Assessment of the potential for the use of service water in Frankfurt am Main

The aim of the project is to determine the potential demand for service water in Frankfurt am Main and at the same time to show ways how this demand can be met. Service water can be used for those commercial, industrial, agricultural, and domestic purposes for which drinking water quality is not absolutely necessary. In addition to rainwater, river water, local groundwater and slightly polluted wastewater (so-called “greywater”) are considered as water sources from which service water can be obtained. Based on different development scenarios for the period of investigation until 2050, a theoretical substitution potential for drinking water is to be estimated. On the basis of these results, further supply areas of Hessenwasser GmbH & Co. KG can be examined.

Research approach

The initial situation requires a practice-oriented and scientifically sound approach, which must be based on a substantiated data basis giving details on the various partial water consumptions as well as plausible assumptions under consideration of the analysis of earlier studies and considerations on drinking water substitution in the supply area. For two urban districts, the potential demand for service water and alternative supply options are estimated. Subsequently, their ecological and socio-economic effects will be identified. Based on this subspatial assessment, the results will then be transferred to the entire urban area and discussed by means of implementation scenarios up to 2050. In order to capture the specification of possible development corridors, social framework conditions (particularly settlement and social-structural ones) as well as economic, ecological, technical and (monetary-)political conditions have to be taken into account. Other potential developments and influencing factors also have to be considered for the analysis of the water infrastructure. Within the framework of a CO2 footprint analysis, the aim is to estimate reliable parameters for the status quo and for novel water systems.

Background

About one third of Frankfurt‘s drinking water comes from local extraction plants: Hessisches Ried and Vogelsberg. Climate change and demographic developments will lead to a future demand for drinking water exceeding current peak demand levels. Without additional measures for extraction, transport and storage as well as for water procurement, there could be restrictions in the drinking water supply during peak load periods. However, not all water requirements depend on drinking water quality. Whether in households, commerce or industry: In order to conserve groundwater resources, service water can be used as an alternative to drinking water for certain purposes. It has to be kept in mind, though, that the effects of simultaneous provision of drinking water and service water are not yet known.

In order to ensure a long-term resource-saving supply of water for the growing metropolitan region, it is important to create new and regional knowledge bases, to examine previous approaches and to weigh up alternatives. Water infrastructure requires far-sighted planning. This also includes identifying changes at an early stage and developing possible adaptation scenarios.