Degradation Of Contaminants Of Emerging Concern Research Articles

Development of dissolved organic matter-based indicators to understand the degradation of organic contaminants in reverse osmosis concentrate from potable reuse systems

Reverse osmosis (RO)-based treatment of municipal wastewater effluent allows for potable reuse, but this process generates reverse osmosis concentrate (ROC) that needs further treatment before disposal. This study investigated the application of UV-based advanced oxidation processes (AOPs) to degrade nine contaminants of emerging concern (CECs) from real ROC waste streams, using UV-only and UV-AOPs with hydrogen peroxide, free chlorine, and persulfate. Dissolved organic matter (DOM) in ROC was characterized using fluorescence excitation emission matrix data and analyzed by a four-component parallel factor (PARAFAC) analysis model. UV-only treatment showed considerable removal of CECs that displayed high values of quantum yields and molar absorption coefficients. UV-AOP treatment of ROC exhibited heavy scavenging of reactive species during CEC degradation. A probe-based approach established that hydroxyl radical was the dominant reactive species in all UV-AOPs. A kinetic analysis of PARAFAC components of DOM showed that the visible humic-like and protein-like components exhibited the higher reaction kinetics compared to UV humic-like and nutrient-like components. The strong linear correlation of protein-like component and seven of the nine CECs across multiple AOPs indicated that they have similar reactivity, enabling the establishment of chemical-reactivity based surrogates for prediction CEC fate in ROC wastes.

Contaminants of emerging concern reduction and microbial community characterization across a three-barrier advanced water treatment system

This research investigated the removal of contaminants of emerging concern (CECs) and characterized the microbial community across an advanced water treatment (AWT) train consisting of Coagulation/Flocculation/Clarification/Granular Media Filtration (CFCGMF), Ozone-Biological Activated Carbon Filtration (O3/BAC), Granular Activated Carbon filtration, Ultraviolet Disinfection, and Cartridge Filtration (GAC/UV/CF). The AWT train successfully met the goals of CECs and bulk organics removal. The microbial community at each treatment step of the AWT train was characterized using 16S rRNA sequencing on the Illumina MiSeq platform generated from DNA extracted from liquid and solid (treatment media) samples taken along the treatment train. Differences in the microbial community structure were observed. The dominant operational taxonomic units (OTU) decreased along the treatment train, but the treatment steps did impact the microbial community composition downstream of each unit process. These results provide insights into microbial ecology in advanced water treatment systems, which are influenced and shaped by each treatment step, the microbial community interactions, and their potential metabolic contribution to CECs degradation.

Tertiary/quaternary treatment of urban wastewater by UV/H2O2 or ozonation: Microplastics may affect removal of E. coli and contaminants of emerging concern

The aim of this study was to investigate the interference of polyethylene microplastics (MPs) on ultraviolet irradiation/hydrogen peroxide (UV/H2O2) and ozonation processes in the inactivation of E. coli bacteria (tertiary treatment) and removal of contaminants of emerging concern (CECs) (quaternary treatment) from simulated and real secondary treated urban wastewater. Three pharmaceuticals were investigated as model CECs, namely carbamazepine, sulfamethoxazole and trimethoprim. Experimental results showed that disinfection efficiency of UV/H2O2 treatment decreased (2.4, 1.8 and 1.3 log reductions of E. coli, initial H2O2 dose of 30 mg/L, 2.5 min treatment) as the initial concentration of MPs was increased (0.25, 0.5 and 1.0 g/L, respectively). Similarly, an increase in MPs concentration (0.25, 0.5 and 1.0 g/L) reduced the inactivation (4.7, 4.1 and 3.7 log reductions) of the target bacteria after 60 min of ozonation treatment. Although the disinfection efficiency of both treatment processes was negatively affected by the presence of MPs, UV/H2O2 was more effective than the ozonation, despite ozonation being investigated at high doses to better discriminate the effect of MPs. Noteworthy, CECs degradation by UV/H2O2 under realistic operating conditions was affected to some extent by MPs, while a lower effect was observed for ozonation, at not realistic ozone dose.

LED-irradiated photo-Fenton process on pollutant removal: outcomes, trends, and limitations.

