The present study investigated the degradation of levonorgestrel (LNG) and gestodene (GES) through an anodic oxidation process mediated by active chlorine species. The independent variables [LNG]₀ and [GES]₀, current density (mA cm⁻²), and [NaCl]₀ (mol L⁻¹) were optimized through a response surface methodology (RSM) based on a four-level central composite design (CCD). Specific energy consumption allowed CCD-RSM analysis and optimization. The decay of progestins was followed to verify the kinetics of the anodic degradation process. Chlorine monitoring showed that excess Cl⁻ concentration did not mean high hormones removal, as well as the excess of current density. Central point conditions ([NaCl]₀ = 0.07 mol L⁻¹, j = 32.5 mA cm⁻², [LNG]₀, and [GES]₀ 1.0 mg L⁻¹) proved to be the best operational option. The performance with real pharmaceutical wastewater confirmed model optimization (2.2 ± 0.2 kWh g⁻¹, with removals of 83.1 ± 0.9% and 75.1 ± 2.8% for LNG and GES, respectively). The selected condition was used for estrogenic activity and acute toxicity assays. The first allowed the identification of the initial estrogenic activity for the mixture of LNG and GES (924 E2-EQ ng L⁻¹). Additionally, the electrochemical process could decrease this environmental parameter by 74.6%. The progestin mixture was classified as acute toxicity to Daphnia similis, with a toxicity unit (TU) of 2.5 100/EC50%. After electrolysis, the hormone solutions reached a fourfold increase in TU value, classified as high acute toxicity. Full article

This work is part of the European research project LIFE15 ENV/ES/00598 whose objective was to develop an efficient and sustainable methodology to eliminate Priority Substances (PS) and Contaminants of Emerging Concern (CEC), in Wastewater Treatment Plants (WWTP). The aim was to achieve reduce the concentration of PSs until their concentration was below the quality limit established in the DIRECTIVE 2013/39/EU, and to achieve reductions of 99% of the initial concentration for the selected CECs. The plant selected for the experimentation was the Benidorm WWTP (Spain). This publication studied the appearance and elimination, in the conventional treatment of this plant, of 12 priority substances (EU) and 16 emerging pollutants (5 of them included in the EU watch lists) during a year of experimentation. The analytical methods of choice were High Performance Liquid Chromatography coupled to a Mass Spectrometer (HPLC-MS/MS) and Gas Chromatography coupled to a Mass Spectrometer (GC-MS/MS). Results showed that the PSs atrazine, brominated diphenyl ether, isoproturon, octylphenol, pentachlorobenzene, simazine, terbutryn, tributyltin, and trifluralin, and the CECs 17-α-ethinylestradiol, 17-β-estradiol, imazalil, orthophenylphenol, tertbutylazine, and thiabendazole, were not detected. The micropollutants with the highest a-verage percentages of removal (>90%) are: chloramphenicol (100%), estriol (100%) and ibuprofen (99%). Partially removed were ketoprofen (79%), chlorpyrifos (78%), di(2-ethylhexyl) phthalate (78%), estrone (76%), sulfamethoxazole (68%), and fluoxetine (53%). The compounds with the lowest average percentage of removal (<50%) are diclofenac (30%), erythromycin (1%), diuron (0%) and carbamazepine (0%). For the micropollutants chlorpyrifos, diclofenac, erythromycin, sulfamethoxazole, carbamazepine, fluoxetine, ibuprofen, and ketoprofen, complementary treatments will be necessary in case there is a need to reduce their concentrations in the WWTP effluent below a certain standard. The presence of the different micropollutants in the samples was not regular. Some of them were presented continuously, such as carbamazepine; however, others sporadically such as chloramphenicol and others were associated with seasonal variations or related to remarkable periods of time, such as sulfamethoxazole. Full article

The present work aimed at the development of Pt-TiO₂/SiO₂ materials applied to the degradation of a pharmaceutical pollutant in a fixed-bed microreactor in continuous mode. First, a wide investigation of the optimal platinum content in TiO₂/SiO₂ was carried out based on extensive characterization through XRD, DRS, SEM, TEM, and XPS techniques. For the content range studied, no significant changes were observed in the crystallinity of the material, with peaks related to the anatase phase and PtO₂ in the diffractograms. SEM images combined with EDS spectra indicated the presence of platinum and a large heterogeneity in the particles. MET analyses showed PtO₂ nanoparticles in close contact with TiO₂, allowing the formation of a type II heterojunction. XPS showed platinum in the 0 and +4 oxidation states, suggesting that platinum metal and PtO₂ are both present. Regarding the degradation experiments, the optimal catalyst achieved 81% degradation of acetaminophen for a residence time of 1 h, while the catalyst without platinum reached only 27% degradation. The catalyst activity dropped from 81 to 57% in 2 h and remained stable for six reuse cycles. Increasing the inlet flow rate and concentration reduced the pollutant degradation although there was an increase in the reaction rate. Finally, a photocatalytic mechanism was proposed in which a type II heterojunction was developed, with generation of hydroxyl radicals by the positive holes in the VB of TiO₂ as well as superoxide radicals by the electrons in the CB of PtO₂. Full article

