Processes in Pathogenic Biocolloidal Contaminants Transport in Saturated and Unsaturated Porous Media: A Review

Abstract

There are several classes of subsurface colloids, abiotic and biotic.

Bacteriophages as Surrogates for the Fate and Transport of Pathogens in Source Water and in Drinking Water Treatment Processes

“…the layer between the land surface and the groundwater table) where much of the subsurface contamination originates, passes through, or can be eliminated before it contaminates surface and subsurface water resources has gained particular attention in recent years. In unsaturated conditions, additional and more complex mechanisms are involved in pathogen transport such as: variability in ionic strength , pH and water content, particle capture at the water-gas interface, particle capture at the solid-water-gas interface, and preferential flow or retention in the immobilization zone (Sen, 2011). Biological processes such as growth and decay, active attachment or detachment, survival, random mobility and chemotaxis are also believed to strongly affect virus transport in saturated and unsaturated porous media (Sen, 2011).…”

“…In unsaturated conditions, additional and more complex mechanisms are involved in pathogen transport such as: variability in ionic strength , pH and water content, particle capture at the water-gas interface, particle capture at the solid-water-gas interface, and preferential flow or retention in the immobilization zone (Sen, 2011). Biological processes such as growth and decay, active attachment or detachment, survival, random mobility and chemotaxis are also believed to strongly affect virus transport in saturated and unsaturated porous media (Sen, 2011). Less information is available regarding the fate of pathogenic protozoa in the vadose zone (Harvey et al, 1995;Hancock et al, 1998;Brush et al, 1999;Harter et al, 2000;Darnault et al, 2004;, however, the physico-chemical processes that affect virus fate and transport also apply to protozoan cysts and oocysts during soil transport, albeit to a different extent .…”

“…Due to the proximity of groundwater to sources of microbial contamination, the increasing occurrence of extreme climate events and the lack of adequate disinfection, groundwater is responsible for a large percentage of the waterborne outbreaks of disease worldwide (WHO, 2004;2011). For example, between 1999 and 2000, 72% of drinking water outbreaks of disease were associated with groundwater.…”

“… As viral models and tracers, bacteriophages are often used at both field and laboratory scales as biocolloids to estimate the fate and transport of pathogenic viruses in surface and subsurface aquatic environments and through natural and manmade saturated and unsaturated porous media. This use of phage as surrogates for pathogen transport applies to protection of surface and groundwater supplies from microbial contamination, assessment of potential health risk from pathogens in groundwater and design of more efficient treatment systems in removing pathogens from drinking water supplies (Sen, 2011).…”

Transport of E. coli in Presence of Naturally Occuring Colloids in Saturated Porous Media

“…The biological components, in aquifers, primarily the microbes, had been delivering the valued ecosystem services of water purification at high quality for centuries [2]. However, the present scenario of groundwater faces increasing threats from anthropogenic activities [3], that comprises contamination with pathogenic microorganisms and viruses [4]. Hence, there is an increased risk for human health from pathogen-contaminated groundwater that makes it unfit and unsafe for consumption.…”