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Multi-scale modeling of biofilm detachment in fluid with a poroviscoelastic model

Applicant Professorin Dr. Insa Neuweiler, since 8/2021
Subject Area Hydrogeology, Hydrology, Limnology, Urban Water Management, Water Chemistry, Integrated Water Resources Management
Term from 2019 to 2025
Project identifier Deutsche Forschungsgemeinschaft (DFG) - Project number 426819984
 
Final Report Year 2024

Final Report Abstract

In this project, a numerical model was developed to predict and to study deformation, detachment and growth processes of biofilm. It built up on the doctoral thesis of the applicant (Dr. Feng), where a growth model for biofilm was developed. In this project, the focus was on the short time scales, the fluid-structure interaction and the detachment. This involved the derivation of a new model concept and a new poroelastic Smoothed Particle Hydrodynamics (SPH) model. More specific: A multidimensional poroelastic fluid-structure interaction (FSI) model was developed based on the weakly compressible SPH method. The model is biphasic by considering the porous material as a mixture of a solid skeleton and the pore liquid inside. Remarkably, although the detailed porous structures are homogenized in the model, different phases of the materials are numerically discretized with different types of elements (particles) which allows transport of the fluid in and out of the porous media freely. Moreover, such a model also allows the change of the porosity of the material locally and adaptively. The model should be applied to study the properties that influence the detachment process. The poroelastic FSI model was set up to investigate the role of the stress field of the bio-material on the deformation and detachment process of a biofilm in a microfluidic channel. Simulation results closely aligned with experimental observations taken from the literature. By further invoking a damage model, the developed model is capable of reproducing several biofilm detachment patterns. The model was also set up for studying the FSI process of heterogeneous porous structure interacting with free surface water. Lacking a biofilm benchmark case, the well-known benchmark problem called ’Dam breaks interact with crushed rock structures’ was investigated. Although this is a problem on very different length scales, it captures the features (poroelastic FSI model) of the biofilm model. Apart from model development, we investigated the bio-chemical behaviour of heterogeneous multispecies biofilms at different time scales. For this purpose, we developed a multi-species biofilm growth model with an example analysis of the Veillonella-S. gordonii symbiotic biofilm system without consideration of detachment and deformation. In the system that was studied, the heterogeneous distribution had a homogenizing effect on the growth. Also, the problem of microbial induced calcite precipitation (MICP) in porous media was studied, which incorporates bacterial growth and decay modeling.

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