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“Lead in drinking water” – This age-long issue is typically associated with old lead piping in residential installations and does not pose a problem today. The installation of lead pipes has been prohibited in Germany since as far back as the 1970s. Recent decades have seen other materials put to use when refurbishing old buildings. At the same time, the limit value for lead in drinking water in

Germany has been progressively lowered, with today’s limit of 10 μg/L having been introduced in 2013.
Lead does not only occur in lead piping, however. It can also be naturally found in ground water; an issue that impacts other countries aside from Germany. Indeed, this phenomenon is a global concern and the result of naturally occurring lead-bearing rock layers.
For those water suppliers reliant on the use of clean raw water to produce drinking water, removing lead content is a challenging prospect. Any failure to permanently and reliably remove the lead has negative consequences for families living in households in the area concerned.

A chemical acidification process is typically used to remove lead from raw water: This involves passing the water through granulated calcium carbonate or a dolomite filter material and binding the free carbonic acid. At higher pH values, the dissolved lead precipitates as insoluble lead hydroxide or lead carbonate, and is filtered off. Despite this process having proved its worth in the past, its limitations come to light when very low lead concentrations need to be achieved and the pH value cannot be raised too high. In these situations, the best option is to specifically remove the lead using a ferric hydroxide adsorbent.

Since July 2021, GEH®102, a granular ferric hydroxide produced by the GEH Wasserchemie company, has been used under real conditions for exactly this purpose at a waterworks in a town located in the west of Germany. In the course of a so-called extended efficacy test (erweiterte Wirksamkeitsprüfung (EWP)) conducted under the leadership of the German Environment Agency (Umweltbundesamt), the effective removal of lead was proven and evaluated by an expert.

After six months of operation, it is now possible to draw an initial conclusion. The capacity of this GEH® Granular Ferric Hydroxide has been successfully corroborated; and it achieved an outstanding lead retention value. The lead was removed to below the analytical limit of detection of <1 μg/L. At the same time, it should be emphasised that the GEH® adsorber is fed in together with raw water exhibiting an especially high lead content of 100 μg/L and a pH value of 5.7 in order to test its efficacy under the most unfavourable conditions imaginable. During the second phase, scheduled to occur in the summer of 2022, its actual operation as a “policing filter” after the deacidification phase will be tested. Whilst it remains to be seen what outcomes the second trial phase will bring, it is to be expected that, following the success of the initial trial phase, GEH® 102 will again pass with flying colours.

To learn more, please read the press releases issued by the town of Mechernich: https://www.mechernich.de/…