Narrow host range phages infect essential bacteria for water purification reactions in groundwater-fed rapid sand filters

Alejandro Palomo; Arnaud Dechesne; Barth F Smets; Yan Zheng

doi:10.1016/j.watres.2023.120655

Narrow host range phages infect essential bacteria for water purification reactions in groundwater-fed rapid sand filters

Water Res. 2023 Oct 15:245:120655. doi: 10.1016/j.watres.2023.120655. Epub 2023 Sep 20.

Authors

Alejandro Palomo¹, Arnaud Dechesne², Barth F Smets², Yan Zheng³

Affiliations

¹ State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
² Department of Environmental and Resource Engineering, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark.
³ State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Guangdong Provincial Key Laboratory of Soil and Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China; Shenzhen Key Laboratory of Precision Measurement and Early Warning Technology for Urban Environmental Health Risks, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China. Electronic address: yan.zheng@sustech.edu.cn.

PMID: 37748347
DOI: 10.1016/j.watres.2023.120655

Abstract

Biofiltration is used worldwide to provide safe potable water due to its low energy demand and excellent treatment performance. For instance, in Denmark, over 95% of drinking water is supplied through groundwater-fed rapid sand filters (RSF). Bacteriophages, viruses that infect bacteria, have been shown to shape the taxonomic and functional composition of microbial communities across a range of natural and engineering systems. However, phages in the biofiltration systems are rarely studied, despite the central role microbes play in water purification. To probe this, metagenomic data from surface water, groundwater and mixed source water biofiltration units (n = 26 from China, Europe and USA) for drinking water production were analysed to characterize prokaryotic viruses and to identify their potential microbial hosts. The source water type and geographical location are found to exert influence on the composition of the phageome in biofilters. Although the viral abundance (71,676 ± 17,841 RPKM) in biofilters is only 14.4% and 17.0% lower than those of the nutrient-rich wastewater treatment plants and fresh surface waters, the richness (1,441 ± 1,046) and diversity (Inverse Simpson: 91 ± 61) in biofiltration units are significantly less by a factor of 2-5 and 3-4, respectively. In depth analysis of data from 24 groundwater-fed RSFs in Denmark revealed a core phageome shared by most RSFs, which was consistently linked to dominant microbial hosts involved in key biological reactions for water purification. Finally, the high number of specific links detected between phages and bacterial species and the large proportion of lytic phages (77%) led to the conjecture that phages regulate bacterial populations through predation, preventing the proliferation of dominant species and contributing to the established functional redundancy among the dominant microbial groups. In conclusion, bacteriophages are likely to play a significant role in water treatment within biofilters, particularly through interactions with key bacterial species.

Keywords: Bacteriophages; Biofiltration; Drinking water treatment; Functional redundancy; Phage-bacteria interaction.