Germany has taken a lead on action to remove micropollutants from municipal wastewater. The state of Baden-Württemberg is at the forefront of that experience, and has recently seen its biggest plant yet come on line in Mannheim. Keith Hayward heard from Steffen Metzger, head of the state’s centre of expertise for micropollutants, about progress and the latest aspects under investigation.
With countries increasingly considering how to act on the issue of micropollutants in municipal wastewater, the German state of Baden-Württemberg has been continuing to progress its now well-established efforts. It already has installations in place in 11 of its wastewater treatment plants, according to expert Dr Steffen Metzger. He heads the state’s centre of expertise for micropollutants, Kompetenzzentrum Spurenstoffe Baden-Württemberg, or KomS BW. These installations include the recent addition of the state’s largest yet, in the city of Mannheim, with further developments on the way.
‘So far, there is still no legal requirement for wastewater treatment plants to build the additional stage for targeted micropollutant removal,’ explains Metzger. Even so, a number of municipalities have made this move, with the Ministry of Environment, Climate and Energy of Baden-Württemberg covering part of the investment costs. Provision of micropollutant removal has now reached a population equivalent of more than two million people, with the state’s total population standing at just over ten million.
‘The measures to eliminate micropollutants which have been taken in Baden-Württemberg up until now are more of a consensus between the plant operators and the authorities,’ continues Metzger. This has meant a focus on the use of treatment based on powdered activated carbon to adsorb the micropollutants. Most plants have been able to operate existing sandfilters to ensure the carbon is not released in the treated effluent. Two of the plants have had cloth filters added for this purpose. Importantly, the carbon and the bound micropollutants leave the plants in the waste sludge stream and are subsequently destroyed by incineration. ‘In Baden-Württemberg, it is not allowed to use the sewage sludge in agriculture anymore,’ explains Metzger. ‘The largest part of the sludge will be burnt and a few large wastewater treatment plants, such as those of Karlsruhe, Stuttgart and Ulm, operate their own sewage sludge incineration facility.’
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- Germany, KomS BW, sewage treatment, micropollutants, activated carbon