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Polycyclic aromatic hydrocarbons (PAHs) belong to the persistent organic pollutant class and are ubiquitously present in the environment. As a consequence of their high hydrophobicity, PAHs in aquatic environments tend to rapidly sink down to the bottom sediments which are the most important reservoirs of PAHs in the aquatic environment. This paper presents the validation and further performance evaluation of a method modified in-house for PAHs’ sample preparation and analysis in sediment using gas chromatography-mass spectrometry (GC-MS). The method validation covers determining the calibration linear range, method detection and quantitation limits, method recovery and precision, method uncertainty and further internal and external quality control steps. Principal component analysis was used to identify the influence of different variables on method performance and indicated main clustering by PAH molecule size. The results of a two-year quality control programme show that the variations in method performance were not statistically significant in comparison to the parameters set during the validation experiments. Trueness expressed as recovery was very similar for spiked sediment samples and the analysed certified reference material (CRM) (70.6–113%). Expanded uncertainty ranged from 40.4% to 50.9% with higher values noted for the highly hydrophobic PAHs benzo(a)pyrene and benzo(g,h,i)perylene.

Microplastics are ubiquitous in aqueous media, and the importance of considering their impact on the behaviour of other compounds in water has often been highlighted. This work thus investigates the adsorption mechanism of six priority substances (as defined by European Union legislation: trichlorobenzenes (1,2,3-TeCB, 1,3,5-TeCB, 1,2,4-TeCB), pentachlorobenzene (PeCB), hexachlorobenzene (HeCB), and trifluralin (TFL)) on primary polyethylene (PE) microplastics (polyethylene standard and polyethylene microparticles isolated from two personal care products) in Danube river water and a synthetic matrix. The maximum adsorbed amounts of the compounds investigated on PEs ranged from 227 μg/g for 1,2,3-TeCB to 333 μg/g for TFL. Equilibrium data was analysed using five isotherm models, with the best fit being described by the Langmuir model and the Dubinin-Radushkevich model indicating chemisorption as the likely sorption mechanism. In general, the Langmuir model showed that the investigated compounds will be better adsorbed on PEs in real river water, with the exception of 1,3,5-TeCB on all studied PEs, where the model predicts better sorption in the synthetic matrix. Compound characteristics and the polymer properties were the most important factors affecting the sorption process, while a significant matrix effect was also observed on PE behaviour. The fact that polyethylene particles derived from personal care products showed greater adsorption capacities than virgin PE demonstrates the necessity of investigating real-world PE samples when assessing the potential impact of MPs in the environment.

Combination of 'green' coagulation and powdered activated carbon adsorption was tested for removal of benzophenone (BP), benzophenone-3 (BP-3) and caffeine (CF) from treated municipal wastewater at realistic concentration levels (1-2 µg/L). At the same time it was tracked how the process affected effluent organic matter (EfOM) by measuring chemical oxygen demand (COD). Green coagulant was produced from dry common bean seed in laboratory. Combined coagulation-adsorption experiments were performed by applying different dosing sequences of process materials. Removal of hydrophobic BP and BP-3 by separate adsorption (from 79 to 98%) was not significantly hindered by the addition of the coagulant (activated carbon dose of 5 or 20 mg/L). However, in some cases negative effects were observed for hydrophilic caffeine, depending on the carbon dose, dosing sequence and presence of total suspended solids (TSS). Thus, when coagulant was firstly added into water without TSS before low activated carbon dose of 5 mg/L, caffeine removal dropped from 26% to 5%. Conversely, when TSS were present in the water sample, the removal of caffeine was not hindered under the same PAC dose and dosing sequence. The importance of the process optimisation related to removal of organic micropollutans of different hydrophilicity has been shown in this paper. Removal of around 30% of COD regardless of the dosing sequence was achieved.

The presence of a large number of micropollutants in the environment, including priority and emerging substances, poses a significant risk to surface and groundwater quality. Among them, trichlorobenzenes are widely used in the syntheses of dyes, pesticides, solvents, and other chemicals and have been identified as priority pollutants by the European Water Framework Directive. The main goal of this study was to investigate the behavior of 1,2,3-trichlorobenzene (TCB) during the sulfate radical–based advanced oxidation processes (SR-AOPs) involving UV activation of persulfate or peroxymonosulfate (UV/S2O82− and UV/HSO5− processes). For this purpose, TCB was subjected to SR-AOPs in synthetic water matrices containing humic acids or hydrogencarbonate and natural water samples and a comparative evaluation of the degradation process was made. The toxicity of the oxidation by-products was also assessed. The evaluation of TCB degradation kinetics results using principal component analysis indicates that the efficacy of the SR-AOPs was highly dependent on the pH, initial oxidant concentration, UV fluence, and matrix characteristics. In natural waters, TCB degradation by the UV/S2O82− process proved to be most effective in acidic conditions (pH 5), while the UV/HSO5− process showed the highest efficacy in basic conditions (pH 9.5), achieving a maximum TCB degradations of 97–99%. The obtained results indicate that UV/S2O82− and UV/HSO5− as new generation oxidation processes have significant potential for TCB removal from water and result in only minor toxicity after treatment (14–23% of Vibrio fischeri bioluminescence inhibition).

