aeration system modelling – case studies from three full-scale … · 2015. 7. 22. · fit of...

Aeration System Modelling – Case Studies from Three Full-scale WWTPs

Magnus Arnell & Ulf Jeppsson IEA, Lund University, Sweden

Lund University / LTH / BME / IEA / Arnell & Jeppsson – Watermatex-15 / 2015-06-16

Energy production

GHG emission

COD/N/P

Energy use

Operational cost

Health


Benchmark Simulation Model no. 2 (BSM2)


Why dynamic modelling of aeration

•  Wastewater is dynamic in composition and load •  DO concentration is strongly influencing treatment

efficiency, energy requirement, greenhouse gas emissions, etc.

•  Air flow is a key control handle at WWTPs •  Engineering purposes


Components of the aeration system


Oxygen transfer model

•  Includes oxygen transfer limitations (α, F) •  Temperature compensation important •  Allows for realistic, i.e. dynamic non-linear, OTE curve •  Important to consider diffusor density and air flow

restrictions (min & max)

Beltrán, S. et al. (2013) Model-based optimization of aeration systems in WWTPs. (ICA2013).


Case studies

•  Three municipal WWTPs •  Case 1 – plant-wide model to answer questions about

marginal environmental effects of stricter effluent limits. Research project.

•  Case 2 – model of water train to evaluate options for enhanced nitrogen removal and forecasted load increase. Consultancy project.

•  Case 3 – plant-wide model to assess operational problems and evaluate future plant expansions. Consultancy project.


Three WWTPs


Fit of SOTE curves


Results Case 1

Difference of means: 4.4 % Goodness of Fit (NRMSE): -8.6


Results Case 2

Difference of means: 13 % Goodness of Fit (NRMSE): -0.032


Results case 3

Difference of means: 5.3 % Goodness of Fit (NRMSE): -0.25


Conclusions

•  Dynamic modelling of aeration system is important and oxygen transfer model is crucial

•  The implemented model is simple and robust with simple case specific adaptations

•  For evaluation on shorter time scale or estimation of peak air flow demand a more detailed calibration of the bio-process model is needed


Thank you for your attention!

Magnus Arnell [email protected]

aeration system modelling – case studies from three full-scale … · 2015. 7. 22. · fit of...

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