Shortcut nitrification-denitrification coupled with sulfide oxidation in a single reactor

Abstract

Nitrogen removal coupled with sulfide oxidation may be a suitable option for the post-treatment of anaerobic reactor effluents that contain ammoniacal nitrogen, which must be nitrified, and sulfide, which could be used as an endogenous electron donor for autotrophic denitrification. This research proposes the application of shortcut nitrification-denitrification coupled with sulfide oxidation in a single reactor to remove nitrogen from effluents of anaerobic reactors treating domestic sewage.A fixed-bed sequencing batch reactor (FBSBR) was used, operating in 8-hour cycles, subjected to intermittent aeration and employing autotrophic denitrification using the sulfide present in the effluent, pretreated anaerobically, as an electron donor.Nitrite accumulation was observed after application of the sulfide shock load, which inhibited the nitriteoxidizing bacteria.However, it was difficult to establish denitrification via nitrite due to the toxicity of this compound to denitrifying microorganisms in the reactor.The low overall efficiency of nitrogen removal and various operational constraints indicated that autotrophic denitrification using sulfide in the FBSBR was not satisfactory.© 2014 de S Moraes B, et al.