© 2020 The Royal Society of Chemistry. In water treatment, the application of advanced oxidation processes (AOPs) which involve the generation of not only hydroxyl but also sulfate radicals has recently attracted increasing attention worldwide. To the best of our knowledge, to date, the application of ultraviolet (UV) activated persulfate and peroxymonosulfate (UV/S2O82- and UV/HSO5-) has not been comprehensively studied for chloroacetanilide herbicide degradation. In our study, this process was investigated under different conditions and compared to the more conventional UV/H2O2 process. Alachlor was investigated due to its toxic properties, and the threat it poses to aquatic environments and human health, which led to its classification as a priority pollutant by the European Water Framework Directive. The alachlor degradation kinetics of different UV-based AOPs were highly dependent on the pH and the water matrix characteristics. The UV/S2O82- and UV/H2O2 processes proved to be most effective under acidic conditions (pH 5), while the UV/HSO5- process showed the highest alachlor degradation efficacy under basic conditions (pH > 8). The groundwater matrix had a greater impact on the AOPs than the surface water. PCA analysis was applied and a predictive model of alachlor degradation by UV-based AOPs was proposed. Alachlor degradation pathways were also evaluated together with NOM transformation during the applied treatments. The obtained results indicate that the more novel UV/S2O82- and UV/HSO5- processes show significant potential for herbicide degradation during water treatment, especially when the raw water is highly loaded with hydrophobic NOM.

Plastic fragments, weathered into or released in the form of micro- and nanoplastics, are persistent and widespread in the environment, and it is anticipated that they have negative environmental impacts. This necessitates immediate efforts for management strategies throughout the entire plastics lifecycle. This opinion paper was initiated by the EU COST Action CA20101 PRIORITY, which focuses on the need to develop an effective global networking platform dealing with research, implementation, and consolidation of ways to address the worldwide challenges associated with micro- and nanoplastics pollution in the environment., Microplastics, 1 (2), ISSN:2673-8929

Synthetic fibers enter wastewater treatment plants together with natural fibers, which may affect treatment efficiency, a fact not considered in previous studies. Therefore, the aim of the present study was to evaluate the efficiency of the coagulation/flocculation process for the removal of a mixture of textile fibers from different water matrices. Natural and synthetic fibers (100 mg/L; cotton, polyacrylonitrile, and polyamide) were added to a synthetic matrix, surface water and laundry wastewater and subjected to coagulation/flocculation experiments with ferric chloride (FeCl3) and polyaluminum chloride (PACl) under laboratory conditions. In the synthetic matrix, both coagulants were found to be effective, with FeCl3 having a lesser advantage, removing textile fibers almost completely from the water (up to 99% at a concentration of 3.94 mM). In surface water, all dosages had approximately similar high values, with the coagulant resulting in complete removal. In laundry effluent, the presence of surfactants is thought to affect coagulation efficiency. PACl was found to be effective in removing textile fibers from laundry wastewater, with the lowest removal efficiency being 89% and all dosages having similar removal efficiencies. Natural organic matter and bicarbonates showed a positive effect on the efficiency of FeCl3 in removing textile fibers from surface water. PACl showed better performance in coagulating laundry wastewater while surfactants had a negative effect on FeCl3 coagulation efficiency.

© 2019, © 2019 Informa UK Limited, trading as Taylor & Francis Group. Arsenic contamination of drinking water sources is a widespread global problem. Of the As species commonly found in groundwater, As(III) is generally more mobile and toxic than As(V). In this work, magnetic nanoparticles (MNp) modified with Fe-Mn binary oxide (MNp-FeMn) were synthesized in order to develop a low cost adsorbent with high removal efficiency for both arsenic species which can be readily separated from water using a magnetic field. MNp-FeMn were characterized using different techniques including SEM/EDS, XRD and BET analysis. Adsorption of As(III) and As(V) on MNp-FeMn was studied as a function of initial arsenic concentration, contact time, pH, and coexisting anions. The BET specific surface area of MNp-FeMn was 109 m2/g and maghemite (γ-Fe2O3) was the dominant precipitated phase. The adsorption rate of As(III) and As(V) on MNp-FeMn was controlled by surface diffusion. FTIR analysis confirms that surface complexation through ligand exchange was the main mechanism for As(III) and As(V) removal on MNp-FeMn, with As(III) conversion to As(V) occurring on the adsorbent surface. The maximal adsorption capacity qmax of MNp for As(III) (26 mg/g) was significantly improved after modification with Fe-Mn binary oxide (56 mg/g), while qmax for As(V) was 51 and 54 mg/g, respectively. PO3−4 , SiO2−3 and CO2− reduced As(III) and As(V) uptake at higher concentrations. MNp-FeMn can be easily regenerated and reused with only a slight reduction in adsorption capacity. The high oxidation and sorption capacity of MNp-FeMn, magnetic properties and reusability, suggest this material is a highly promising adsorbent for treatment of arsenic contaminated groundwater.