To investigate the impact of antidepressants (ANT) in water, estimates of the direct and indirect photolysis of standard fluoxetine hydrochloride (FLX) and a pharmaceutical alternative, fluoxetine sulfate (FLXSO₄), were evaluated. The second-order kinetic constants of the ANT and reactive photoinduced species (RPS) (singlet oxygen, ¹O₂; hydroxyl radicals, HO^•; and triplet excited states of chromophoric dissolved organic matter, ³CDOM*) were obtained by competition kinetics under simulated solar radiation. These parameters were used in combination with water characteristics to assess the environmental persistence of the ANT based on mathematical kinetic simulations. The results indicated that the reactions with HO^• (k_FLX,HO^• = (2.54 ± 0.06) × 10⁹ L mol⁻¹ s⁻¹; k_{FLXSO4,HO^•} = (3.07 ± 0.03) × 10⁹ L mol⁻¹ s⁻¹) and ³CDOM* (k_FLX,³CDOM* = (2.67 ± 0.05) × 10⁹ L mol⁻¹ s⁻¹; k_{FLXSO4,³CDOM*} = (1.48 ± 0.03) × 10⁹ L mol⁻¹ s⁻¹) play a more important role in the degradation of ANT compared to the reactions with ¹O₂ (k_FLX,¹O2 = (1.37 ± 0.07) × 10⁷ L mol⁻¹ s⁻¹; k_FLXSO4,¹O2 = (1.63 ± 0.33) × 10⁷ L mol⁻¹ s⁻¹). The main removal pathways were biodegradation and direct photolysis with persistence in the following order FLX > FLXSO₄. Therefore, the presence of sulfate anions can contribute to the degradation of fluoxetine in sunlit environmental waters. Full article

Hydrogels have attracted great attention as good adsorbents due to their extraordinary water retention capacity, unique hydrophilic nature, biocompatibility, and abundance in availability. In this work, a superabsorbent polymer (SAP) hydrogel and its composite were synthesized, with the introduction of activated charcoal (SAP-AC) for deep removal of the ecotoxic organic dye methylene blue (MB). The formation of the hydrogel was confirmed by FTIR analysis, and scanning electron microscopy (SEM) revealed the appearance of a porous microstructure due to the incorporation of AC. A continuous upflow column was set up, and the adsorption parameters were optimized using an experimental Doehlert uniform array design. The residual concentration of MB was analyzed by UV-Vis spectrophotometry at 665 nm (λ_max). The experimental data were also discussed in terms of adsorption kinetics and adsorption isotherm models. Accordingly, MB adsorption followed pseudo second-order kinetics and better fits the Freundlich isotherm, suggesting a chemisorption mechanism and a multilayer MB adsorption system. The maximum adsorption capacity was 202.84 mg g⁻¹ (96.96%) using the SAP and 213.2 mg g⁻¹ (99.48%) using the SAP-AC. The present study proved that the synthesized composite hydrogel has good activity and selectivity for deep removal of the MB dye and can be effectively used in wastewater treatment. Full article

The reduction of organic micropollutants (OMP) in rivers, lakes and groundwater is an essential legal obligation of the European Water Framework Directive. Since OMP treatment in full-scale wastewater treatment plants (WWTPs) is not state of the art yet, there is little knowledge regarding removal performances, in particular during wet weather. We aimed to contribute to filling this knowledge gap by providing insights from a German case study. On-site measurements were conducted to investigate the impact of rain events on OMP removal with activated carbon processes using powdered activated carbon (PAC) and granular activated carbon (GAC). The study focused on 26 OMPs with different entry paths in the combined sewer system (CSS) and various physico-chemical properties. The monitored OMPs showed higher mass loads during wet weather at all sampling points: effluent of the secondary clarifier, effluent of the PAC treatment stage, and effluent of the GAC filter. As a result of shortened hydraulic retention time (HRT) due to rain events, the overall OMP removal was significantly lower (42% PAC and 46% GAC) than during dry weather (68% PAC and 62% GAC). In order to achieve constant removal rates during all weather conditions, the critical process control parameters are currently being investigated in ongoing studies. Full article

This work presents an empirical and scaling-up study of the degradation and mineralization of amoxicillin (AMX) from expired pharmaceutical formulations by O₃-based processes. A set of UV–ozone-based experiments was used to model the kinetics of AMX degradation, considering several chemical/photochemical mechanisms (hydrolysis, direct ozonation, radical reactions, and photolysis). Finally, the modeling data were used for scaling-up purposes, considering CAPEX and OPEX costs on the US Gulf Coast basis. In terms of experimental results, the amoxicillin (AMX) pharmaceutical effluent was successfully degraded by ozone technology at high pH values. The semi-batch ozonation process was effective after 60 min of treatment in all experimental conditions, producing degradation intermediates recalcitrant to O₃ oxidative process. From the bench-scale kinetics, scaling-up simulations indicate that the gain provided by adding a UV unit does not compensate for the increase in capital and operational costs of adding irradiation equipment. It suggests ozonation at high pH as the best cost-effective approach to degrade AMX. The figures-of-merit electric energy consumption per order (E_EO) corroborates the scaling-up simulations. E_EO results indicate no-UV ozonation as the best option to degrade AMX at high pH values. The E_EO of the present work showed a lower energy consumption system than previous papers from the literature. Full article

Pharmaceutically active compounds (PhACs) are continuously introduced into the environment by human and livestock excretion, hospital sewage and pharmaceutical effluents. While the performance of UV photolysis regarding PhACs degradation may be limited by low quantum yields, it may be efficient when the contaminants significantly absorb UV radiation. In this work, the direct photolysis under 254 nm UVC radiation of acetaminophen (ACT), atenolol (ATL), bezafibrate (BZF), diclofenac (DIC) and ibuprofen (IBU), isolated and in mixture, was investigated. The results showed that PhAC photolysis followed apparent first-order kinetics, with removals ranging from 32% to 99% after 60 min, while all the compounds exhibited lower photolysis rates when mixed in solution. Less than 13% mineralization was achieved. The toxicity of irradiated solutions of Vibrio fischeri remained the same or slightly decreased for ATL, BZF and IBU, increased for ACT, and notably decreased for DIC; nevertheless, the solution of mixed PhACs became very toxic following irradiation, showing the need for oxidant addition for removing residual toxicity. Full article