[Removal of microorganisms by soil filters for bathing ponds].

"Bathing ponds" are artificial outdoor water pools without disinfection. Whereas in conventional pools, chlorine promptly kills pathogens shed by bathers, such quick inactivation is missing in bathing ponds. We have explored the retention of indicator bacteria and viruses by a vertically operated, reed grown soil filter.

[The drinking water ordinance--successful or requiring revision?].

The current regulatory approach in Germany combines regulations defined in the Drinking Water Ordinance with a comprehensive catalogue of technical rules as well as with guidelines and recommendations by the Federal Environment Agency and the Drinking Water Commission. This approach has proven successful in practice. Some parts would benefit from revision.

The effect of groundwater composition on uranium(VI) sorption onto bacteriogenic iron oxides.

In this study, we investigated the effect of groundwater composition on the sorption of U(VI) onto bacteriogenic iron oxides (BIOS) and synthetic ferrihydrite (HFO). The concentration of carbonate was found to be the key factor controlling U(VI) sorption onto both BIOS and HFO. However, the efficiency of HFO to adsorb uranium(VI) was higher than that of BIOS at pH 7.

Removal of microcystins by slow sand filtration.

To assess the elimination potential of slow sand filters for cyanobacterial hepatotoxins (microcystins), two full-scale experiments were conducted using the German Federal Environment Agency's experimental field in Berlin, Germany. One experiment was carried out with dissolved microcystins extracted from a cyanobacterial bloom on one of Berlin's lakes, dosed as short-term, single-pulse application. The other experiment simulated natural conditions more closely, with a longer-term exposure of the filter to living cyanobacterial cells (collected from the same lake) so that most toxins were initially contained inside the cells.