Removal of pharmaceuticals during drinking water treatment

The wettability of gas bubbles: from macro behavior to nano structures to applications

In recent years, various interfaces related to bubble wettability have been fabricated, which have already been widely applied in various disciplines and fields. Therefore, to better research and understand the wettability of gas bubbles, recent progress with interfaces and wettability of bubbles in aqueous media, including superaerophilicity and superaerophobicity, is summarized. Many biological interfaces which exhibit marvelous characteristics are discussed for reference. Because of the similar behavior between gas bubbles in aqueous media and droplets in air, the two wetting conditions are compared together to better illustrate theories of gas bubble wettability. Based on these theories, effective and available manipulation of gas bubbles' wettability provides a novel idea and method to solve practical problems in various aspects, i.e., superaerophobic electrodes for gas evolution reactions, superaerophilic electrodes for gas compensation reactions, superaerophilic interfaces for directional collection and transportation of gas bubbles, and so on.

Application of advanced oxidation processes and toxicity assessment of transformation products

Advanced Oxidation Processes (AOPs) are the techniques employed for oxidation of various organic contaminants in polluted water with the objective of making it suitable for human consumption like household and drinking purpose. AOPs use potent chemical oxidants to bring down the contaminant level in the water. In addition to this function, these processes are also capable to kills microbes (as disinfectant) and remove odor as well as improve taste of the drinking water. The non-photochemical AOPs methods include generation of hydroxyl radical in absence of light either by ozonation or through Fenton reaction. The photochemical AOPs methods use UV light along with H₂O₂, O₃ and/or Fe⁺² to generate reactive hydroxyl radical. Non-photochemical method is the commonly used whereas, photochemical method is used when conventional O₃ and H₂O₂ cannot completely oxidize organic pollutants. However, the choice of AOPs methods is depended upon the type of contaminant to be removed. AOPs cause loss of biological activity of the pollutant present in drinking water without generation of any toxicity. Conventional ozonation and AOPs can inactivate estrogenic compounds, antiviral compounds, antibiotics, and herbicides. However, the study of different AOPs methods for the treatment of drinking water has shown that oxidation of parent compound can also lead to the generation of a degradation/transformation product having biological activity/chemical toxicity similar to or different from the parent compound. Furthermore, an increased toxicity can also occur in AOPs treated drinking water. This review discusses various methods of AOPs, their merits, its application in drinking water treatment, the related issue of the evolution of toxicity in AOPs treated drinking water, biocatalyst, and analytical methods for identification of pollutants /transformed products and provides future directions to address such an issue.

Wastewater chemical contaminants: remediation by advanced oxidation processes

Approximately 70% of the terrestrial area is covered with water, but only a small water fraction is compatible with terrestrial life forms. Due to the increment in human consumption, the need for water resources is increasing, and it is estimated that more than 40% of the population worldwide will face water stress/scarcity within the next few decades. Water recycling and reuse may offer the opportunity to expand water resources. For that, the wastewater treatment paradigm should be changed and adequately treated wastewater should be seen as a valuable resource instead of a waste product. It is easily understandable that the exact composition and constituent concentration of wastewater vary according to its different sources (industrial, agricultural, urban usage of water). Consequently, a variety of known and emerging pollutants like heavy metals, antibiotics, pesticides, phthalates, polyaromatic hydrocarbons, halogenated compounds and endocrine disruptors have been found in natural water reservoirs, due to the limited effectiveness of conventional wastewater treatment. The conventional approach consists of a combination of physical, chemical and biological processes, aiming at the removal of large sediments such as heavier solids, scum and grease and of organic content in order to avoid the growth of microorganisms and eutrophication of the receiving water bodies. However, this approach is not sufficient to reduce the chemical pollutants and much less the emerging chemical pollutants. In this review, after some considerations concerning chemical pollutants and the problematic efficiency of their removal by conventional methods, an update is presented on the successes and challenges of novel approaches for wastewater remediation based on advanced oxidation processes. An insight into wastewater remediation involving the photodynamic approach mediated by tetrapyrrolic derivatives will be underlined.

The changes of bacterial communities and antibiotic resistance genes in microbial fuel cells during long-term oxytetracycline processing

Microbial fuel cell (MFC) is regarded as a promising alternative for enhancing the removal of antibiotic pollutants. In this study, oxytetracycline served as an electron donor in the anode chamber of MFCs, and after continuous operation for 330 days, the efficiency of removal of 10 mg/L oxytetracycline in MFCs increased to 99.00% in 78 h, whereas removal efficiency of only 58.26% was achieved in microbial controls. Compared to microbial controls, higher ATP concentration and persistent electrical stimulation mainly contributed to bioelectrochemical reactions more rapidly to enhance oxytetracycline removal in MFCs. In addition, the analysis of bacterial communities revealed that Eubacterium spp.-as the main functional bacterial genus responsible for oxytetracycline biodegradation-flourished starting from merely 0.00%-91.69% ± 0.27% (mean ± SD) in MFCs. High-throughput quantitative PCR showed that the normalized copy numbers of total antibiotic resistance genes (ARGs) and mobile genetic elements in MFCs were 1.7364 and 0.0065 copies/cell respectively, which were markedly lower than those in the microbial controls. Furthermore, there was no significant correlation between oxytetracycline concentration in the influent and abundance of ARGs in effluent from MFCs. Nevertheless, Tp614, a transposase gene, was found to be enriched in both MFCs and microbial reactors, suggesting that it may be a common challenge for different biological processes for wastewater treatment. This study therefore showed a lower probability of upregulation and transmission of ARGs in MFCs when compared to a traditional anaerobic microbial treatment.

