Pharmaceutical compounds in waters. Investigations on hospital effluents as a source of environmental contamination and on their treatability.

Abstract

The activity research done during this Ph.D., was born as an overview of pharmaceutical compounds (PhCs) in wastewaters (WWs). In particular, the aim of this work was evaluate the occurrence of these emerging pollutants in the hospital’s wastewaters (HWWs), considered one of the main sources of these contaminants in the public sewage and in the environment. To do this, many water samples (withdrawn from different kind of waters: groundwaters, surface waters, drinking waters, urban wastewaters, hospital wastewaters, bottle waters) were analysed in order to investigate the problem and have more data to compare HWWs with urban ones. The chemical’s analysis includes conventional macropollutants like BOD5, COD, SS, N compounds. . . as well as pharmaceuticals (till 73 compounds were monitored). Chapter 2 of the thesis, explains the diffusion of PhCs into the environment. It starts from a literature’s basis that explains the occurrence, fate of PhCs, the health risk and the consequent ecotoxicological effects; the experimental investigation regards different samples taken from surface waters of Po River, groundwaters (GW) from the first aquifer below the Po River and drinking waters (DW) at different steps of the Ferrara’s waters work. The aim of this chapter is investigate the occurrence of PhCs in the environment (by comparing our conclusions to the literature results) and verify if the treatments adopted at water works of Ferrara, could guarantee a sufficient removal of the investigated compounds. Chapter 3 represents the central chapter (the core chapter) of this work. It refers to hospital and urban effluents, it compares these two kinds ofWWs in terms of flow rates and concentration and loads of conventional macroparameters (mainly BOD5, COD, SS). All these treated aspects are about the basis of literature and they compare them data with the data that we will find in our experimental investigations. The final part of the chapter show the analytical results done on PhCs in two real hospital effluents that have been studied (Lagosanto and Ferrara). In this chapter are also analysed the different water consumption in the hospital structures because for a single user (the typical user in the hospital is normally the patient, expressed in terms of bed) the water consumption is really different from the usual inhabitant equivalent. Chapter 4 explains all the experimental investigation carried out in these research years. The chapter is divided in 6 sections. Each section takes in consideration a different experimental investigation. The first section regards the raw hospital effluents disinfection. This kind of treatment should not be the only and the first one but in some developing countries, where WWTPs are not presents, hospital’s effluents should be at least pre-treated by sedimentation and disinfection before they will be discharged into the environment. The aim of the research was evaluate the correct dose of disinfectant (peracetic acid or hypochlorite) used for direct discharge of raw effluent into the environment, in order to avoid health and environmental risks. The second experimental campaign was about the treatment of the raw hospital effluent of Lagosanto (near Ferrara, 300 beds) where two different MBR pilot plants (with equipped microfiltration and ultrafiltration membranes) were tested by analysing macroparameters and some PhCs. This experimental section had the purpose to compare the MBR performance with the CAS, one with respect to macro and micro parameters. Also the experimental campaign performed in La Spezia WWTP (north west of Italy) compared the difference between conventional treatments (CAS) and MBR performances, but in this case, the feed to the plant was the UWWs. In the final part of this investigation was also tested a final treatment with ozone. A further investigation was done at Ferrara’s WWTP, in order to evaluate the contribution in the removal of 73 PhCs by a CAS and a polishing treatment, that consist in a horizontal subsurface flow system. During this investigation in Ferrara’s WWTP, two different study steps were developed. The first one using the effluent of the WWTP as influent of the CW, in order to evaluate the final efficiency by removing the 73 studied compounds. The second one add a mixture solution of Ciprofloxacin, Sulphametoxazole and Trimethoprin at the influent of the natural system, with the aim of verify the efficiency of the natural treatment with high concentration of the spiked compounds. The final section of this chapter discusses and compares the different tested technologies, with particular attention to the natural systems and to the concept of the multibarrier system able to remove a great number of PhCs from WWs. Chapter 5 is mainly focused on the different technologies that are able to remove the PhCs on the basis of a deeper literature’s research. The chapter deals the physico-chemical treatments, the conventional and advanced biological treatments, the nanofiltration technology, the reverse osmosis, the chlorination, a rapid overview about ozonation and AOPs treatment, the natural polishing treatment and, to conclude, the photodegradation. In the last part, the chapter presents and deals the treatment sequence adopted on the effluent of the new hospital under construction near Ferrara (900 beds).