In recent years, many of micropollutants have been widely detected because of continuous input of pharmaceuticals and personal care products (PPCPs) into the environment and newly developed ...state-of-the-art analytical methods. PPCP residues are frequently detected in drinking water sources, sewage treatment plants (STPs), and water treatment plants (WTPs) due to their universal consumption, low human metabolic capability, and improper disposal. When partially metabolized PPCPs are transferred into STPs, they elicit negative effects on biological treatment processes; therefore, conventional STPs are insufficient when it comes to PPCP removal. Furthermore, the excreted metabolites may become secondary pollutants and can be further modified in receiving water bodies. Several advanced treatment systems, including membrane filtration, granular activated carbon, and advanced oxidation processes, have been used for the effective removal of individual PPCPs. This review covers the occurrence patterns of PPCPs in water environments and the techniques adopted for their treatment in STP/WTP unit processes operating in various countries. The aim of this review is to provide a comprehensive summary of the removal and fate of PPCPs in different treatment facilities as well as the optimum methods for their elimination in STP and WTP systems.
•There is a large variation in PPCP removal in STPs and WTPs (−157–100%).•PPCP removal is dependent on compound characteristics and process-specific factors.•Advanced treatment technologies are effective for PPCP removal.
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Advanced oxidation processes (AOPs) are promising technologies for partial or complete mineralization of contaminants of emerging concern by highly reactive hydroxyl, hydroperoxyl, superoxide, and ...sulphate radicals. Detailed investigations and reviews have been reported for conventional AOP systems that have been installed in full-scale wastewater treatment plants. However, recent efforts have focused on the peroxymonosulphate, persulphate, catalytic ozonation, ultrasonication and hydrodynamic cavitation, gamma radiation, electrochemical oxidation, modified Fenton, and plasma-assisted AOPs. This critical review presents the detailed mechanisms of emerging AOP technologies, their performance for treatment of contaminants of emerging concern, the relative advantages and disadvantages of each technology, and the remaining challenges to scale-up and implementation. Among the evaluated technologies, the modified electrochemical oxidation, gamma radiation, and plasma-assisted systems demonstrated the greatest potential for successful and sustainable implementation in wastewater treatment due to their environmental safety, compatibility, and efficient transformation of contaminants of emerging concern by a variety of reactive species. The other emerging AOP systems were also promising, but additional scale-up trials and a deeper understanding of their reaction kinetics in complex wastewater matrices are necessary to determine the technical and economic feasibility of full-scale processes.
•Recent updates in the field of advanced oxidation processes are summarized.•Advantages, and disadvantages of emerging advanced oxidations are elucidated.•Real-scale commercialization status of emerging advanced oxidations are discussed.•Bottlenecks and prospects related to advanced oxidations are discussed.
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•The influence of water matrix on the efficiency of AOTs is overviewed.•Photolysis, photocatalysis, UV/H2O2-, Fenton-, and O3-based processes are reviewed.•Dissolved organic matter ...and inorganics can act as inhibitors and/or promoters.•The effect results from the interplay of the co-existing substances.•The knowledge on the role of matrix constituents is crucial for installation of AOTs.
Micropollutants (MPs) in the aquatic compartments are originated from many sources and particularly from the effluents of urban wastewater treatment plants (UWWTPs). Advanced oxidation technologies (AOTs) usually applied after biological processes, have recently emerged as effective tertiary treatments for the removal of MPs, but the oxidation rates of the single compounds may be largely affected by the constituent species of the water matrix. These species include dissolved organic matter and inorganic species (e.g., carbonate, bicarbonate, nitrite, sulphate, chloride). This review analyses the impact of such substances on common AOTs including photolysis, UV/H2O2, Fenton, photocatalysis, and ozone-based processes. The degradation efficiency of single MPs by AOTs results from the combined impact of the water matrix constituents, which can have neutral, inhibiting or promoting effect, depending on the process and the mechanism by which these water components react. Organic species can be either inhibitors (by light attenuation; scavenging effects; or adsorption to catalyst) or promoters (by originating reactive oxygen species (ROS) which enhance indirect photolysis; or by regenerating the catalyst). Inorganic species can also be either inhibitors (by scavenging effects; formation of radicals less active than hydroxyl radicals; iron complexation; adsorption to catalyst or decrease of its effective surface area) or promoters (e.g., nitrate ions by formation of ROS; iron ions as additional source of catalyst). The available data reviewed here is limited and the role and mechanisms of individual water components are still not completely understood. Further studies are needed to elucidate the wide spectrum of reactions occurring in complex wastewaters and to increase the adoption of AOTs in UWWTPs.