This manuscript critically reviews the state of the art on the application of photo-Fenton processes irradiated by light-emitting diode arrays (LED) with a focus on the removal of contaminants of emerging concern (CEC) from aqueous matrices. LEDs are clean, low-cost radiation sources with longer lifespan compared to mercury lamps. This study covers the influence of LED sources, wavelengths, and dose upon CEC removal, and the potential for disinfection, abatement of antibiotic-resistant bacteria (ARB), and genes (ARG). The bibliographic search was performed in Scopus database using keyword combinations and resulted in a portfolio containing 52 relevant articles published between 2010-2023. According to reviewed papers, LED photoreactor design has evolved in the past decade aiming to improve CEC degradation in aqueous matrices while reducing construction and operation costs, and energy consumption. Among several reactors (annular, fluidized bed, parallel plate, wireless, pathway systems, and microreactor) surveyed for their performance and scalability, LED chips and strips are particularly suitable for application due to their wide emission angle (≈120°) and small size (mm2), which allow for, respectively, efficient illumination coverage and flexible arrangement and design. LED microreactors are very efficient in the degradation of contaminants and scalable with reduced area requirements. Although most studies were performed in synthetic solutions and at laboratory scale, the externally LED irradiated cylindrical reactor was successful for application in full-scale municipal water treatment plants. Future studies should focus on evaluating CEC removal in wastewater using scalable devices for continuous operation of solar photo-Fenton at night.

Simultaneous degradation of contaminants of emerging concern and disinfection by solar photoelectro-Fenton process at circumneutral pH in a solar electrochemical raceway pond reactor

Simultaneous contaminants of emerging concern (CECs) removal and wild microorganisms’ inactivation was evaluated by applying solar photoelectro-Fenton (SPEF) process in actual secondary effluent collected from a real municipal wastewater treatment plant (MWWTP). 20 L of a mixture of four CECs was used as model pollutants (200 μg/L of acetaminophen, caffeine, sulfamethazine, and sulfamethoxazole each one). The SPEF process was carried out on fully sunny days, at circumneutral pH using the complex Fe3+-EDDS, in a solar electrochemical – raceway pond reactor (SEC-RPR). Initially, the optimal conditions for CECs degradation were determined using a response surface model based on current density, iron complex concentration and Fe3+-EDDS addition time (to allow previous accumulation of H2O2) as model inputs. A current density of 24.6 mA/cm2, a Fe3+-EDDS complex concentration of 0.089 mM and 3.8 min of previous H2O2 accumulation were the resulting optimum conditions that were afterwards applied for the simultaneous degradation of the CECs synthetic mixture and wild microorganisms inactivation in actual secondary effluent. About 85% CECs removal and complete E. coli inactivation were achieved in 30 min, approximately, while E. faecalis and total coliforms could be inactivated under detection limit in 60 min and 75 min, respectively.

UV-induced degradation of contaminants of emerging concern in the presence of monobromoamine: Role of N-Br bond and degradation mechanisms

The N-Br bond in monobromoamine (NH2Br) can be cleaved by UV irradiation to generate Br• and subsequently HO•, resulting in an advanced oxidation condition (i.e., UV/NH2Br). This study investigated the degradation of six contaminants of emerging concern (CECs) in the UV/NH2Br process, including the phenolic hydrocarbons phenol and bisphenol A (BPA), the amines aniline and sulfadiazine (SDZ), and the persistent organic pollutants ibuprofen (IBP) and carbamazepine (CBZ). The results showed that UV/NH2Br process significantly improved the degradation of CECs following pseudo-first order kinetics, and the degradation of CECs was enhanced with the increase of NH2Br dosage. UV/NH2Br was more efficient in degrading CECs containing phenolic hydroxyl groups (100 %), followed by those containing amine groups (> 95 %). The degradation efficiency was influenced by the pH value and was highest at pH 7. It was found that low concentrations of Cl− (< 0.5 mM) and HCO3− (< 0.5 mM) promoted the degradation of SDZ and IBP, but further increases in Cl− and HCO3− (0.5 ∼ 5.0 mM) resulted in inhibition. SDZ and IBP degradation was inhibited by photo absorption competition and free radical depletion in natural organic matter and actual water. Probe experiments showed that reactive bromine species (RBS), reactive nitrogen species (RNS), and hydroxyl radical (HO•) played a dominant role in CEC degradation. During the degradation of IBP by UV/NH2Br, hydroxylation, bromination, and quinylation were proposed as the primary reaction mechanisms. As compared to HOCl disinfection, NH2Cl disinfection after the UV/NH2Br process produced lower concentrations of disinfection by-products (DBPs).