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. This study investigates the impact of humic acid (HA) on the toxicity of selected herbicides and their binary mixtures to aquatic plants. The focus was on two auxin simulators (2,4-D and dicamba) and two photosynthetic inhibitors (atrazine and isoproturon). The results suggested that the addition of HA to the standard synthetic medium does not affect Lemna minor growth nor the toxicity of atrazine, but increases the toxicity of 2,4-D and the binary mixture of atrazine and 2,4-D. The addition of HA to the standard synthetic medium reversibly decreased the growth (biomass) of Myriophyllum aquaticum and enhanced the toxicity of individually tested herbicides (isoproturon and dicamba) as well as their binary mixture. The results showed delayed toxic effects of auxin simulators, especially 2,4-D in the Lemna test. The recovery after the exposure to individual photosystem II inhibitors (atrazine and isoproturon) is fast in both plant species, regardless of the presence of HA. In the case of selected mixtures (atrazine + 2,4-D and isoproturon + dicamba), recovery of both plant species was noted, while the efficiency depended on the herbicide concentration in the mixture rather than the presence or absence of HA.

© 2019, The Author(s). Background: Whole sediment contact tests provide realistic exposure scenarios, but the inherent properties of sediments may play a significant role in organism’s response and interfere with result interpretation. Recently, a sediment contact test with a rooted aquatic macrophyte Myriophyllum aquaticum has been standardized. The present study aims to distinguish between effects of basic sediment properties and sediment-bound pollutants on M. aquaticum growth and evaluate the method as a tool in sediment quality assessment. Tests with artificial sediments with different organic matter, sand and clay content, as well as freshwater sediments with different levels of contamination were conducted. Results: Results were based on comparison to the standard artificial control sediment. Organic matter content and grain size distribution in different variants of artificial sediments significantly affected M. aquaticum growth. Growth was impaired in formulations with low (1%) and high (10%) organic matter content, while better growth of plants compared to control was recorded in artificial samples with higher fine particles content. Because of the presence of unmeasured pollutants in freshwater sediments and inherent sediment properties, results of the M. aquaticum sediment contact tests were not always in accordance with the results of chemical analysis. Whorl, shoot and root parameters had different variability and showed a particular growth pattern in natural sediments. If the threshold of 20% for sediment toxicity is applied, then about 60% of tested natural sediments may be considered as toxic. As sediment structure may influence plant growth, this interpretation may be false as the physico–chemical properties of the control sediment used for comparison are considerably different from the properties of natural sediments. Conclusions: Since inherent properties showed a significant effect on plant growth, the use of suitable controls more similar to tested natural sediments is advisable. To avoid over-, but also under-estimations, the use of the strict toxicity threshold of 20% or even higher inhibition for this test can be recommended, provided the statistical power of the test is high. The results of this study might contribute to the ongoing process of including effect-based methods in water quality monitoring under the Water Framework Directive.

This study evaluates the effect of photochemical advanced oxidation processes (AOPs) (O3/UV, H2O2/UV and O3/H2O2/UV) on the formation potential (FP) of emerging disinfection by-products including nitrogenous by-products (N-DBPs) and haloketones (HKs) in groundwater from part of the Pannonian Basin (AP Vojvodina, Republic of Serbia). Among the N-DBPs, the haloacetonitrile (HAN) precursor contents were 9.83 ± 0.59 μg/L while precursors of halonitromethanes, particularly trichloronitromethane (TCNM) were not detected. Similarly, precursors of HKs as carbonaceous DBPs were also not detected in raw water. Ozonation alone and the H2O2/UV process with a lower UV dose maximally decomposed HAN precursors (about 70%) while during O3-based AOPs, HANFP varied significantly. Application of UV photolysis and H2O2/UV processes with increasing UV dose doubled the HANFP. Ozone alone, O3/UV and H2O2/UV slightly increased HK formation potential, particularly 1,1-dichloro-2-propanone FP (0.93 ± 0.21 to 2.01 ± 0.37 μg/L). None of the investigated treatments influenced the formation of TCNM precursors. The effect of the applied treatments on bromide incorporation was most evident for HANs.

