BACKGROUND: The ongoing emission of nitric oxide (NO) is a serious persistent environmental problem, because it contributes to atmospheric ozone destruction and global warming. A novel and effective system was developed for the complete treatment of NO from flue gases. The system features NO absorption by FeII(EDTA) and biological denitrification in a rotating drum biofilter (RDB). RESULTS: After 100 mg L1 FeII(EDTA) was added to the nutrient solution, the results show that the NO removal efficiency was improved from 70.56% to 80.15%, the optimal temperature improved from 32.5 degrees C to 40.5 degrees C, and the pH improved from 7.5 to 8.08.3. A maximum NO removal efficiency of 96.5% was achieved when 500 mg L1 FeII(EDTA) was used in the nutrient solution. CONCLUSION: This experiment demonstrates that FeII(EDTA) could not only improve the mass transfer efficiency of NO from gas to liquid, but also serve as an electron donor for the biological reduction of NO to N2. The new integrated treatment system seemed to be a promising alternative for the complete treatment of NO from flue gases. (c) 2012 Society of Chemical Industry