Fate of Carbamazepine during Water Treatment

Abstract

Seven transformation products of carbamazepine generated by at least one of three common water treatment technologies (UV-radiation, oxidation with chlorine dioxide (ClO2), and biological treatment with activated sludge) were identified by complementary use of ion trap, single quadrupole, and quadrupole-time-of-flight mass spectrometers. Acridine was formed during all of the three treatment processes, while acridine 9-carbaldehyde was identified as an intermediate during ClO2 oxidation. Further treatment of acridine with ClO2 produced 9-hydroxy-acridine. UV-treatment resulted in the formation of acridone, hydroxy-(9H,10H)-acridine-9-carbaldehyde, acridone-N-carbaldehyde, and 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione, while biological breakdown of acridine yielded acridone. In parallel, the transformation product iminostilbene was observed during sample analysis. In addition, this study compared the treatment technologies according to the removal of carbamazepine and the production and decay of its transformation products. The most successful method for the removal of carbamazepine was UV treatment while acridine and acridone were more susceptible to biological treatment. Therefore, based on the enhanced biodegradability of carbamazepine residues achieved by UV irradiation, we propose a coupled treatment technology involving an initial UV treatment step followed by biological treatment which may satisfactorily remove the parent compound and its transformation products.

Ecotoxicity of carbamazepine and its UV photolysis transformation products

“…It is assumed that removal of carbamazepine from surface waters will occur largely via the photodegradation pathway as sorption of carbamazepine is very limited (Ternes et al, 2002;Scheytt et al, 2005;Clara et al, 2004) and it is resistant to biodegradation (Clara et al, 2004;Kosjek et al, 2009). Hence, the formation of stable photodegradation products is not only relevant to wastewater treatment processes, where UV treatment may be implemented to assist with microbial disinfection (e.g.…”

“…Concentration profiles of the two transformation products were both below the detection limit after 120 minutes of UV treatment. Although methanol, a potential radical scavenger, was used as the solvent for the carbamazepine stock solution, Kosjek et al (2009) showed that the concentration of methanol used in this experiment should not have inhibited the decay of carbamazepine or the identified transformation products during treatment. Their investigation used the same benchtop UV-treatment system as the current experiment and showed no significant difference in carbamazepine decay in the presence of 1.2, 2.5 and 6.2 % methanol.…”

“…Stackelberg et al, 2004Stackelberg et al, , 2007Togola and Budzinski, 2008;Heberer et al, 2004). It is also noted to be highly resistant to biodegradation and thus highly recalcitrant under standard biological wastewater treatment conditions (Clara et al, 2005;Kosjek et al, 2009, Falås et al, 2012. Under these circumstances, advanced oxidation processes (AOPs) may offer additional treatment value (von Gunten, 2003;Huber et al, 2005;Macova et al, 2010;Kosjek et al, 2011, Hey et al, 2012Keen et al, 2012), however complete oxidation and mineralisation is not always achievable and stable transformation products formed during AOPs may also pose environmental risks (Aguerra et al (2005).…”

Identification and ecotoxicity of degradation products of chloroacetamide herbicides from UV-treatment of water

“…A particular emphasis has been focused on pharmaceuticals with several reviews and studies dedicated to their degradation products in the environment (FattaKassinos et al, 2011a;Fatta-Kassinos et al, 2011b;Horvat et al, 2012) and in water treatment systems e.g. water works (Ternes et al, 2002;Kosjek and Heath, 2008;Kosjek et al, 2009). In these artificial systems biodegradation occurs concurrently with engineered processes like oxidation reactions with chlorine, chlorine dioxide, ozone and transformations by UV (Kosjek and Heath, 2008;Hollender et al, 2009;Kosjek et al, 2009).…”

“…water works (Ternes et al, 2002;Kosjek and Heath, 2008;Kosjek et al, 2009). In these artificial systems biodegradation occurs concurrently with engineered processes like oxidation reactions with chlorine, chlorine dioxide, ozone and transformations by UV (Kosjek and Heath, 2008;Hollender et al, 2009;Kosjek et al, 2009). …”