Fe(II)EDTA Complexation Based Reduction of NO to N2 in an Autotrophic Up-flow Bioreactor with Sponge Iron Bed. Fe(II)EDTA Complexation Based Reduction of NO to N2 in an Autotrophic Up-flow Bioreactor with Sponge Iron Bed

Integrated Fe(II)EDTA absorption and anaerobic ammonia oxidation process can remove NO from flue gas, but Fe(Ⅱ)EDTA was easily oxidized to Fe(Ⅲ)EDTA, which is not capable of binding NO. Regeneration of Fe(Ⅱ)EDTA is the key to this process. A novel autotrophic up-flow bioreactor with sponge iron bed was developed. During 80-day continuous operation of the reactor, NO was almost completely removed, the average removal rate was up to 7.57mM·d-1, and N2O in the outlet gas was lower than the limit of detection. Since part of NO was chemically reduced to NH4+ by sponge iron, the ratio of NO-N removal to NH4+-N consumption was up to 5. Sponge iron work excellently on in-situ regeneration of Fe(II)EDTA, and the average loss rate of Fe(II)EDTA was only 0.190mM d-1.