Comparison of Sorption to Carbon-Based Materials and Nanomaterials Using Inverse Liquid Chromatography

Sorption studies of carbon-based materials and nanomaterials are typically conducted using batch experiments, but the analysis of weakly sorbing compounds may be challenging. Column chromatography represents a promising complement as higher sorbent to solution ratios can be applied. The sorbent is packed in a column, and sorption data are calculated by relating sorbate retention times to that of a nonretarded tracer. In this study, sorption of heterocyclic organic compounds (pyrazole, pyrrole, furan, and thiophene) by carbon-based materials (activated carbon, biochar, and graphite) and nanomaterials (functionalized carbon nanotubes and graphene platelets) was compared for the first time using column chromatography. D₂O was used as nonretarded tracer. Sorption isotherms were nonlinear and described well by the Freundlich model. Sorption differed between the materials regarding determined Freundlich coefficients ( K_f) by more than two orders of magnitude for isotherms in a similar concentration range. Normalization of K_f with the surface area of the sorbent significantly reduced but did not remove the differences between the sorbents. Overall, column chromatography represents the opportunity to study sorption of weakly sorbing compounds to diverse carbon-based sorbent materials with a single experimental approach, which is challenging in batch experiments because of the very different sorption properties of some sorbent materials.

Adsorption of estrone with few-layered boron nitride nanosheets: Kinetics, thermodynamics and mechanism

Boron nitride Nanosheets (BNNSs) was fabricated with a method of heating the mixture of boric acid and urea in N₂ atmosphere and used to remove estrone (E₁) from water. The obtained BNNSs exhibited a higher surface area of 896 m²/g, a large pore volume of 0.76 cm³/g, and only few layers (0.398 nm) with the boric acid and urea ratio of 1:80. The layer number of BNNSs decreased from 15 to 4 with the mole ratio of boric acid and urea decreasing from 1:20 to 1:80, which was identified by SEM, TEM, AFM and BET measurements. More importantly, BNNSs presented an outstanding adsorption performance for estrone with the adsorption capacity of 249.15 mg E₁/g BNNSs. The adsorption process could be best fitted by pseudo second-order kinetic model and the equilibrium data at different temperatures were well fitted by Langmuir isotherm model. The thermodynamics analysis revealed that E₁ adsorption on BNNSs was spontaneous (ΔG = -29.33 kJ mol^-1), enthalpy-retarded (ΔH = 29.75 kJ mol^-1), entropy-driven (ΔS = 198.26 J mol^-1 K^-1), and mostly chemical adsorption. The adsorption rates of E₁ in water were sharply enhanced with thinner BNNSs as absorbents and removal efficiency by BN-60 regenerated after 6 times was above 95%, it was shown that the surface areas, mesopores and remarkable structure played important roles in the adsorption process. The firmness of E₁ onto BNNSs and the stability of adsorption efficiency made BNNSs as a potential absorbent for efficient removal of E₁ from wastewater.

Comparative study of substituted poly(4-vinylbenzyl chloride/ethylene glycol dimethacrylate) sorbents for enrichment of selected pharmaceuticals and estrogens from aqueous samples

This study reports the syntheses of four polymeric sorbents based on nucleophilic substitution of Poly(4-vinylbenzylchloride/ethylene glycol dimethacrylate). Polymerization was executed by a simple thermal initiated bulk polymerization procedure. Ground polymer particles were functionalized through reaction with the nucleophiles triethylamine, imidazole, piperidine and pyrrolidine. Mixed-mode phases were characterized by infrared spectroscopy, nitrogen sorption porosimetry and potentiometric titration for determination of chloride content. Furthermore, materials were tested and evaluated for enrichment of seven pharmaceutical and endocrine-disrupting compounds at low ng mL^-1 levels. Results demonstrate that the imidazole modified sorbent led to high and constant recovery rates for nearly all tested compounds. Therefore, this polymer was further tested for applicability with two environmental samples. Spiked tap and river water showed similar results as in evaluation experiments. Moreover, the developed method was validated regarding linearity, repeatability, instrumental limits and stability of analytes according to international guidelines.

Advanced oxidation process-mediated removal of pharmaceuticals from water: A review

Pharmaceuticals, which are frequently detected in natural and wastewater bodies as well as drinking water have attracted considerable attention, because they do not readily biodegrade and may persist and remain toxic. As a result, pharmaceutical residues pose on-going and potential health and environmental risks. To tackle these emerging contaminants, advanced oxidation processes (AOPs) such as photo-Fenton, sonolysis, electrochemical oxidation, radiation and ozonation etc. have been applied to remove pharmaceuticals. These processes utilize the high reactivity of hydroxyl radicals to progressively oxidize organic compounds to innocuous products. This review provides an overview of the findings from recent studies, which have applied AOPs to degrade pharmaceutical compounds. Included is a discussion that links various factors of TiO₂-mediated photocatalytic treatment to its effectiveness in degrading pharmaceutical residues. This review furthermore highlights the success of AOPs in the removal of pharmaceuticals from different water matrices and recommendations for future studies are outlined.

Removal of sulfamethoxazole and diclofenac from water: strategies involving O3 and H2O2

Diclofenac (DCF) and Sulfamethoxazole (SMX) are two of the most frequently detected pharmaceutical compounds in water and are hardly removed by biological treatment systems. The presence of H₂O₂ was investigated in the ozonation of these two compounds. Experiments were carried out with both using distilled water and secondary effluent from a municipal wastewater treatment plant spiked with pharmaceuticals. Chemical oxygen demand (COD) abatement rate improved when H₂O₂ was added at the beginning of the ozonation process and when the ozone inlet concentration increased, attaining a maximum value of 91% and simultaneously a lower ozone waste for a H₂O₂ initial concentration of 5 mM and an ozone inlet concentration of 20 g Nm^-3. For these operation conditions, the water matrix has no significant impact on SMX and DCF removal, which were totally degraded in 45 and 60 min, respectively. Nevertheless, lower COD degradation and ozone usage were obtained when the secondary effluent was used. Inorganic ions such as chloride, sulphate and nitrate and short-chain organic compounds were detected as by-products of the SMX and DCF oxidation. Vibrio fischeri luminescence inhibition tests revealed that simultaneous use of ozone and H₂O₂ reduced acute toxicity.

