellobiosecontrasting

confidence: 80%

A Model for Bioaugmented Anaerobic Granulation

et al. 2020

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Anaerobic granular sludge comprises of highly organized microorganisms with a sophisticated metabolic network. Such aggregates can withstand storage, temperature fluctuations and changes in the substrate supplied for anaerobic digestion. However, substrate change leads to long adaptation of granular consortia, creating lags in the reactor operations. To speed up adaptation and increase digestion efficiency, bioaugmentation with a robust consortium can be performed. The computational study described here aims to elucidate the mechanisms of bioaugmenting anaerobic granules, utilizing the current body of knowledge on metabolic and biochemical interactions between bacteria in such aggregates. Using a cDynoMiCs simulation environment, an agent-based model was developed to describe bioaugmentation for adaptation of cellobiose-degrading granular consortium to a lipid-rich feed. Lipolytic bacteria were successfully incorporated in silico to the stable granular consortia after 40 days of simulation. The ratio of cellobiose and the lipid-derivative, oleate, in the feed played key role to ensure augmentation. At 0.5 g/L of both cellobiose and oleate in the feed, a homogeneous stable augmented consortium was formed and converted the given amount of substrate to 10.9 mg/L of methane as a final product of anaerobic digestion. The demonstrated model can be used as a planning tool for anaerobic digestion facilities considering transition of the inoculum to a new type of feed.

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Section: Formation Of a Granule On Cellobiosecontrasting

confidence: 80%

A Model for Bioaugmented Anaerobic Granulation

et al. 2020

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“…The initial concentrations for soluble species are adapted from Batstone et al (2006) and Doloman et al (2017), choosing a glucose concentration corresponding to 100 mg chemical oxygen demand (COD) per liter.…”

Section: Resultsmentioning

confidence: 99%

“…Since the landmark paper of Kreft et al (1998), IbM have gained wider acceptance, being employed for the study of ecological behaviors, for example, cooperation vs. competition (Xavier and Foster, 2007), public goods dilemma (Mitri et al, 2011), division of labor (Dragoš et al, 2018), and survival strategies, such as bacteriocin production (Bucci et al, 2011) or response to phage infection (Simmons et al, 2017). IbM have a variety of environmental applications, especially in wastewater treatment systems [activated sludge systems (Picioreanu et al, 2004; Matsumoto et al, 2010; Ofiteru et al, 2014), anaerobic digestion (Batstone et al, 2006; Doloman et al, 2017) and microbial fuel cells (Picioreanu et al, 2010)] and are, if large enough, well suited to the study of evolution, most recently in the sea (Hellweger et al, 2018). A recent authoritative review highlighted the advantages, disadvantages, potential and challenges of IbM (Hellweger et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Individual Based Model Links Thermodynamics, Chemical Speciation and Environmental Conditions to Microbial Growth

Gogulancea

González-Cabaleiro

et al. 2019

Front. Microbiol.

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Individual based Models (IbM) must transition from research tools to engineering tools. To make the transition we must aspire to develop large, three dimensional and physically and biologically credible models. Biological credibility can be promoted by grounding, as far as possible, the biology in thermodynamics. Thermodynamic principles are known to have predictive power in microbial ecology. However, this in turn requires a model that incorporates pH and chemical speciation. Physical credibility implies plausible mechanics and a connection with the wider environment. Here, we propose a step toward that ideal by presenting an individual based model connecting thermodynamics, pH and chemical speciation and environmental conditions to microbial growth for 5·10 5 individuals. We have showcased the model in two scenarios: a two functional group nitrification model and a three functional group anaerobic community. In the former, pH and connection to the environment had an important effect on the outcomes simulated. Whilst in the latter pH was less important but the spatial arrangements and community productivity (that is, methane production) were highly dependent on thermodynamic and reactor coupling. We conclude that if IbM are to attain their potential as tools to evaluate the emergent properties of engineered biological systems it will be necessary to combine the chemical, physical, mechanical and biological along the lines we have proposed. We have still fallen short of our ideals because we cannot (yet) calculate specific uptake rates and must develop the capacity for longer runs in larger models. However, we believe such advances are attainable. Ideally in a common, fast and modular platform. For future innovations in IbM will only be of use if they can be coupled with all the previous advances.

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“…Former change was considered reasonable, given that the single substrate in these experiments—corn stalk—is a negligible source of ammonia. Meanwhile, the argument for extending the range of VFA inhibition on methanogens lies in their sensitivity to undissociated organic acids [67], as well as the dilute reactor medium, which in general might limit the availability of physical shelter and granule-forming sites for methanogens [68, 69]. The above described VFA inhibition effect was kinetically controlled similar to the original acetic acid inhibition effect, using inhibition constants with manually estimated values of 315 mg/L and 365 mg/L for R1 and R2, respectively.…”

Section: Methodsmentioning

confidence: 99%

Early warning indicators for mesophilic anaerobic digestion of corn stalk: a combined experimental and simulation approach

Kovalovszki

Pan

et al. 2019

Biotechnol Biofuels

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Background Monitoring and providing early warning are essential operations in the anaerobic digestion (AD) process. However, there are still several challenges for identifying the early warning indicators and their thresholds. One particular challenge is that proposed strategies are only valid under certain conditions. Another is the feasibility and universality of the detailed threshold values obtained from different AD systems. In this article, we report a novel strategy for identifying early warning indicators and defining threshold values via a combined experimental and simulation approach. Results The AD of corn stalk (CS) was conducted using mesophilic, completely stirred anaerobic reactors. Two overload modes (organic and hydraulic) and overload types (sudden and gradual) were applied in order to identify early warning indicators of the process and determine their threshold values. To verify the selection of experimental indicators, a combined experimental and simulation approach was adopted, using a modified anaerobic bioconversion mathematical model (BioModel). Results revealed that the model simulations agreed well with the experimental data. Furthermore, the ratio of intermediate alkalinity to bicarbonate alkalinity (IA/BA) and volatile fatty acids (VFAs) were selected as the most potent early warning indicators, with warning times of 7 days and 5–8 days, respectively. In addition, IA, BA, and VFA/BA were identified as potential auxiliary indicators for diagnosing imbalances in the AD system. The relative variations for indicators based on that of steady state were observed instead of the absolute threshold values, which make the early warning more feasible and universal. Conclusion The strategy of a combined approach presented that the model is promising tool for selecting and monitoring early warning indicators in various corn stalk AD scenarios. This study may offer insight into industrial application of early warning in AD system with mathematical model. Electronic supplementary material The online version of this article (10.1186/s13068-019-1442-7) contains supplementary material, which is available to authorized users.

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Modeling de novo granulation of anaerobic sludge

Cited by 26 publications

References 62 publications

A Model for Bioaugmented Anaerobic Granulation

A Model for Bioaugmented Anaerobic Granulation

Individual Based Model Links Thermodynamics, Chemical Speciation and Environmental Conditions to Microbial Growth

Early warning indicators for mesophilic anaerobic digestion of corn stalk: a combined experimental and simulation approach

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