Tertiary denitrification and organic matter variations of secondary effluent from wastewater treatment plant by the 3D-BER system

Shan Huang; Yuan Lu; Xin Li; Yongze Lu; Guangcan Zhu; Mahdi Hassan

doi:10.1016/j.envres.2020.109937

Tertiary denitrification and organic matter variations of secondary effluent from wastewater treatment plant by the 3D-BER system

Environ Res. 2020 Oct:189:109937. doi: 10.1016/j.envres.2020.109937. Epub 2020 Jul 15.

Authors

Shan Huang¹, Yuan Lu², Xin Li³, Yongze Lu⁴, Guangcan Zhu⁵, Mahdi Hassan⁶

Affiliations

¹ School of Energy and Environment, Southeast University, Nanjing, 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: 18270911541@163.com.
² School of Energy and Environment, Southeast University, Nanjing, 210096, China; Huatian Engineering & Technology Corporation, Nanjing, Jiangsu, 210019, China. Electronic address: 542079600@qq.com.
³ School of Energy and Environment, Southeast University, Nanjing, 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: lix@seu.edu.cn.
⁴ School of Energy and Environment, Southeast University, Nanjing, 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: yzlu@seu.edu.cn.
⁵ School of Energy and Environment, Southeast University, Nanjing, 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: gc-zhu@seu.edu.cn.
⁶ School of Energy and Environment, Southeast University, Nanjing, 210096, China; State Key Laboratory of Environmental Medicine Engineering, Ministry of Education, Southeast University, Nanjing, Jiangsu, 210096, China. Electronic address: engrmahdi@gmail.com.

PMID: 32678745
DOI: 10.1016/j.envres.2020.109937

Abstract

A three-dimensional biofilm-electrode reactor (3D-BER) was constructed to facilitate the tertiary denitrification of the secondary effluent of wastewater treatment plants (SEWTP) under 12 mA and in the absence of a carbon source. The TN removal efficiency was 63.8%. The path of the formation and transformation of nitrogen, the relationship between the TN and COD removal rate and the relative concentration and composition of organic matter in the influent and effluent were analyzed to clarify the possible pathways of N and C transformation in the 3D-BER system. Under the action of an electric current, 4.4 mg NH₄⁺-N·L^-1 and 17.7 mg COD·L^-1 accumulated in the 3D-BER system, and the removal rates of TN and COD were strongly and positively correlated (R² = 0.9353). The microorganisms in the 3D-BER system under the action of electric current secreted organic matter, some of which (humic acid and microbial metabolites) could be further electrolyzed by microorganisms into bioavailable organic matter for heterotrophic denitrification. Partially dissolved organic matter (DOM, tryptophan aromatic protein, humic acid and microbial metabolites) in the SEWTP could be hydrolyzed under the action of the electric current in the 3D-BER system and consisted of bioavailable organic matter for heterotrophic denitrification. The contribution of heterotrophic denitrification to TN removal was greater than 11.7%. Therefore, the 3D-BER system removed a portion of DOM through microbial electrohydrolysis and promoted the coupling of hydrogen autotrophic denitrification and heterotrophic denitrification to enhance the effectiveness of nitrogen removal in SEWTP. Overall, this technique is effective for enhancing tertiary denitrification in SEWTP.

Keywords: 3D-BER; DOM; Heterotrophic denitrification; Hydrogen autotrophic denitrification; The secondary effluent of wastewater treatment plants.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Autotrophic Processes
Bioreactors
Denitrification*
Nitrogen / analysis
Wastewater
Water Purification*

Substances

Waste Water
Nitrogen