Modeling the acclimation of activated sludge to a xenobiotic

Chong, Nyuk-Min

doi:10.1016/j.biortech.2009.06.071

Cited by 21 publications

(15 citation statements)

References 14 publications

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“…Firstly, it must be clarified that in a xenobiotic-degrading activated sludge, only part of the bulk biomass is 2,4-D degrader (Chong and Chang 2009). For examples, 21 % of the bulk activated sludge biomass was degrader (Chong and Huang 2012;Chong 2009), and the highly acclimated sludge used in this study contained approximately 25 % of degrader calculated from the complete model. It is the cooperative effort of degraders and non-degraders that make xenobiotic mineralization functional.…”

Section: Discussionmentioning

confidence: 99%

“…Complete model results also provide yield y a for the degrader and S xa the ratio of xenobiotic substrate mass used by the degrader for growth (for details, see Chong (2009) and Chong and Huang (2012)). The S-model gives the gross substrate utilization rates under the initial sludge concentrations, an S-curve whose shape is true to the Haldane equation but does not give the specific growth rate along the growth curve, nor the X to S proportionality factor of yield y.…”

Section: Calculationsmentioning

confidence: 99%

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Conditions for supplemental biogenic substrates to enhance activated sludge degradation of xenobiotic

Nguyen

Chong

2015

Appl Microbiol Biotechnol

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The effects of biogenic presence on the degradation of xenobiotic organics by natural microbial populations have been reported as either advantageous or disadvantageous. The inconsistency of the reports implies there could be a turning point from disadvantageous to advantageous outcomes so that conditions may exist that could bring an optimum advantage. This study tested the supplementations of varying concentrations of sucrose and peptone, separately and combined, to acclimated activated sludge degradation of xenobiotic 2,4-D, while other operational and microbiological conditions were held constant. Our test results showed that biogenic may indeed enhance or slow down xenobiotic degradation rates. The highest enhancements exist at concentrations of 50 and 80 mg/L, respectively, for sucrose and peptone when supplemented separately, and 20 mg/L sucrose and 40 mg/L peptone combined. Conditions for advantageous biogenic supplementation were identified for activated sludge degradation of a xenobiotic; specifically, the highest degradation rate enhancements occurred when biogenic supplementation was approximately 0.5 to 0.7 the concentration of 2,4-D base on chemical oxygen demand (COD), which brought a biomass yield of approximately double that yielded by 2,4-D. Kinetics analyses provided clues for the possible causes of advantageous and disadvantageous effects due to biogenic supplementation.

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Section: Discussionmentioning

confidence: 99%

Section: Calculationsmentioning

confidence: 99%

Conditions for supplemental biogenic substrates to enhance activated sludge degradation of xenobiotic

Nguyen

Chong

2015

Appl Microbiol Biotechnol

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“…Only after the easier more natural substrate has been exhausted, the cells switch to the second, resulting in two separate growth phases. There are some previous studies which the effects of diauxic growth on 2,4-D acclimation and degradation [21]. The results showed that: If we feed sugar with a proper concentration and at the proper time, it can make 2,4-D acclimation lag time shorten.…”

Section: Introductionmentioning

confidence: 90%

Effects of combined growth of biogenic and xenobiotic substrates on degradation of xenobiotic by activated sludge

et al. 2017

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Abstract. The purpose of this study was to research about supplementation of different concentrations of the substrate on the degradation rate of xenobiotic and to determine the optimal concentrations of the auxiliary substrates that are most beneficial of xenobiotic degradation rate. 2,4-dichlorophenol acid (2,4-D) was used representative xenobiotic organic compounds, while peptone and sugar used for auxiliary substrates. The activated sludge was completely break down 100 mg/l of 2,4-D for three consecutive times. The different concentrations between biogenic substracts of sucrose and peptone were fed separately or combined into the medium containing 200 mg/l of 2,4-D and 140 mg SS/l of activated sludge. The results showed that sugar and peptone could affect 2,4-D degradation rate to several different degree at different concentrations. In separate supplementation, 2,4-D degradation completed within 25 hours, 40 mg/l sugar and 150 mg/l peptone concentrations were found to be the optimal concentrations. In combined case, 2,4-D was consumed totally within 20 hours and the optimal concentration of the combined sugar and peptone concentrations were 40 and 150 mg/l, respectively.

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“…This model would output degrader and nondegrader concentrations and the final effluent concentration of organic residue. The present work is a further development from the batch reaction acclimation model by this author (Chong 2009). This new modeling contains all terms and features of the previous model, with major and suitable addition of terms for CSTR growth, substrate mass flow, and degrader inheritance.…”

Section: Introductionmentioning

confidence: 97%

Model development with defined biological mechanisms for xenobiotic treatment activated sludge at steady state

Chong

2015

Environ Sci Pollut Res

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Activated sludge treatment of a xenobiotic organic compound, much different from treatment of biogenic organics, must be modeled with interactions involving a two-part biomass of degrader and nondegrader, which selectively or competitively grow on a two-part substrate of input xenobiotic and its biogenic metabolites. A xenobiotic treatment model was developed which incorporates kinetics of the growth of degrader and nondegrader, the line dividing metabolites into xenobiotic and biogenic, yields of degrader and nondegrader from utilization of their parts of substrates, and kinetics of degrader reversion to nondegrader due to instability of the degradative element degraders carry. Experimental activated sludge operated for treatment of a xenobiotic generated data for calibration of the model. With the input of influent xenobiotic concentration, mean cell and hydraulic residence times, and calibrated parameters, the model readily outputs concentrations of degrader, nondegrader, and effluent biogenic residue that closely match the results obtained from experiments.

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Modeling the acclimation of activated sludge to a xenobiotic

Cited by 21 publications

References 14 publications

Conditions for supplemental biogenic substrates to enhance activated sludge degradation of xenobiotic

Conditions for supplemental biogenic substrates to enhance activated sludge degradation of xenobiotic

Effects of combined growth of biogenic and xenobiotic substrates on degradation of xenobiotic by activated sludge

Model development with defined biological mechanisms for xenobiotic treatment activated sludge at steady state

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