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In view of the valorisation of the green microalga Scenedesmus obliquus biomass, it was used for the biosorption of two nonsteroidal anti-inflammatory drugs, namely salicylic acid and ibuprofen, from water. Microalgae biomass was characterized, namely by the determination of the point of zero charge (pHPZC), by Fourier transform infrared (FT-IR) analysis, simultaneous thermal analysis (STA) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Kinetic and equilibrium batch experiments were carried out and results were found to fit the pseudo-second order equation and the Langmuir isotherm model, respectively. The Langmuir maximum capacity determined for salicylic acid (63 mg g−1) was larger than for ibuprofen (12 mg g−1), which was also verified for a commercial activated carbon used as reference (with capacities of 250 and 147 mg g−1, respectively). For both pharmaceuticals, the determination of thermodynamic parameters allowed us to infer that adsorption onto microalgae biomass was spontaneous, favourable and exothermic. Furthermore, based on the biomass characterization after adsorption and energy associated with the process, it was deduced that the removal of salicylic acid and ibuprofen by Scenedesmus obliquus biomass occurred by physical interaction.

The biomass growth, pharmaceutical removal and light conversion efficiency of Chlorella sorokiniana under the presence of paracetamol (PC) and salicylic acid (SaC) were assessed and compared at two different concentrations of these pharmaceuticals (I: 25 mg l-1, II: 250 mg l-1). Microalgae were resistant to these concentrations and, moreover, their growth was significantly stimulated (p ≤ 0.05) under these drugs (biomass concentration increased above 33% PCI, 35% SaCI, 13% PCII and 45% SaCII, as compared with the respective positive controls). At the steady state of the semicontinuous culture, C. sorokiniana showed removal efficiencies above 41% and 69% for PCI and PCII, respectively; and above 93% and 98% for SaCI and SaCII, respectively. Under an irradiance of 370 μE m-2 s-1, higher quantum yields were reached by microalgae under the presence of drugs, either at dose I or II, than by the respective positive controls. These results point to C. sorokiniana as a robust strain for the bioremediation of paracetamol and salicylic acid concentrated wastewaters.

In view of the valorisation of the green microalga Scenedesmus obliquus biomass, it was used for the biosorption of two nonsteroidal anti-inflammatory drugs, namely salicylic acid and ibuprofen, from water. Microalgae biomass was characterized, namely by the determination of the point of zero charge (pHPZC), by Fourier transform infrared (FT-IR) analysis, simultaneous thermal analysis (STA) and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS). Kinetic and equilibrium batch experiments were carried out and results were found to fit the pseudo-second order equation and the Langmuir isotherm model, respectively. The Langmuir maximum capacity determined for salicylic acid (63 mg g&minus, 1) was larger than for ibuprofen (12 mg g&minus, 1), which was also verified for a commercial activated carbon used as reference (with capacities of 250 and 147 mg g&minus, 1, respectively). For both pharmaceuticals, the determination of thermodynamic parameters allowed us to infer that adsorption onto microalgae biomass was spontaneous, favourable and exothermic. Furthermore, based on the biomass characterization after adsorption and energy associated with the process, it was deduced that the removal of salicylic acid and ibuprofen by Scenedesmus obliquus biomass occurred by physical interaction.

In this work, zebrafish embryo bioassays were performed to assess the efficiency of microalgae in the removal of acetaminophen from water. Chlorella sorokiniana (CS), Chlorella vulgaris (CV) and Scenedesmus obliquus (SO) were the strains used for water treatment. Toxic effects on zebrafish embryo caused by effluents from microalgae treatment were compared with those observed under exposure to experimental solutions with known concentrations of acetaminophen. The three microalgae strains allowed for the reduction of acetaminophen concentration and its toxic effects, but CS was the most efficient one. At the end of the batch culture, a 67% removal was provided by CS with a reduction of 62% in the total abnormalities on the exposed zebrafish embryo. On the other hand, toxic effects observed under exposure to effluents treated by microalgae were alike to those determined for acetaminophen experimental solutions with equivalent concentration. Thus, it may be inferred that microalgae biodegradation of acetaminophen did not involve an increased toxicity for zebrafish embryo.

