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In the context of an EU-wide surveillance system for SARS-CoV-2 in wastewater, recommended by the European Commission, this study aims to provide scientific support to the adequacy of transport and storage conditions of samples both in terms of duration and samples temperature. Three laboratories in Slovenia, Cyprus and Estonia investigated the short-term, one-week, isochronous stability of wastewater samples by RT-qPCR based detection of SARS-CoV-2 genes. The results were tested for statistical significance to determine uncertainty of quantification and shelf-life, at testing temperatures of + 20 °C and − 20 °C, relative to reference at + 4 °C. Samples were collected from three urban wastewater treatment plant influents and analysed respectively for SARS-CoV-2 genes N1, N2 (Laboratory 1), N2, E (Laboratory 2) and N3 (Laboratory 3), with various analytical methods. For a period of 7/8 days at + 20 °C, decreasing trends of measured concentrations were observed for all genes resulting in instability according to the statistical analysis, while at − 20 °C the trend of variation was stable only for N1, N2 (Laboratory 1) and N3 (Laboratory 3). Trends for gene E concentrations at − 20 °C (Laboratory 2) could not be tested statistically for stability because of lack of data. Over a period of just 3 days at + 20 °C, the variation was statistically non-significant indicating stability for genes N1, E and N3 for laboratories 1, 2 and 3, respectively. Nonetheless, the outcome of the study presents evidence to support the choice of the selected temperature at which samples shall be preserved during storage before analysis or transport to the laboratory. The conditions (+4 °C, ∼ few days) chosen for EU wastewater surveillance are in accordance with these results, highlighting the importance of stability testing of environmental samples to determine the short-term analytical uncertainty. [Display omitted] [ABSTRACT FROM AUTHOR]

The overall aim of this work was to examine the degradation of trimethoprim (TMP), which is an antibacterial agent, during the application of two advanced oxidation process (AOP) systems in secondary treated domestic effluents. The homogeneous solar Fenton process (hv/Fe2+/H2O2) and heterogeneous photocatalysis with titanium dioxide (TiO2) suspensions were tested. It was found that the degradation of TMP depends on several parameters such as the amount of iron salt and H2O2, concentration of TiO2, pH of solution, solar irradiation, temperature and initial substrate concentration. The optimum dosages of Fe2+ and H2O2 for homogeneous ([Fe2+] =5 mg L-1, [H2O2] = 3.062 mmol L-1) and TiO2 ([TiO2] = 3 g L-1) for heterogeneous photocatalysis were established. The study indicated that the degradation of TMP during the solar Fenton process is described by a pseudo-first-order reaction and the substrate degradation during the heterogeneous photocatalysis by the Langmuir-Hinshelwood kinetics. The toxicity of the treated samples was evaluated using a Daphnia magna bioassay and was finally decreased by both processes. The results indicated that solar Fenton is more effective than the solar TiO2 process, yielding complete degradation of the examined substrate within 30 min of illumination and dissolved organic carbon (DOC) reduction of about 44% whereas the respective values for the TiO2 process were ∼70% degradation of TMP within 120 min of treatment and 13% DOC removal. [ABSTRACT FROM AUTHOR]

In this work, a sensitive and highly selective method was developed and validated to study the degradation of two antibiotic compounds (ofloxacin (OFX) and trimethoprim (TMP)), spiked in secondary treated domestic effluents, by the solar Fenton process. Three different chromatographic columns were tested on a ultra performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) instrument working in the electrospray ionization (ESI) mode with twelve combinations of eluting solvents. Samples were enriched prior to the analysis by solid phase extraction using the hydrophilic-lipophilic balanced (HLB) reversed phase polymeric sorbent. The method was optimized and showed very good performance characteristics and was successfully applied to study the degradation kinetics of the selected antibiotics during the solar Fenton process applied. The degradation was found to follow a pseudo first-order kinetics for both compounds at initial concentration of 100 μg L-1 with k=0.0345 min-1 for OFX and k=0.0768 min-1 for TMP, whereas the complete removal was achieved after 120 mm of treatment for both compounds. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the efficiency of solar and UV-A photocatalysis with suspended TiO2 to degrade ibuprofen and carbamazepine in aqueous matrices. Emphasis was given on the effect of various operating conditions such as catalyst type (six commercially available titanium oxide samples were tested) and concentration (50-3000 mg/L), initial drug concentration (5-20 mg/L), solution pH (3-10), the addition of hydrogen peroxide (0.07-1.4 mM), and the matrix (pure water and treated domestic wastewater) on degradation and mineralization. The former was assessed monitoring sample absorbance at each drug's characteristic wavelength, while the latter measuring dissolved organic carbon. The best performance was achieved at lower drug concentrations irradiated by UV-A in the presence of Degussa P25 catalyst and hydrogen peroxide in pure water. [ABSTRACT FROM AUTHOR]

