Microbial denitrification characteristics of typical decentralized wastewater treatment processes based on 16S rRNA sequencing

Shanqian Huang; Yaping Kong; Yao Chen; Xuewen Huang; Pengfei Ma; Xuexin Liu

doi:10.3389/fmicb.2023.1242506

Microbial denitrification characteristics of typical decentralized wastewater treatment processes based on 16S rRNA sequencing

Front Microbiol. 2023 Sep 14:14:1242506. doi: 10.3389/fmicb.2023.1242506. eCollection 2023.

Authors

Shanqian Huang¹, Yaping Kong¹, Yao Chen¹, Xuewen Huang², Pengfei Ma³, Xuexin Liu¹

Affiliations

¹ Center of Environment Protection, China Academy of Transportation Sciences, Beijing, China.
² Anhui Transportation Holding Group CO., LTD., Hefei, China.
³ Qinghai Expressway Maintenance Service CO., LTD., Xining, China.

Abstract

Despite the widespread application of decentralized wastewater treatment (WWT) facilities in China, relatively few research has used the multi-media biological filter (MMBF) facilities to investigate the microorganism characteristics. This study utilizes 16S rRNA high-throughput sequencing (HTS) technology to examine the microbial biodiversity of a representative wastewater treatment (WWT) system in an expressway service area. The pathways of nitrogen removal along the treatment route were analyzed in conjunction with water quality monitoring. The distribution and composition of microbial flora in the samples were examined, and the dominant flora were identified using LEfSe analysis. The FAPROTAX methodology was employed to investigate the relative abundance of genes associated with the nitrogen cycle and to discern the presence of functional genes involved in nitrogen metabolism. On average, the method has a high level of efficiency in removing COD, TN, NH3-N, and TP from the effluent. The analysis of the microbial community identified a total of 40 phyla, 111 classes, 143 orders, 263 families, and 419 genera. The phyla that were predominantly observed include Proteobacteria, Acidobacteria, Chloroflexi, Actinobacteria, Nitrospirae, Bacteroidetes. The results show that the system has achieved high performance in nitrogen removal, the abundance of nitrification genes is significantly higher than that of other nitrogen cycle genes such as denitrification, and there are six nitrogen metabolism pathways, primarily nitrification, among which Nitrospirae and Nitrospira are the core differentiated flora that can adapt to low temperature conditions and participate in nitrification, and are the dominant nitrogen removal flora in cold regions. This work aims to comprehensively investigate the diversity and functional properties of the bacterial community in decentralized WWT processes.

Keywords: 16S rRNA; FAPROTAX; LEfSe; decentralized wastewater treatment; denitrification flora; multi-media biofilter.

Grants and funding

This work was supported by Basic Scientific Research Expenses of Central Public-interest Scientific Institutions (20210603); Science and Technology Program of Gansu Province (21ZD8JA003); National Key Research and Development Program of China (2022YFB2601901); Key Science and Technology Project Inventory of Anhui Provincial Transport Department (2021-KJQD-005); Science and Technology Project of Qinghai Provincial Transport Department (2023–02).