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1.6b Decision support for sustainable management of infiltration and inflow to wastewater systems


Water from infiltration and inflow or I/I-water is all water in pipes for sanitary sewage that is not sanitary sewage. This water can consist of, for example, stormwater intentionally or unintentionally connected to the system or leaking groundwater. I/I-water contributes to the need for more water to be treated but can also cause basement flooding and discharge of untreated sewage into lakes and watercourses.

 How much I/I-water can we accept, and how much resources should be allocated to rebuilding current systems to manage negative consequences?

Expected outcome

In this project, we tackle the challenge from a socio-economic perspective and create a model that can serve as a basis for decision-making. We use, among other things, cost-benefit analysis where the benefits and costs associated with I/I-water and measures to reduce I/I-water are estimated. In addition to including purely economic aspects, we also consider other costs to society, such as inconvenience due to basement flooding and environmental consequences of discharge into watercourses.

 Other important parts of the project include analyzing how different system boundaries affect the results and how and in what way measurements in the sewage network should be made to achieve the greatest positive effect.

Societal impact

  • Reduced costs for municipalities, society, and the environment.
  • A holistic perspective on inflow water management.
  • Decision support method that can be integrated into the operations of Swedish municipalities.