MNMs: a model for the simulation of depth filtration of non-Newtonian suspensions in granular media

MNMs is a software (www.polito.it/groundwater/software) able to simulate transport, attachment/detachment processes and clogging occurring during depth filtration in granular porous media. The software was developed in the framework of the FP7 NANOREM project with the aim of simulating the transport of non-Newtonian suspensions of micro- and nanoparticles in saturated porous media (e.g. aquifer systems). Colloid transport mechanisms are controlled by particle-collector and particle-particle interactions, modelled by a non equilibrium kinetic model accounting for deposition and release processes. The key aspects included in MNMs are: influence of water chemistry (changes in ionic strength), clogging phenomena (i.e. reduction of porosity and permeability due to particles deposition), and the rheological properties of the carrier fluid. The influence of colloid transport on porosity, permeability, and fluid viscosity is explicitly lumped into the model by a modified Darcy law generalized for non Newtonian fluids. MNMs was used for the simulation of: (i) clogging processes and pressure buildup during depth filtration [2,3], (ii) distribution of micro- and nanoscale iron particles suspended in shear thinning fluids for the remediation of contaminated aquifer systems [2,3], (iii) attachment and detachment of colloidal particles under variable ionic strength [1].