Nitrogen and sulfide removal from effluent of UASB reactor in a sequencing fed-batch biofilm reactor under intermittent aeration

• Published in: Journal of biotechnology Vol. 164; no. 3; pp. 378 - 385
• Main Authors: Moraes, B.S., Orrú, J.G.T., Foresti, E.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 10-04-2013
• Subjects: aeration; Aerobiosis; ammonium compounds; anaerobic conditions; autotrophs; Bacteria - metabolism; biofilm; Biofilms; Bioreactors; denitrification; Effluents; Feeding; Immobilized cells; Nitrates - metabolism; Nitrification; Nitrites - metabolism; nitrogen; Nitrogen - metabolism; oxidation; Oxidation-Reduction; Quaternary Ammonium Compounds - metabolism; Reactors; Sequencing; Sequencing fed-batch reactor; Simultaneous nitrification/denitrification; Strategy; Sulfide-oxidizing autotrophic denitrification; Sulfides; Sulfides - metabolism; upflow anaerobic sludge blanket reactor; Waste Disposal, Fluid; Water Pollutants, Chemical - metabolism; Sequencing fed-batch reactor; Immobilized cells; Sulfide-oxidizing autotrophic denitrification; Simultaneous nitrification/denitrification
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/j.jbiotec.2012.06.032

► Nitrogen and sulfide removal from effluent of UASB reactor treating domestic sewage. ► Sequencing fed-batch biofilm reactor under intermittent aeration for post-treatment. ► Start-up and feeding strategies for simultaneous nitrification/denitrification. ► Lower nitrification efficiency in favorable autotrophic denitrification conditions. ► Elemental sulfur accumulation and requirement of external alkalinity addition.
Simultaneous nitrification/denitrification (SND) coupled with sulfide oxidation may be suitable for the post treatment of effluents from anaerobic reactors. These effluents contain ammonium, which must be nitrified, and sulfide, which could be used as an endogenous electron donor for autotrophic denitrification. The SND process occurred in a sequencing fed-batch biofilm reactor of 8h cycles, operated under intermittent aeration. The effect of the start-up period and the feeding strategy were evaluated. The previous establishment of nitrification process with subsequent application of sulfide in low concentrations was the best start-up strategy to enable the occurrence of SDN. The fed-batch mode with sulfide application in excess only in the anoxic periods was the best feeding strategy, providing average efficiencies of 85.7% and 53.0% for nitrification and denitrification, respectively. However, the low overall nitrogen removal efficiency and some operational constraints indicated that autotrophic denitrification using sulfide in a single SBR was not suitable for SND under the assayed conditions.