Micropollutants in drinking water from source to tap - Method development and application of a multiresidue screening method

A multi-residue screening method for simultaneous measurement of a wide range of micropollutants in drinking water (DW) resources was developed. The method was applied in a field study in central Sweden on water from source to tap, including samples of surface water (upstream and downstream of a wastewater treatment plant, WWTP), intake water before and after a DW treatment plant (DWTP, pilot and full-scale), treated DW leaving the plant and tap water at end users. Low detection limits (low ng L^-1 levels) were achieved by using large sample volumes (5 L) combined with ultra performance liquid chromatography high resolution mass spectrometry (UPLC-HRMS). In total, 134 different micropollutants were analyzed, including pesticides, pharmaceuticals and personal care products (PPCPs), drug-related compounds, food additives, and perfluoroalkyl substances (PFASs). Of these 134 micropollutants, 41 were detected in at least one sample, with individual concentrations ranging from sub ng L^-1 levels to ~80 ng L^-1. Two solid phase extraction (SPE) cartridges (Oasis HLB and Bond-Elut ENV) were shown to be complementary in the field study, with three compounds detected exclusively using HLB. The total concentration in treated drinking water (56-57 ng L^-1) was at a similar level as upstream from the WWTP (79-90 ng L^-1). The composition of micropollutants changed along the water path, to a higher fraction of food additives and PFASs. Median treatment efficiency in the full-scale DWTP was close to 0%, but with high variability for individual compounds. In contrast, median treatment efficiency in the pilot-scale DWTP was ~90% when using nanofiltration followed by a freshly installed granulated active carbon (GAC) filter.

Behaviour of aqueous sulfamethizole solution and temperature effects in cold plasma oxidation treatment

The increase in volume and variety of pharmaceuticals found in natural water bodies has become an increasingly serious environmental problem. The implementation of cold plasma technology, specifically gas-phase pulsed corona discharge (PCD), for sulfamethizole abatement was studied in the present work. It was observed that sulfamethizole is easily oxidized by PCD. The flow rate and pH of the solution have no significant effect on the oxidation. Treatment at low pulse repetition frequency is preferable from the energy efficiency point of view but is more time-consuming. The maximum energy efficiency was around 120 g/kWh at half-life and around 50 g/kWh at the end of the treatment. Increasing the solution temperature from room temperature to 50 °C led to a significant reaction retardation of the process and decrease in energy efficiency. The pseudo-first order reaction rate constant (k₁) grows with increase in pulse repetition frequency and does not depend on pH. By contrast, decreasing frequency leads to a reduction of the second order reaction rate constant (k₂). At elevated temperature of 50 °C, the k₁, k₂ values decrease 2 and 2.9 times at 50 pps and 500 pps respectively. Lower temperature of 10 °C had no effect on oxidation efficiency compared with room temperature.

Occurrence, distribution, and seasonality of emerging contaminants in urban watersheds

The widespread occurrence of natural and synthetic organic chemicals in surface waters can cause ecological risks and human health concerns. This study measured a suite of contaminants of emerging concern (CECs) in water samples collected by the U.S. Environmental Protection Agency Region 8 around the Denver, Colorado, metropolitan area. The results showed that 109 of 144 analyzed pharmaceutical compounds, 42 of 55 analyzed waste-indicator compounds (e.g., flame retardants, hormones, and personal care products), and 39 of 72 analyzed pesticides were detected in the water samples collected monthly between April and November in both 2014 and 2015. Pharmaceutical compounds were most abundant in the surface waters and their median concentrations were measured up to a few hundred nanograms per liter. The CEC concentrations varied depending on sampling locations and seasons. The primary source of CECs was speculated to be wastewater effluent. The CEC concentrations were correlated to streamflow volume and showed significant seasonal effects. The CECs were less persistent during spring runoff season compared with baseflow season at most sampling sites. These results are useful for providing baseline data for surface CEC monitoring and assessing the environmental risks and potential human exposure to CECs.

Oxidation Processes in Water Treatment: Are We on Track?

Chemical oxidants have been applied in water treatment for more than a century, first as disinfectants and later to abate inorganic and organic contaminants. The challenge of oxidative abatement of organic micropollutants is the formation of transformation products with unknown (eco)toxicological consequences. Four aspects need to be considered for oxidative micropollutant abatement: (i) Reaction kinetics, controlling the efficiency of the process, (ii) mechanisms of transformation product formation, (iii) extent of formation of disinfection byproducts from the matrix, (iv) oxidation induced biological effects, resulting from transformation products and/or disinfection byproducts. It is impossible to test all the thousands of organic micropollutants in the urban water cycle experimentally to assess potential adverse outcomes of an oxidation. Rather, we need multidisciplinary and automated knowledge-based systems, which couple predictions of kinetics, transformation and disinfection byproducts and their toxicological consequences to assess the overall benefits of oxidation processes. A wide range of oxidation processes has been developed in the last decades with a recent focus on novel electricity-driven oxidation processes. To evaluate these processes, they have to be compared to established benchmark ozone- and UV-based oxidation processes by considering the energy demands, economics, the feasibilty, and the integration into future water treatment systems.

