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Over the past years, there has been an increasing concern about the occurrence of antineoplastic drugs in water bodies. The incomplete removal of these pharmaceuticals from wastewaters has been confirmed by several scientists, making it urgent to find a reliable technique or a combination of techniques capable to produce clean and safe water. In this work, the combination of nanofiltration and ozone (O 3)-based processes (NF + O 3 , NF + O 3 /H 2 O 2 and NF + O 3 /H 2 O 2 /UVA) was studied aiming to produce clean water from wastewater treatment plant (WWTP) secondary effluents to be safely discharged into water bodies, reused in daily practices such as aquaculture activities or for recharging aquifers used as abstraction sources for drinking water production. Nanofiltration was performed in a pilot-scale unit and O 3 -based processes in a continuous-flow column. The peroxone process (O 3 /H 2 O 2) was considered the most promising technology to be coupled to nanofiltration, all the target pharmaceuticals being removed at an extent higher than 98% from WWTP secondary effluents, with a DOC reduction up to 92%. The applicability of the clean water stream for recharging aquifers used as abstraction sources for drinking water production was supported by a risk assessment approach, regarding the final concentrations of the target pharmaceuticals. Moreover, the toxicity of the nanofiltration retentate, a polluted stream generated from the nanofiltration system, was greatly decreased after the application of the peroxone process, which evidences the positive impact on the environment of implementing a NF + O 3 /H 2 O 2 process. [Display omitted] • The combination of nanofiltration and ozonation was studied for 11 pharmaceuticals. • Nanofiltration + peroxone process ensures complete removal of antineoplastic drugs. • Clean water produced by the combined process may be safe for consumption. • A Dissolved Organic Carbon reduction up to 92% was reached. • Nanofiltration retentate stream toxicity decreased after ozone-based processes. [ABSTRACT FROM AUTHOR]

This work aimed to investigate the possible effect of 2 quenchers commonly used in H 2 O 2 -based advanced oxidation technologies (AOTs), i.e. catalase and sodium sulphite (Na 2 SO 3), on the analytical signal of 3 detectors coupled to liquid chromatography (LC): tandem mass spectrometry (LC-MS/MS), fluorescence detection (LC-FD) and LC-diode array detection (LC-DAD). The observation of analytical interferences for a group of compounds when studying the removal by continuous mode UV/H 2 O 2 of 26 micropollutants (MPs) from a spiked surface water (SW), for which the residual H 2 O 2 in the samples was quenched by Na 2 SO 3 , triggered the need of understanding these effects and thus catalase was used as comparative quencher. From the 26 MPs having a wide range of polarity and p K a , those monitored after electrospray ionization (ESI) under positive ionization (PI) mode and presenting a p K a higher than 5.9 revealed a great signal suppression, but only when using Na 2 SO 3 as H 2 O 2 quencher. In this sense, we further explored this effect by selecting 2 MPs, metoprolol and diclofenac, which had respectively signal suppression and no interference in the LC-MS/MS response. These MPs were analysed before and after addition of H 2 O 2 and catalase or Na 2 SO 3 in reaction vials, using: (i) different detectors coupled to LC, namely LC-MS/MS with ESI under PI and negative ionization (NI) modes, LC-FD and LC-DAD; (ii) different environmental matrices (SW, drinking water, wastewater) and ultrapure water; and (iii) different magnitude levels (0.1–10 mg L−1). The results demonstrated a remarkable signal suppression in LC-MS/MS analyses under PI mode for those compounds with p K a higher than 5.9, confirming the interfering effect of H 2 O 2 /Na 2 SO 3. To the best of our knowledge, the analytical interference in the LC-MS/MS analysis, after adding Na 2 SO 3 to quench H 2 O 2 in AOTs experiments was never reported before and the results presented herein support the recommendation to use catalase instead of Na 2 SO 3 as quencher in AOTs studies. Unlabelled Image • Sodium sulphite is not recommended as quencher in AOTs when using LC-MS/MS. • Catalase should be used as quencher of H 2 O 2 , when analysing by LC-MS/MS. • Matrix matched analytical validated methods are always recommended. • Analytical method validation must consider all the experimental steps of AOTs. [ABSTRACT FROM AUTHOR]