This work aimed to compare the adsorptive removal of diclofenac from ultrapure and wastewater by different adsorbents. Batch kinetic and equilibrium experiments were carried out using two different activated carbons (GPP20 and WP70, from Chemviron Carbon) and a non-ionic polymeric resin (SP207, from Resindion). The pseudo-second-order equation fitted the kinetic experimental results and the corresponding k2 (g mg−1 min−1) determined for the activated carbons was one order of magnitude higher than for the polymeric resin. The equilibrium results were fitted by the Langmuir–Freundlich isotherm. The determined maximum adsorption capacity (Qm, mg g−1) and the adsorbent–adsorbate affinity parameter (KLF, mg g−1 (mg L−1)−1/n) were one order of magnitude higher for the activated carbons than for the polymeric resin. With respect to the influence of the aqueous matrix, both the k2 and the Qm remained the same in ultrapure as in wastewater. Differently, the KLF showed one order of magnitude higher values i...

Pharmaceuticals represent an especially worrying class of micropollutants because they are biologically active. Thus, their occurrence in the aquatic environment may cause undesirable effects in living organisms and, if present in water sources for human consumption, may constitute a public health issue. Actually, wastewater treatment plants (WWTP), which were not designed for the removal of pharmaceuticals and cannot guarantee their full elimination, are considered hotspots for their dissemination in natural waters. In this context, the present Special Issue (SI) was launched to contribute to the assessment of the current challenges and advances on the removal of pharmaceuticals from wastewater. The SI consists of seven works with any of two different perspectives: (i) fate and removal of pharmaceuticals by conventional treatments applied in existing WWTP; (ii) advanced and alternative green approaches to remove pharmaceuticals from water. The papers in this SI included five experimental works, two literature reviews, and one case study, all of them presenting unconventional approaches, original views, innovative research and/or novel methodologies. We hope that readers of this SI published by Water may find these papers useful for their research or actual activity and may share the findings with their colleagues and community stakeholders.

In the present work, the adsorptive removal of diclofenac from water by biosorption onto non-living microalgae biomass was assessed. Kinetic and equilibrium experiments were carried out using biomass of two different microalgae strains, namely Synechocystis sp. and Scenedesmus sp. Also, for comparison purposes, a commercial activated carbon was used under identical experimental conditions. The kinetics of the diclofenac adsorption fitted the pseudo-second order equation, and the corresponding kinetic constants indicating that adsorption was faster onto microalgae biomass than onto the activated carbon. Regarding the equilibrium results, which mostly fitted the Langmuir isotherm model, these pointed to significant differences between the adsorbent materials. The Langmuir maximum capacity (Qmax) of the activated carbon (232 mg∙g&minus, 1) was higher than that of Scenedesmus sp. (28 mg∙g&minus, 1) and of Synechocystis sp. (20 mg∙g&minus, 1). In any case, the Qmax values determined here were within the values published in the recent scientific literature on the utilization of different adsorbents for the removal of diclofenac from water. Still, Synechocystis sp. showed the largest KL fitted values, which points to the affinity of this strain for diclofenac at relative low equilibrium concentrations in solution. Overall, the results obtained point to the possible utilization of microalgae biomass waste in the treatment of water, namely for the adsorption of pharmaceuticals.

The performance of a polymeric resin (Sepabeads SP207, from Resindion, Binasco, Italy) was compared with that of an activated carbon (GPP20, from Chemviron Carbon, Feluy, Belgium) in the adsorption of acetaminophen and ibuprofen from either ultrapure or waste water. Kinetic and equilibrium adsorption experiments were carried out under batch operation conditions, and fittings of the obtained results to different models were determined. The kinetic experimental results fitted the pseudo-first and -second order equations, and the corresponding kinetic rates evidenced that the pharmaceuticals adsorption was faster onto GPP20 than onto Sepabeads SP207, but was mostly unaffected by the aqueous matrix. The equilibrium results fitted the Langmuir-Freundlich isotherm model. The corresponding maximum adsorption capacity (Qm, mg&minus, 1) was larger onto GPP20 (202 mg g&minus, 1 &le, Qm &le, 273 mg g&minus, 1) than onto the polymeric resin (7 mg g&minus, 18 mg g&minus, 1). With respect to the parameter KLF (mg g&minus, 1 (mg L&minus, 1)&minus, 1/n), which points to the adsorbent-adsorbate affinity, greater values were determined for the pharmaceuticals adsorption onto GPP20 than onto Sepabeads SP207. For both adsorbents and pharmaceuticals, neither Qm or KLF were affected by the aqueous matrix.