Competitive adsorption of PPCP and humic substances by carbon nanotube membranes: Effects of coagulation and PPCP properties

Natural organic matter (NOM) and pharmaceuticals and personal care products (PPCP) are known to compete for adsorption sites on carbon nanotubes (CNT), resulting in decreasing PPCP adsorption onto CNT. In this study, four types of PPCP, as such acetaminophen (AAP), caffeine (CAF), triclosan (TCS), and carbendazim (CBD) were used to investigate the effects of PPCP properties and NOM coagulation on the competitive adsorption of PPCP and NOM. Coagulation preferentially removed HS from a natural surface water, thereby increasing adsorption of AAP, CAF, TCS and CBD by 19%, 13%, 17% and 11%, respectively. Similar trends were obtained with synthetic natural waters, for which the adsorption of AAP, CAF, TCS, and CBD increased by 29%, 7%, 44% and 69%, respectively, as humic acid (HA) concentration decreased from 10mgL^-1 to 0mgL^-1. Furthermore, PPCP properties also affected their competition with NOM for adsorption by CNT membranes Because CAF existed in cationic form at pH ranging from 7 to 8.3, its adsorption was less affected by the presence/coagulation of NOM than AAP, CBD, and TCS. Based upon these findings, coagulation has the potential to be integrated with CNT adsorption for the removal of PPCP compounds during advanced drinking water treatment.

Morphology- and size-controlled synthesis of a metal-organic framework under ultrasound irradiation: An efficient carrier for pH responsive release of anti-cancer drugs and their applicability for adsorption of amoxicillin from aqueous solution

In this study, we have reported a biocompatible metal-organic framework (MOF) with ultra-high surface area, which we have shown to have uses as both a cancer treatment delivery system and for environmental applications. Using a sonochemical approach, highly flexible organic H₃BTCTB and ditopic 4,4'-BPDC ligands, along with modulators of acetic acid and pyridine were combined to prepare a Zn(II)-based metal-organic framework, DUT-32, [Zn₄O(BPDC)(BTCTB)_4/3(DEF)_39.7(H₂O)_11.3]. Powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize, the particle size, shape, and structure of the DUT-32. To show the effects of shape and size of DUT-32 micro/nano-structures on doxorubicin (DOX) drug release and amoxicillin (AMX) adsorption, time of sonication, initial reagent concentrations, irradiation frequency, and acetic acid to pyridine molar ratios were optimized. The drug-loaded DUT-32 was soaked in simulated body fluid (SBF) and the drug release ratio was monitored through release time to perform in vitro drug release test. A slow and sustained release was observed for DUT-32 micro/nano-structures, having a considerable drug loading capacity. At the pH values 7.4-4.5, various profiles of pH-responsive release were achieved. Also, the prepared DUT-32 micro/nano-structures are found to be biocompatible with PC3 (prostate cancer) and HeLa (cervical cancer) cell lines, when tested by MTT assay. Moreover, DUT-32 micro/nano-structures were studied to show AMX adsorption from aqueous solution. Finally, kinetic studies indicated that AMX adsorption and drug release of DOX via this MOF are of first-order kinetics.

Effective removal of bromate in nitrate-reducing anoxic zones during managed aquifer recharge for drinking water treatment: Laboratory-scale simulations

The removal of bromate (BrO₃^-) as a by-product of ozonation in subsequent managed aquifer recharge (MAR) systems, specifically in anoxic nitrate (NO₃^-)-reducing zones, has so far gained little attention. In this study, batch reactors and columns were used to explore the influence of NO₃^- and increased assimilable organic carbon (AOC) due to ozonation pre-treatment on BrO₃^- removal in MAR systems. 8 m column experiments were carried out for 10 months to investigate BrO₃^- behavior in anoxic NO₃^--reducing zones of MAR systems. Anoxic batch experiments showed that an increase of AOC promoted microbial activity and corresponding BrO₃^- removal. A drastic increase of BrO₃^- biodegradation was observed in the sudden absence of NO₃^- in both batch reactors and columns, indicating that BrO₃^- and NO₃^- competed for biodegradation by denitrifying bacteria and NO₃^- was preferred as an electron acceptor under the simultaneous presence of NO₃^- and BrO₃^-. However, within 75 days' absence of NO₃^- in the anoxic column, BrO₃^- removal gradually decreased, indicating that the presence of NO₃^- is a precondition for denitrifying bacteria to reduce BrO₃^- in NO₃^--reducing anoxic zones. In the 8 m anoxic column set-up (retention time 6 days), the BrO₃^- removal achieved levels as low as 1.3 μg/L, starting at 60 μg/L (98% removal). Taken together, BrO₃^- removal is likely to occur in vicinity of NO₃^--reducing anoxic zones, so MAR systems following ozonation are potentially effective to remove BrO₃^-.

Micropollutant removal from black water and grey water sludge in a UASB-GAC reactor

The effect of granular activated carbon (GAC) addition on the removal of diclofenac, ibuprofen, metoprolol, galaxolide and triclosan in a up-flow anaerobic sludge blanket (UASB) reactor was studied. Prior to the reactor studies, batch experiments indicated that addition of activated carbon to UASB sludge can decrease micropollutant concentrations in both liquid phase and sludge. In continuous experiments, two UASB reactors were operated for 260 days at an HRT of 20 days, using a mixture of source separated black water and sludge from aerobic grey water treatment as influent. GAC (5.7 g per liter of reactor volume) was added to one of the reactors on day 138. No significant difference in COD removal and biogas production between reactors with and without GAC addition was observed. In the presence of GAC, fewer micropollutants were washed out with the effluent and a lower accumulation of micropollutants in sludge and particulate organic matter occurred, which is an advantage in micropollutant emission reduction from wastewater. However, the removal of micropollutants by adding GAC to a UASB reactor would require more activated carbon compared to effluent post-treatment. Additional research is needed to estimate the effect of bioregeneration on the lifetime of activated carbon in a UASB-GAC reactor.

Waste-based alternative adsorbents for the remediation of pharmaceutical contaminated waters: Has a step forward already been taken?

When adsorption is considered for water treatment, commercial activated carbon is usually the chosen adsorbent for the removal of pollutants from the aqueous phase, particularly pharmaceuticals. In order to decrease costs and save natural resources, attempts have been made to use wastes as raw materials for the production of alternative carbon adsorbents. This approach intends to increase efficiency, cost-effectiveness, and also to propose an alternative and sustainable way for the valorization/management of residues. This review aims to provide an overview on waste-based adsorbents used on pharmaceuticals' adsorption. Experimental facts related to the adsorption behaviour of each adsorbent/pharmaceutical pair and some key factors were addressed. Also, research gaps that subsist in this research area, as well as future needs, were identified. Simultaneously, this review aims to clarify the current status of the research on pharmaceuticals' adsorption by waste-based adsorbents in order to recognize if the right direction is being taken.