Abstract The presence of organic micropollutants (MPs) in the aquatic environment is strongly related to their difficult elimination by conventional water and wastewater treatment processes. Therefore, alternative treatment technologies are required to overcome this problem. In this domain, constructed wetlands (CWs) have gained increasing attention in the last years, mainly due to the low-cost, simple operation/maintenance and environmental friendliness of these systems. However, studies on the application of CWs to remove MPs from freshwater aquaculture effluents are still scarce. In this work, planted (Phragmites australis) vertical subsurface flow CWs, at microcosm scale, were investigated for the removal of MPs found in non-spiked freshwater aquaculture effluents, namely atrazine, isoproturon, perfluorooctanesulfonic acid (PFOS), clarithromycin, erythromycin, fluoxetine, norfluoxetine, and 2-ethylhexyl-4-methoxycinnamate (EHMC). A wider multi-component set of 36 MPs was also studied by adding these MPs at 100 ng L−1 to the same matrix (alachlor, atrazine, chlorfenvinphos, isoproturon, PFOS, azithromycin, clarithromycin, erythromycin, diclofenac, methiocarb, acetamiprid, clothianidin, thiacloprid, thiamethoxam, EHMC, simazine, atorvastatin, bezafibrate, carbamazepine, cephalexin, ceftiofur, citalopram, clindamycin, clofibric acid, diphenhydramine, enrofloxacin, fluoxetine, ketoprofen, metoprolol, norfluoxetine, ofloxacin, propranolol, tramadol, trimethoprim, venlafaxine, and warfarin). High weekly removal efficiencies (>87%) were observed for all MPs in both non-spiked and spiked experiments, with the exception of EHMC (removal rates between 0 and 86%). These results emphasize the potential of CWs to remove MPs from freshwater aquaculture effluents, but also the need to enhance the performance of these systems for the elimination of some recalcitrant MPs, such as EHMC, which was found at high concentrations in the studied effluents. Graphical abstract Unlabelled Image Highlights • Constructed wetland microcosms studied for the removal of organic micropollutants. • Spiked (36 micropollutants) and non-spiked aquaculture effluents were investigated. • Most micropollutants found in effluents were removed to below the detection limit. • Weekly removal efficiencies were higher than 87% for most spiked micropollutants. • The UV filter EHMC was the only recalcitrant micropollutant. [ABSTRACT FROM AUTHOR]

• Ozonation investigated for the removal of antibiotics from aquaculture effluents. • Oxytetracycline, sulfamethoxazole and trimethoprim attacked by O 3 directly. • Florfenicol removed by hydroxyl radicals (HO•) only. • Sulfadimethoxine degradation is significantly affected by the water matrix. • Toxicological evaluation did not show increase of water toxicity after ozonation. Antibiotics are often applied in aquaculture to prevent fish diseases. These substances can cause disturbances on receiving waters, when not properly eliminated from the aquaculture effluents. In this work, ozone (O 3) was investigated as a possible oxidizing agent to remove fishery antibiotics from aquaculture effluents: florfenicol (FF), oxytetracycline (OTC), sulfadimethoxine (SDM), sulfamethoxazole (SMX), and trimethoprim (TMP). Batch experiments were performed using ultrapure water and aquaculture effluents spiked with a mixture of target antibiotics at relatively high concentrations (10 mg L-1 each). OTC, SMX and TMP were fully removed (< 30 min) regardless of the tested conditions, mainly by O 3 direct attack. In contrast, FF was partially removed in 30 min (∼ 10 and 60%, in aquaculture effluents and ultrapure water, respectively), but only in the presence of hydroxyl radicals (HO•), the FF concentrations reaching levels below the detection limits in ultrapure water after 60 min. In the case of SDM, its degradation was highly influenced by the selected water matrix, but with removals always higher than 68%. In continuous-flow experiments applying more environmentally relevant antibiotic concentrations (100 ng L-1 each) and low O 3 doses (1.5 mg L−1), ozonation highly removed (> 98%) all tested antibiotics from aquaculture effluents with a hydraulic retention time (HRT) of 10 min, except FF (68%). Although by-products were detected in treated samples, zebrafish (Danio rerio) embryotoxicity tests did not show a toxicity increase by applying this ozonation treatment. Ozonation is thus a possible solution to remove antibiotics from aquaculture effluents. Still, full-scale studies in aquaculture farms are needed, and generation of HO• may be favoured to readily oxidize the FF antibiotic. [Display omitted] [ABSTRACT FROM AUTHOR]

