RBF_Cover (for eps) - National Water Research Institute

Session 5: Dynamics
Temporal Changes of Natural Attenuation Processes
During Bank Filtration
Paul Eckert, Ph.D.
Stadtwerke Düsseldorf AG
Düsseldorf, Germany
Rudolf Irmscher, Ph.D.
Stadtwerke Düsseldorf AG
Düsseldorf, Germany
RBF is a well-proven natural purification step in water supply. Sustainable water management
should be based specifically on natural purification methods, as declared by the International
Association of Waterworks in the Rhine Catchment Area, in their 2003 memorandum. To
achieve this aim, a profound knowledge of the purification capacity of bank filtration is essential.
At the Düsseldorf Waterworks in Germany, the influence of long-term — as well as periodic —
changes of both hydraulics and river-water quality on natural attenuation processes were
investigated.
The improvement of Rhine River water quality over the last 30 years enabled the Düsseldorf
Waterworks to reduce their technical treatment expenses. Temperature variations throughout the
year and flood events significantly influenced the purification capacity of bank filtration. This
reinforces the need for flexible technical treatment methods capable of adapting to changing rawwater
quality.
Even though the complete replacement of subsequent technical treatment steps might be seen as
an unreachable vision, the substantial knowledge we have acquired on the purification capacity
of bank filtration enables the design of tailor-made treatment methods.
Site Description and Treatment Concept
The City of Düsseldorf is situated in northwestern Germany, in the lower Rhine Valley (Figure 1).
The Düsseldorf Waterworks supply 600,000 inhabitants with treated bank filtrate. A multiprotective
barrier concept ensures the constant production of high-quality drinking water (Figure 2).
Natural attenuation processes during bank filtration form the first and most efficient protective
barrier. The subsequent protective barrier is raw-water treatment, including ozonation, biological
active filtration, and active carbon adsorption.
The Rhine River has a length of 1,320 kilometers and a catchment area of 185,000 square kilometers;
it is the third biggest river and the largest source of drinking water in Europe. The mean discharge
of the Rhine at Düsseldorf is 2,200 m 3 /s, while the Waterworks use less than 2 m 3 /s. During flood
events, discharge increases up to 9,900 m 3 /s.
Correspondence should be addressed to:
Paul Eckert, Ph.D.
Head of the Water Management Department
Stadtwerke Düsseldorf AG
Abt. Wasserwirtschaft • Höherweg 100 • 40233 Düsseldorf, Germany
Phone: +0211/8218359 • Fax: +0211/821778359 • Email: peckert@swd-ag.de
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