Abstract
A mathematical model able to simulate the physical, chemical and biological interactions prevailing in multispecies biofilms in the presence of a toxic heavy metal is presented. The free boundary value problem related to biofilm growth and evolution is governed by a nonlinear ordinary differential equation. The problem requires the integration of a system of nonlinear hyperbolic partial differential equations describing the biofilm components evolution, and a systems of semilinear parabolic partial differential equations accounting for substrates diffusion and reaction within the biofilm. In addition, a semilinear parabolic partial differential equation is introduced to describe heavy metal diffusion and sorption. The biosoption process modeling is completed by the definition and integration of other two systems of nonlinear hyperbolic partial differential equations describing the free and occupied binding sites evolution, respectively. Numerical simulations of the heterotrophic-autotrophic interaction occurring in biofilm reactors devoted to wastewater treatment are presented. The high biosorption ability of bacteria living in a mature biofilm is highlighted, as well as the toxicity effect of heavy metals on autotrophic bacteria, whose growth directly affects the nitrification performance of bioreactors.
Highlights
Most of the living microbial communities organize themselves in complex structures where the interaction between different species leads to advantageous environmental conditions for their growth [1,2]
A free boundary problem related to biofim growth and evolution during heavy metal exposition in wastewater treatment plants has been discussed
Numerical results showed the crucial role of heterotrophic bacteria on biosorption processes occurring in wastewater treatment plants
Summary
Most of the living microbial communities organize themselves in complex structures where the interaction between different species leads to advantageous environmental conditions for their growth [1,2]. Many experimental studies demonstrated the possibility of using bacteria to govern heavy metal mobility in different aquatic ecosystems [20,21,22], but additional efforts are still required to completely understand the complex dynamics and interactions occurring between biofilms and heavy metals In this context, mathematical modeling represents an appropriate tool to provide basic information on specific biosorption phenomena and stimulate further research on the multiplicity of mechanisms regulating biosorption process by biofilms [2]. If a macro-scale output is required, as in the case of engineering biofilm reactors, 1D formulations have been recognized as efficient tools to analyze bioreactor performances in terms of biomass accumulation and degradation of substrates [27] To this aim, a 1D mathematical model reproducing a biosorption phenomenon occurring in a typical biofilm reactor devoted to wastewater treatment has been proposed. Numerical simulations remarked on the consistency of the model and showed the effect of toxic heavy metals on different microbial species coexisting in a multispecies biofilm
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
