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Combining Computational Fluid Dynamics with a Biokinetic Model for Predicting Ammonia and Phosphate Behavior in Aeration Tanks
Author(s) -
Zima Piotr,
Makinia Jacek,
Swinarski Marek,
Czerwionka Krzysztof
Publication year - 2009
Publication title -
water environment research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.356
H-Index - 73
eISSN - 1554-7531
pISSN - 1061-4303
DOI - 10.2175/106143009x407294
Subject(s) - aeration , wastewater , nitrification , dispersion (optics) , tracer , pollutant , phosphate , chemistry , advection , environmental engineering , bioreactor , environmental science , thermodynamics , nitrogen , physics , organic chemistry , nuclear physics , optics
The aim of this study was to use computational fluid dynamics for predicting the behavior of reactive pollutants (ammonia and phosphate) in the aerobic zone of the bioreactor located at the Wschod wastewater treatment plant in Gdansk, Poland. The one‐dimensional advection‐dispersion equation was combined with simple biokinetic models incorporating the Monod‐type expressions as source terms for the two pollutants. The problem was solved numerically by a multi‐step splitting technique algorithm. The dispersion coefficient, E L , was estimated using a statistical method and numerical optimization based on experimental data from three tracer studies. With the first method, the values of E L varied within the range 1082 to 1860 m 2 /h and 695 to 1355 m 2 /h, respectively, in sections 1 and 2 of the aerobic zone. Except for one case, deviations of the corresponding numerically optimized values of E L did not exceed 14%. The maximum specific rates of nitrification [ r n,max,20 = 4.6 g N/(kg VSS·h)] and phosphate uptake [r Pupt,max,20 = 13.5 g P/(kg VSS·h)] at T = 20°C were determined based on laboratory batch experiments. With minor adjustments of the kinetic parameters, the model was capable of accurately predicting the longitudinal profiles of ammonia and phosphate in the aerobic zone, and the simulation results were presented using the actual horizontal geometry of the bioreactor as a background.