Dissolved organic nitrogen in wastewater treatment processes: Transformation, biosynthesis and ecological impacts

Fang Zheng; Jie Wang; Rui Xiao; Wenbo Chai; Defeng Xing; Huijie Lu

doi:10.1016/j.envpol.2021.116436

Dissolved organic nitrogen in wastewater treatment processes: Transformation, biosynthesis and ecological impacts

Environ Pollut. 2021 Jan 6:273:116436. doi: 10.1016/j.envpol.2021.116436. Online ahead of print.

Authors

Fang Zheng¹, Jie Wang¹, Rui Xiao¹, Wenbo Chai¹, Defeng Xing², Huijie Lu³

Affiliations

¹ Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, 310058, Hangzhou, China.
² State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China.
³ Key Laboratory of Environment Remediation and Ecological Health, Ministry of Education, College of Environmental Resource Sciences, Zhejiang University, 310058, Hangzhou, China; State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, 150090, China. Electronic address: luhuijie@zju.edu.cn.

PMID: 33493760
DOI: 10.1016/j.envpol.2021.116436

Abstract

With the upgrade of wastewater treatment plants (WWTPs) to meet more stringent discharge limits for nutrients, dissolved organic nitrogen (DON) is present at an increasing percentage (up to 85%) in the effluent. Discharged DON is of great environmental concern due to its potentials in stimulating algal growth and forming toxic nitrogenous disinfection by-products (N-DBPs). This article systematically reviewed the characteristics, transformation and ecological impacts of wastewater DON. Proteins, amino acids and humic substances are the abundant DON compounds, but a large fraction (nearly 50%) of DON remains uncharacterized. Biological treatment processes play a dominant role in DON transformation (65-90%), where DON serves as both nutrient and energy sources. Despite of the above progress, critical knowledge gaps remain in DON functional duality, relationship with dissolved inorganic nitrogen (DIN) species, and coupling/decoupling with the dissolved organic carbon (DOC) pool. Development of more rapid and accurate quantification methods, modeling transformation processes, and assessing DON-associated eutrophication and N-DBP formation risks should be given priority in further investigations.

Keywords: Biosynthesis; Dissolved organic nitrogen; Ecotoxicity; Transformation; Wastewater treatment.

Publication types

Review