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Zupanc M.,Jozef Stefan Institute | Zupanc M.,Jožef Stefan International Postgraduate School | Zupanc M.,Ecological Engineering Institute Ltd. | Kosjek T.,Jozef Stefan Institute | And 7 more authors.
Ultrasonics Sonochemistry | Year: 2014

In this study, the removal of clofibric acid, ibuprofen, naproxen, ketoprofen, carbamazepine and diclofenac residues from wastewater, using a novel shear-induced cavitation generator has been systematically studied. The effects of temperature, cavitation time and H2O2 dose on removal efficiency were investigated. Optimisation (50 C; 15 min; 340 mg L-1 of added H2O2) resulted in removal efficiencies of 47-86% in spiked deionised water samples. Treatment of actual wastewater effluents revealed that although matrix composition reduces removal efficiency, this effect can be compensated for by increasing H2O2 dose (3.4 g L-1) and prolonging cavitation time (30 min). Hydrodynamic cavitation has also been investigated as either a pre- or a post-treatment step to biological treatment. The results revealed a higher overall removal efficiency of recalcitrant diclofenac and carbamazepine, when hydrodynamic cavitation was used prior to as compared to post biological treatment i.e., 54% and 67% as compared to 39% and 56%, respectively. This is an important finding since diclofenac is considered as a priority substance to be included in the EU Water Framework Directive. © 2013 Elsevier B.V. All rights reserved.


Vrzel J.,Ecological Engineering Institute Ltd | Vrzel J.,Jožef Stefan International Postgraduate School | Ogrinc N.,Jožef Stefan International Postgraduate School | Ogrinc N.,Jozef Stefan Institute
Journal of Soils and Sediments | Year: 2015

Purpose: The first comprehensive evaluation and trend analysis of long-term nitrogen (N) and phosphorus (P) data was performed for the Sava River Basin (SRB) at locations in Slovenia, Croatia, and Serbia. Materials and methods: Data on long-term water quality at eight selected locations were evaluated statistically based on the period of reporting, availability of flow data, and the experience from our previous investigations. Trends in NO3 − and PO4 3− concentrations at locations were identified using simple linear regressions on log-transformed data. Results and discussion: Analysis indicated spatial and seasonal variability between locations. The highest long-term annual mean NO3 − and PO4 3− concentrations were observed in Croatia and Serbia at locations that are susceptible to anthropogenic nutrient loading arising from high human population densities and intensive agricultural land use. Temporal variations indicate that river flow plays an important role in the distribution of NO3 − and PO4 3− concentrations. Low flow during the summer months promotes reductive conditions leading to a minimum in annual mean NO3 − concentrations and a maximum in annual mean PO4 3− concentrations resulting from the release of inorganic P from sediments. The highest annual mean NO3 − concentrations were observed in winter/autumn under higher flow conditions that leach NO3 − from soil and banks into the river. The results of trend analysis show a reduction of nutrients at the majority of locations ranging from 8 to 58 %. Conclusions: Although trends in NO3 − and PO4 3− concentrations indicate a decrease at the majority of selected locations, it is still necessary to apply appropriate removal technologies in order to reduce the nutrient loads into the Sava River Basin and thereby improve water quality. © 2015, The Author(s).


Kotnik K.,Jozef Stefan Institute | Kotnik K.,Jožef Stefan International Postgraduate School | Kotnik K.,Ecological Engineering Institute Ltd | Kosjek T.,Jozef Stefan Institute | And 4 more authors.
Chemosphere | Year: 2016

This study investigates the environmental fate of eight benzophenone derivatives (the pharmaceutical ketoprofen, its phototransformation products 3-ethylbenzophenone and 3-acetylbenzophenone, and five benzophenone-type UV filters) by evaluating their photolytic behaviour. In addition, the genotoxicity of these compounds and the produced photodegradation mixtures was studied. Laboratory-scale irradiation experiments using a medium pressure UV lamp revealed that photodegradation of benzophenones follows pseudo-first-order kinetics. Ketoprofen was the most photolabile (t1/2 = 0.8 min), while UV filters were more resistant to UV light with t1/2 between 17 and 99 h. The compounds were also exposed to irradiation by natural sunlight and showed similar photostability as predicted under laboratory conditions. Solar photodegradation experiments were performed in distilled water, lake and seawater, and revealed that photosensitizers present in natural waters significantly affect the photolytic behaviour of the investigated compounds. In this case, the presence of lake water resulted in accelerated photodecomposition, while seawater showed different effects on photodegradation, depending on a compound. Further, it was shown that the transformation products of ketoprofen 3-ethylbenzophenone and 3-acetylbenzophenone were formed under environmental conditions when ketoprofen was exposed to natural sunlight. Genotoxicity testing of parent benzophenone compounds using the SOS/umuC assay revealed that UV filters exhibited weak genotoxic activity in the presence of a metabolic activation system, however the concentrations tested were much higher than found in the environment (≥125 μg mL-1). After irradiation of benzophenones, the produced photodegradation mixtures showed that, with the exception of benzophenone that exhibited weak genotoxic activity, all the other compounds tested did not elicit any activity when exposed to UV light. © 2015 Elsevier Ltd.


Kotnik K.,Jozef Stefan Institute | Kotnik K.,Jožef Stefan International Postgraduate School | Kotnik K.,Ecological Engineering Institute Ltd | Kosjek T.,Jozef Stefan Institute | And 3 more authors.
Analytical and Bioanalytical Chemistry | Year: 2014

This study describes a procedure for determining eight benzophenone-derived compounds in surface waters and sediments. These include the pharmaceutical ketoprofen, its phototransformation products 3-ethylbenzophenone and 3-Acetylbenzophenone, and five benzophenone-type ultraviolet (UV) filters. The proposed analytical method involves the pre-concentration of water samples by solid-phase extraction (SPE) and microwave-Assisted extraction (MAE) of sediment samples followed by derivatization and analysis by gas chromatography-mass spectrometry. Different parameters were investigated to achieve optimal method performance. Recoveries of 91 to 96 % from water samples were obtained using HLB Oasis SPE cartridges, whereas MAE of sediments (30 min at 150 °C) gave recoveries of 80 to 99 %. Limits of detection were between 0.1 and 1.9 ng L -1 for water samples and from 0.1 to 1.4 ng g-1 for sediment samples. The developed method was applied to environmental samples and revealed the presence of UV filters in the majority of the surface waters with up to 690 ng L-1 of 2-hydroxy-4-methoxybenzophenone. By contrast, ketoprofen (=2,900 ng L-1) and its degradation products (=320 ng L-1) were found in only two rivers, both receiving wastewater treatment plant effluents. Sediment analysis revealed benzophenone to be present in concentrations up to 650 ng g-1, whereas concentrations of other compounds were considerably lower (=32 ng L-1). For the first time, quantifiable amounts of two ketoprofen transformation products in the aqueous environment are reported. © Springer-Verlag Berlin Heidelberg 2014.

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