process for the impregnation of the filter material with metal li and metal compounds to catalytic action and bactericidal and bacteria.

摘要

A filter pad, of the type combining coarse and fine fibres with the pores filled with silica gel or some other material of very high specific surface area, is impregnated with aqs. soln. of a salt of a metal in the 2nd to the 6th periods of the periodic table; these salts are practically insoluble in the liq. to be filtered, pref. taking the form of hydroxides or oxides of metals such as silver, copper, chromium, which have a bactericidal effect as well as promoting adbsorption of unpleasant tastes and flavours. The pad provides an economical combination of filtration and biological treatment for small scale drinking water supplies.