Cocaine (COC) and benzoylecgonine (BE), the main COC metabolite, have been detected in aquatic ecosystems. Studies focusing on wild fish are, however, very limited, and no reports concerning ...elasmobranchs are available. This study investigated COC and BE levels in Brazilian Sharpnose sharks (Rhizoprionodon lalandii) (n = 13) using LC-MS/MS. All samples (13/13) tested positive for COC, with 92 % (12/13) testing positive for BE. COC concentrations (23.0 μg kg−1) were over 3-fold higher than BE (7.0 μg kg−1). COC levels were about three-fold significantly higher in muscle (33.8 ± 33.4 g kg−1) compared to liver (12.2 ± 14.2 μg kg−1). Females presented higher COC concentrations in muscle (40.2 ± 35.8 μg kg−1) compared to males (12.4 ± 5.9 μg kg−1). Several positive statistical correlations were noted between COC and BE (rho = 0.84) in females, indicating systemic COC transport and metabolization, as well as between BE and weight (rho = 0.62), and between COC and the Condition Factor (rho = 0.73). A strong correlation was noted between BE and COC in the muscle of non-pregnant females (rho = 1.00). This study represents the first COC and BE report in free-ranging sharks, and the findings point to the potential impacts of the presence of illicit drugs in environments.
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•Cocaine (COC) and benzoylecgonine (BE) were detected in Brazilian Sharpnose sharks.•Muscle tissue contained higher COC concentrations compared to liver.•COC exhibited greater bioaccumulation potential compared to BE.•Muscle COC and BE differed significantly among pregnant and non-pregnant females.•This is the first COC and BE report for free-ranging sharks worldwide.
Conventional urban wastewater treatment plants (UWTPs) are poorly effective in the removal of most contaminants of emerging concern (CECs), including antibiotics, antibiotic resistant bacteria and ...antibiotic resistance genes (ARB&ARGs). These contaminants result in some concern for the environment and human health, in particular if UWTPs effluents are reused for crop irrigation. Recently, stakeholders' interest further increased in Europe, because the European Commission is currently developing a regulation on water reuse. Likely, conventional UWTPs will require additional advanced treatment steps to meet water quality limits yet to be officially established for wastewater reuse. Even though it seems that CECs will not be included in the proposed regulation, the aim of this paper is to provide a technical contribution to this discussion as well as to support stakeholders by recommending possible advanced treatment options, in particular with regard to the removal of CECs and ARB&ARGs. Taking into account the current knowledge and the precautionary principle, any new or revised water-related Directive should address such contaminants. Hence, this review paper gathers the efforts of a group of international experts, members of the NEREUS COST Action ES1403, who for three years have been constructively discussing the efficiency of the best available technologies (BATs) for urban wastewater treatment to abate CECs and ARB&ARGs. In particular, ozonation, activated carbon adsorption, chemical disinfectants, UV radiation, advanced oxidation processes (AOPs) and membrane filtration are discussed with regard to their capability to effectively remove CECs and ARB&ARGs, as well as their advantages and drawbacks. Moreover, a comparison among the above-mentioned processes is performed for CECs relevant for crop uptake. Finally, possible treatment trains including the above-discussed BATs are discussed, issuing end-use specific recommendations which will be useful to UWTPs managers to select the most suitable options to be implemented at their own facilities to successfully address wastewater reuse challenges.
