title: An updated process model for carbon oxidation, nitrification, and denitrification.
abstract: The currently available comprehensive activated sludge models, ASM#1 (Grady et al., 1986) and its successor ASM#3 (Gujer et al., 1999), do not adequately describe nitrification and denitrification, with respect to ammonia oxidation inhibition, nitrite accumulation, or emissions of nitric oxide and nitrous oxide. A new comprehensive activated sludge process model, the Activated Sludge Model for Nitrogen (ASMN), is presented. The ASMN incorporates two nitrifying populations-ammonia-oxidizing bacteria and nitrite-oxidizing bacteria-using free ammonia and free nitrous acid, respectively, as their true substrates. The ASMN incorporates four-step denitrification (sequential reduction of nitrate to nitrogen gas via nitrite, nitric oxide, and nitrous oxide) using individual, reaction-specific parameters. Simulation results for ammonia, nitrate, soluble substrate, and biomass concentrations determined by using ASMN for three activated sludge process configurations under steady-state and dynamic municipal-type influent conditions are shown to be comparable with ASM#1 results.
authors.affiliation: SCH2M Hill Inc., Spartanburg, South Carolina, USA.
authors.forename: William C
authors.initials: WC
authors.lastname: Hiatt
authors.forename: C P Leslie
authors.initials: CP
authors.lastname: Grady
mesh_terms: D001419:Bacteria / Q000378:metabolism; D018533:Biomass; D019149:Bioreactors; D002244:Carbon / Q000737:chemistry / Q000378:metabolism*; D002947:Cities; D006863:Hydrogen-Ion Concentration; D008954:Models, Biological; D009569:Nitric Oxide / Q000737:chemistry / Q000378:metabolism; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism*; D009584:Nitrogen / Q000737:chemistry / Q000378:metabolism; D009609:Nitrous Oxide / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D012722:Sewage; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
chemical_list: D009573:Nitrites; D012722:Sewage; D009569:Nitric Oxide; D002244:Carbon; D009609:Nitrous Oxide; D009584:Nitrogen