American Society of Civil Engineers


Speciation and Chemical Interactions in Nitrifying Biofilms. II: Sensitivity Analysis


by Edna M. C. V. Flora, (Grad. Student, Dept. of Civ. and Envir. Engrg., Univ. of Cincinnati, Cincinnati, OH 45221-0071), Makram T. Suidan, M.ASCE, (Prof. of Envir. Engrg., Dept. of Civ. and Envir. Engrg., Univ. of Cincinnati, Cincinnati, OH), Joseph R. V. Flora, (Assoc. Prof. of Envir. Engrg., Dept. of Civ. and Envir. Engrg., Univ. of South Carolina, Columbia, SC 29208), and Byung J. Kim, (Res. Engr., U.S. Army Constr. Engrg. Res. Lab., Champaign, IL 61820)

Journal of Environmental Engineering, Vol. 125, No. 9, September 1999, pp. 878-884, (doi:  http://dx.doi.org/10.1061/(ASCE)0733-9372(1999)125:9(878))

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Document type: Journal Paper
Abstract: Steady-state models of nitrifying biofilms have been developed that take into account the mass transfer of neutral and ionic species, electroneutrality, pH-dependent Monod kinetics, chemical equilibrium, and the presence of a boundary layer. Under the conditions investigated, the models predict significant changes in the biomass speciation and percent conversions in nitrifying biofilms as functions of pH, buffer capacity [in terms of total inorganic carbons], and, for the reactor models, volumetric flow rate per unit surface area of biofilm and total ammonium loading. To a lesser extent, the models also predict sensitivity to biofilm thickness, total ammonium, total nitrite, dissolved oxygen concentration, and total biomass density. Nitrogen conversions are only a very weak function of boundary layer thickness, total nitrate concentration, and the ratio of the chemical species’ diffusivity in the biofilm to its diffusivity in water.


ASCE Subject Headings:
Biofilm
Biomass
Chemicals
Effluents
Models
Nitrification
Sensitivity analysis