BKG Water Solutions

Düsseldorf, Germany

BKG Water Solutions

Düsseldorf, Germany
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Braun G.,Cologne University of Applied Sciences | Hater W.,BKG Water Solutions | Kolk C.z.,BKG Water Solutions | Dupoiron C.,BKG Water Solutions | And 2 more authors.
Desalination | Year: 2010

In reverse osmosis systems with high silica water severe and irreversible membrane scaling can be observed. But suitable test methods to find an appropriate antiscalant agent and the optimal dosage are missing. Usually only the silicate concentration in the feed water is regarded. In this paper the results of laboratory experiments about the influence of Ca2+- and Mg2+-ions on the behaviour of supersaturated solutions of silica in different test waters are discussed first. After that the new developed membrane-based test method to determine the effectiveness of antiscalants is presented. The applied different methods of analysis enabled the differentiation of three groups of silicates: 'monomeric', 'polymeric' and 'filterable'. With the test method the strong impact of silicate scaling was proven, even if only small amounts of scale had been formed. It could be shown, that the 'polymeric silica' is mainly responsible for the membrane scaling. The kinetic of the formation of 'polymeric silica' is strongly influenced by the cations and the pH-value. It could be demonstrated that the use of a suitable antiscalant makes it possible to operate the plant at significantly higher recovery rates. © 2009 Elsevier B.V. All rights reserved.


Hater W.,BKG Water Solutions | Kolk C.Z.,BKG Water Solutions | Dupoiron C.,BKG Water Solutions | Braun G.,Cologne University of Applied Sciences | And 2 more authors.
Desalination and Water Treatment | Year: 2011

Scaling calculations are usually only based on the silicate concentration in the feed water, because suitable test methods for the interaction of silica with other ions are missing. As the contents of the other ions, i.e. above all calcium and magnesium are not considered, this method is incorrect and can lead to substantial problems. In this paper first the results of laboratory experiments investigating the influence of different cations on the behaviour of supersaturated solutions of silica in different test waters are discussed. Subsequently, the results of the new membrane-based test method considering the influence of Ca2+ and Mg2+, the pH value and the addition of antiscalants are discussed. Different methods of analysis made it possible to distinguish three groups of silicates: 'monomeric', 'polymeric' and 'filterable'. Ca2+ and Mg2+ ions have a strong influence on the formation of filterable silicate and on the kinetics of the formation of the different silicate species. The 'polymeric silica' is mainly responsible for the membrane scaling, and the kinetic of its formation is strongly influenced by the cations and the pH value. The antiscalant Osmotech 1309 makes it possible to operate the plant at significantly higher recovery rates, resp. at higher SiO2 concentrations. © 2011 Desalination Publications. All rights reserved.

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