EN
The paper presents results of the microbiological research on the biological membrane of anaerobic packed-bed reactors (including pathogens) and post-culture effluent in the cultures of denitrifying bacteria in the medium containing: nitrates from ground water and ethanol, sodium acetate or methanol in the hybrid system biological denitrification-ultrafiltration. First, the most effective and safe source of carbon and energy in the cultures of denitrifying bacteria was determined, and subsequently, the post-culture effluent was subjected to ultrafiltration. Methanol has proved to be the most effective source of carbon. Pathogenic bacteria and bacteria which reduce sulphates have not been found in this culture.