Experimental determination of the heterotroph anoxic yield in anoxic-aerobic activated sludge systems treating municipal wastewater

Muller, AW; Wentzel, M. C.; Ekama, G. A.

doi:10.4314/wsa.v30i5.5113

Cited by 2 publications

(3 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The stoichiometric parameters, X52 and X53, required only minor adjustments from default within ± 0.07 mgCOD/mgCOD for each. This was to be expected given the greater observed sensitivity of the model to these parameters, while still conforming to previously advised values determined experimentally 97 . While the kinetic parameters, X16 and X12, observed greater deviation from default with ± 0.11 1/day and ± 0.09 (–) respectively, the disparity remained marginal.…”

Section: Variance-based Sensitivity Analysissupporting

confidence: 88%

Modelling the performance of an integrated fixed-film activated sludge (IFAS) system: a systematic approach to automated calibration

Pryce

Kapelan

Memon

2022

Sci Rep

View full text Add to dashboard Cite

IFAS systems are inherently complex due to the hybrid use of both suspended and attached bacterial colonies for the purpose of pollutant degradation as part of wastewater treatment. This poses challenges when attempting to represent these systems mathematically due to the vast number of parameters involved. Besides becoming convoluted, large effort will be incurred during model calibration. This paper demonstrates a systematic approach to calibration of an IFAS process model that incorporates two sensitivity analyses to identify influential parameters and detect collinearity from a subset of 68 kinetic and stoichiometric parameters, and the use of the Nelder–Mead optimization algorithm to estimate the required values of these parameters. The model considers the removal of three critical pollutants including biochemical oxygen demand (BOD), total nitrogen (TN) and total suspended solids (TSS). Results from the sensitivity analyses identified four parameters that were the primary influence on the model. The model was found to be most sensitive to the two stoichiometric parameters including aerobic heterotrophic yield on soluble substrate whose total effects were responsible for 92.4% of the model’s BOD output sensitivity and 92.8% of the model’s TSS output sensitivity. The anoxic heterotrophic yield on soluble substrate was observed to be responsible for 54.3% of the model’s TN output sensitivity. To a lesser extent the two kinetic parameters, aerobic heterotrophic decay rate and reduction factor for denitrification on nitrite, were responsible for only 8.0% and 13.1% of the model’s BOD and TN output sensitivities respectively. Parameter estimation identified the need for only minor adjustments to default values in order to achieve sufficient accuracy of simulation with deviation from observed data to be only ± 3.6 mg/L, ± 1.3 mg/L, and ± 9.5 mg/L for BOD, TN and TSS respectively. Validation showed the model was limited in its capacity to predict system behaviour under extreme dissolved oxygen stress.

show abstract

Section: Variance-based Sensitivity Analysissupporting

confidence: 88%

Modelling the performance of an integrated fixed-film activated sludge (IFAS) system: a systematic approach to automated calibration

Pryce

Kapelan

Memon

2022

Sci Rep

View full text Add to dashboard Cite

show abstract

“…27 Since both heterotrophic and autotrophic growth rates have been reported to be very dependent on the pH, 38 its influence was taken into account. For heterotrophic biomass, the influence of pH obtained for a similar nitrifying-denitrifying biomass was considered.…”

Section: Activated Sludge Model Extended For Nitrite Route Descriptionmentioning

confidence: 99%

“…27 Lineal death was established for the decay process of both heterotrophic and autotrophic organisms in order to make the mathematical model as simple as possible.…”

Section: Activated Sludge Model Extended For Nitrite Route Descriptionmentioning

confidence: 99%

Modelling a sequencing batch reactor to treat the supernatant from anaerobic digestion of the organic fraction of municipal solid waste

Dosta

Galí

Macé

et al. 2007

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

In this study, a lab-scale sequencing batch reactor (SBR) has been tested to remove chemical oxygen demand (COD) and NH 4 + -N from the supernatant of anaerobic digestion of the organic fraction of municipal solid waste. This supernatant was characterized by a high ammonium concentration (1.1 g NH 4 + -N L −1 ) and an important content of slowly biodegradable and/or recalcitrant COD (4.8 g total COD L −1 ). Optimum SBR operating sequence was reached when working with 3 cycles per day, 30• C, SRT 12 days and HRT 3 days. During the time sequence, two aerobic/anoxic steps were performed to avoid alkalinity restrictions. Oxygen supply and working pH range were controlled to promote the nitrification over nitrite. Under steady state conditions, COD and nitrogen removal efficiencies of more than 65% and 98%, respectively, were achieved. A closed intermittentflow respirometer was used to characterize and model the SBR performance. The activated sludge model ASM1 was modified to describe the biological nitrogen removal over nitrite, including the inhibition of nitrification by unionized ammonia and nitrous acid concentrations, the pH dependency of both autotrophic and heterotrophic biomass, pH calculation and the oxygen supply and stripping of CO 2 and NH 3 . Once calibrated by respirometry, the proposed model showed very good agreement between experimental and simulated data.

show abstract

Experimental determination of the heterotroph anoxic yield in anoxic-aerobic activated sludge systems treating municipal wastewater

Cited by 2 publications

References 0 publications

Modelling the performance of an integrated fixed-film activated sludge (IFAS) system: a systematic approach to automated calibration

Modelling the performance of an integrated fixed-film activated sludge (IFAS) system: a systematic approach to automated calibration

Modelling a sequencing batch reactor to treat the supernatant from anaerobic digestion of the organic fraction of municipal solid waste

Contact Info

Product

Resources

About