Bank Filtration and Aquifer Recharde for Drinking Water Production: Application, Efficiency and Perspectives - An Integration of NASRI outcomes and International Experiences

Zusammenfassung

Bank filtration (BF) and aquifer recharge (AR): aquifer storage recharge (ASR), aquifer storage transport recharge (ASTR); are natural and semi-natural methods for drinking water treatment and constitute a major barrier within water supply system. Recent investigations have shown that about 60 % of Berlin’s drinking water is produced via BF or AR (Zippel & Hannappel 2008). Most drinking water therefore originates from surface waters within the cities limits and is pumped from wells adjacent to it’s many lakes and rivers. Since more than 100 years this system has been supplying safe drinking water so that post-treatment is limited to aeration and subsequent sand filtration. Disinfection is usually not applied (SenStadtUm 2008). The research project NASRI (“Natural and Artificial Systems for Recharge and Infiltration”, KWB 2002 – 2006), funded by the Berliner Wasserbetriebe (BWB) and Veolia (VE) had the aim to characterize the specific hydraulic and hydrochemical conditions at selected BF and AR sites in Berlin and to assess the behaviour of major water constituents, trace organic substances, algal toxins and pathogens during subsurface passage. For this, field investigations at three transsects (Lake Tegel BFsite, Lake Tegel AR-site and Lake Wannsee), laboratory and technical scale experiments were carried out by 7 different working groups. The results of the investigations were documented in 6 extensive research reports and were the basis for nearly 50 scientific publications. In 2007 the IC-NASRI project (Integration & Consolidation of the NASRI outcomes) was initiated by VE and BWB in order to support the practical implementation and optimization of bank filtration and aquifer recharge for drinking water production with the experience gained during the NASRI project. The aim was to derive practical guidelines for design and operation of BF & AR systems by i) further interpretation of the NASRI data and ii) integrating experience from other BF / AR sites world wide. Although subsurface passage is characteristic to many systems of managed aquifer recharge (MAR) the investigations within IC-NASRI concentrated on systems where drinking water is produced by infiltration of surface water either from the banks of a lake / river or from infiltration ponds (or similar systems like ditches or irrigation fields). A transfer of the presented results to other MAR systems, which use different recharge methods (e.g. ASR) or different sources (e.g. treated wastewater) therefore needs to be considered carefully, even though many statements may be true for them as well. This reports aims at providing engineers and scientists involved in drinking water production by BF & AR with up-to-date information on settings of similar systems world wide and on the systems’ performance with regard to drinking water treatment. The aim was to give the reader a condensed overview of the topic whereas further details can be taken from the large number of references given in the bibliography.

Publikation
Kompetenzzentrum Wasser Berlin gGmbH