期刊
JOURNAL OF HAZARDOUS MATERIALS
卷 440, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.jhazmat.2022.129775
关键词
Dissolved organic nitrogen; Nitrogenous disinfection byproducts; Amino acids; Metagenomics; Orbitrap LC-MS
资金
- Key Research and Development Program of Zhejiang [2022C03075]
- Fundamental Research Funds for the Central Universities [226-2022-00084]
Denitrifiers were identified as major contributors to mDON synthesis, and the molecular composition, influential factors, and synthetic microorganisms of denitrification-derived mDON compounds leading to N-DBP formation were further revealed, elucidating the composition of mDON and its impact on N-DBP.
Microbially derived dissolved organic nitrogen (mDON) is a major fraction of effluent total nitrogen at waste-water 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 mu g/mg mDON and 12.21 mu g/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.
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