This paper investigates the removal of arsenic from water using an environmentally friendly modified biosorbent, chitosan coated with Fe–Mn binary oxide (Chit-FeMn), simply prepared with an one-pot low-cost procedure by simultaneous oxidation and coprecipitation. The sorbent was characterized by SEM, EDS, XRD, FTIR, BET specific surface area, and point of zero charge (pHpzc) measurements. The kinetic data fitted a pseudo-second order model for both As(III) and As(V), suggesting chemical adsorption on the sorbent surface and that intra-particle diffusion is not the only rate-limiting step during adsorption. The adsorption isotherms were best fit to the Freundlich model, and the non-monolayer adsorption model for arsenic on Chit-FeMn is therefore proposed. Below pH 9, the effect of pH on As(III) and As(V) removal by Chit-FeMn was insignificant, with As removals remaining above 85 %. Cl- and NO3 - had negligible influences on As(III) and As(V) removal, whereas PO4 3-, SiO3 2-, CO3 2- and SO4 2- were observed to compete with arsenic species for adsorption sites. The adsorbent was successfully applied to remove arsenic from real arsenic contaminated groundwater samples to below 10 μg L-1 suggesting that Chit-FeMn is a promising candidate for the low cost removal of both As(V) and As(III) during drinking water treatment. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. III43005 and Grant no. TR37004]

This study presents the results from a bench-scale UV irradiation experiment of benzophenone (BP) in different water matrices. Despite the reported resistance of BP to UV-irradiation, it was successfully degraded in solution when intensively irradiated by UV light in a batch reactor for 4 h. In this way, it was possible to remove 56 and 45 % of 1.0 and 10 μg·L-1 of BP in Milli-Q water, respectively. The addition of a mixture of anions suppressed the degradation of BP at the lower concentration level by 20 %. The addition of a dissolved organic carbon (DOC) surrogate mixture (DOC:BP mole ratio of 3000:1) increased the degradation of BP in Milli-Q water (removal 80 %). At 1.0 μg·L-1 of BP and 1.0 mg·L-1 of DOC, removal was 70 %, while at 10 μg·L-1 of BP and 10 mg·L-1 of DOC, there was no observable difference in removal compared with the removal in Milli-Q water. The results show that both DOC and anions influence the photodegradation of BP. Furthermore, it was shown that the removal efficiency depends on the concentration of BP. These findings show the importance of a detailed characterisation of the water matrix in studies relating to the removal of micropollutants during UV irradiation. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI172028]

Starting from the assumption that wastewater treatments can have a significant impact on the interactions between microplastics (MPs) and various pollutants in different matrices, a focus must be directed on examination of classic and redesigned treatments to remove synthetic dyes in the presence of MPs from wastewater. This paper investigates the potential application of Fenton-like process for the removal of water-based printing dye (Cyan) from aqueous solution containing MPs in a form of granulated polyethylene (PEg). The influence of five quantitative parameters on decolorization efficiency was investigated: initial dye concentration (20-180 mgL-1), nano zero valent iron (nZVI) dosage (0.75-60 mgL-1), PEg concentration (1-10 gL-1), hydrogen-peroxide concentration (1-11 mM) and pH value (2-10). A novel statistical approach, definitive screening design, resulted with the optimization process which yielded highest removal efficiency of 92% under following conditions: initial dye concentration of 155 mgL-1, nZVI dosage of 55 mgL-1, PEg concentration of 2.35 gL-1, H2O2 concentration of 2 mM and pH value 2.5. Available data indicate that in the future, wastewater containing MPs will dictate ways to reuse this water in terms of closing the water material cycle and reducing environmental pollution. Therefore, the industrial wastewater reuse is an important component of sustainable wastewater management practices, namely, water resource augmentation and pollutant reduction.

The characteristics of the Danube river alluvial sediment are of great importance in assessing the risk for transport of pollutants to drinking water sources. Characterization of the sediment column layers has shown that the alluvial sediment, sampled near the city of Novi Sad, is a mesoporous sandy material with certain differences in the properties of individual layers. In order to investigate the sorption mechanisms of four chlorinated phenols (CPs) on the alluvial deposit, static sorption experiments were performed at pH 4, 7 and 10. The results of sorption experiments, confirmed by principal components analysis sugest different mechanisms govern the sorption process at different pH conditions. This can be attributed to the molecular characteristics of CPs, geosorbent properties and to variations in the surface charge of the sorbent at different pH conditions.

We acknowledge the research support by Copan Italia S.p.A Inc., and Clearblue, SPD Swiss Precision Diagnostics GmbH. This study is part of a PhD Thesis conducted at the Official Doctoral Programme in Biomedicine of the University of Granada, Spain. We are grateful to Ana Yara Postigo-Fuentes for her assistance with English language., Current knowledge suggests that the uterus harbours its own microbiota, where the microbes could influence the uterine functions in health and disease; however, the core uterine microbial composition and the host-microbial relationships remain to be fully elucidated. Different studies are indicating, based on next-generation sequencing techniques, that microbial dysbiosis could be associated with several gynaecological disorders, such as endometriosis, chronic endometritis, dysfunctional menstrual bleeding, endometrial cancer, and infertility. Treatments using antibiotics and probiotics and/or prebiotics for endometrial microbial dysbiosis are being applied. Nevertheless there is no unified protocol for assessing the endometrial dysbiosis and no optimal treatment protocol for the established dysbiosis. With this review we outline the microbes (mostly bacteria) identified in the endometrial microbiome studies, the current treatments offered for bacterial dysbiosis in the clinical setting, and the future possibilities such as pro- and prebiotics and microbial transplants for modifying uterine microbial composition., This work is supported by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and European Regional Development Fund (FEDER): grants RYC-2016-21199 and ENDORE SAF2017-87526-R; Programa Operativo FEDER Andalucía (B-CTS-500-UGR18) and by the University of Granada Plan Propio de Investigación 2016—Excellence actions: Unit of Excellence on Exercise and Health (UCEES)—and Plan Propio de Investigación 2018—Programa Contratos-Puente, and the Junta de Andalucía, Consejería de Conocimiento, Investigación y Universidades, European Regional Development Funds (ref. SOMM17/6107/UGR). A.S.-L. is funded by the Spanish Ministry of Science, Innovation and Universities (PRE2018-0854409).