Review of the Integration of Drying and Thermal Treatment Processes for Energy Efficient Reduction of Contaminants and Beneficial Reuse of Wastewater Treatment Plant Biosolids

Biosolids have been traditionally used as a beneficial resource in the agricultural industry. However, contaminants of emerging concern (CECs) threaten their reuse due to concerns of toxicity, bioaccumulation, and increased regulations on acceptable CEC concentrations in biosolids. The thermal treatment of biosolids has the potential to destroy/mineralize these contaminants as well as transform the biosolids into valuable biochar. However, the thermal processing of biosolids is highly energy intensive due to the energy costs associated with drying biosolids to the required moisture content for thermal processing. This article performs a brief review of the drying of biosolids from a physical and theoretical viewpoint. It also provides an overview of pyrolysis and gasification. It explains the impact that moisture can have on both the degradation of CECs and the products that can be obtained through the thermal treatment of biosolids. Additionally, model-based, lab-based, and pilot-scale examples of integrated drying and thermal treatment processes are reviewed. Key challenges, such as the need for co-pyrolysis and co-gasification, as well as the impact of biosolids composition on energetic viability, are identified.

Periodic mesoporous organosilicas containing naphthalenediimides as organic sensitizers for sulfadiazine photodegradation.

In this work, periodic mesoporous organosilicas (PMO) functionalized with the organic sentisizer naphthalenediimide (NDI) were employed as heterogeneous catalysts for the photodegradation of the antibiotic sulfadiazine (SDZ), taken as a model for contaminants of emerging concern (CECs). The catalysts, designated as PMONDI, were prepared by surfactant-directed co-condensation of the precursor N,N'-bis(3-triethoxysilylpropyl)-1,4,5,8-naphthalenediimide with tetraethoxysilane. The synthesized PMONDI were characterized using transmission electron microscopy, nitrogen adsorption isotherms and small and large angle x-ray scattering. The performance of PMONDI catalysts in the photodegradation of SDZ was compared to that of TiO2 nanoparticles impregnated into SBA-15 mesoporous silica (TiO2/SBA-15), under irradiation with a Hg lamp with a bandpass filter of 320-500nm. Under optimal conditions, PMONDI degraded 100% of the SDZ in 45min, while the total degradation of SDZ was achieved only after 150min with TiO2/SBA-15. PMONDI also performed better than TiO2/SBA-15 in reuse tests. The mechanism of photodegradation with PMONDI involves the formation of excited triplet states of NDI (3NDI*) upon irradiation, which can then react with molecular oxygen to form reactive oxygen species, which degrade SDZ. Analysis of the SDZ degradation products indicated two main pathways: (1) hydroxylation of the aniline ring and (2) SO2 extrusion and rearrangement, followed by oxidation of the aniline ring to nitrobenzene. In conclusion, the great potential of the PMONDI materials as photocatalysts for CECs degradation was demonstrated in this work, encouraging further research on these materials for the degradation of pollutants.

Electrochemically assisted photocatalytic degradation of contaminants of emerging concern in simulated wastewater using WO3 – Elucidation of mechanisms

In this work, the performance of a photoelectrochemical cell to degrade a mixture of contaminants of emerging concern (CECs) in distilled water and simulated wastewater effluents (SWWE) was assessed. The CECs mixture included trimethoprim (TMP), diclofenac (DFC), sulfamethoxazole (SMX) and carbamazepine (CBZ) (100 μg·L−1 each). WO3 nanoplate-like structures synthesized on fluorine tin oxide coated glass (FTO) were used as the photoanode with Pt or carbon gas diffusion electrodes (GDE) as the counter electrode. The most efficient degradation of the CECs was obtained with the WO3-GDE combination. Significant degradation of the CECs was observed under visible only radiation. Even under visible radiation, reasonable rate constants 5.67·10-3, 5.35·10-3, 2.9·10-3 and 4.35·10-3 min−1 were obtained for TMP, SMX, CBZ and DFC degradation. The degradation mechanism at the cathode and the photoanode was elucidated using a two-compartment cell, which allowed the identification of reactive species generated at each electrode. Photogenerated holes were the main responsible for CEC degradation in SWWE. With the carbon GDE, a high Faradaic efficiency (55 %) for H2O2 production was observed.

