University of Oulu

Elisangela Heiderscheidt, Axumawit Tesfamariam, Hannu Marttila, Heini Postila, Stefano Zilio, Pekka M. Rossi, Stable water isotopes as a tool for assessing groundwater infiltration in sewage networks in cold climate conditions, Journal of Environmental Management, Volume 302, Part B, 2022, 114107, ISSN 0301-4797, https://doi.org/10.1016/j.jenvman.2021.114107

Stable water isotopes as a tool for assessing groundwater infiltration in sewage networks in cold climate conditions

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Author: Heiderscheidt, Elisangela1; Tesfamariam, Axumawit1; Marttila, Hannu1;
Organizations: 1Water, Energy and Environmental Engineering Research Unit, Faculty of Technology, P.O. Box 4300, FI-90014, University of Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 2.5 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2021122262970
Language: English
Published: Elsevier, 2022
Publish Date: 2021-12-22
Description:

Abstract

Effective identification and quantification of groundwater (GW) infiltration into sewage collection networks represents an important step towards sustainable urban water management. In many countries, including northern regions, sewage networks are aging to the point where renovation is needed. This study focused on the utilization of stable water isotopes as tracer substances for GW infiltration detection. The main objectives were to investigate the validity of the method for quantifying GW infiltration in cold climate conditions and to test the robustness of this method under assumed low GW infiltration rates. In general, the stable water isotopes (δ¹⁸O) produced reliable results regarding origin identification and quantification of GW infiltration rates in winter conditions (continuous below zero temperatures and snow accumulation during preceding months). The 1.6‰ distinction between the δ¹⁸O isotope composition signals of the two water sources (drinking water from river and groundwater) in the studied network was sufficient to allow source separation. However, a larger distinction would reduce the uncertainties connected to GW-fraction identification in situations where low GW infiltration rates (<8%) are expected. Due to the climate conditions (no surface water inflow), GW infiltration to the network branch monitored represented the totality of I/I (infiltration/surface inflow) flows and was estimated to reach a maximum daily rate of 6.5%. This being substantially lower than the 29% yearly average I/I rate of ca 29% reported for the city's network. Overall, our study tested the stable water isotope method for GW infiltration detection in sewage networks successfully and proved the suitability of this method for network assessment in cold climate conditions. Isotope sampling could be part of frequent monitoring campaigns revealing potential infiltration and, consequently, the need for renovation.

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Series: Journal of environmental management
ISSN: 0301-4797
ISSN-E: 1095-8630
ISSN-L: 0301-4797
Volume: 302
Issue: Part B
Article number: 114107
DOI: 10.1016/j.jenvman.2021.114107
OADOI: https://oadoi.org/10.1016/j.jenvman.2021.114107
Type of Publication: A1 Journal article – refereed
Field of Science: 212 Civil and construction engineering
218 Environmental engineering
Subjects:
Funding: This study was mainly supported by the project “Älykkäät vesiprosessit ja monitorointi”, funded by the European development fund (ERDF) program via Business Finland (ie Tekes) and writing was supported by water supply tenure position funding from Maa-ja vesitekniikan tuki ry (MVTT), Finnish Water Utilities Association (FIWA), and Pohjois-Suomen vesivaliokunta (OUKE).
Copyright information: © 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
  https://creativecommons.org/licenses/by/4.0/