© 2020, © 2020 Informa UK Limited, trading as Taylor & Francis Group. This paper investigates the fate of natural organic matter (NOM) during the full-scale drinking water treatment plant supplied by Danube river bank filtration. After the recent reconstruction of the plant, special attention was devoted to the effects of ozone dose and granulated activated carbon (GAC) filtration on the formation and behaviour of oxidation by-products (carbonyl compounds and bromate), as well as carbonaceous and nitrogenous chlorination by-products. For the oxidation of aromatic NOM moieties that absorb light at UV254, a lower ozone dose (1.0 g O3/m3) is sufficient, whereas to achieve a measurable reduction (about 20%) of total organic carbon, an ozone dose of 1.5 g O3/m3 is required. The content of carbonyl compounds in the water after ozonation increases relative to the content before oxidation treatment, and is up to 12 times higher in the case of aldehydes and up to 2 times higher in the case of carboxylic acids. Seasonal variations, including changes in temperature and the amount of precipitation, were also shown to affect the content of organic matter in the raw water, with slight effects on the quality of the treated water. In the winter, the organic matter content is slightly higher, meaning their transformation products aldehydes and carboxylic acids, are also higher during the winter than the summer.

The COVID-19 anthropause has impacted human activities and behaviour, resulting in substantial environmental and ecological changes. It has assisted in restoring the ecological systems by improving, for instance, air and water quality and decreasing the anthropogenic pressure on wildlife and natural environments. Notwithstanding, such improvements recessed back, even to a greater extent, when considering increased medical waste, hazardous disinfectants and other chemical compounds, and plastic waste disposal or mismanagement. This work critically reviews the short- and long-term implications of measures against COVID-19 spreading, namely on human activities and different environmental compartments. Furthermore, this paper highlights strategies towards environmental restoration, as the recovery of the lost environment during COVID-19 lockdown suggests that the environmental degradation caused by humans can be reversible. Thus, we can no longer delay concerted international actions to address biodiversity, sustainable development, and health emergencies to ensure environmental resilience and equitable recovery., Thanks to CESAM (UIDP/50017/2020 + UIDB/50017/2020), with the financial support from FCT/MCTES through national funds and to the Programme for Cooperation in Science between Portugal and Serbia 2020–2022, project “Investigation of microplastic influence on water resources”. A.L.P.S. was funded by Portuguese Science Foundation (FCT) through CEECIND/01366/2018 research contract under POCH funds, co-financed by the European Social Fund and Portuguese National Funds from MEC.

Waterworks which utilise river bank filtration water sources often have to apply aeration and sand filtration to remove iron and manganese during the drinking water treatment process. After some time, the sand becomes saturated and the spent filter sand (SFS) must be disposed of and replaced. In order to valorize this waste stream, this paper investigates the reuse of SFS as an adsorbent for the treatment of arsenic contaminated drinking water. The arsenic removal performance of SFS is compared with two synthetic iron oxide coated sands (IOCS). The sorbents were first characterized by SEM, EDS, BET specific surface area, and point of zero charge (pHpzc) measurements, and then investigated under a variety of conditions. The surface of the SFS was revealed to be coated with iron manganese binary oxide. The Freundlich model best described the isotherm experiment data, indicating a non monolayer adsorption model for arsenic adsorption on the three IOCS investigated. As(III) and As(V) removals were negatively effected by the presence of PO43− and HA anions as they competed with the arsenic species for adsorption sites. However, given the status of SFS as a waste material, the results obtained in this paper suggest it may be successfully reused as a very economically and environmentally sustainable solution for small waterworks requiring both As(V) and As(III) removal during drinking water treatment.

© 2018, Springer-Verlag GmbH Germany, part of Springer Nature. This study investigates measurement procedure validation for the determination of hexachlorobenzene, pentachlorobenzene and trifluralin as priority hazardous pesticides in water with suspended solids < 12 mg/L by liquid–liquid extraction with hexane and gas chromatography with electron capture detector analysis. Two water matrices were used: synthetic matrix and a natural matrix—Danube surface water. Limit of detection was in the range 2.2 ng/L–3.9 ng/L. Trueness expressed as recovery was determined at pesticide concentrations of 20 ng/L and 50 ng/L in both water matrices. The intermediate precision was determined as relative standard deviations (RSD) and represents an agreement between replicates. Trueness was 72 %–121 % with RSD < 20 %. Expanded uncertainty of measurement was similar for all compounds (33.3 %–37.5 %) with a 95 % confidence level, for coverage factor k = 2. The validity of the measurement procedure was confirmed by participation in a PT Scheme with satisfactory |z|-score smaller than 2. Based on these results, it can be concluded that this low-cost measurement procedure is fit for the intended use measurements.