Semiconductors Application Forms and Doping Benefits to Wastewater Treatment: A Comparison of TiO2, WO3, and g-C3N4

Photocatalysis has been vastly applied for the removal of contaminants of emerging concern (CECs) and other micropollutants, with the aim of future water reclamation. As a process based upon photon irradiation, materials that may be activated through natural light sources are highly pursued, to facilitate their application and reduce costs. TiO2 is a reference material, and it has been greatly optimized. However, in its typical configuration, it is known to be mainly active under ultraviolet radiation. Thus, multiple alternative visible light driven (VLD) materials have been intensively studied recently. WO3 and g-C3N4 are currently attractive VLD catalysts, with WO3 possessing similarities with TiO2 as a metal oxide, allowing correlations between the knowledge regarding the reference catalyst, and g-C3N4 having an interesting and distinct non-metallic polymeric structure with the benefit of easy production. In this review, recent developments towards CECs degradation in TiO2 based photocatalysis are discussed, as reference catalyst, alongside the selected alternative materials, WO3 and g-C3N4. The aim here is to evaluate the different techniques more commonly explored to enhance catalyst photo-activity, specifically doping with multiple elements and the formation of composite materials. Moreover, the possible combination of photocatalysis and ozonation is also explored, as a promising route to potentialize their individual efficiencies and overcome typical drawbacks.

Efficient Activation of Peroxymonosulfate by Biochar-Loaded Zero-Valent Copper for Enrofloxacin Degradation: Singlet Oxygen-Dominated Oxidation Process.

Simple SummaryThe misuse of antibiotics has caused ecological and human health risks on a global scale. Peroxymonosulfate can generate reactive oxygen species with extremely strong oxidative properties, which can degrade most types of antibiotics. For efficient removal of antibiotics in the aqueous environment, an economic biochar-loaded zero-valent copper was prepared by a simple pyrolysis method to activate peroxymonosulfate so that it can generate reactive oxygen species to oxidative and degrade the typical antibiotics, enrofloxacin. It was shown that complete degradation of enrofloxacin could be achieved within 30 min using biochar-loaded zero-valent copper to activate peroxymonosulfate, and the process of reactive oxygen species generation and the degradation pathway of enrofloxacin were also revealed.The removal of contaminants of emerging concern (CECs) has become a hot research topic in the field of environmental engineering in recent years. In this work, a simple pyrolysis method was designed to prepare a high-performance biochar-loaded zero-valent copper (CuC) material for the catalytic degradation of antibiotics ENR by PMS. The results showed that 10 mg/L of ENR was completely removed within 30 min at an initial pH of 3, CuC 0.3 g/L, and PMS 2 mmol/L. Further studies confirmed that the reactive oxygen species (ROS) involved in ENR degradation are ·OH, ·, 1O2, and . Among them, 1O2 played a major role in degradation, whereas · played a key role in the indirect generation of 1O2. On the one hand, CuC adsorbed and activated PMS to generate ·OH, · and ·. · was unstable and reacted rapidly with H2O and ·OH to generate large amounts of 1O2. On the other hand, both the self-decomposition of PMS and direct activation of PMS by C=O on biochar also generated 1O2. Five byproducts were generated during degradation and eventually mineralized to CO2, H2O, , and F−. This study provides a facile strategy and new insights into the biochar-loaded zero-valent transition-metal-catalyzed PMS degradation of CECs.

