Nitrate removal in a fixed-film column reactor using Paracoccus denitrificans affected by different carbon sources

Immobilized cells play an important role in removing organic and inorganic compounds taken from domestic sources and industrial plants. Biofilm or fixed film reactors are widespread form of immobilized cells for wastewater treatment. In this paper, a fixed film column reactor was used with Paracoccus denitrificans (hetetrophic microorganisms), which were immobilized on pumice as filling material. Artificial components were used for the preparation of the feeding solution and the effect of different carbon sources (ethanol, methanol, acetic acid, glucose) on the nitrate removal rate was examined. The best nitrate removal rate was observed at the optimum C/N ratio of 3 and with methanol as carbon source.