© 2018, Islamic Azad University (IAU). This research evaluates the effect of ultraviolet photolysis, ozonation and ozonation/ultraviolet advanced oxidation processes on different disinfection by-product precursors, during the treatment of water with low organic matter and moderate bromide contents. After different combinations of ultraviolent fluence and ozone, the formation potentials of trihalomethanes and haloacetic acids were investigated. Bromine incorporation factors were used to give specific insight into the behaviour of brominated disinfection by-products, and inorganic bromate formation was also determined. The ozone/ultraviolet process was found to be more effective in reducing the total natural organic matter content than ozonation or ultraviolet photolysis alone. Ultraviolet photolysis was more successful removing the precursors of brominated trihalomethanes than chlorinated trihalomethanes, but slightly increased the precursors of both brominated and chlorinated haloacetic acids. During ozonation, reductions in the haloacetic acid formation potential were significantly better than those of the trihalomethanes formation potential (up to 54 and 27%, respectively). In the combined ozonation/ultraviolet process, increasing the ultraviolet fluence had a varying effect on trihalomethane and haloacetic acid precursor behaviour, depending on the ozone dose applied. Bromine incorporation after ozonation alone increased to up to 38% of the total bromide, largely as a result of bromate formation. The combined process curtailed all bromate formation, but increased the bromine incorporation up to 48% at higher ozone doses, with disinfection by-product formation shifting towards the more toxic brominated species.

© 2017 Elsevier Ltd In this study, laboratory scale experiments were conducted with the horizontal continuous-flow EC reactor as a standalone technology with the capacity of 300 L/day with iron (Fe) plate bipolar electrodes to assess its efficiency in the removal of arsenic from raw groundwater without pre- and post-treatment pH modification of groundwater. The optimum EC reactor operating conditions were determined to be current density of 1.98 A/m2, charge loading of 54 C/L, flow rate of 12 L/h. The EC reactor was able to remove 96% of arsenic from raw groundwater and met respective World Health Organization (WHO) guideline value of 10 μg As/L within the 4 h experimental runs. The Fe electrode polarity change at 30 min successfully controlled passivation of Fe electrodes and enabled a steady reactor operation with the high As removal efficiency. Residual Fe concentration in treated groundwater was in the range 0.17 ± 0.07 mg/L and met WHO guideline value for drinking water. The preliminary estimated operating cost at the optimum operating conditions was 0.0135 €/m3.

The main objective of this study was to gain more detailed knowledge of how four selected polycyclic aromatic hydrocarbons (PAHs) interact on six nondegradable types of microplastics (MPs) and one biodegradable plastic (BP) in two water matrices. The results were evaluated using the popular Freundlich and Langmuir isotherm models, as well as a new modified mathematical model. The modified mathematical model was developed to additionally elucidate the adsorption mechanism, to investigate transfer kinetics of PAHs and to predict the variation of adsorption rate and capacity as a function of time. The adsorption kinetics of selected PAHs onto MPs and biodegradable plastic were described best by the pseudo-second order kinetic model (R2 = 0.810–0.999), implying that chemisorption is possibly the adsorption mechanism. The results of the adsorption isotherm study also indicated that adsorption of PAHs on selected types of microplastics was best described by the Langmuir model, implying that adsorption of PAHs is more dominant on powdered types of MPs in both synthetic and real water matrices. On the other hand, the lowest adsorption affinity was achieved for adsorption of PAHs on polylactic acid, indicating that this type of biodegradable plastic would have significantly less impact on the transport and distribution of PAHs through environment.

This study investigates the photochemical degradation of alachlor, a chloroacetanilide herbicide. All experiments were conducted in ultra-pure deionized water (ASTM Type I quality) using direct ultraviolet (UV) photolysis and the UV/H2O2 advanced oxidation process. The direct UV photolysis and UV/H2O2 experiments were conducted in a commercial photochemical reactor with a quartz reaction vessel equipped with a 253.7 nm UV low pressure mercury lamp (Philips TUV 16 W). The experimental results demonstrate that UV photolysis was very effective for alachlor degradation (up to 97% removal using a high UV fluence of 4200 mJ/cm2). The UV/H2O2 process promoted alachlor degradation compared to UV photolysis alone, with a high degree of decomposition (97%) achieved at a significantly lower UV fluence of 600 mJ/cm2 when combined with 1 mg H2O2/L. The application of UV photolysis alone with a UV fluence of 600 mJ/cm2 gave a negligible 4% alachlor degradation. The photo degradation of alachlor, in both direct UV photolysis and the UV/H2O2 process, followed pseudo first-order kinetics. The degradation rate constant was about 6 times higher for the UV/H2O2 process than for UV photolysis alone.

