Nordic efforts to prevent pharmaceuticals affecting the environment include Danish management of hospital wastewater and a Swedish large-scale sewage plant for removal of pharmaceutical residues.
Wastewater from hospitals can contain traces of viruses, multi-resistant bacteria, medical contrast agents, chemicals for cancer treatment, small amounts of hormone-disrupting substances, and other medicine residues. For this reason it is urgent that hospital wastewater is treated before being released to sewers and the aquatic environment.
Tackling this problem, the engineering consultancy company DHI and Grundfos BioBooster A/S has developed a new method to treat the wastewater, which enables an efficient cleaning. With the new method the treated water produced can be used for recreational purposes in the local stream and be re-used as cooling water in hospitals.
The process includes a membrane bioreactor (MBR) that carries out the biological treatment of the wastewater, as well as a complete removal of bacteria. This treatment is followed by a combination of polishing technologies (consisting of ozone, activated carbon and UV rays to eliminate toxic chemicals), which remove all critical pharmaceuticals that remain in the water.
Biobooster solution Herlev hospital. Photo: DHI
A new standard for hospital wastewater treatment
The new method has been used at the 900-bed Herlev Hospital, on the outskirts of Copenhagen in Denmark, since May 2014. The solution handles all hospital wastewater in one centralized process. It is not necessary to separate wastewater containing problematic substances from other kinds of wastewater, and this makes it possible to move hospital wards without changing the piping. “This could become a financial and practical benefit for the hospital and facilitates future planning efforts when building new wards and clinics,” stated Grundfos.
Two years later, the treatment and the economic efficiency of the technology were evaluated in an independent report by DHI: “Full scale advanced wastewater treatment at Herlev Hospital Treatment performance and evaluation.” The report revealed that the method could treat the wastewater containing pharmaceuticals efficiently so that these were no longer toxic to aquatic environment. It also showed the technology to be effective in removing all traces of bacteria, including antibiotic resistant bacteria, which cause hard-to-treat diseases. In fact, it was demonstrated the treated wastewater to be very close to drinking water quality and therefore can be re-used or discharged directly to the aquatic environment.
The total operating and maintenance costs for this treatment at Herlev Hospital is EUR 1.5/square metre, including service man-hours and onsite sludge-drying and air/odeur-treatment, says Ulf Nielsen, Chief Planner at DHI. ”This is well below the existing municipal sewer tax of EUR 3.4 which is what the hospital pays today.”
The project, the BioBooster water waste treatment project has been the most advanced in Denmark, and Herlev Hospital is the first site in Denmark where it is possible to clean wastewater efficiently before it leaves the hospital.
“The Danish Ministry of the Environment and the municipalities want to remove the dangerous substances at the source – in this case the hospital – since the municipal sewage cleaning plants can only to a limited extent remove antibiotics, cancer medicine, pain drugs and a number of other pharmaceuticals from the wastewater. The consequences for the water environment, plants and animals could amongst others be hormone disturbances, which can result in growth-related problems and deformities in fish and water fleas,” explained Ulf Nielsen.
“All over the country, municipalities have been waiting for a solution that shows how and how well the hospitals’ wastewater could be cleansed in order for them to precisely express emission requirements to the hospitals. Now it has been documented that the solution exists and the municipalities can thereby make demands that are feasible to meet,” says Jakob Søholm, Sales Manager at Grundfos BioBosster in a press release.
Local Government Denmark (KL), the association and interest organization of Danish municipalities, currently regards the BioBooster solution as the best available technology (BAT) in the field, and the solution may become a landmark for other municipalities working to handle problematic hospital wastewater.
The next hospitals to use this treatment method will be Aalborg University Hospital (2019), New Odense University Hospital (2020) and New Rigshospitalet (2023).
Sweden’s first permanent large-scale drug treatment plant
Pharmaceutical residues can spread to our oceans, seas and watercourses via wastewater. Even low concentrations of pharmaceuticals can affect the aquatic environment, for example estrogen may inhibit the reproduction of fish, and psychotropics can alter their behavior so that they become more voracious, braver and less social. The substances are often difficult to degrade as they are designed to withstand the acidic environment of the stomach, which also makes it difficult to break these down in the existing process steps at a conventional wastewater treatment plant.
In 2017 the current Minister for the Environment, Karolina Skog, inaugurated the Nykvarn wastewater plant outside Linköping as Sweden’s first permanent large-scale plant for removal of pharmaceutical residues and personal care products from wastewater. The ozonation treatment used at the plant had been evaluated in collaboration with IVL Swedish Environment Research Institute and Tekniska verken, who run the plant, and today the Nykvarn plant purifies waste water from 140 000 Linköping residents.
Ozonation
Ozone is a gas that has proved to be effective at removing pharmaceuticals and personal care product residues such as endocrine disruptors and antibiotics from wastewater.
“Using ozonation as a treatment method is somewhat controversial because there is an accompanying risk for harmful breakdown products. Its application at Tekniska verken, however, is designed in such a way as to utilize ozone’s effects to the maximum, even for the purification of compounds other than then persistent organic substances, and to avoid any negative effects by a smart process integration,” says Christian Baresel at IVL, Project Manager for the pilot tests.
In a reactor with a capacity of 600 square meters, ozone is mixed with the waste water. The reactor is designed so that all of the ozone, with a comfortable margin, can finish reacting before the water goes on to the next step in the purification process. After the ozone purification the water is treated in a biological process that catches degraded substances from the ozone purification. Besides drug treatment, the combination of ozone purification and the following biological purification steps may improve the total purification of organic carbon and nitrogen. With this new treatment method more than 90 percent of the waste/pharmaceutical residues reaching the plant can be purified.
Swedish efforts
Last year the government in Sweden gave the Swedish Medical Products Agency the mission to establish a knowledge center for pharmaceuticals in the environment. The center will among other things work to increase knowledge about the environmental effects of pharmaceuticals. It will be established in Uppsala and the Swedish government will contribute MSEK 5 annually to this center, starting from 2018. The Swedish government is also staking MSEK 50 this year and MSEK 20 next year on advanced treatment of wastewater.