Degradation of contaminants of emerging concern in UV/Sodium percarbonate Process: Kinetic understanding of carbonate radical and energy consumption evaluation

UV/sodium percarbonate (UV/SPC) advanced oxidation process is an efficient and green technology to remove contaminants of emerging concern (CECs), with the simultaneous formation of hydroxyl radical (•OH) and carbonate radical (CO3•−). This study investigated the degradation of eight CECs in UV/SPC process, including phenol, atrazine, bisphenol A, ibuprofen, sulfadiazine, acetaminophen, carbamazepine, and diuron. A model was established to simulate the experimental results, which shows that both •OH and CO3•− played crucial roles in UV/SPC process, and the steady-state concentrations of CO3•− were much higher than that of •OH. The higher concentration compensates for the low reactivity of CO3•− with CECs and the loss of •OH depleting by CO3•−. Also, the Hammett constants decreased linearly with increasing natural logarithms of rate constants, indicating the selectivity of CO3•− with electron-donating substituents. In real water, CEC degradation was significantly inhibited due to the competition for light absorption from background compounds and scavenging of free radicals, especially CO3•−, by water matrix. Further, demethylation, decarbonylation, hydroxylation, amino oxidation, and quinonization were proposed as the main reactions for CEC degradation in UV/SPC process. The minimum electrical energy per order (EE/O) was calculated as 0.152 kWh m−3, with SPC dose of 0.138 mM and UV intensity of 2.02 × 10-7 Einstein L−1 s−1.

Emerging Contaminants: An Overview of Recent Trends for Their Treatment and Management Using Light-Driven Processes

The management of contaminants of emerging concern (CECs) in water bodies is particularly challenging due to the difficulty in detection and their recalcitrant degradation by conventional means. In this review, CECs are characterized to give insights into the potential degradation performance of similar compounds. A two-pronged approach was then proposed for the overall management of CECs. Light-driven oxidation processes, namely photo/Fenton, photocatalysis, photolysis, UV/Ozone were discussed. Advances to overcome current limitations in these light-driven processes were proposed, focusing on recent trends and innovations. Light-based detection methodology was also discussed for the management of CECs. Lastly, a cost–benefit analysis on various light-based processes was conducted to access the suitability for CECs degradation. It was found that the UV/Ozone process might not be suitable due to the complication with pH adjustments and limited light wavelength. It was found that EEO values were in this sequence: UV only &gt; UV/combination &gt; photocatalyst &gt; UV/O3 &gt; UV/Fenton &gt; solar/Fenton. The solar/Fenton process has the least computed EEO &lt; 5 kWh m−3 and great potential for further development. Newer innovations such as solar/catalyst can also be explored with potentially lower EEO values.

Enhanced degradation of contaminants of emerging concern by electrochemically activated peroxymonosulfate: Performance, mechanism, and influencing factors

Electrochemically activated persulfate is an emerging advanced oxidation process for the removal of contaminants of emerging concern (CECs). The degradation of CECs, including carbamazepine (CBZ), bisphenol S (BPS), propranolol (PPL) and sulfamethoxazole (SMX) using electrochemically activated peroxymonosulfate (EA-PMS) was systematically investigated in this work. Over 80% of all the forementioned CECs were removed within 30 min. It exhibited a good synergistic effect between PMS and electrolysis on the degradation of CECs. The results of linear sweep voltammetry (LSV) indicated that a transition structure between BDD anode and PMS (BDD (PMS)*) was likely responsible for the synergistic effect. Hydroxyl radical (HO·) and sulfate radical (SO4·−) were proved to be the primary reactive species, of which HO· played the leading role. The increase of current density and PMS dosage accelerated the degradation of SMX, while initial pH from 3.0 to 11.0 had a limited effect on the degradation of SMX. Moreover, the influences of common ions and natural organic matter (NOM) on the degradation of SMX were comprehensively assessed using response surface methodology (RSM), and a prediction model was built via RSM. The performance of EA-PMS on the degradation of SMX in actual water was even better than that in pure water in this study. EA-PMS can serve as a novel and promising technology for the degradation of CECs and has great potential in practical application.