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•This work gathers the efforts of international experts from NEREUS COST Action.•Advantages and drawbacks of BATs discussed according to CECs removal and AR control•Possible advanced treatment options to make wastewater reuse safer recommended•Smart combination of BATs and a suitable monitoring program necessary for a safe reuse•Further comparative studies among different advanced treatment methods recommended
Microalgal-based wastewater treatment plants are conceived as low cost and low energy consuming systems. The operation of these plants involves the management of primary sludge and microalgal ...biomass. The aim of this study is to analyse the anaerobic co-digestion of both by-products in terms of biogas production and contaminants of emerging concern removal. The co-digestion of microalgae and primary sludge (25/75% on a volatile solids basis) was investigated in continuous reactors and compared to microalgae mono-digestion at a hydraulic retention time of 20days. Results showed how the co-digestion enhanced the anaerobic digestion of microalgal biomass, since primary sludge is a more readily biodegradable substrate, which increased the methane production by 65% and reduced the risk of ammonia toxicity. Regarding the contaminants, musk fragrances (galaxolide and tonalide) and triclosan showed the highest abundance on primary sludge (0.5–25μg/g TS), whereas caffeine, methyl dihydrojasmonate and triphenyl phosphate were barely detected in both substrates (<0.1μg/g TS). The removal of these contaminants was compound-depending and ranged from no removal to up to 90%. On the whole, microalgae mono-digestion resulted in a higher removal of selected contaminants than the co-digestion with primary sludge.
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•Co-digestion of microalgae and primary sludge was evaluated in continuous reactors.•Occurrence and fate of the most common emerging organic contaminants was evaluated.•Methane yield increased by 65% with co-digestion versus microalgae mono-digestion.•An energy assessment shows that co-digestion generated 4.5-fold the energy consumed.•Removal of emerging organic contaminants ranged from no removal to 90%.
•Removal of contaminants of emerging concern (CECs) in membrane treatment was reviewed.•Valuable CEC removal mechanism was provided for applications of membrane filtration in water treatment.•Areas ...of future research for the removal of CECs in membrane treatment were suggested.
This review summarizes comprehensive recent studies on the removal of contaminants of emerging concern (CECs) by forward osmosis (FO), reverse osmosis (RO), nanofiltration (NF), and ultrafiltration (UF) membrane treatments, and describes important information on the applications of FO, RO, NF, and UF membranes in water and wastewater (WW) treatment. The main objective of this review was to synthesize findings on membrane treatments of CECs in water and WW, and to highlight upcoming research areas based on knowledge gaps. In particular, this review aimed to address several key parameters, including the physicochemical properties of CECs (solute molecular weight/size/geometry, charge, and hydrophobicity), water quality conditions (pH, solute concentration, temperature, background inorganics, and natural organic matter), and membrane properties and operating conditions (membrane fouling, membrane pore size, porosity, charge, and pressure) that influence the removal of CECs during membrane filtration. Future research directions regarding membrane treatment for the removal of CECs from water and WW are also discussed.
•Removal of contaminants of emerging concern by MOF nanoadsorbents was comprehensively reviewed.•Comprehensively information was provided for applications of MOF nanoadsorbents in water ...industry.•Areas of future research for the removal of various contaminants in MOF nanoadsorbents were suggested.
Over the last two decades, various contaminants of emerging concern (CECs), such as endocrine disrupting compounds, along with pharmaceuticals and personal care products (PPCPs), have been of interest to the water industry because of their incomplete removal during the typical water and wastewater treatment processes. Recently, the potential environmental applications of metal-organic frameworks (MOFs) and MOF-based nanoadsorbents (MOF-NAs) have been widely studied. In particular, the use of these nanoadsorbents for CECs in water and wastewater treatment processes has been a rapidly growing area of interest in the recent literature due to their unique physicochemical properties. Therefore, it is necessary to understand the adsorption phenomena of various CECs by MOF-NAs, particularly because the physicochemical properties of various CECs create unique challenges for the removal of these compounds from water. In addition, the adsorption of CECs on MOF-NAs is significantly influenced by the physicochemical properties of the MOF-NAs and the water quality conditions. Therefore, this review provides a comprehensive assessment of recent studies on the removal of various CECs (e.g., analgesics, antibiotics, antiepileptics, antiseptics, and etc.) with different physicochemical properties by various MOF-NAs under various water quality conditions (e.g., pH, background ions/ionic strength, natural organic matter, and temperature). In addition, this review briefly discusses the recent literature on the synthesis of MOF-NAs, regeneration of MOF-NAs, and removal of CECs during water and wastewater treatment processes.
