VOLATILE FATTY-ACIDS AS ORGANIC-CARBON SOURCES IN DENITRIFICATION

We have evaluated the possibilities of waste water denitrification usi ng volatile fatty acids (VFA) as the sole carbon and electron source i n an activated sludge culture continuously fed with a mixture of aceta te, propionate, butyrate and valerate. All the VFA were biodegraded in denitrification conditions by a mixed adapted bacterial population wi th 5 predominant different bacterial strains (Ochrobactrum anthropi, M oraxella lacunata, Pseudomonas testosteroni, Paracoccus denitrificans, and Pasteurella gr. EF4). The denitrification (20 mg N-NO(x) g-1 MES h-1) and carbon consumption rates (60 mg C g-1 MES h-1) obtained in ba tch conditions were the same for acetate, butyrate, valerate used alon e or for a mixture of the 4. Propionate was almost not metabolized (3 mg N-NO(x) g-1 MES h-1 and 8 mg C g-1 MES h-1).