Enhanced nitrogen and phosphorus removal by a novel ecological floating bed integrated with three-dimensional biofilm electrode system

Qingyu Wu; Yao Chen; Yang He; Qiming Cheng; Qiong Wu; Zhen Liu; Yunqing Li; Zhenmei Yang; Yuqing Tan; Ying Yuan

doi:10.1016/j.jenvman.2023.119346

Enhanced nitrogen and phosphorus removal by a novel ecological floating bed integrated with three-dimensional biofilm electrode system

J Environ Manage. 2023 Dec 15:348:119346. doi: 10.1016/j.jenvman.2023.119346. Epub 2023 Oct 21.

Authors

Qingyu Wu¹, Yao Chen², Yang He¹, Qiming Cheng¹, Qiong Wu¹, Zhen Liu³, Yunqing Li¹, Zhenmei Yang⁴, Yuqing Tan¹, Ying Yuan¹

Affiliations

¹ School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China.
² School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China; Engineering Laboratory of Environmental Hydraulic Engineering of Chongqing Municipal Development and Reform Commission, Chongqing Jiaotong University, Chongqing, 400074, China. Electronic address: chenyao@cqjtu.edu.cn.
³ School of River and Ocean Engineering, Chongqing Jiaotong University, Chongqing, 400074, China; Engineering Laboratory of Environmental Hydraulic Engineering of Chongqing Municipal Development and Reform Commission, Chongqing Jiaotong University, Chongqing, 400074, China.
⁴ Jiangjin Ecological Environment Monitoring Station, Chongqing, 402260, China.

PMID: 37866187
DOI: 10.1016/j.jenvman.2023.119346

Abstract

The ecological floating bed (EFB) has been used extensively for the purification of eutrophication water. However, the traditional EFB (T-EFB) often exhibits a decline in nitrogen and phosphorus removal because of the limited adsorption capacity of fillers and inadequate electron donors. In the present study, a series of electrolysis-ecological floating beds (EC-EFBs) were constructed to investigate the decontamination performance of conventional pollutants. EC-EFB outperformed T-EFB in terms of nitrogen and phosphorus removal. Its removal efficiency of total nitrogen and total phosphorus was 20.51-32.95% and 45.06-96.20%, which were higher than that in T-EFB.. Moreover, the plants in EC-EFB demonstrated higher metabolic activity than those in T-EFB. Under the electrolysis condition of 0.51 mA/cm² for 24 h, the malondialdehyde content and superoxide dismutase activity in EC-EFB were 6.08 nmol/g and 22.61 U/g, which were significantly lower compared to T-EFB (38.65 nmol/g and 26.13 U/g). And the soluble protein content of plant leaves increased from 3.31 mg/g to 5.72 mg/g in EC-EFB. Microbial analysis revealed that electrolysis could significantly change the microbial community and facilitate the proliferation of nitrogen-functional microbes, such as Thermomonas, Hydrogenophaga, Deinococcus, and Zoogloea. It is important to highlight that the hydrogen evolution reaction at the cathode area facilitated phosphorus removal in EC-EFB, thereby inhibiting phosphorus leaching. This study provides a promising and innovative technology for the purification of eutrophic water.

Keywords: Biofilm; Ecological floating bed; Electrochemical; Nutrient removal; Plant.

MeSH terms

Biofilms
Nitrogen*
Phosphorus*
Water

Substances

Nitrogen
Phosphorus
Water