title: Optimization of a mainstream nitritation-denitritation process and anammox polishing.
abstract: This paper deals with an almost 1-year long pilot study of a nitritation-denitritation process that was followed by anammox polishing. The pilot plant treated real municipal wastewater at ambient temperatures. The effluent of high-rate activated sludge process (hydraulic retention time, HRT=30 min, solids retention time=0.25 d) was fed to the pilot plant described in this paper, where a constant temperature of 23 °C was maintained. The nitritation-denitritation process was operated to promote nitrite oxidizing bacteria out-selection in an intermittently aerated reactor. The intermittent aeration pattern was controlled using a strategy based on effluent ammonia and nitrate+nitrite concentrations. The unique feature of this aeration control was that fixed dissolved oxygen set-point was used and the length of aerobic and anoxic durations were changed based on the effluent ammonia and nitrate+nitrite concentrations. The anaerobic ammonia oxidation (anammox) bacteria were adapted in mainstream conditions by allowing the growth on the moving bed bioreactor plastic media in a fully anoxic reactor. The total inorganic nitrogen (TIN) removal performance of the entire system was 75±15% during the study at a modest influent chemical oxygen demand (COD)/NH4+-N ratio of 8.9±1.8 within the HRT range of 3.1-9.4 h. Anammox polishing contributed 11% of overall TIN removal. Therefore, this pilot-scale study demonstrates that application of the proposed nitritation-denitritation system followed by anammox polishing is capable of relatively high nitrogen removal without supplemental carbon and alkalinity at a low HRT.
authors.affiliation: Brown and Caldwell, 1600 Duke Street, Suite 310, Alexandria, VA 22314, USA E-mail: pregmi@brwncald.com; pregm001@gmail.com.
authors.forename: Pusker
authors.initials: P
authors.lastname: Regmi
authors.affiliation: Hazen and Sawyer, P.C., New York, NY, USA.
authors.forename: Becky
authors.initials: B
authors.lastname: Holgate
authors.affiliation: Hazen and Sawyer, P.C., New York, NY, USA.
authors.forename: Dana
authors.initials: D
authors.lastname: Fredericks
authors.affiliation: Civil and Environment Engineering Department, Virginia Tech, Blacksburg, VA 24060, USA.
authors.forename: Mark W
authors.initials: MW
authors.lastname: Miller
authors.affiliation: ARA Consult, Innsbruck, Austria.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wett
authors.affiliation: DC Water Authority, 5000 Overlook Ave. SW, Washington, DC 20032, USA.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Murthy
authors.affiliation: Hampton Roads Sanitation District, 1436 Air Rail Ave., Virginia Beach, VA 23455, USA.
authors.forename: Charles B
authors.initials: CB
authors.lastname: Bott
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D000693:Anaerobiosis; D001419:Bacteria / Q000378:metabolism; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors; D009566:Nitrates / Q000378:metabolism*; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D010865:Pilot Projects; D012722:Sewage / Q000032:analysis; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D000641:Ammonia; D009566:Nitrates; D009573:Nitrites; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical