Process for purifying organically polluted wastewater

摘要

A process for purifying organically polluted water, e.g. for obtaining drinking water, entails the untreated water being vigorously mixed with ozone in an ozone-treatment unit (2) and subsequently being passed through a filter (4) which is composed of different layers. To optimise the film of microorganisms which forms in the filter, sulphur is metered in, in the form of a compound which is available for assimilation by microorganisms, e.g. a sulphide, between the ozone-treatment unit (2) and the filter (4). The filter (4) preferably consists of an upper layer of filter carbon and an underlying layer of fine sand. Suitable and preferred as assimilable sulphur compound is aqueous sodium sulphide solution (3) or else hydrogen sulphide, sodium sulphite or sodium thiosulphate. An ozone treatment at the end of the process ensures that any traces of bioavailable sulphur are oxidised to the sulphate form.