BMWi-Verbundvorhaben: Aufbereitung von Grundwässern mit erhöhtem Sulfatgehalt: Innovative Optionen und Grenzen eines ressourcen- und energieeffizienten Trinkwassermanagements

Project Acronym
Project Title
BMWi-cooperation project: Treatment of groundwater with increased sulfate concentration: innovative options and limits of resource and energy efficient drinking water management (SULEMAN)
Principal Investigator
Project Abstract
Water suppliers have to deal with increasing sulfate concentrations in ground water and bank filtrate used for drinking water production. There are several reasons for the increase of sulfate concentration.

- Shut-down and flooding of open brown coal pits cause increased sulfate concentration in surface water. From the surface water, sulfate can migrate into near-surface groundwater that is used for drinking water production

- Increasing concentrations of nitrate and the related oxidation of pyrite in pyrite dominated extraction sites result in oxidation of sulfide to sulfate with consequential effects on the ground water quality

- Deep groundwaters, as present in northern German extraction sites, are partially in exchange with salt domes (especially gypsum) and therefore enrich sulfate

The limit value for sulfate in drinking water is at 250 mg/L as prescribed in the German Drinking Water Regulation and must be strictly adhered by all drinking water suppliers.

Within the project commercially available technologies (low pressure reverse osmosis LPRO, ion exchange process CARIX) are tested regarding energetically optimized, sustainable sulfate removal for the treatment of different raw waters for drinking water application. In Hamburg, deep and salty ground waters (anaerobic before and aerobic after deferrization) are tested, in Berlin near-surface bank filtrate is treated.

Results from semi-technical scale (plant capacities ca. 1 m³/h) are extrapolated regarding available literature data and are compared through ecological (life cycle assessment) and economical assessment. Evaluation criteria are amongst others specific energy consumption, application behavior and sustainability of each technology under varying raw water compositions.

Beyond the industrially available technologies LPRO and CARIX a commercial Polymer-UF-Membrane is post modified by a novel coating process and thus optimized for the target substance sulfate. This innovative technology of Capillary-NF runs at low operating pressures compared to the state of the art processes and will therefore be able to realize operation at lower energy demand for the treatment of waters with increased sulfate concentration. The experiments are run in parallel to the LPRO and CARIX trials in technical scale. The operation data of the Capillary-NF are regarded in the ecological assessment and are critically compared with results of LPRO and CARIX.