Water supply and wastewater disposal put to the test in Germany

Germany's sewers are in a terrible state. Approx. 12 billion Euro will have to be found in the next 15 years for operation, maintenance and new construction work.

Corroding pipelines gobble billions / Fraunhofer-ISI suggest two effective alternatives / planning for the next 100 years

Aug. 26, 2003 -- Germany's sewers are in a terrible state. Approx. 12 billion Euro will have to be found in the next 15 years for operation, maintenance and new construction work.

Commissioned by the Westdeutsche Landesbank Foundation Zukunft NRW, the Fraunhofer Institute for Systems and Innovation Research ISI, Karlsruhe, together with water resource management associations, companies and research institutions is searching for alternative systems of urban water supply and wastewater disposal.

The basic concept of today's urban water infrastructure systems (water supply and wastewater) in Germany as in other industrialized countries dates back more than 100 years. Since then the systems have been continuously extended to spreading urban areas, adapted to changing needs of the population served, and to changing requirements with respect to public health and environmental concerns.

"As with an old car, if the costs for repairs and renovations start to increase, you should think about whether to make further investments in the old system or whether a new system would be more sensible in the long term", recommends Dr. Harald Hiessl, project leader at the Fraunhofer-ISI. "We still act as though water simply comes out of the tap. And then it goes down the plughole along the lines of 'out of sight, out of mind'".

The Fraunhofer-ISI and its partners investigated alternative water infrastructure systems in the AKWA 2100 project based on the example of the North Rhine-Westphalian communities of Dortmund-Asseln and Selm-Bork. Dortmund-Asseln represents a heavily built-up, inner town location, Selm-Bork a rural settlement structure with a dense centre.

The researchers developed two long-term scenarios for each community which were compared with the scenario "Continuation!", which corresponds to a continuation of the centralised water supply and sewage disposal practised today.

- In the first alternative scenario, labelled "Municipal Water Reuse" treated wastewater is supplied to households and small businesses via a dual water distribution network providing non-potable water. This non-potable water is used for washing clothes, watering gardens, flushing toilets and the sewer system as well as for process and cooling application in industry and business.

- In the second scenario called "Local Recycling", the scientists make do without the cost-intensive water distribution network and sewer system. Drinking water is prepared from rainwater in a decentralised membrane based process and wastewater is re-used, having passed through a decentralised treatment process.

Applied to the case studies, the scenario "Local Recycling" proved to be the most sustainable, but costs 5 to 15 per cent more than the "Continuation!"-scenario. The "Municipal Water Reuse" scenario also costs about 20 per cent more than "Continuation!", although it performs better from an ecological viewpoint.

Despite the slightly higher costs, the head of the project, Dr. Hiessl, favours the "Local Recycling" scenario. For him, alongside sustainability advantages, its exportability is a decisive factor: "Our present water infrastructure system is not suitable for export because of its high water consumption. If the German water industry wants to keep up internationally, it has to develop ecologically well thought-out and effective concepts and demonstrate them at home" demands Dr. Hiessl.

The detailed description and evaluation of the scenarios are compiled in the book "Alternativen der kommunalen Wasserversorgung und Abwasserentsorgung: AKWA 2100" (Options for sustainable urban water infrastructure systems: AKWA 2100).

It has been published as Volume 53 of the series "Technik, Wirtschaft und Politik" (Technology, Economy and Policy) of the Fraunhofer Institute for Systems and Innovation Research ISI by the Heidelberger Physica publishing house.

The Fraunhofer Institute for Systems and Innovation Research ISI complements the techno-scientific spectrum of the Fraunhofer Society with economic and societal aspects, analysing technological developments, their market potentials and their impacts on economy, state and society. The Institute's interdisciplinary teams focus their work especially on the fields of energy, environment, production, communication and biotechnology, as well as regional research and innovation policy.

For more information, contact Dr. Harald Hiessl at e-mail h.hiessl@isi.fraunhofer.de or Bernd Müller at e-mail b.mueller@isi.fraunhofer.de.

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