Risk of L. pneumophila with heating networks

Effect of heating networks

Current expectations are that heating networks will play a major role in the energy transition for the transportation of sustainable heat. At the same time, like climate change, these heating networks may result in the heating up of drinking water in the mains system and/or drinking water plants. This could lead to an increase in numbers of pathogenic microorganisms. An example is the opportunistic pathogen Legionella pneumophila. The installation of heating networks therefore requires striking a balance between the importance of sustainable energy and potential public health risks.

From conceptual model to risk estimation

In this project, a qualitative microbiological risk analysis is being conducted to determine the effect of using heating networks for domestic connections on the number of patients with L. pneumophila. In addition, we are using this analysis to identify knowledge gaps in the reliable estimation of risks of this kind.

A conceptual model will first be established to identify all the factors that have an effect on the growth of L. pneumophila in the drinking water environment and the infection of humans, as well as the relationships between those factors. On the basis of this conceptual model, a desk study will be conducted to search for information about the main factors determining this growth and infection, and the effect that heating networks have on them. Finally, that information will be used to run through different scenarios for the use of heating networks in order to qualitatively determine the risk of L. pneumophila.

Heating networks and public health

The project provides information that can be used to engage in discussions with stakeholders about the risk of contracting Legionnaires’ disease when heating networks are used that lead to the warming up of drinking water. This process will consist of the following steps:

• A first step towards determining the risk of heating networks resulting in infection with L. pneumophila when people drink water from a drinking water plant.
• On that basis (in consultation with the RIVM), a rough estimate will be made of how the number of cases of Legionnaires’ disease will develop if heating networks are scaled up.
• The identification of knowledge gaps to reliably determine the above risk and recommendations for research to remedy these knowledge gaps.