Developments in the intensification of photo-Fenton and ozonation-based processes for the removal of contaminants of emerging concern in Ibero-American countries

Contaminants of emerging concern (CECs), such as pharmaceuticals, personal care products, pesticides, synthetic and natural hormones and industrial chemicals, are frequently released into the environment because of the inability of conventional processes in municipal wastewater treatment plants to remove them. Some examples of alternative options to remove such pollutants are photo-Fenton and ozone-based processes, which are two techniques widely studied in Ibero-American countries. In fact, this region has been responsible for delivering frequently publications and conferences on advanced oxidation processes. This work is a critical review of recent developments in the intensification of the two aforementioned advanced oxidation techniques for CECs elimination in the Ibero-American region. Specifically for the photo-Fenton process (pF), this study analyses strategies such as iron-complexation with artificial substances (e.g., oxalic acid and ethylenediamine-N,N′-disuccinic acid) and natural compounds (such as humic-like substances, orange juice or polyphenols) and hybrid processes with ultrasound. Meanwhile, for ozonation, the enhancement of CECs degradation by adding hydrogen peroxide (i.e., peroxone), ultraviolet or solar light, and combining (i.e., photolytic ozonation) with catalysts (i.e., catalytic ozonation) was reviewed. Special attention was paid to how efficient these techniques are for removing contaminants from water matrices, and any potentialities and weak points of the intensified processes.

UV365 induced elimination of contaminants of emerging concern in the presence of residual nitrite: Roles of reactive nitrogen species

The presence of nitrite (NO2−) is inevitable with concentrations of several mg L−1 in some typical water bodies. In this study, UV at wavelength of 365 nm was investigated to degrade contaminants of emerging concern (CECs) in the presence of NO2− at environmentally relevant concentrations (0.1–5.0 mg L−1). Six selected CECs with different structures were efficiently removed because of the generation of reactive nitrogen species (RNS) and hydroxyl radical (HO•) from photolysis of NO2−. Contributions of UV365 photolysis, RNS, and HO• to CEC degradation in UV365/NO2− system were calculated, and RNS were found to be the predominant species that are responsible for CEC degradation. The second major contributor is HO• for the degradation of selected CECs except for the case of sulfadiazine. Impacts of water matrix components (including dissolved oxygen, solution pH, and natural organic matter) on CEC degradation in UV365/NO2− system were evaluated. Furthermore, evolution profiles of CECs and NO2− in UV365/NO2− system were tracked when actual water samples were used as background, and a simultaneous removal of CECs and NO2− was observed. Transformation products of bisphenol A and carbamazepine were proposed according to the results of HPLC/MS and quantum chemistry calculations. Nitration induced by RNS and hydroxylation induced by HO• are main reactions occurred during CEC degradation in UV365/NO2− system. Overall, UV365 is a potential technology to remove CECs and NO2− in aquatic environment when residual NO2− is present. Our present study also provides possibility for the application of sunlight to remediate water co-polluted by CECs and NO2−.

Solar light-assisted remediation of domestic wastewater by NB-TiO2 nanoparticles for potable reuse

Water reuse has become a worldwide necessity due to scarcity of fresh water supplies. Recently, advanced oxidation processes (AOPs) has been incorporated into water reuse treatment train to destroy residual organics in water before its discharge. Yet, the currently applied ultraviolet/H2O2 AOP is associated with high electrical demand by the UV process in addition to transport and storage problems of H2O2. Accordingly, the current work investigates the use of solar light/NB-TiO2 as an efficient AOP for water reuse industry. The technology was developed and tested for degradation of five contaminants of emerging concern (CECs) spiked in Milli-Q water and different wastewater samples. All CECs were successfully removed from individual and quinary systems, even in presence of natural levels of common inorganic quenching agents. Roles of different reactive species involved on the degradation of CECs were explored. Using mass spectroscopy, transformation products from CECs degradation were identified and degradation pathways were hypothesized.