Effectivity of advanced wastewater treatment: reduction of in vitro endocrine activity and mutagenicity but not of in vivo reproductive toxicity

Conventional wastewater treatment plants (WWTPs) have a limited capacity to eliminate micropollutants. One option to improve this is tertiary treatment. Accordingly, the WWTP Eriskirch at the German river Schussen has been upgraded with different combinations of ozonation, sand, and granulated activated carbon filtration. In this study, the removal of endocrine and genotoxic effects in vitro and reproductive toxicity in vivo was assessed in a 2-year long-term monitoring. All experiments were performed with aqueous and solid-phase extracted water samples. Untreated wastewater affected several endocrine endpoints in reporter gene assays. The conventional treatment removed the estrogenic and androgenic activity by 77 and 95 %, respectively. Nevertheless, high anti-estrogenic activities and reproductive toxicity persisted. All advanced treatment technologies further reduced the estrogenic activities by additional 69-86 % compared to conventional treatment, resulting in a complete removal of up to 97 %. In the Ames assay, we detected an ozone-induced mutagenicity, which was removed by subsequent filtration. This demonstrates that a post treatment to ozonation is needed to minimize toxic oxidative transformation products. In the reproduction test with the mudsnail Potamopyrgus antipodarum, a decreased number of embryos was observed for all wastewater samples. This indicates that reproductive toxicants were eliminated by neither the conventional nor the advanced treatment. Furthermore, aqueous samples showed higher anti-estrogenic and reproductive toxicity than extracted samples, indicating that the causative compounds are not extractable or were lost during extraction. This underlines the importance of the adequate handling of wastewater samples. Taken together, this study demonstrates that combinations of multiple advanced technologies reduce endocrine effects in vitro. However, they did not remove in vitro anti-estrogenicity and in vivo reproductive toxicity. This implies that a further optimization of advanced wastewater treatment is needed that goes beyond combining available technologies.

Chlorination, chloramination and ozonation of carbamazepine enhance cytotoxicity and genotoxicity: Multi-endpoint evaluation and identification of its genotoxic transformation products

Investigations have focused on the removal and transformation of pharmaceuticals during drinking water and wastewater treatment. In the present study, we investigated for the first time the changes of the cytotoxicity and genotoxicity based on different modes of action (MoAs) during chlorination, chloramination and ozonation processes of the anti-epileptic drug carbamazepine (CBZ). The results illustrated that ozonation enhanced the cytotoxicity and the chromosome damage effects on CHO-K1 cells detected by cytokinesis-block micronucleus (CBMN) assay based on high-content screening technique, though ozonation showed the highest removal efficiency for CBZ. Non-target chemical analysis followed by quantitative structure-activity relationship (QSAR) analysis for the transformation products (TPs) suggested that the chromosomal damage effects could probably be attributed to 1-(2-benzaldehyde)-4-hydro-(1H,3H)-quinazoline-2-one (BQM) and 1-(2-benzaldehyde)-(1H,3H)-quinazoline-2,4-dione (BQD). In contrast to CBZ itself and the ozonated sample, the chlorinated and chloraminated samples caused DNA damage effects in SOS/umu test. Acridine, 9 (10) H-acridone, chlorinated 9 (10) H-acridone and TP-237, which were first identified in the chlorination or chloramination processes, were predicted to be the DNA damaging agents. These genotoxic TPs were primarily generated from the oxidation of seven-membered N-heterocyclic in CBZ. This study highlighted the potential adverse effects generated in ozonation process and the oxidation of N-heterocyclic containing pollutants.

Degradation and intermediates of diclofenac as instructive example for decomposition of recalcitrant pharmaceuticals by hydroxyl radicals generated with pulsed corona plasma in water

Seven recalcitrant pharmaceutical residues (diclofenac, 17α-ethinylestradiol, carbamazepine, ibuprofen, trimethoprim, diazepam, diatrizoate) were decomposed by pulsed corona plasma generated directly in water. The detailed degradation pathway was investigated for diclofenac and 21 intermediates could be identified in the degradation cascade. Hydroxyl radicals have been found primarily responsible for decomposition steps. By spin trap enhanced electron paramagnetic resonance spectroscopy (EPR), OH-adducts and superoxide anion radical adducts were detected and could be distinguished applying BMPO as a spin trap. The increase of concentrations of adducts follows qualitatively the increase of hydrogen peroxide concentrations. Hydrogen peroxide is eventually consumed in Fenton-like processes but the concentration is continuously increasing to about 2mM for a plasma treatment of 70min. Degradation of diclofenac is inversely following hydrogen peroxide concentrations. No qualitative differences between byproducts formed during plasma treatment or due to degradation via Fenton-induced processes were observed. Findings on degradation kinetics of diclofenac provide an instructive understanding of decomposition rates for recalcitrant pharmaceuticals with respect to their chemical structure. Accordingly, conclusions can be drawn for further development and a first risk assessment of the method which can also be applied towards other AOPs that rely on the generation of hydroxyl radicals.

