The water treatment technology used most often in Denmark to convert groundwater into drinking water is aeration and filtration for removal of iron, manganese and ammonium. This is a chemical-free and natural process using just compressed air as the oxidation media. This treatment method is now also used in Hungary for the 12.000 inhabitants of Tolna, a city 135 km south of Budapest.

The new waterworks has a good working environment with no wastewater problems and safe and easy operation, and the citizens now enjoy superior drinking water free of chemicals. This is a break with tradition, because as all drinking water in Hungary has previously been treated using sand filters and chemicals - the Tolna waterworks is the very first that has stopped adding chemicals.