The work aims towards isolating organisms capable of treating high nitrate wastewater and optimizing the process for maximum denitrification rate. A denitrifying bacterium strain, isolated from the wastewater of a fertilizer denitrification plant (FDP), was screened from a total of 160 isolated cultures based on its high nitrate removal efficiency. Biochemical tests and 16S rDNA sequence analysis showed the bacterium genus to be Pseudomonas and close to aeruginosa species. The culture on acclimatization to high strength nitrate waste [10000 ppm NO3 (2258 ppm NO3-N)] in a sequence batch reactor, showed complete degradation in a time period of just 1.75 h. The specific nitrate and nitrite degradation rate of the process using the acclimatized culture was further increased by 54.4 % and 15 % respectively on optimizing the process using orthogonal array method. The applicability of this isolate for high rate denitrification process was investigated in a 4 L reactor and the two important enzymes involved in the first two steps of denitrification process, NaR and NiR were assayed. This provided an invitro index of the ability of the cells to reduce nitrate and nitrite. The reactor was run successfully for 2 months without any change in the activity.
Nair, Rashmi R. Dr; Dhamole, Pradip B. Dr; and DSouza, Stanislaus Francis Dr
"Nitrate Removal from Synthetic High Nitrate Waste by a Denitrifying Bacterium,"
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy:
Vol. 15, Article 19.
Available at: http://scholarworks.umass.edu/soilsproceedings/vol15/iss1/19