Sanitary discharges Isala Hospital

Building innovative wastewater treatment for removal of medicine residues

On the building site of the Groot Salland Water Board, the construction of an innovative treatment plant, specifically for waste water from the nearby Isala Hospital, location Sophia, was started on Thursday 11 February 2010. The new chairman, Herman Dijk, gave the go-ahead together with Marjanne Sint, chairman of the Isala Hospital/Clinics.

The project is named SLIK (The Dutch abbreviation of  “Sanitary discharging Isala Hospital”) and is co-financed by Europe. The aim is to conduct practical research into the removal of drug residues from wastewater streams. In this case, about 200,000 liters of waste water, daily from the Isala Hospital.

The water board and the Isala Hospital work closely together to improve the removal of medicine residues from waste water. Research from water boards, for example, shows that medicine remains difficult to remove from the wastewater. The current generation of wastewater treatment plants (WWTPs) is insufficiently equipped to break down these substances in the treatment process. As a result, the medicine residues end up in the aquatic environment.

With SLIK it is the intention to investigate whether medicine residues can be better removed with an innovative method of waste water treatment.  In addition to hospital waste water, medicine residues also occur in waste water from residential homes and domestic waste water.


The Groot Salland Water Board is the initiator of the SLIK project. A good cooperation partner has been found in the Isala Hospital. In the coming years on the actual location of the Sophia Hospital at  Dr. van Heesweg a new hospital will arise. The Isala Hospital are preparing a building plan that provides for the realization of approximately 100,000 m2 of new construction.

Design and build

The overall design of the installation was made by Grontmij (now called Sweco). Logisticon Water Treatment took care of the detail engineering and built the final waste water treatment with subcontractors Elmon and MWH. Other contractors are BAM, Moekotte, Pharmafilter and Berson UV technology. The wastewater treatment generally consists of a coarse pre-treatment, biological purification, MBR (membrane bio reactor), ozone/UV treatment and activated carbon. The MBR is of the BioAir ™ type. The BioAir system is an innovative way of operating a membrane bio reactor where the water is purified in an energy-efficient way. The medicine remains are removed with ozone/UV and activated carbon (the latter from Norit). The installation is realised in the first half of 2010. The second half of 2010 is dominated by the actual research.

Example function

Various partners are united in the preparation process. In addition to the practical cooperation with the Isala Hospital, Water Board Groot Salland works together with the municipality of Zwolle, Drinking water company Vitens, reseach institute STOWA and the RIVM. The project is financially supported by the Province of Overijssel and the Ministry of Transport, Public Works and Water Management. It is expected that SLIK will have an important role model for similar initiatives in the Netherlands and Europe. The total costs of the SLIK project amount to approximately € 3.1 million. Half of this amount finances Europe (with an Interreg IV B subsidy) because of its innovative character and its contribution to international knowledge exchange. Cooperation partners from Germany, Luxembourg, Switzerland and Scotland carrying out similar projects were found for this project.

This international umbrella partnership is called PILLS (Pharmaceutical Inputs and eLimination from Local Sources).

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