title: Toward Universal Half-Saturation Coefficients: Describing Extant K(s) as a Function of Diffusion.
abstract: Observed (extant) K(s) is not a constant and it is strongly influenced by diffusion. This paper argues that diffusion can be used to describe bacterial kinetic effects that are sometimes attributed to "K-strategists" and, in fact, the physics of the system is the dominant mechanism affecting the apparent (extant) Ks--not intrinsic biological characteristics--in real water resource recovery facility systems. Four different biological processes have been modeled using the "porter-diffusion" model that was originally developed by Pasciak and Gavis (1974) for aquatic systems. The results demonstrate that diffusion is the dominant mechanism affecting K(s) in all four biological processes. Therefore, the authors argue that for treatment processes in which substrate concentrations are low, it is important to consider shifting to variable extant K(s) values or explicitly modeling the effects of diffusion.
authors.forename: Andrew
authors.initials: A
authors.lastname: Shaw
authors.forename: Imre
authors.initials: I
authors.lastname: Takacs
authors.forename: Krishna
authors.initials: K
authors.lastname: Pagilla
authors.forename: Rumana
authors.initials: R
authors.lastname: Riffat
authors.forename: Haydee
authors.initials: H
authors.lastname: DeClippeleir
authors.forename: Christopher
authors.initials: C
authors.lastname: Wilson
authors.forename: Sudhir
authors.initials: S
authors.lastname: Murthy
mesh_terms: D019149:Bioreactors; D007700:Kinetics; D008954:Models, Biological; D064091:Waste Disposal Facilities; D014865:Waste Disposal, Fluid / Q000379:methods; D014874:Water Pollutants, Chemical / Q000737:chemistry*
chemical_list: D014874:Water Pollutants, Chemical