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Mature landfill wastewater is a complex effluent due to its low biodegradability and high organic matter content. Currently, mature leachate is treated on-site or transported to wastewater treatment plants (WWTPs). Many WWTPs do not have the capacity to receive mature leachate due to its high organic load leading to an increase in the cost of transportation to treatment plants more adapted to this type of wastewater and the possibility of environmental impacts. Many techniques are used in the treatment of mature leachates, such as coagulation/flocculation, biological reactors, membranes, and advanced oxidative processes. However, the isolated application of these techniques does not achieve efficiency to meet environmental standards. In this regard, this work developed a compact system that combines coagulation and flocculation (1st Stage), hydrodynamic cavitation and ozonation (2nd Stage), and activated carbon polishing (3rd Stage) for the treatment of mature landfill leachate. The synergetic combination of physicochemical and advanced oxidative processes showed a chemical oxygen demand (COD) removal efficiency of over 90% in less than three hours of treatment using the bioflocculant PGα21Ca. Also, the almost absolute removal of apparent color and turbidity was achieved. The remaining CODs of the treated mature leachate were lower when compared to typical domestic sewage of large capitals (COD ~ 600 mg L-1), which allows the interconnection of the sanitary landfill to the urban sewage collection network after treatment in this proposed system. The results obtained with the compact system can help in the design of landfill leachate treatment plants, as well as in the treatment of urban and industrial effluents which contains different compounds of emerging concern and persistence in the environment.

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Eprinomectin, a veterinary drug within the family of avermectins, is widely used in the agricultural sector to combat a variety of parasites, mainly nematodes. However, only 10% of the drug is metabolized in the organism, so large quantities of the drug are released into the environment through urine and/or feces. Soil is the first and main environmental compartment to be contaminated by it, and nontargeted organisms can be affected. Thus, the present study aims to evaluate the phytotoxicity (through the evaluation of germination, root development, and germination speed) and genotoxicity (through an assessment of the induction of micronuclei and chromosomal aberrations) of eprinomectin. For the analyses, Allium cepa seeds were germinated in soil contaminated with a range of concentrations of eprinomectin: from 0.5 to 62.5 µg/g for the genotoxicity test and from 0.5 to 128.0 µg/g for the phytotoxicity test. The results showed that seed germination was not affected, but root development was affected at concentrations of 0.5 µg/g, 1.0 µg/g, 4.0 µg/g, 8.0 µg/g, 64.0 µg/g, and 128.0 µg/g, and germination speed was significantly changed at concentrations of 1.0 µg/g, 4.0 µg/g, 16.0 µg/g, 32.0 µg/g, and 64.0 µg/g. Significant differences in the mitotic index and genotoxicity index were observed only at concentrations of 2.5 µg/g and 12.5 µg/g, respectively. Only the 0.5 µg/g concentration did not show significant induction of micronuclei in the meristematic cells, but the damage observed at other concentrations did not persist in F1 cells. According to the results, eprinomectin is both phytotoxic and genotoxic, so the release of eprinomectin into the environment should be minimized.

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The concerns regarding the occurrence of pharmaceuticals in wastewater treatment plants have increased in the last decades. Gatifloxacin (GAT), the fourth generation of fluoroquinolones, has been widely used to treat both Gram-positive and Gram-negative bacteria and has a limited metabolization. The present study aimed to evaluate ozonation as a technique to degrade GAT. An exchange A UHPLC-MS/MS by an UHPLC-MS/MS method was used to quantify the residual of GAT and to assess its degradation products. The removal efficiency was higher under alkaline conditions (pH = 10), reaching up to 99% of GAT after 4 min. It was also observed that the first ozone attack on the GAT molecule was through the carboxylic group. In contrast, under acid conditions (pH = 3), the ozone attack was first to the piperazinyl ring. The antimicrobial activity was evaluated using Escherichia coli and Bacillus subtilis as test organisms, and it was observed that the residual activity reduced most under alkaline conditions. In contrast, the best condition to remove the residual toxicity evaluated for the marine bacteria V. fischeri was the acidic one. Due to this, ozonation seemed to be an exciting process to remove GAT in aqueous media.

