期刊
SCIENCE OF THE TOTAL ENVIRONMENT
卷 752, 期 -, 页码 -出版社
ELSEVIER
DOI: 10.1016/j.scitotenv.2020.141919
关键词
Unsaturated zone; Enhanced oxygen supplement; Slow-released organic carbon; Nitrogen removal; DO microelectrode; Bacterial community
资金
- Key Project of Natural Science Foundation of Shandong Province [ZR2018ZC08N4]
- Major Scientific and Technological Innovation Projects of 2019 Key RD Plans [2019JZZY010411]
- Doctoral Natural Science Foundation of Shandong Province [ZR2019BEE020]
- Fundamental Research Funds of Shandong University [11440078614025]
- 64th China Postdoctoral Science Foundation [2018M640633]
- Postdoctoral Innovation Program of Shandong Province, China
The study demonstrated that adding microfiber and slow-release carbon source in the constructed wetland can significantly enhance the efficiency of nitrogen removal, increase the number of microbes, and solve the denitrification efficiency issue caused by low carbon-to-nitrogen ratio.
The partially unsaturated constructed wetland was demonstrated to be able to enhance the oxygen supplement for the microbial nitrification. However, the fast gravity flow of wastewater on the smooth surface of substrate in unsaturated zone led to a short contact time between wastewater and biofilm on the surface of substrate for the microbial pollutant oxidation process. While, the strengthened oxygen supplement also consumed organic carbon, intensifying the shortage of electron donator for the denitrification process. To further enhance the efficiency of both nitrification and denitrification processes, two strategies were conducted as follows: (1) adding microfiber in unsaturated zone to extend the hydraulic retention time (HRT) and improve the oxygenating efficiency; (2) adding slow-release carbon source (Poly butylenes succinate, PBS) as electron donor in saturated zone for denitrification. Results showed that the ammonia oxidation efficiency reached up to 97.0% in the microfiber-enhanced constructed wetland. Additionally, adding microfiber provided more sites for microbes and increased the total number of microbes in unsaturated zone. The addition of PBS in the saturated zone obviously improved the denitrification efficiency with the total nitrogen (TN) removal rate raising from 20.6 +/- 4.0% to 90.4 +/- 2.7%, which excellently solved the problem of poor denitrification efficiency caused by low ratio of carbon to nitrogen (C/N). In conclusion, the association of microfiber and PBS in partially unsaturated constructed wetland finally accomplished the thorough nitrogen removal. (C) 2020 Elsevier B.V. All rights reserved.
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