Persistence, mobility and bioavailability of emerging organic contaminants discharged from sewage treatment plants

Little is known about the impact of emissions of micropollutants from small and large-scale sewage treatment plants (STPs) on drinking water source areas. We investigated a populated catchment that drains into Lake Mälaren, which is the drinking water source for around 2 million people including the inhabitants of Stockholm, Sweden. To assess the persistence, mobility, bioavailability and bioaccumulation of 32 structurally diverse emerging organic contaminants, sediment, integrated passive and grab water samples were collected along the catchment of the River Fyris, Sweden. The samples were complemented with STP effluent and fish samples from one sampling event. Contaminants identified as persistent, mobile, and bioavailable were 4,6,6,7,8,8-hexamethyl-1,3,4,7-tetrahydrocyclopenta[g]isochromene (galaxolide), 2,4,7,9-tetramethyl-5-decyn-4,7-diol, tris(2-chloro-ethyl) phosphate, tris(1,3-dichloro-2-propyl) phosphate, and tris(1-chloro-2-propyl) phosphate. Galaxolide and 2,4,7,9-tetramethyl-5-decyn-4,7-diol were additionally found to be bioaccumulative, whereas n-butylbenzenesulfonamide was found to be only persistent and mobile. The total median mass flux of the persistent and mobile target analytes from Lake Ekoln into the drinking water source area of Lake Mälaren was estimated to be 27kg per year. Additionally, 10 contaminants were tentatively identified by non-target screening using NIST library searches and manual review. Two of those were confirmed by reference standards and further two contaminants, propylene glycol and rose acetate, were discharged from STPs and travelled far from the source. Attenuation of mass fluxes was highest in the summer and autumn seasons, suggesting the importance of biological degradation and photodegradation for the persistence of the studied compounds.

Application of ozone micro-nano-bubbles to groundwater remediation

Ozone is widely used for water treatment because of its strong oxidation ability. However, the efficiency of ozone in groundwater remediation is limited because of its relatively low solubility and rapid decomposition in the aqueous phase. Methods for increasing the stability of ozone within the subsurface are drawing increasing attention. Micro-nano-bubbles (MNBs), with diameters ranging from tens of nanometres to tens of micrometres, present rapid mass transfer rates, persist for a relatively long time in water, and transport with groundwater flow, which significantly improve gas concentration and provide a continuous gas supply. Therefore, MNBs show a considerable potential for application in groundwater remediation. In this study, the characteristics of ozone MNBs were examined, including their size distribution, bubble quantity, and zeta potential. The mass transfer rate of ozone MNBs was experimentally investigated. Ozone MNBs were then used to treat organics-contaminated water, and they showed remarkable cleanup efficiency. Column tests were also conducted to study the efficiency of ozone MNBs for organics-contaminated groundwater remediation. Based on the laboratory tests, field monitoring was conducted on a trichloroethylene (TCE)-contaminated site. The results showed that ozone MNBs can greatly improve remediation efficiency and represent an innovative technology for in situ remediation of organics-contaminated groundwater.

Ecotoxicological efficiency of advanced ozonation processes with TiO2 and black light used in the degradation of carbamazepine

The aim of the present study was to evaluate the ecotoxicological efficiency of two advanced ozonation processes (AOzPs), the catalytic ozonation (O₃/TiO₂) and the photocatalytic ozonation (O₃/TiO₂/black light), in the remotion of carbamazepine. The ecotoxicological efficiency was assessed through the use of lethal and sublethal assays with species Vibrio fischeri and Daphnia magna. Results demonstrated that the AOzPs presented an efficiency of carbamazepine removal higher than 99% (carbamazepine < 2 μg/L) after 12 min of treatment. Relatively to ecotoxicological evaluation, application of acute assay to V. fischeri and chronic assay to D. magna allowed us to highlight that these technologies may form some transformation products that induce toxicity in the bacteria and the crustacean, once these organisms exposed to the undiluted solutions (100%) showed a decrease in the bioluminescence (vibrio) and end up dying before and during the first reproduction (daphnia). Despite that, when the chronic results obtained with the diluted solutions (50 and 25%; important to assess a more realistic scenario considering the dilution factor at the environment) were analyzed, no mortality at the mothers was observed. Compared to a carbamazepine solution (200 μg/L), diluted solutions improved of the reproduction parameters, and no toxic effects in the juvenoid system and in the embryonic development were observed. Relatively to the ecdysteroid effect of a carbamazepine solution (200 μg/L), only the photocatalytic ozonation treatment was able to remove the action of the drug. These results highlight the importance of complementing chemical analysis with ecotoxicological bioassays to assess the best technology to improve the surface water and effluent quality.

A novel biodegradation pathway of the endocrine-disruptor di(2-ethyl hexyl) phthalate by Pleurotus ostreatus based on quantum chemical investigation

Di(2-ethyl hexyl) phthalate (DEHP) is a plasticizer that interfere with endocrine systems in mammals. Growth parameters for Pleurotus ostreatus grown on media containing glucose and different concentrations of DEHP (0, 500 and 1000mg/L) were evaluated. The highest biomass production was observed in medium supplemented with 1000mg of DEHP/L. Half-life of DEHP biodegradation, biodegradation constant of DEHP, and percentage of removal efficiency (%E) were also determined. P. ostreatus degraded 100% of DEHP after 504h. %E was 99.3% and 98.4% for 500 and 1000mg of DEHP/L, respectively. Intermediate compounds of biodegraded DEHP were identified by GC-MS and a DEHP biodegradation pathway was proposed using quantum chemical investigation. DEHP might be metabolized through three pathways; a de-esterification pathway, an oxidation pathway and an oxidation-hydrolysis pathway, forming phthalic acid, acetic acid and butanediol, respectively. P. ostreatus degrades and uses (as carbon and energy source) high concentrations of DEHP.

Triclosan removal from surface water by ozonation - Kinetics and by-products formation

Removal of triclosan from surface water by ozonation was investigated. The results showed that complete elimination of triclosan from a surface water bearing 1-5 mg/L triclosan via continuous ozonation at 5 mg/L, require an ozonation time of 20-30 min depending on pH. Triclosan oxidation followed pseudo-first order kinetics with an apparent reaction rate constant varying from 0.214 min^-1 to 0.964 min^-1 depending on pH, initial triclosan concentration and water composition. Although the effect of pH was complex due to possible existence of different moieties, higher TCS removal efficiencies were obvious at weak-base conditions. Experiments performed to identify degradation by-products showed the formation of four by-products, namely, 2,4-dichlorophenol, 4-chlorocatechol and two unidentified compounds. Additionally, 2,4-dichloroanisole was detected when a methyl moieties exist in water. By-products were found to be eliminated upon further ozonation. The required exposure time varied from 20 to 30 min depending on pH of water. The ozone demand exerted for the complete oxidation of triclosan and its by-products was calculated as 13.04 mg ozone per mg of triclosan. A triclosan degradation pathway, which was found to be highly pH dependent, was proposed.