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•Microplastics (MPs) interaction with micropollutants increase their toxicity.•Biological degradation of MPs takes excessively long times.•Advanced oxidation processes (AOPs) reduce ...time required for MPs oxidation in water.•Intermediates formed during the oxidation of MPs pose no danger to microorganisms.•AOPs efficiency is severely affected by MPs size and shape.
Microplastics have become a hot topic in the scientific community as they promote adverse effects to living beings. Various analytical tools must be used simultaneously for identification and characterization of microplastics and their transformation products in environmental compartments. Despite limitations associated to the reproduction of real conditions of microplastics occurrence in environmental matrices (composition, size, concentration), increased toxicity has been observed as a consequence of their interaction with contaminants of emerging concern and/or heavy metals. Yet, some factors (i.e., pH, particle age and size of microplastic, among others) may affect this phenomenon. Membrane filtration and coagulation-flocculation-settling treatments are non-destructive, needing an additional step to degrade microplastics. Biological treatment has been demonstrated as unsatisfactory (<15% degradation) for microplastics treatment. On the other hand, a few recent works have pointed out advanced oxidation processes as feasible alternatives, since they present high efficiency of microplastic degradation (≈ 30–95%). However, more studies should be conducted to evaluate the performance of advanced oxidation processes on the degradation of microplastics in real matrices under solar irradiation. Identification of transformation products, elucidation of degradation mechanisms, and toxicity assays using in vivo and in vitro tests, as well as computational tools, are needed to improve the assumption of these processes as feasible treatment alternatives. Added to this, tests in larger treatment systems are critical to promote scale up for application in real scale.
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•A sustainable solution for tertiary treatment of urban wastewater was investigated.•Solar photo Fenton with EDDS was the most effective AOP to remove CECs.•N-TiO2/sunlight less ...efficient than homogeneous solar AOPs.•No acute toxicity observed after N-TiO2/sunlight and solar photo Fenton with EDDS.•Solar photo Fenton with EDDS comparatively more sustainable than other solar AOPs.
The release of toxic contaminant of emerging concern from urban wastewater treatment plants (UWTPs) into the environment calls for more effective (tertiary) treatment methods. In this manuscript, homogeneous solar-driven advanced oxidation processes (AOPs), namely H2O2/sunlight, solar photo-Fenton (Fe+2/H2O2/sunlight) and solar photo-Fenton with ethylenediamine-N,N'-disuccinic acid (EDDS) complex (Fe+2/H2O2/EDDS/sunlight) were compared to a new heterogeneous process (supported nitrogen-doped TiO2 (N-TiO2)/sunlight), with the aim of contributing to fill the gap between lab scale tests and full scale applications as well as to provide a sustainable solution for tertiary treatment in small UWTPs. Process efficiency was evaluated in terms of effluent toxicity and degradation of a mixture of three pharmaceuticals (namely carbamazepine (CBZ), diclofenac and trimethoprim), at initial concentration of 200 µg/L each, in deionized water (DW) and real wastewater (WW). Fe2+/H2O2/EDDS/sunlight was found to be the most effective process (98% removal of CBZ from WW in 60 min, 5.6 kJ/L as cumulative solar energy per unit of volume). Conventional solar photo Fenton was drastically and negatively affected by water matrix, due to the spontaneous neutral pH and iron precipitation in real WW. Although N-TiO2/sunlight process was not so affected by water matrix, it was found to be less efficient (30% removal of CBZ in 180 min, 13.3 kJ/L) than Fe2+/H2O2/EDDS/sunlight process. Toxicity values were found to be lower in WW compared to DW matrix. Class weight scores for WW samples showed a toxicity reduction up to the no acute toxicity level for N-TiO2/sunlight and Fe2+/H2O2/EDDS/sunlight treatments, while H2O2/sunlight and Fe2+/H2O2/sunlight increased the final effluent toxicity up to slightly acute levels.
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