title: Fate of dissolved organic nitrogen during biological nutrient removal wastewater treatment processes.
abstract: Due to its potential to form toxic nitrogenous disinfection byproducts (N-DBPs), dissolved organic nitrogen (DON) is considered as one of the most important parameters in wastewater treatment plants (WWTP). This study describes a comprehensive investigation of variations in DON levels in orbal oxidation ditches. The results showed that DON increased gradually from 0.71 to 1.14 mg I(-1) along anaerobic zone, anoxic zone, aerobic zone 1 and aerobic 2. Molecular weight fractionation of DON in one anaerobic zone and one aerobic zone (aerobic zone 2) was performed. We found that the proportion of small molecular weight (<6 kDa) decreased and large molecular weight (> 20 kDa) showed opposite trend. This variation may have been caused due to the release of different types of soluble microbial products (SMPs) during biological processes. These SMPs contained both tryptophan protein-like and aromatic protein-like substances, which were confirmed by three-dimensional excitation-emission matrix (EEM) analysis.
authors.forename: Bing
authors.initials: B
authors.lastname: Liu
authors.forename: Huirong
authors.initials: H
authors.lastname: Lin
authors.forename: Guozhong
authors.initials: G
authors.lastname: Yu
authors.forename: Shenghua
authors.initials: S
authors.lastname: Zhang
authors.forename: Chengmei
authors.initials: C
authors.lastname: Zhao
mesh_terms: D058465:Nitrification; D009584:Nitrogen / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D014874:Water Pollutants, Chemical; D009584:Nitrogen