Superwettability of Gas Bubbles and Its Application: From Bioinspiration to Advanced Materials

Gas bubbles in aqueous media are common and inevitable in, for example, agriculture and industrial processes. The behaviors of gas bubbles on solid interfaces, including generation, growth, coalescence, release, transport, and collection, are crucial to gas-bubble-related applications, which are always determined by gas-bubble wettability on solid interfaces. Here, the recent progress regarding the study of interfaces with gas-bubble superwettability in aqueous media, i.e., superaerophilicity and superaerophobicity, is summarized. Some examples illustrate how to design microstructures and chemical compositions to achieve reliable and effective manipulation of gas-bubble wettability on artificial interfaces. These designed interfaces exhibit excellent performance in gas-evolution reactions, gas-adsorption reactions, and directional gas-bubble transportation. Moreover, progress in the theoretical investigation of gas-bubble superwettability is reported. Lastly, some challenges are presented, such as the reliable manipulation of gas-bubble wettability and the establishment of mature theory for exactly and systematically explaining gas-bubble wetting phenomena.

NH2Fe3O4@SiO2 supported peroxidase catalyzed H2O2 for degradation of endocrine disrupter from aqueous solution: Roles of active radicals and NOMs

In this work, magnetic Fe₃O₄ was utilized to immobilize horseradish peroxidase (IM-HRP) in order to improve its stability and reusability by crosslinking method process with glutaraldehyde. The physicochemical properties of NH₂Fe₃O₄@SiO₂ and IM-HRP were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Thermo-gravimetric Analysis (TGA) and Transmission electron microscopy (TEM). The thermal stability of immobilized-HRP was considerably improved in comparison with free counterpart. The catalytic performance of IM-HRP for estrogens removal from aqueous solution was evaluated, it was found that the presence of natural organic matters (NOM) have no significant effects on E2 removal and the E2 enzyme-degradation reached around 80% when pH = 7.0 with 0.552 × 10^-3 ratio of IM-HRP/H₂O_2. In addition, the active radicals responsible for estrogens degradation were identified with electro-spin resonance spectra (ESR). It was found that immobilization process on Fe₃O₄ showed no adverse effects on catalytic performance on HRP, estrogens degradation could be fitted well with pseudo-second kinetic equation. Estrogens degradation efficiency was reduced in the presence of humic substances. Both O₂^- and OH were detected in IM-HRP catalyzed H₂O₂ system and radicals quenching test indicated O₂^- played a more important role in estrogens removal. IM-HRP exhibited excellent stability and E2 removal efficiency could reach 45.41% after use seven times. Therefore, HRP enzymes immobilized on NH₂Fe₃O₄@SiO₂ by cross-linking method in glutaraldehyde solutions was an effective way to improve stability and reusability of HRP, and which could avoid potential secondary pollution in water environment caused by free HRP after treatment.

Pharmaceutical Removal from Water Effluents by Adsorption on Activated Carbons: A Monte Carlo Simulation Study

Adsorption on activated carbons of five pharmaceutical molecules (ibuprofen, diclofenac, naproxen, paracetamol, and amoxicillin) in aqueous mixtures has been investigated by molecular simulations using the Grand Canonical Monte Carlo (GCMC) method. A virtual nanoporous carbon model based on polyaromatic units with defects and polar-oxygenated sites was used for this purpose. The simulation results show excellent agreement with available experimental data. The adsorption capacities of the carbons for the five drugs were quite different and were linked, essentially, to their molecular dimensions and atom affinities. The uptake behavior follows the trend PRM > DCF, NPX > IBP > AMX in all the studied structures. This work is a further step in order to describe macroscopic adsorption performance of activated carbons in drug removal applications.

Occurrences and removal of pharmaceuticals and personal care products (PPCPs) in drinking water and water/sewage treatment plants: A review

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.

A novel Fe(II)/citrate/UV/peroxymonosulfate process for micropollutant degradation: Optimization by response surface methodology and effects of water matrices

This paper applied the response surface methodology (RSM) to optimizing a novel Fe(II)/citrate/UV/PMS process in the degradation of a model micropollutant, carbamazepine (CBZ), a persistent emerging contaminant frequently detected in surface water and groundwater. The experimental conditions in terms of two responses, CBZ removal efficiency (Y1) and cost per unit CBZ removal (Y2), were optimized by the central composite design (CCD) in RSM. Modeling data exhibited that the optimum condition resulting in the lowest Y2 while achieving >70% of Y1 was at a UV dose of 265.5 mJ/cm² and Fe(II), PMS and citrate concentrations of 12.2 μM, 100 μM and 26.4 μM, respectively. Increasing Fe(II) concentration led to the decrease in CBZ degradation and cost-effectiveness of the process. On the other hand, increasing the UV dose, PMS concentration and citrate/Fe(II) ratio over 265.5 mJ/cm², 100 μM and 2.16:1, respectively, slightly increased the CBZ degradation, but significantly increased the cost. Under the optimized condition, the experimentally obtained values for Y1 and Y2 were 70.44% and 0.0104 H K$/%/m³, respectively. The predicted Y1 and Y2 were 71.07% and 0.0098 H K$/%/m³, respectively, suggesting that RSM can be readily used to determine the optimum condition of the Fe(II)/citrate/UV/PMS process for CBZ degradation. Other aqueous constituents which impacted the CBZ removal in the Fe(II)/citrate/UV/PMS process are in the following order: NOM > alkalinity > bromide > ammonia ≈ chloride (both negligible).

