title: Optimization of operating parameters of intermittent aeration-type activated sludge process for nitrogen removal: a simulation-based approach.
abstract: Biological nitrogen removal is becoming a proven approach to reducing the total nitrogen discharged from wastewater treatment facilities. Simulation performed with intermittent aeration-type activated sludge process using Activated Sludge Model No. 1 predicted that up to 90% total nitrogen removal could be attained when the total cycle time and its anoxic phase were balanced adequately. This control limits electron donor and acceptor levels--ammonia-nitrogen (NH4(+)-N) in the aerobic phase and nitrate-nitrogen (NO3(-)-N) in the anoxic phase. Specifically, maximum nitrogen removal appears to be achieved with a 2- to 3-hour cycle time, during which, anoxic conditions were present for 40 to 50% of the time. A 10- to 16-hour hydraulic retention time appears adequate to achieve these results. The solids retention time studied was between 15 and 25 days, as this range was deemed sufficient to establish the nitrifying organism population in most applications. Predictions indicate that the conventional activated sludge system can be retrofitted for better nitrogen management at the treatment plants.
authors.affiliation: Mississippi State University, 47A Rakhal Das Auddy Road, Calcutta 700 027, India. ayan1973@gmail.com
authors.forename: Ayanangshu
authors.initials: A
authors.lastname: Dey
authors.forename: Dennis D
authors.initials: DD
authors.lastname: Truax
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Magbanua
mesh_terms: D000641:Ammonia / Q000737:chemistry; D003198:Computer Simulation; D008956:Models, Chemical; D009584:Nitrogen / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014867:Water / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
chemical_list: D012722:Sewage; D014867:Water; D000641:Ammonia; D009584:Nitrogen; D010100:Oxygen