The use of low frequency (20 kHz), high energy ultrasound for the degradation of the antibiotic ofloxacin in water was investigated. Experiments were performed with a horn-type ultrasound generator at varying applied power densities (130-640 W/L), drug concentrations (5-20 mg/L), hydrogen peroxide concentrations (0-100mM) and sparging gases (air, oxygen, nitrogen and argon). In general, conversion (which was assessed following sample absorbance at 288 nm) increased with increasing ultrasound energy and peroxide concentration and decreasing initial drug concentration. Moreover, reactions under an argon atmosphere were faster than with diatomic gases, possibly due to argon's physical properties (e.g. solubility, thermal conductivity and specific heat ratio) favoring sonochemical activity. Overall, low to moderate levels of ofloxacin degradation were achieved (i.e. it never exceeded 50%), thus indicating that radical reactions in the liquid bulk rather than thermal reactions in the vicinity of the cavitation bubble are responsible for ofloxacin degradation. [ABSTRACT FROM AUTHOR]

Abstract: The photocatalytic conversion of two β-blockers, namely atenolol and propranolol in aqueous TiO2 suspensions was investigated. Irradiation was provided by a solar simulator equipped with 1kW Xe-OP lamp, while emphasis was given on the effect of catalyst type and loading (50–3000mg/L), substrate concentration (5–30mg/L), initial solution pH (3–10), and the addition of H2O2 (0.07–1.4mM) and oxygen on degradation in two matrices (i.e. pure water and treated municipal effluent). Of the various catalysts tested, Degussa P25 was highly active yielding up to about 80% conversion after 120min of reaction. In general, conversion was favored at lower substrate concentrations, near-neutral pH values and in the absence of other organics (i.e. in pure water), while the addition of H2O2 did not accelerate kinetics which seem to follow the Langmuir–Hinshelwood model. Toxicity to D. magna was evaluated prior to and after photocatalytic treatment. Toxicity increased during the early stages of the reaction and then progressively decreased upon the elimination of the substrate and its reaction intermediates, with propranolol being more toxic than atenolol. [Copyright &y& Elsevier]

Abstract: Two different technical approaches based on advanced oxidation processes (AOPs), solar Fenton homogeneous photocatalysis (hv/Fe2+/H2O2) and heterogeneous photocatalysis with titanium dioxide (TiO2) suspensions were studied for the chemical degradation of the fluoroquinolone ofloxacin in secondary treated effluents. A bench-scale solar simulator in combination with an appropriate photochemical batch reactor was used to evaluate and select the optimal oxidation conditions of ofloxacin spiked in secondary treated domestic effluents. The concentration profile of the examined substrate during degradation was determined by UV/Vis spectrophotometry. Mineralization was monitored by measuring the dissolved organic carbon (DOC). The concentrations of Fe2+ and H2O2 were the key factors for the solar Fenton process, while the most important parameter of the heterogeneous photocatalysis was proved to be the catalyst loading. Kinetic analyses indicated that the photodegradation of ofloxacin can be described by a pseudo-first-order reaction. The rate constant (k) for the solar Fenton process was determined at different Fe2+ and H2O2 concentrations whereas the Langmuir–Hinshelwood (LH) kinetic expression was used to assess the kinetics of the heterogeneous photocatalytic process. The conversion of ofloxacin depends on several parameters based on the various experimental conditions, which were investigated. A Daphnia magna bioassay was used to evaluate the potential toxicity of the parent compound and its photo-oxidation by-products in different stages of oxidation. In the present study solar Fenton has been demonstrated to be more effective than the solar TiO2 process, yielding complete degradation of the examined substrate and DOC reduction of about 50% in 30 min of the photocatalytic treatment. [ABSTRACT FROM AUTHOR]