Service-lines as major contributor to water quality deterioration at customer ends

Jiaxing Fang; Zihan Dai; Xiaoming Li; Jan Peter van der Hoek; Dragan Savic; Gertjan Medema; Walter van der Meer; Gang Liu

doi:10.1016/j.watres.2023.120143

Service-lines as major contributor to water quality deterioration at customer ends

Water Res. 2023 Aug 1:241:120143. doi: 10.1016/j.watres.2023.120143. Epub 2023 May 30.

Authors

Jiaxing Fang¹, Zihan Dai², Xiaoming Li², Jan Peter van der Hoek³, Dragan Savic⁴, Gertjan Medema⁵, Walter van der Meer⁶, Gang Liu⁷

Affiliations

¹ Key Lab of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, PR China; Membrane Science and Technology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500, AE, Enschede, the Netherlands; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600, GA, Delft, the Netherlands.
² Key Lab of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, PR China.
³ Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600, GA, Delft, the Netherlands; Waternet, P.O. Box 94370, 1090, GJ Amsterdam, the Netherlands.
⁴ KWR Water Research Institute, P.O. Box 1072, 3430, BB, Nieuwegein, the Netherlands; Centre for Water Systems, University of Exeter, Exeter EX4 4QF, United Kingdom; University of Belgrade, Faculty of Civil Engineering, Department for Hydraulic and environmental engineering, Bulevar kralja Aleksandra 73, Belgrade, Serbia.
⁵ Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600, GA, Delft, the Netherlands; KWR Water Research Institute, P.O. Box 1072, 3430, BB, Nieuwegein, the Netherlands; Department of Fisheries and Wildlife, Michigan State University, East Lansing, MI, 48823, USA.
⁶ Membrane Science and Technology, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500, AE, Enschede, the Netherlands; Oasen Water Company, PO BOX 122, 2800, AC, Gouda, the Netherlands.
⁷ Key Lab of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 100085, Beijing, PR China; Sanitary Engineering, Department of Water Management, Faculty of Civil Engineering and Geosciences, Delft University of Technology, P.O. Box 5048, 2600, GA, Delft, the Netherlands. Electronic address: gliu@rcees.ac.cn.

PMID: 37276656
DOI: 10.1016/j.watres.2023.120143

Abstract

Biofilm detachment contributes to water quality deterioration. However, the contributions of biofilm detachment from different pipes have not been quantified or compared. Following the introduction of partial reverse osmosis (RO) in drinking water production, this study analyzed particles at customers' ends and tracked their origins to water distribution mains and service lines. For doing so, filter bags were installed in front of water meters to capture upstream detached particles, while biofilm from water main and service line were sampled by cutting pipe specimens. The results showed that elemental concentrations of the biofilm in mains were higher than those of service lines (54.3-268.5 vs. 27.1-44.4 μg/cm²), both dominated by Ca. Differently, filter bags were dominated by Fe/Mn (77.5-98.1%). After introducing RO, Ca significantly decreased in biofilms of mains but not service lines, but the released Fe/Mn rather than Ca arrived at customers' ends. The ATP concentrations of service lines were higher than mains, which decreased on mains but increased in service lines after introducing RO. For the core ASVs, 13/24 were shared by service lines (17), mains (21), and filter bags (17), which were assigned mainly to Nitrospira spp., Methylomagnum spp., Methylocytis spp., and IheB2-23 spp. According to source tracking results, service lines contributed more than mains to the particulate material collected by filter bags (57.6 ± 13.2% vs. 13.0 ± 11.6%). To the best of our knowledge, the present study provides the first evidence of service lines' direct and quantitative contributions to potential water quality deterioration at customers' ends. This highlights the need for the appropriate management of long-neglected service line pipes, e.g., regarding material selection, length optimization, and proper regulation.

Keywords: Biofilm detachment; Drinking water distribution systems; Microbial source tracking; Particle-associated bacteria; Service line.

MeSH terms

Bacteria
Biofilms
Drinking Water*
Water Microbiology
Water Quality*
Water Supply

Substances

Drinking Water