Abstract: Contaminated water is contacted with an agent which contains salts or cations of mono-, di-, or trivalent metals in a maximum amount of 50 masspercent and rock granules containing at least 25 masspercent zeolite, preferably clinoptilolite and/or mordenite. The amount of metal salts respectively cations present in the parent zeolitic rock can be increased according to necessity by ion-exchange, adsorption and/or impregnation, i.e. by combination of these processes following eventual dehydration. The agent obtained is homogenized. The exhausted bed can be regenerated biologically or with aqueous solution of a potassium salt.

Abstract: The invention serves for conditioning and sterilization of sludges originating from sewage treatment plants, and from water preparing plants, respectively, in such a manner, that both the homogenization and the mixing with coagulating agent of the sludge as well as the flotation separation of solid phase are carried out by ultrasonic treatment, while the microorganisms, among them also the pathogene ones, are decomposed. The conditioning agent added in the final phase of the ultrasonic treatment of a few minutes is metallic salt in case of biological sludges, and polyeletrolyte in case of sludges containing chemicals.