© 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group. Results from a lab-scale investigation of a hybrid in/out ultrafiltration and powdered activated carbon adsorption PAC/UF for removal of diclofenac (c0= 5 mg/L) are presented. The efficiency of the process was compared for single pulse and continuous carbon dosing (PAC dose 5 mg/L) in dechlorinated tap water under fluxes of 87 and 135 L/(m2 h). For higher flux conditions, it was observed that single pulse dosing has an advantage over continuous dosing procedure when comparing cycle average removal efficiency. Increase of carbon dose under these conditions increased cycle average removal only to a limited extent. PAC dose above 15 mg/L did not give improvements of the removal. Hypothesis was made that non-effective carbon distribution might be the possible reason.

© 2020 Elsevier B.V. In this work, we have investigated the stability of pindolol (PIN), a non-selective β1-blocker detected in the river and wastewater of hospitals, in water solution under solar irradiation. Further, detailed insights into the stability of PIN were obtained by the density functional theory (DFT) calculations and molecular dynamics simulations. The kinetics of PIN photocatalytic degradation and mineralization has been studied using four commercial photocatalysts ZnO and TiO2 (P25, Hombikat, and Wackherr). It was found that the major role in degradation of PIN play the reactive hydroxyl radicals. The structures of degradation intermediates were suggested by LC–ESI–MS/MS and DFT calculations. Also, DFT calculations were used to refine molecular structures of intermediates and obtain their geometries. Toxicity of PIN and its mixtures formed during photocatalytic degradation were investigated using mammalian cell lines (H-4-II-E, HT-29, and MRC-5). The H-4-II-E cell line was the most sensitive to PIN and its photodegradation mixtures. The computational results were combined with the experimental data on the amounts of degradation intermediates for determination of the intermediates that were principally responsible for the toxicity. Intermediate with two hydroxyl groups, positioned on indole ring in meta and para positions, was proposed as the one with the highest contribution to toxicity.

Microplastics and chlorinated phenols (CPs) are pollutants found ubiquitously in freshwater systems. Meanwhile, bioplastics are attracting much attention as alternatives to conventional plastics, but there is little data about their effect on the behaviour of pollutants. This work therefore investigates the sorption of four CPs (4-chlorophenol&mdash, 4-CP, 2,4-dichlorophenol&mdash, 2,4-DCP, 2,4,6-trichlorophenol&mdash, 2,4,6-TCP and pentachlorophenol&mdash, PCP) on three different plastics (polyethylene (PЕg), polypropylene (PP) and polylactic acid (PLA)) using kinetics and isotherm studies. All experiments were carried out in a synthetic water matrix and in spiked Danube river water. In all cases, adsorption kinetics fitted well with the pseudo-second order rate model. Adsorption proceeded through two linear phases, corresponding to transport from the bulk solution to the external surfaces and then into the interior pores of the sorbents. Maximum adsorption capacities calculated with the Langmuir isotherm indicated that whereas adsorption of 4-CP was not significantly affected by the type of plastic present, the adsorption of 2,4-DCP, 2,4,6-TCP and PCP varied greatly, with polypropylene showing the greatest affinity for CPs adsorption. The differences observed between the adsorption behaviour of CPs in the synthetic and natural water matrices suggest further investigation is required into how the different fractions of natural organic matter impact interactions between CPs and plastics.

Plastic waste are introduced into the environment inevitably and their exposure in the environment causes deterioration in mechanical and physicochemical properties and leads to the formation of plastic fragments, which are considered as microplastics when their size is 5 mm. In recent years, microplastic pollution has been reported in all kinds of environments worldwide and is considered a potential threat to the health of ecosystems and humans. However, knowledge on the environmental degradation of plastics and the formation of microplastics is still limited. In this review, potential hotspots for the accumulation of plastic waste were identified, major mechanisms and characterization methods of plastic degradation were summarized, and studies on the environmental degradation of plastics were evaluated. Future research works should further identify the key environmental parameters and properties of plastics affecting the degradation in order to predict the fate of plastics in different environments and facilitate the development of technologies for reducing plastic pollution. Formation and degradation of microplastics, including nanoplastics, should receive more research attention to assess their fate and ecological risks in the environment more comprehensively.

