Biological denitrification of high nitrate water: Influence of type of carbon source and nitrate loading

An anoxic static bed column was used to investigate the influence of type of carbon source and nitrate loading on the denitrification process of nitrate contaminated drinking water. The system was operated at various nitrate loadings and various carbon sources. The study state system performance using various types of carbon sources was evaluated with respect to the effluent nitrate and nitrite concentrations. Nitrate loadings in the range 0.240 - 1.30 kg NO3-N/m(3).day were investigated. Results of the study have shown that the system should be operated at a maximum nitrate loading of 0.45 kg.NO3-N/m(3).day to treat waters having a nitrate concentration of 500 mg/l to the allowable effluent nitrate and nitrite concentrations. On a stoichiometric basis, ethanol as a substrate for biodenitrification, gave better results as compared with methanol and acetic acid. Methanol also gave very good results with respect to nitrate removal, however, nitrite accumulation problem was evident by the observed high nitrite concentrations in the effluent of the reactor.