Simultaneous removal of atrazine and nitrate using a biological granulated activated carbon (BGAC) reactor

The objective of this research was to characterize the performance of granulated activated carbon (GAC) as a carrier for Pseudomonas ADP in a non‐sterile continuous fluidized bed reactor for atrazine degradation under anoxic conditions. The GAC was compared with two non‐adsorbing carriers: non‐adsorbing carbon particles (‘Baker product’) having the same surface area available for biofilm growth as the GAC, and sintered glass beads. The initial atrazine degradation efficiency was higher than 90% in the reactors with the non‐adsorbing carriers, but deteriorated to 20% with time due to contamination by foreign denitrifying bacteria. In contrast, no deterioration was observed in the biological granulated activated carbon (BGAC) reactor. A maximal atrazine volumetric and specific degradation rate of 0.820 ± 0.052 g atrazine dm−3 day−1 and 1.7 ± 0.4 g atrazine g−1 protein day−1 respectively were observed in the BGAC reactor. Concurrent atrazine biodegradation and desorption from the carrier was shown and an effluent concentration of 0.002 mg dm−3 (below the EPA standard) was achieved in the BGAC reactor. The advantages of the BGAC reactor over the non‐adsorbing carrier reactors can probably be explained by the adsorption–desorption mechanism providing favorable microenvironmental conditions for atrazine–degrading bacteria. Copyright © 2004 Society of Chemical Industry