This work presents the application of a new system for wastewater treatment in the food industry, which is based in the injection of pure oxygen in the homogenization tank of a traditional physicochemical treatment. This system operates stably under a wide variety of both input chemical oxygen demand (COD) and total suspended solids (TSS). Compared with the previous physicochemical system, it has been proved that the new one is more efficient and implies important economic savings for the dairy. Compared with a traditional anaerobic treatment, it has been shown that the oxygen injection system avoids the relatively high costs associated to the initial investment and operating costs and is environmentally friendlier. In this work it is shown that oxygen injection may be an interesting option for the dairy industry wastewater treatment.

Benzotriazole is used as corrosion inhibitor in many industrial sectors, such as the dairy industry. Due to its widespread use in various applications and everyday consumer products, this chemical easily reaches the aquatic environment, where it may have deleterious effects. In fact, benzotriazole has been included among the so-called emerging contaminants. In this work, the occurrence and fate of a benzotriazole based anticorrosive (BTA-A) during wastewater treatment in a dairy industry has been assessed. At this dairy, a new system for wastewater treatment based on the injection of pure oxygen was recently started. This system has been proved to be efficient, economic and able to stably operate under a wide range of chemical oxygen demand and total suspended solids inputs. Then, after detecting the presence of BTA-A in the effluent of the wastewater treatment plant, it was aimed to optimize oxygen injection for the removal of this anticorrosive together with the regulated parameters. The performance of the system was evaluated at a real scale during a month period, during which the mean removal performance of the oxygen injection based treatment was 91%, 90% and 99% for chemical oxygen demand, total suspended solids and BTA-A, respectively.

Thermal valorization of organic wastes by co-processing with coal may be a management option for such wastes. In this work, the separate pyrolysis of coal and primary and secondary pulp mill sludge was assessed by thermogravimetric (TG) analysis. Then, under the same experimental conditions, the pyrolysis TG curves of the coal blends with a 10 mass% of either primary or secondary pulp mill sludge were obtained. The corresponding differential thermogravimetry curves made evident that the devolatilization of coal starts at higher temperature and reaches higher char yields than that of primary or secondary paper mill sludge. Under blending, lower devolatilization temperatures and char yields, close to the weighted calculated ones, are observed. Non-isothermal kinetic analysis showed that the Arrhenius activation energy (E) corresponding to the pyrolysis of coal was lower than that corresponding to either L1 or L2. Moreover, lower E than the weighted calculated ones was determined for the co-pyrolysis of the blends.

Microalgae are aquatic photosynthetic prokaryotic or eukaryotic microorganisms which cultivation for the fixation of CO2 and the production of biofuels has received large attention. However, the sustainable development of an algal biorefinery is still a challenge. In this context, the valorization of microalgae biomass for a wastewater adsorptive treatment may be an option to explore. Recently, the presence of emerging contaminants (ECs) in natural waters and the associated risks have led to a great concern, especially in the case of pharmaceuticals. In the present work, the elimination of paracetamol from water by biosorption onto microalgae, namely Synechocystis sp., has been studied. Kinetic and equilibrium parameters have been determined and compared with those obtained when using a commercial activated carbon under the same experimental conditions. Although the adsorption kinetics are very similar onto both materials, at the equilibrium, the Langmuir maximum capacity of the activated carbon (278 mg g−1) is five times higher than that of Synechocystis sp. (53 mg g−1). In any case, it must be considered that the utilization of microalgae may be considered an environmentally friendly process with important associated savings.