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Pharmaceuticals in wastewater purified by nature

We urinate out and flush down large amounts of medications every day. The amount of pharmaceutical residues in our wastewater is increasing at a dangerous pace, as the treatment plants only partially purify these substances. Part of the solution to increase the purification may be mimicking nature. Research at Halmstad University examines how wetlands decompose drugs.

Per-Magnus Ehde measures the amount of water that has passed through a wetland. The research plant with its 18 experimental wetlands, is just outside of Halmstad.

Testing six different drugs

In August, the researchers start their tests in a controlled wetland plant outside of Halmstad. Each sample has five days retention time, which means that the contaminated water flows slowly through the wetland during five days. It is the natural degradation of six different drugs that will be studied: an antibiotic, an epilepsy medication and four painkillers. Drug residues that reach our waterways via wastewater affect the aquatic animals negatively and disrupt sensitive ecosystems. It is therefore important to develop effective methods for treating wastewater.

– We hope that more wastewater treatment plants around Europe will start using wetlands as a final step of purification where the water is "polished". If our study shows that wetlands are just as effective in decomposing pharmaceutical residues as we predict, the wastewater can be purified without adding unnecessary chemicals, says Per-Magnus Ehde, senior lecturer in chemistry at Halmstad University and one of the project’s researchers.

Plants decompose drug residues

The project is carried out in collaboration between researchers at the Wetland Research Centre at Halmstad University and researchers at Kristianstad University. The test period is between August and October, and the results are expected in January 2016. The degradation of drug substances in a wetland occurs in several ways, for example through the biofilm (formed on the part of the plant which is below the surface and on the sediment) by sunlight and through the plants metabolism.

The research project about decomposing pharmaceutical residues is one of many projects at the Wetland research Center at Halmstad University. The Wetland Research Centre brings together researchers working on applied aspects of wetland ecology.

Read more about the research project “Removing pharmaceutical residues: phyto remediation in constructed wetlands” (in Swedish) and see the videoexternal link (in Swedish).



Hristina Bodin from Kristianstad University and Stefan Weisner from Halmstad University are taking plant samples from one of the wetlands.

The researchers are studying what type of vegetation in a wetland that is most efficient for decomposing drug residues. The degradation of drug substances in a wetland occurs in several ways, for example through the plants metabolism.

Stefan Weisner, Professor in Biology and Environmental Science at School of Business, Engineering and Science at Halmstad University, is one of the project’s researchers.

Updated 2018-02-23