(EP486578-A1)      Contaminated material such as industrial waste is purified by bacterial action while travelling in a close circuit. Bacteria and waste come into contact in a fixed bed or a rotary drum reactor, after the waste has been moistened, waste water from the process is collected and re-used for moistening. The required breakdown of contaminants is facilitated and accelerated by admixt. with the starting material of activated slugde, e.g. from a standard sewage treatment plant. The sludge may operate aerobically and/or aerobically in one process a first stage is with non-ventilated anaerobic sludge, with the next stage using aerated aerobic sludge. During circulation, the used waste water may pass through a filter or ion-exchanger.    USE/ADVANTAGE -   Used for contaminated gases which possibly after initial purificn. are bubbled through the treatment medium. Initial treatment in a bio-reactor may provide the activated sludge with special factors needed for the envisaged application. Treatment cost is reduced.    (JP4507371-W)      Contaminated material such as industrial waste is purified by bacterial action while travelling in a closed circuit. Bacteria and waste come into contact in a fixed bed or a rotary drum reactor and after the waste has been moistened, waste water from the process is collected and re-used for moistening. The required breakdown of contaminants is facilitated and accelerated by admixture with the starting material of activated sludge, e.g. from a standard sewage treatment plant. The sludge may operate aerobically and/or aerobically in one process a first stage is with non-ventilated anaerobic sludge, with the next stage using aerated aerobic sludge. During circulation, the used waste water may pass through a filter or ion-exchanger. The procedure is also applicable to contaminated gases which possibly after initial purificn. are bubbled through the treatment medium. Initial treatment in a bio-reactor may provide the activated sludge with special factors needed for the envisages application.    ADVANTAGE -   Treatment cost is reduced    (EP486578-B1)      A process for the biological decontamination of polluted material in a closed circuit by means of microorgansims, in which the polluted material is brought onto a treatment surface, irrigated, and treated by the micro-organisms which remove the pollution, and in which the waste water generated is collected and returned for further use in irrigation, the process being characterised by stimulated substances in the form of activated sludge from sewage treatment plants being added to the polluted material on the treatment surface, to be specific sludge from the aerobic treatment basins and/or fresh surplus sludge from the aerobic treatment basin and/or the sludge that is found in the decomposition tower during the fermentation phase.