The presence of 48 emerging micropollutants was tested in influent and effluent from primary and secondary treatment at a municipal wastewater treatment plant (WWTP) in Serbia. Sixteen emerging micropollutants (active pharmaceutical ingredients, bisphenols, parabens and UV filters) had concentrations >LOQ (max. conc. 33.4 μg/L). The removal efficiency of primary treatment ranged from 2.0% - 96.0%. In the case of secondary treatment, except for ketoprofen (61.0%), diclofenac (62.6%) and carbamazepine (−20.0%), all other measured micropollutants had removal efficiency above 77.0%. Advanced non-oxidative lab-scale treatments were investigated. Powdered activated carbon (PAC) adsorption achieved removal efficiencies in the range 52.4–99.9%, novel coagulation with natural coagulant isolated from beans achieved removal efficiencies in range 3.2–99.9%, conventional coagulation with ferric chloride 3.12–96.4%, combined adsorption/coagulation 2.69–99.9% and combined PAC/ultrafiltration (PAC/UF) 60–99.9%. For most of the micropollutants, their removal efficiencies were similar to that reported in the literature. Novel natural coagulant showed significant potential compared to the conventional coagulant during a short episode of sub-optimal WWTP operation. When natural coagulant was applied as a part of an adsorption/coagulation hybrid process, there was no negative effect on PAC adsorption, while for conventional coagulant that was not always the case. Also, a structure property relationship (SPR) study revealed correlations between the removal efficiency of the majority of treatments applied and total polar surface area (TPSA) of the micropollutants.

This paper presents the results of a pilot scale investigation of coagulation using aluminium based coagulants (polyaluminium chloride sulphate (PACL1) and polyaluminium chloride (PACL2)), combined with pre-ozonation and pH adjustment, on natural organic matter (NOM) removal from groundwater. Tests were conducted at a semi-industrial pilot plant, using groundwater with a high content of NOM (5.1 ± 0.8 mg C/L dissolved organic carbon (DOC); 0.211 ± 0.007 cm−1 UV absorbance at 254 nm (UV254)) and trihalomethane formation potential (THMFP (273 ± 73 μg/L)). It was determined that both coagulants showed similar efficacy in reducing DOC (∼50%), UV254 (∼60%) and THMFP (∼65%). Application of pre-ozonation enhanced total coagulation efficiency (up to 61% and 80% for DOC and UV254, respectively), probably due to its microflocculation effect. THMFP in the treated water fluctuated depending on ozone dose, coagulant type and pH. The pre-treatment resulted in NOM oxidation to lower molecular weight hydrophilic organic substances. PACL1 coagulation did not efficiently remove these new THM precursors, whereas PACL2 was able to reduce THMFP to 77 μg/L at a low ozone dose of 0.4 mg O3/mg DOC, suggesting differences in the coagulation mechanism for the two coagulants. This difference confirms the necessity of optimizing the combined treatment depending upon the choice of coagulant applied.

This study investigates the effects of UV photolysis, ozonation and different advanced oxidation processes (O3/UV, H2O2/UV and O3/H2O2/UV) on the oxidation of groundwater natural organic matter (NOM) and by-product formation. Although the investigated treatments only slightly reduce the total organic carbon content (4–15%), the NOM character was changed significantly. The fulvic acid fraction decreased and the content of the hydrophilic acid fraction increased in ozone treated water and even more noticeably in water treated by O3/H2O2/UV. All treatments led to significant increases in polar oxidation by-products such as aldehydes (up to 8 times) and carboxylic acids (up to 34 times), with no clear relationship between the changes in concentrations of these by-products and the addition of H2O2 and the UV dose. Statistical analysis showed a good correlation between carboxylic acids with ozone applications and carboxylic acids and UV254. Trihalomethane and haloacetic acid formation potentials were reduced best (43% for THMFP and 68% for HAAFP) during the O3/H2O2/UV process (0.5 mg O3 per mg DOC; 10 mg H2O2 per L: 600 mL cm−2) using the lower UV dose, and were also well correlated (R = 0.847) during all water treatments. Bromate formation was observed only in the processes involving ozone.

Sediment represents a sink for toxic and persistent chemicals such as hexachlorobenzene (HCB) and lindane (γ-HCH). This paper investigates the possibility of reducing the risks associated with the presence of these pollutants in sediments by amending the sediment with carbon-rich materials (activated carbon (AC) and humus (HC)) to sequester the contaminants and render them biologically unavailable. The effects of the dose and contact time between the sediment and the carbon-rich amendments on the effectiveness of the detoxification are estimated. Four doses of carbon-rich amendments (0.5-10%) and four equilibration contact times (14-180 days) were investigated. Results have shown that the bioavailable fraction of γ-HCH and HCB decreased significantly in comparison to the unamended sediment. Regarding the AC amendments, almost 100% for both compounds; and for HC amendments around 95% for γ-HCH, and 75% for HCB. Aging caused further reductions in the bioavailable fraction, compared to the untreated sediment. Phytotoxicity tests showed that Zea mays accumulated significantly higher amount of γ-HCH and HCB from unamended sediment, comparing to Cucurbita pepo and Lactuca sativa. Toxicity of HC and AC amended sediment assessed by Vibrio fischeri luminescence inhibition test and by measuring Zea mays germination and biomass yield was significantly reduced in the amended sediment samples. γ-HCH and HCB accumulation in the Zea mays biomass in the unamended sediment were a significantly higher than in the all HC and AC amended sediment. Both sorbents show potential to be used as remediation agents for organically contaminated sediment, but AC exhibited the better performance.