Dissolved organic nitrogen derived from wastewater denitrification: Composition and nitrogenous disinfection byproduct formation.

Abstract

Microbially derived dissolved organic nitrogen (mDON) is a major fraction of effluent total nitrogen at wastewater treatment plants with enhanced nutrient removal, which stimulates phytoplankton blooms and formation of toxic nitrogenous disinfection by-products (N-DBPs). This study identified denitrifiers as major contributors to mDON synthesis, and further revealed the molecular composition, influential factors and synthetic microorganisms of denitrification-derived mDON compounds leading to N-DBP formation. The maximum mDON accumulated during denitrification was 8.92% of converted inorganic nitrogen, higher than that of anammox (4.24%) and nitrification (2.76%). Sodium acetate addition at relatively high C/N ratio (5-7) favored mDON formation, compared with methanol and low C/N (1-3). Different from acetate, methanol-facilitated denitrification produced 13-69% more lignin-like compounds than proteins using Orbitrap LC-MS. The most abundant N-DBPs formed from denitrification-derived mDON were N-nitrosodibutylamine and dichloroacetonitrile (13.32 μg/mg mDON and 12.21 μg/mg mDON, respectively). Major amino acids, aspartate, glycine, and alanine were positively correlated with typical N-DBPs. Biosynthesis and degradation pathways of these N-DBP precursors were enriched in denitrifiers belonging to Rhodocyclaceae, Mycobacteriaceae and Hyphomicrobiaceae. As intensive disinfection is applied at worldwide wastewater treatment plants during COVID-19, carbon source facilitated denitrification should be better managed to reduce both effluent inorganic nitrogen and DON, mitigating DON and N-DBP associated ecological risks in receiving waters.

• Authors: Jie Wang, Fang Zheng, Zhaoniao Yu, Jinrong Chen, Huijie Lu
• Journal: Journal of hazardous materials (J Hazard Mater) Vol. 440 Pg. 129775 (10 15 2022) ISSN: 1873-3336 [Electronic] Netherlands
• PMID: 35994914 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2022 Elsevier B.V. All rights reserved.

Chemical References

• Dissolved Organic Matter
• Waste Water
• Water Pollutants, Chemical
• Aspartic Acid
• Sodium Acetate
• Carbon
• Lignin
• Nitrogen
• Alanine
• Glycine
• Methanol

Topics

• Alanine
• Aspartic Acid
• COVID-19
• Carbon
• Denitrification
• Disinfection
• Dissolved Organic Matter
• Glycine
• Humans
• Lignin
• Methanol
• Nitrogen (chemistry)
• Sodium Acetate
• Wastewater (analysis)
• Water Pollutants, Chemical (analysis)
• Water Purification