Aquaculture is the fastest growing animal food-producing sector. Water is the central resource for aquaculture, and it is essential that its quality be preserved. Micropollutants (MPs) can reach aquaculture through anthropogenic addition or inlet water, and may cause harmful effects such as endocrine disruption and antibiotic resistance, adversely affecting the fish species being farmed. Furthermore, the discharge of aquaculture effluents into the environment may contribute to the deterioration of water courses. In this sense, the implementation of environmentally responsible measures in aquaculture farms is imperative for the protection of ecosystems and human health. The European Commission (EC) has recently launched a guiding document promoting ecological aquaculture practices; however, options for water treatment are still lacking. Conventional processes are not designed to deal with MPs; this review article consolidates relevant information on the application of advanced oxidation technologies (AOTs) and constructed wetlands (CWs) as potential strategies in this regard. Although 161 studies on the application of AOTs or CWs in aquaculture have already been published, only 34 focused on MPs (28 on AOTs and 6 on CWs), whereas the others reported the removal of contaminants such as bacteria, organic matter, solids and inorganic ions. No study coupling both treatments has been reported to date for the removal of MPs from aquaculture waters. AOTs and CWs are prospective alternatives for the treatment of aquacultural aqueous matrices. However, the type of aquaculture activity and the specifications of these available technologies should be considered while selecting the most suitable treatment option. [Display omitted] • Micropollutants in aquaculture water is a concern of the European Commission. • Chemical and biological treatments to remove these micropollutants are reviewed. • Studies with real matrices are scarce for advanced oxidation technologies (AOTs). • More studies conducted at full scale are needed for constructed wetlands (CWs). • Both AOTs and CWs can remove conventional pollutants from aquaculture waters. [ABSTRACT FROM AUTHOR]

• BTL racemate and enantiomers can modulate biochemical responses. • A significant increase in mortality was found at the highest rac-BTL concentration. • Enantioselective effects were observed in morphophysiological parameters. • AOTs efficiencies to remove BTL were below 29 %. • The toxicity of BTL-spiked wastewater effluents was reduced after AOTs treatments. Butylone (BTL) is a chiral synthetic cathinone available as a racemate and reported as contaminant in wastewater effluents. However, there are no studies on its impact on ecosystems and possible enantioselectivity in ecotoxicity. This work aimed to evaluate: (i) the possible ecotoxicity of BTL as racemate or its isolated (R)- and (S)- enantiomers using Daphnia magna ; and (ii) the efficiency of advanced oxidation technologies (AOTs) in the removal of BTL and reduction of toxic effects caused by wastewaters. Enantiomers of BTL were obtained by liquid chromatography (LC) using a chiral semi-preparative column. Enantiomeric purity of each enantiomer was > 97 %. For toxicity assessment, a 9-day sub-chronic assay was performed with the racemate (at 0.10, 1.0 or 10 μg L−1) or each enantiomer (at 0.10 or 1.0 μg L−1). Changes in morphophysiological, behavioural, biochemical and reproductive endpoints were observed, which were dependent on the form of the substance and life stage of the organism (juvenile or adult). Removal rates of BTL in spiked wastewater (10 μg L−1) treated with different AOTs (ultraviolet, UV; ozonation, O 3 ; and UV/O 3) were similar and lower than 29 %. The 48 h D. magna acute toxicity assays demonstrated a reduction in the toxicity of the treated spiked effluents, but no differences were found amongst AOTs treatments. These results warn for the contamination and negative impact of BTL on ecosystems and highlight the need for efficient removal processes. [ABSTRACT FROM AUTHOR]