title: Alternate anoxic/aerobic operation for nitrogen removal in a membrane bioreactor for municipal wastewater treatment.
abstract: A large pilot-scale membrane bioreactor (MBR) with a conventional denitrification/nitrification scheme for municipal wastewater treatment has been run for one year under two different aeration strategies in the oxidation/nitrification compartment. During the first five months air supply was provided according to the dissolved-oxygen set-point and the system run as a conventional predenitrification MBR; then, an intermittent aeration strategy based on effluent ammonia nitrogen was adopted in the aerobic compartment in order to assess the impact on process performances in terms of N and P removal, energy consumption and sludge reduction. The experimental inferences show a significant improvement of the effluent quality as COD and total nitrogen, both due to a better utilization of the denitrification potential which is a function of the available electron donor (biodegradable COD) and electron acceptor (nitric nitrogen); particularly, nitrogen removal increased from 67% to 75%. At the same time, a more effective biological phosphorus removal was observed as a consequence of better selection of denitrifying phosphorus accumulating organisms (dPAO). The longer duration of anoxic phases also reflected in a lower excess sludge production (12% decrease) compared with the standard pre-denitrification operation and in a decrease of energy consumption for oxygen supply (about 50%).
authors.affiliation: Department of Civil and Environmental Engineering, University of Trento, 38100 Trento, Italy. giuseppe.guglielmi@etc-eng.it
authors.forename: G
authors.initials: G
authors.lastname: Guglielmi
authors.forename: G
authors.initials: G
authors.lastname: Andreottola
mesh_terms: D000332:Aerobiosis; D000693:Anaerobiosis; D019149:Bioreactors; D002947:Cities; D005374:Filtration; D008567:Membranes, Artificial; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism*; D010100:Oxygen; D010865:Pilot Projects; D014865:Waste Disposal, Fluid / Q000379:methods*
chemical_list: D008567:Membranes, Artificial; D009584:Nitrogen; D010100:Oxygen