Degradation of contaminants of emerging concern by UV/H2O2 for water reuse: Kinetics, mechanisms, and cytotoxicity analysis

Advanced oxidation using UV and hydrogen peroxide (UV/H2O2) has been widely applied to degrade contaminants of emerging concern (CECs) in wastewater for water reuse. This study investigated the degradation kinetics of mixed CECs by UV/H2O2 under variable H2O2 doses, including bisphenol A, estrone, diclofenac, ibuprofen, and triclosan. Reverse osmosis (RO) treated water samples from Orange County Water District’s Groundwater Replenishment System (GWRS) potable reuse project were collected on different dates and utilized as reaction matrices with spiked additions of chemicals (CECs and H2O2) to assess the application of UV/H2O2. Possible degradation pathways of selected CECs were proposed based on high resolution mass spectrometry identification of transformation products (TPs). Toxicity assessments included cytotoxicity, aryl hydrocarbon receptor-binding activity, and estrogen receptor-binding activity, in order to evaluate potential environmental impacts resulting from CEC degradation by UV/H2O2. Cytotoxicity and estrogenic activity were significantly reduced during the degradation of mixed CECs in Milli-Q water by UV/H2O2 with high UV fluence (3200 mJ cm−2). However, in GWRS RO-treated water samples collected in April 2017, the cytotoxicity and estrogen activity of spiked CEC-mixture after UV/H2O2 treatment were not significantly eliminated; this might be due to the high concentration of target CEC and their TPs, which was possibly affected by the varied quality of the secondary treatment influent at this facility such as sewer-shed and wastewater discharges. This study aimed to provide insight on the impacts of post-UV/H2O2 CECs and TPs on human and ecological health at cellular level.

Influence of terminal electron-accepting conditions on the soil microbial community and degradation of organic contaminants of emerging concern

Better understanding of the fate and persistence of trace organic contaminants of emerging concern (CEC) in agricultural soils is critical for assessing the risks associated with using treated wastewater effluent to irrigate crops and land application of wastewater biosolids. This study reports on the influence of prevailing terminal electron-accepting processes (TEAPs, i.e., aerobic, nitrate-reducing, iron(III)-reducing, and sulfate-reducing conditions) and exposure to a mixture of nine trace CEC (90 ng/g each) on both the microbial community structure and CEC degradation in agricultural soil. DNA analysis revealed significant differences in microbial community composition following establishment of different TEAPs, but no significant change upon exposure to the mixture of CEC. The largest community shift was observed after establishing nitrate-reducing conditions and the smallest shift for sulfate-reducing conditions. Two of the CEC (atrazine and sulfamethoxazole) showed significant degradation in both bioactive and abiotic (i.e., sterilized) conditions, with half-lives ranging from 1 to 64 days for different TEAPs, while six of the CEC (amitriptyline, atenolol, trimethoprim, and three organophosphate flame retardants) only degraded in bioactive samples, with half-lives ranging from 27 to 90 days; carbamazepine did not degrade appreciably within 90 days in any of the incubations. Amplicon sequence variants (ASVs) from Firmicutes Hydrogenispora, Gemmatimonadetes Gemmatimonadaceae, and Verrucomicrobia OPB34 soil group were identified as potentially responsible for the biodegradation of organophosphate flame retardants, and ASVs from other taxa groups were suspected to be involved in biodegrading the other target CEC. These results demonstrate that CEC fate and persistence in agricultural soils is influenced by the prevailing TEAPs and their influence on the microbial community, suggesting the need to incorporate these factors into contaminant fate models to improve risk assessment predictions.

Two strategies of solar photo-Fenton at neutral pH for the simultaneous disinfection and removal of contaminants of emerging concern. Comparative assessment in raceway pond reactors

For the first time, two strategies of solar photo-Fenton at neutral pH (with FeSO4 and Fe3+-EDDS) are techno-economically assessed. With the target of simultaneous wastewater disinfection and removal of contaminants of emerging concern (CECs), a cost estimation ranging from 0.13 to 0.49 €/m3 as a function of the treatment goal is presented. To this end, the effects of liquid depth (5, 10 and 15 cm) and the iron species were studied at lab-scale. Afterwards, the feasibility of both operating strategies was evaluated and validated outdoors at pilot plant scale in low-cost raceway pond reactors. For the joint-removal of bacteria and CECs, the use of FeSO4 as iron source was cheaper than Fe3+-EDDS. However, it is important to highlight that although bacterial inactivation reached > 3 log, only around 35 % of CEC degradation was achieved with FeSO4, while more than 80 % CEC load was removed with Fe3+-EDDS.