Modeling the formation of microorganism-derived dissolved organic nitrogen (mDON) in the activated sludge system. (1st May 2020)

• Record Type: Journal Article
• Authors: Hu, Haidong; Liao, Kewei; Xie, Wenming; Wang, Jinfeng; Wu, Bing; Ren, Hongqiang
• Is Part Of: Water research. Volume 174(2020)
• Publication Date: 2020-05-01
• Subjects: Mathematical model -- Dissolved organic nitrogen -- Microbial products -- Activated sludge systems -- Wastewater treatment; Water -- Pollution -- Research -- Periodicals; 363.7394
• DOI: 10.1016/j.watres.2020.115604
• Languages: English
• ISSNs: 0043-1354

Abstract

Abstract: Microorganism-derived dissolved organic nitrogen (mDON) represents a significant and inevitable portion of dissolved organic nitrogen (DON) in the wastewater biotreatment processes. In the existing method, mDON concentrations are indirectly measured by the values of DON concentrations from the reactors with DON-free influent. However, this becomes problematic when influent contains DON. Especially when the real wastewater is involved, the paucity of the direct methods to quantitatively measure mDON is a major barrier to further research. This limitation is due to the difficulty of segregating mDON from the other nitrogenous organics, e.g., influent DON. In this study, we propose the ASM-mDON model based on ASM #1, which incorporates the production and consumption of mDON in the activated sludge processes to predict the mDON concentrations. In four independent lab-scale tests, our model was established and calibrated to obtain the accurate values of mDON (R 2 = 0.929, p < 0.05), and the validity and applicability of the model were successfully examined by comparing the simulated and measured data. Moreover, the universality of the ASM-mDON model was further confirmed by simulating mDON production in a full-scale wastewater treatment plant. A reasonable prediction of mDON formation was shown in a full-scale test (1.98 ± 0.71 mg/L in June and 1.51 ± 0.54 mg/L in July) and is indirectly supported by an algal bioassay ( p < 0.05, t -test). This study provides a useful approach to the efficient and accurate evaluation of mDON formation, which will improve current strategies designed to minimize the effluent mDON in wastewater bioprocesses. Graphical abstract: Image 1 Highlights: Production and consumption of microorganism-derived dissolved organic nitrogen is incorporated into the conventional models. Microorganism-derived dissolved organic nitrogen formation is accurately quantified (R 2 = 0.929, p < 0.05). Microorganism-derived dissolved organic nitrogen is correctly simulated under various operational conditions. A useful tool is provided for controlling strategies and further research.