ABSTRACT
Adsorption of animal viruses to natural surfaces is a common phenomenon. In fact, most viruses in the environment exist in the adsorbed state. Invasion of a host by viruses is initiated by its adsorption to the host's mucous membranes. Adsorption to natural materials has been a major topic, sometimes implicitly, of several reviews of the literature on the fate and persistence of viruses. The major forces and properties that determine adsorption of viruses to natural surfaces and other colloids are well known. Adsorption isotherms are useful in expressing results of virus adsorption experiments. Of the various expressions the Freundlich isotherm has proven the most appropriate in many cases. Association of viruses in sewage to allochthonous or activated sludge solids has been noted by several workers, but no information on the mechanisms has been given. Anthracite coal is used as natural filter material in water and advanced wastewater treatment plants.