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In a post-pandemic scenario, indoor air monitoring may be required seeking to safeguard public health, and therefore well-defined methods, protocols, and equipment play an important role. Considering the COVID-19 pandemic, this manuscript presents a literature review on indoor air sampling methods to detect viruses, especially SARS-CoV-2. The review was conducted using the following online databases: Web of Science, Science Direct, and PubMed, and the Boolean operators "AND" and "OR" to combine the following keywords: air sampler, coronavirus, COVID-19, indoor, and SARS-CoV-2. This review included 25 published papers reporting sampling and detection methods for SARS-CoV-2 in indoor environments. Most of the papers focused on sampling and analysis of viruses in aerosols present in contaminated areas and potential transmission to adjacent areas. Negative results were found in 10 studies, while 15 papers showed positive results in at least one sample. Overall, papers report several sampling devices and methods for SARS-CoV-2 detection, using different approaches for distance, height from the floor, flow rates, and sampled air volumes. Regarding the efficacy of each mechanism as measured by the percentage of investigations with positive samples, the literature review indicates that solid impactors are more effective than liquid impactors, or filters, and the combination of various methods may be recommended. As a final remark, determining the sampling method is not a trivial task, as the samplers and the environment influence the presence and viability of viruses in the samples, and thus a case-by-case assessment is required for the selection of sampling systems.

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Photoperoxidation (UV/H2O2) was used to degrade three of the worldwide most consumed antidepressant pharmaceuticals-bupropion, escitalopram, and fluoxetine-in ultrapure water, drinking tap water, surface water, and reclaimed water. The study was performed with antidepressants in concentration levels in which these compounds usually occur in the water matrices. Online solid-phase extraction coupled to UHPLC-MS/MS was used to quantify the analytes during degradation studies. The UV/H2O2 process was able to degrade bupropion and fluoxetine in ultrapure water, using 0.042 mmol L-1 of H2O2 and 1.9 kJ of UV-C irradiation. Nevertheless, escitalopram, which had the most recalcitrant character among the studied antidepressants, needed a tenfold more oxidant and UV-C irradiation. The primary metabolites of the antidepressants were identified as the major by-products generated by the UV/H2O2 process, and they persisted in the solution even when the parent compound was degraded. The residual toxicity of the solution was evaluated for two different trophic levels. The UV/H2O2 process reduced the toxicity of the solution to Raphidocelis. subcapitata microalgae after 30 min of reaction. On the other hand, the toxicity of the residual solution increased over the reaction time to the marine bacteria Vibrio fischeri (reaching up to 48.3% of bioluminescence inhibition after 60 min of reaction). Thus, our results evidenced that the toxicity against different trophic levels and the monitoring of the by-products formed are important aspects to be considered regarding the safety of the treated solution and the optimization of the treatment process.

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Benzimidazoles (BZ) are among the most used drugs to treat parasitic diseases in both human and veterinary medicine. In this study, solutions fortified with albendazole (ABZ), fenbendazole (FBZ), and thiabendazole (TBZ) were subjected to photoperoxidation (UV/H2O2). The hydroxyl radicals generated by the process removed up to 99% of ABZ, and FBZ, in the highest dosage of H2O2 (i.e., 1.125 mmol L-1; 4.8 kJ L-1). In contrast, 20% of initial TBZ concentration remained in the residual solution. In the first 5 min of reaction (i.e., up to 0.750 mmol L-1 of H2O2), formation of the primary metabolites of ABZ-ricobendazole (RBZ), albendazole sulfone (ABZ-SO2), and oxfendazole (OFZ)-was observed. However, these reaction products were converted after the reaction time was doubled. The residual ecotoxicity was investigated using the Raphidocelis subcapitata microalgae and the marine bacteria Vibrio fischeri. The results for both microorganisms evidence that the residual solutions are less harmful to these microorganisms. However, after 30 min of reaction, the treated solution still presents a toxic effect for V. fischeri, meaning that longer reaction times are required to achieve an innocuous effluent.

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This study presents a comparison of three methods for TiO2-N synthesis that were applied in the photocatalytic oxidation of the fluoroquinolones (FQs) ciprofloxacin, ofloxacin, and lomefloxacin in aqueous solution. The TiO2-N bandgap is small enough to allow the use of solar energy in the photocatalytic oxidation (PCO) reactions. The TiO2 doped by a sol-gel method with titanium butoxide (TiO2-N-BUT) and titanium isopropoxide (TiO2-N-PROP) as the precursor were effective as the TiO2 (P25) impregnation with urea (TiO2-N-P25) to degrade the FQs. The FQ degradation was higher by 74, 65, and 91%, respectively for TiO2-N-BUT, TiO2-N-PROP, and TiO2-N (load 50 mg L-1, 20 min of reaction under 28 W UV-ASolar). The TiO2-P25 with urea showed the best performance in FQ degradation. The reaction intermediates might present modifications in their acceptor groups by PCO and, because of that the antimicrobial activity dropped as the reaction time increased. Reactions with TiO2-N-P25 (100 mg L-1) and TiO2-N-BUT (100 mg L-1) achieved ≥ 80% of antimicrobial activity removal from the mixed FQ solution (Cciprofloxacin = 100 µg L-1; Cofloxacin = 100 µg L-1; Clomefloxacin = 100 µg L-1) after 40 min of reaction, for both for Escherichia coli and Bacillus subtilis.

