Active and synchronous control of nitrogen and organic matter release from sediments induced with calcium peroxide

Wen-Huai Wang; Yi Wang; Ke-Xin Zhao; Zheng Zhu; Xue-Yi Han

doi:10.1016/j.scitotenv.2021.149855

Active and synchronous control of nitrogen and organic matter release from sediments induced with calcium peroxide

Sci Total Environ. 2022 Jan 1:802:149855. doi: 10.1016/j.scitotenv.2021.149855. Epub 2021 Aug 24.

Authors

Wen-Huai Wang¹, Yi Wang², Ke-Xin Zhao¹, Zheng Zhu¹, Xue-Yi Han¹

Affiliations

¹ School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China.
² School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, China; Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: wangyi1003@xauat.edu.cn.

PMID: 34455280
DOI: 10.1016/j.scitotenv.2021.149855

Abstract

In order to realize the active and synchronous control of nitrogen (N) and organic matter (OM) release from sediments, this study compared the spatiotemporal changes in the physical, chemical, and biological indicators in the water system under different CaO₂ dosing modes. Results from 90-day incubation experiment showed that CaO₂ formed a dense barrier layer near its dosing position, improved the anoxic condition of water system, increased the physical adsorption of pollutants by sediments, and reduced the nutrients in overlying water, interstitial water, and sediments. Comprehensive comparison, the improvement effect of shallow injection group (I1) was the most obvious. Meanwhile, the activities of ammonia oxidizing bacteria and nitrite oxidizing bacteria near dosing position and those of denitrifiers and anammox bacteria adjacent to dosing site were significantly increased in all test groups (p < 0.01), thereby realizing the biological removal of N and OM in sediments. In addition, DO and ORP were steadily higher than 5 mg L^-1 and 100 mV in I1, where the NH₄⁺-N concentration in overlying water was stable below 1 mg L^-1, and the easily released N content in the upper (0-3 cm) and middle (4-6 cm) sediments decreased by 41.64% and 43.56%, respectively. Compared with the large pollutant flux in control (14.31 TN mg m^-2 d^-1 and 194.05 mg TCOD m^-2 d^-1), I1 completely inhibited the pollutant release and reduced the original nutrients in overlying water. In general, CaO₂ efficiently and synchronously controlled the endogenous release of N and OM under the combined actions of physical interception, physical adsorption, chemical oxidation, and biological transformation. Therefore, this study may provide valuable reference and guidance for the active and synchronous removal of N and OM in sediments and inhibition of endogenous pollutant release under anoxic condition.

Keywords: Active control; Dosing mode optimization; Endogenous release; Microbial transformation; Nitrogen; Organic matter.

MeSH terms

Geologic Sediments
Nitrogen* / analysis
Peroxides
Phosphorus
Water Pollutants, Chemical* / analysis

Substances

Peroxides
Water Pollutants, Chemical
Phosphorus
calcium peroxide
Nitrogen