Biodegradation

, Volume 10, Issue 5, pp 315–330

Modeling speciation effects on biodegradation in mixed metal/chelate systems

  • Jeanne M. VanBriesen
  • Bruce E. Rittmann
Article

DOI: 10.1023/A:1008375722721

Cite this article as:
VanBriesen, J.M. & Rittmann, B.E. Biodegradation (1999) 10: 315. doi:10.1023/A:1008375722721

Abstract

A new model, CCBATCH, comprehensively couples microbially catalyzed reactions to aqueous geochemistry. The effect of aqueous speciation on biodegradation reactions and the effect of biological reactions on the concentration of chemical species (e.g. H2CO3, NH4+, O2) are explicitly included in CCBATCH, allowing systematic investigation of kinetically controlled biological reactions. Bulk-phase chemical speciation reactions including acid/base and complexation are modeled as thermodynamically controlled, while biological reactions are modeled as kinetically controlled. A dual-Monod kinetic formulation for biological degradation reactions is coupled with stoichiometry for the degradation reaction to predict the rate of change of all biological and chemical species affected by the biological reactions. The capability of CCBATCH to capture pH and speciation effects on biological reactions is demonstrated by a series of modeling examples for the citrate/Fe(III) system. pH controls the concentration of potentially biologically available forms of citrate. When the percentage of the degradable substrate is low due to complexation or acid/base speciation, degradation rates may be slow despite high concentrations of substrate Complexation reactions that sequester substratein non-degradable forms may prevent degradation or stopdegradation reactions prior to complete substrate utilization. The capability of CCBATCH to couple aqueous speciation changes to biodegradation reaction kinetics and stoichiometry allows prediction of these key behaviors in mixed metal/chelate systems.

biogeochemistry biodegradation modeling coupled processes citrate citric acid 

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Jeanne M. VanBriesen
    • 1
    • 1
  • Bruce E. Rittmann
    • 1
  1. 1.Department of Civil EngineeringNorthwestern UniversityEvanstonUSA