Study On No Biogolcal Removal Coupled With The Absorption By Fe^Ⅱ (EDTA)

Nitrogen oxides (NOx) are major atmospheric pollutants. Biofiltration has more advantages over traditional methods for NO control. However, there are major drawbacks of existent biofilters like the uneven distribution of nutrients, excess of biomass and meida clogging. To deal with these problems, an innovative biofilter, namely, the rotaing drum biofilter (RDB) has been developed and become a new effective technique to control waster gas. The poor NO solubility in water limits the NO mass transfer in bioreactor, so that the application of biological treatment is also limited.In the present investigation, development of a new integrated system for the complete treatment of NO from flue gases was described. The treatment system consisted of NO absorption (from gas to liquid phase) by FeⅡ(EDTA) and a denitrification process in RDB. Effects of different parameters on NO removal were studied with the addition of FeⅡ(EDTA). Effects of different factors on bio-reduction of FeⅡ(EDTA)NO and FeⅢ(EDTA) were studied.Experimental results indicated that while 1.3 mmol/L FeⅡ(EDTA) was added NO removal efficiency increased from 60.11% to 94.67% and elimination capacity from 16.29 mg/(m3·h) to 26.79 mg/(m3·h). Study on reactions in RDB indicated that FeⅡ(EDTA) acting as an activator in NO elimination.Study on bio-reduction of FeⅡ(EDTA)NO indicated that glucose was a favorite carbon source and electron donor for bio-reduction of FeⅡ(EDTA)NO. Over-adding of glucose proved useless for FeⅡ(EDTA)NO reduction. Maximal reduction rate occurred when temperature was 40℃and pH 7. Recuction rate of FeⅡ(EDTA)NO increased with the increase of initial FeⅡ(EDTA)NO concentration. FeⅡ(EDTA)NO reduction rate increased while FeⅡ(EDTA) was added and decreased while FeⅢ(EDTA) was added.Study on bio-reduction of FeⅢ(EDTA) indicated that glucose was a favorite carbon source and electron donor and NH4Cl nitrogen source for bio-reduction of FeⅡ(EDTA)NO. Over-adding of glucose and NH4Cl proved useless for FeⅡ(EDTA)NO reduction. Maximal reduction rate occurred when temperature was 40℃and pH between 6 and 7. Recuction rate of FeⅢ(EDTA) increased with the increase of initial FeⅢ(EDTA) concentration while decreased when FeⅡ(EDTA) and FeⅢ(EDTA) was added. Adding of SO42- proved little effect on FeⅡ(EDTA)NO reduction while adding 15 mmol/L SO32- obviously restrained FeⅡ(EDTA)NO reduction. FeⅡ(EDTA)NO reduction rate decreased when NO2- on concentration increased.