Removal of pharmaceuticals with ozone at 10 Swedish wastewater treatment plants F. Nilsson a,b, *, M. Ekblad a,c , J. la Cour Jansen a and K. Jönsson a a Water and Environmental Engineering at the Department of Chemical Engineering, Lund University, P.O. Box 124, Lund SE-221 00, Sweden b Primozone Production AB, Terminalvägen 2, Löddeköpinge SE-246 42, Sweden c Sweden Water Research AB, Ideon Science Park, Scheelevägen 15, Lund 223 70, Sweden *Corresponding author. E-mail: filip.nilsson@primozone.com Abstract Pilot-scale tests were run with ozonation for reduction of 24 pharmaceuticals at 10 full-scale wastewater treat- ment plants in southern Sweden. Reduction was evaluated based on doses of 3, 5 and 7 g O 3 /m 3 at all plants. The reduction of pharmaceuticals reached on average 65% at 3 g O 3 /m 3 , 78% at 5 g O 3 /m 3 and 88% for 7 g O 3 /m 3 in terms of total concentration of pharmaceuticals. Specific ozone dose (ratio O 3 :TOC) was found to be highly influ- ential on pharmaceutical removal. At two WWTPs, the pharmaceutical removal was severely reduced. Key words: ozonation, pharmaceuticals, pilot-scale INTRODUCTION Many countries are considering the need for reduction of pharmaceuticals and other organic micro- pollutants in wastewater. In Switzerland the legal framework is already in place (Eggen et al. 2014), in the EU, the list of priority pollutants already include organic micropollutants and the ‘watch list’ has recently been extended with a number of pharmaceuticals (2013/39/EU). In Sweden, the first full- scale installation based on ozonation, is under construction (IVL 2016) even though the needs and requirements of such a treatment step are still debated. Ozonation and activated carbon treatment, or a combination seems to be the winning technologies for reduction of organic micropollutants. Full-scale installations have only been reported in a few countries (Cimbritz et al. 2016) but pilot-scale installations have been running at several places in order to test the technology and to give guidelines for design (Hollender et al. 2009; Wert et al. 2009; Ibáñez et al. 2013; Margot et al. 2013). Such guidelines are problematic as long as the sub- stances included in the control program and the limits and control methods are not selected at the same time. Typically, a number of substances in high concentration for which reasonable analytical methods exist are selected and the final effluent concentration or the percentage reduction is used as evaluation criteria (Huber et al. 2005; Hansen et al. 2010; Antoniou et al. 2013). For design of equipment and estimation of the economy in ozonation, guidelines for the needed ozone dose is typically based on the content of organic material in the treated wastewater. As the major part of the ozone is consumed by organic matter left after the normal treatment only a minor part is used to oxidize micropollutants. In addition, pH, alkalinity and a number of substances that might be present in treated wastewater are known to have a significant impact on ozone © IWA Publishing 2017 Water Practice & Technology Vol 12 No 4 871 doi: 10.2166/wpt.2017.087 Downloaded from https://iwaponline.com/wpt/article-pdf/12/4/871/215444/wpt0120871.pdf by guest on 13 July 2020