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Giardia is a protozoan parasite of primary concern for the drinking water industry. High contact times are required for Giardia inactivation by chlorination, while ozonation may be effective at much lower Ct products. In this study, we have assessed the occurrence of Giardia cysts in raw water, and in chlorinated or ozonated water from a drinking water treatment plant (DWTP) in Brazil, over a 16-month period. Moreover, we analyzed the effects of primary disinfection on cysts, and calculated the infection risk caused by the occurrence of Giardia cysts in raw water, chlorinated or ozonated water. Furthermore, we assessed the correlation of Giardia cysts with indicator bacteria in raw water. Data referring to concentration of Giardia cysts in raw water showed adherence to a gamma distribution at a significance level α = 0.05. The detection frequency and the mean concentration of Giardia cysts were higher in raw water (86.6%, 26 cysts∙L-1), than in chlorinated (46.1%, 15.7 cysts·L-1) or ozonated water (43.5%, 11.1 cysts·L-1). Overall, Giardia non-viable cysts were detected more frequently in ozonated water (80%) than in chlorinated water (68.2%) or raw water (37.7%). Ozonation and chlorination resulted, respectively, in ≈27.5- and ≈13- fold reduction of Giardia infection risk, when compared to the risk calculated for raw water. Total coliform and Escherichia coli proved to be suitable surrogates to predict the occurrence of Giardia cysts in raw surface water, however, the indicator bacteria may not be suitable surrogates to predict the disinfection of Giardia cysts, as no correlation was found between indicator bacteria and Giardia cysts in treated water. To our knowledge, this is the first study reporting the efficacy of chlorine and ozone at Ct products actually applied at a full-scale drinking water treatment plant against Giardia cysts naturally occurring in the source water, i.e. real situation. Ozonation has proven more efficient than chlorination against Giardia cysts in surface water. Escherichia coli proved to be suitable surrogate to predict Giardia cysts in raw surface water.

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Advanced oxidation processes (AOPs) have been highly efficient in degrading contaminants of emerging concern (CEC). This study investigated the efficiency of photolysis, peroxidation, photoperoxidation, and ozonation at different pH values to degrade doxycycline (DC) in three aqueous matrices: fountain, tap, and ultrapure water. More than 99.6% of DC degradation resulted from the UV/H2O2 and ozonation processes. Also, to evaluate the toxicity of the original solution and throughout the degradation time, antimicrobial activity tests were conducted using Gram-positive (Bacillus subtilis) and Gram-negative (Escherichia coli) bacteria, and acute toxicity test using the bioluminescent marine bacterium (Vibrio fischeri). Antimicrobial activity reduced as the drug degradation increased in UV/H2O2 and ozonation processes, wherein the first process only 6 min was required to reduce 100% of both bacteria activity. In ozonation, 27.7 mg L-1 of ozone was responsible for reducing 100% of the antimicrobial activity. When applied the photoperoxidation process, an increase in the toxicity occurred as the high levels of degradation were achieved; it means that toxic intermediates were formed. The ozonated solutions did not present toxicity.

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In this study, a solution containing the fluoroquinolones (FQs) ciprofloxacin, lomefloxacin, and ofloxacin (antimicrobial agents) was subjected to photocatalytic oxidation under UVA irradiation, employing the commercial titanium dioxide as catalyst. On-line solid phase extraction coupled to ultra-high-performance liquid chromatography-mass spectroscopy was used to pre-concentrate and quantify the analytes. The process provided an almost 95% degradation efficiency for all the FQs. The TiO2 PC500 (100% anatase) was more efficient than TiO2 P25 (80% anatase) for FQs degradation. The matrix effect on the efficiency of the process was evaluated by ultrapure water - UW, simulated water - SW, bottled water -BW, and public drinking tap water - TW. Simulated water showed lower interference, compared to drinking water and bottled mineral water, due to the lower concentrations of hydroxyl radical scavengers. The assessment of the residual antimicrobial activity in the solution, when using 50 mg L-1 PC500 or 100 mg L-1 P25, showed reductions of biological activity (after 120 min of reaction) of 92.4% and 95.4% for Escherichia coli, and 78.1% and 84.2% for Bacillus subtilis, respectively. It shows that the photocatalytic oxidation process was able to not only degrade the FQs but also deactivate its biological activity in the resultant solution.

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