The enrichment of more functional microbes induced by the increasing hydraulic retention time accounts for the increment of autotrophic denitrification performance

Sicheng Yuan; Qingbo Zhong; Hongjun Zhang; Wentao Zhu; Weibo Wang; Meng Li; Xinhua Tang; Shiyang Zhang

doi:10.1016/j.envres.2023.116848

The enrichment of more functional microbes induced by the increasing hydraulic retention time accounts for the increment of autotrophic denitrification performance

Environ Res. 2023 Nov 1;236(Pt 2):116848. doi: 10.1016/j.envres.2023.116848. Epub 2023 Aug 7.

Authors

Sicheng Yuan¹, Qingbo Zhong¹, Hongjun Zhang¹, Wentao Zhu¹, Weibo Wang², Meng Li¹, Xinhua Tang¹, Shiyang Zhang³

Affiliations

¹ School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China.
² CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, PR China.
³ School of Civil Engineering and Architecture, Wuhan University of Technology, Wuhan, 430070, PR China. Electronic address: zhangshiyang@whut.edu.cn.

PMID: 37558114
DOI: 10.1016/j.envres.2023.116848

Abstract

With pyrite (FeS₂) and polycaprolactone (PCL) as electron donors, three denitrification systems, namely FeS₂-based autotrophic denitrification (PAD) system, PCL-supported heterotrophic denitrification (PHD) system and split-mixotrophic denitrification (PPMD) system, were constructed and operated under varying hydraulic retention times (HRT, 1-48 h). Compared with PAD or PHD, the PPMD system could achieve higher removals of NO₃^--N and PO₄^3--P, and the effluent SO₄^2- concentration was greatly reduced to 7.28 mg/L. Similarly, the abundance of the dominant genera involved in the PAD (Thiobacillus, Sulfurimonas, and Ferritrophicum, etc.) or PHD (Syntrophomonas, Desulfomicrobium, and Desulfovibrio, etc.) process all increased in the PPMD system. Gene prediction completed by PICRUSt2 showed that the abundance of the functional genes involved in denitrification and sulfur oxidation all increased with the increase of HRT. This also accounted for the increased contribution of autotrophic denitrification to total nitrogen removal in the PPMD system. In addition, the analysis of metabolic pathways disclosed the specific conversion mechanisms of nitrogen and sulfur inside the reactor.

Keywords: Hydraulic retention time (HRT); Metabolic pathway; Polycaprolactone; Pyrite; Split-mixotrophic denitrification.

Publication types

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

MeSH terms

Autotrophic Processes
Bioreactors
Denitrification*
Nitrates*
Nitrogen
Sulfur

Substances

Nitrates
Nitrogen
Sulfur