In the Berson hospital trial, UV is applied in combination with hydrogen peroxide (H2O2) to generate OH- radicals in a so-called advanced oxidation process (AOP). The very reactive OH- radicals attack the pharmaceutical residues in the wastewater, breaking them down into H2O, CO2 and harmless metabolites.
As with all hospitals, the wastewater from the Isala Hospital in Zwolle, the Netherlands, contains elevated levels of X-ray contrast compounds and various other pharmaceutical residues.
Prior to UV/ H2O2 treatment the complete wastewater stream is pre-treated in a membrane bioreactor (MBR). The wastewater then passes through a Berson InLine medium pressure UV system, into which specific amounts of H2O2 are injected. The treated wastewater is then discharged as treated sewage into the municipal sewage system.
This is the first full-scale trial for the treatment of hospital wastewater in Europe and is part of the Europe-wide PILLS project, which is investigating which treat­ment methods are best suited to eliminate pharmaceutical residues from hospital wastewater. At present wastewater plants are not able to remove pharmaceutical residues from their wastewater. Studies show that there is a link between elevated levels of substances such as the hormone ethinylestradiol, which is contained in con­traceptive pills, and the reproductive rate of fish.