Colloid and Microbe Migration in Granular Environments: A Discussion of Modelling Methods

Predicting the migration of colloids (e.g., clays, manufactured nanomaterials, etc) or biocolloids (e.g., bacteria and viruses) in granular porous media is of significant interest in a number of environmental applications such as granular (deep-bed) filtration used in water and wastewater treatment, riverbank filtration (

Medema et al. 2000

),

in-situ

bioremediation (

Steffan et al. 1999

) and protection of groundwater supplies from microbial pathogens and (bio)colloid-associated pollutants (

Ferguson et al. 2003

). Viruses, protozoa (e.g.,

Cryptosporidium

) and certain bacteria are pathogens which may be introduced into the subsurface from various sources such as leaking landfills, septic tanks or land disposal of treated wastewater effluents (

Mawdsley et al. 1995

;

Smith and Perdek 2004

). Growing concerns over widespread groundwater contamination and the potential for bioterrorism attacks to the drinking water supply have further prompted the need to develop improved mathematical models of colloid and biocolloid migration in such settings.