Study of the simulated sunlight photolysis mechanism of ketoprofen: the role of superoxide anion radicals, transformation byproducts, and ecotoxicity assessment

The aim of this study was to investigate the photolysis mechanism of ketoprofen (KET) under simulated sunlight. The results demonstrated that the photolysis of KET aligned well with pseudo first-order kinetics. Radical scavenging experiments and dissolved oxygen experiments revealed that the superoxide anion radical (O₂˙^-) played a primary role in the photolytic process in pure water. Bicarbonate slightly increased the photodegradation of KET through generating carbonate radicals, while DOM inhibited the photolysis via both attenuating light and competing radicals. Moreover, Zhujiang river water inhibited KET phototransformation. Potential KET degradation pathways were proposed based on the identification of products using LC/MS/MS and GC/MS techniques. The theoretical prediction of reaction sites was derived from Frontier Electron Densities (FEDs), which primarily involved the KET decarboxylation reaction. The ecotoxicity of the treated solutions was evaluated by employing Daphnia magna and V. fischeri as biological indicators. Ecotoxicity was also hypothetically predicted through the "ecological structure-activity relationship" (ECOSAR) program, which revealed that toxic products might be generated during the photolysis process.

Direct and indirect electrochemical reduction prior to a biological treatment for dimetridazole removal

Two different electrochemical reduction processes for the removal of dimetridazole, a nitroimidazole-based antibiotic, were examined in this work. A direct electrochemical reduction was first carried out in a home-made flow cell in acidic medium at potentials chosen to minimize the formation of amino derivatives and then the formation of azo dimer. Analysis of the electrolyzed solution showed a total degradation of dimetridazole and the BOD₅/COD ratio increased from 0.13 to 0.24. An indirect electrochemical reduction in the presence of titanocene dichloride ((C₅H₅)₂TiCl₂), which is used to reduce selectively nitro compounds, was then investigated to favour the formation of amino compounds over hydroxylamines and then to prevent the formation of azo and azoxy dimers. UPLC-MS/MS analyses showed a higher selectivity towards the formation of the amino compound for indirect electrolyses performed at pH 2. To confirm the effectiveness of the electrochemical reduction, a biological treatment involving activated sludge was then carried out after direct and indirect electrolyses at different pH. The enhancement of the biodegradability was clearly shown since mineralization yields of all electrolyzed solutions increased significantly.

Diclofenac degradation in water by FeCeOx catalyzed H2O2: Influencing factors, mechanism and pathways

The degradation of diclofenac in a like Fenton system, FeCeO_x-H₂O₂, was studied in details. The influencing factors, reaction kinetics, reaction mechanism and degradation pathways of diclofenac were investigated. The optimum conditions were at a solution pH of 5.0, H₂O₂ concentration of 3.0mmol/L, diclofenac initial concentration of 0.07mmol/L, FeCeO_x dosage of 0.5g/L, and 84% degradation of diclofenac was achieved within 40min. The kinetics of FeCeO_x catalyzed H₂O₂ process involved adsorption-dominating and degradation-dominating stages and fitted pseudo-second order model and pseudo-first order model, respectively. Singlet oxygen ¹O₂ was the primary intermediate oxidative species in the degradation process; superoxide radical anion O₂^- also participated in the reaction. The surface cerium and iron sites and the oxygen vacancies in the FeCeO_x catalyst were proposed to play an important role in H₂O₂ decomposition and active species generation. The detected intermediates were identified as hydroxylated derivatives (m/z of 310, 326 and 298), quinone imine compounds (m/z of 308, 278 and 264) and hydroxyl phenylamine (m/z of 178). The majority intermediates were hydroxylated derivatives and the minority was hydroxyl phenylamine. The degradation pathways were proposed to involve hydroxylation, decarboxylation, dehydrogenation and CN bond cleavage.

Transport behavior of the pharmaceutical compounds carbamazepine, sulfamethoxazole, gemfibrozil, ibuprofen, and naproxen, and the lifestyle drug caffeine, in saturated laboratory columns

Despite the large number of pharmaceutically active compounds found in natural environments little is known about their transport behavior in groundwater, which is complicated by their wide range of physical and chemical properties. The transport behavior of five widely used and often detected pharmaceutical compounds and one lifestyle drug has therefore been investigated, using a set of three column experiments. The investigated compounds were the anticonvulsant carbamazepine, the lifestyle drug caffeine, the antibiotic sulfamethoxazole, the lipid regulator gemfibrozil, and the nonsteroidal anti-inflammatories ibuprofen and naproxen. The columns were filled with three different types of sand. The substrates consisted of artificially prepared iron-coated sand, artificially prepared organic carbon sand (with 5% leaf compost), and natural aquifer sand from Long Point, Ontario (Canada). The experiments were conducted simultaneously under the same hydraulic conditions and with the same input solution of about 1μg·L^-1 of each compound. The transport behavior of the organic compounds differed significantly between both the different columns and the different compounds. A strong correlation was observed between the retardation factors for carbamazepine, gemfibrozil, and ibuprofen and the organic carbon content of the substrate. While the retardation increased with increasing organic carbon content, no direct relationship was observed between the organic carbon content and the removal of these compounds. In contrast, the retardation factors for sulfamethoxazole and naproxen showed no correlation with the organic carbon content but these compounds were significantly removed in the presence of organic matter. The influence of the Fe³⁺ surfaces in the iron-coated sand was less significant than expected, with all compounds except for sulfamethoxazole having retardation factors <1.8. Caffeine was so strongly removed during transport through those substrates containing organic carbon that no reliable retardation factor could be determined.

Comparison study on photocatalytic oxidation of pharmaceuticals by TiO2-Fe and TiO2-reduced graphene oxide nanocomposites immobilized on optical fibers

Incorporating reduced graphene oxide (rGO) or Fe³⁺ ions in TiO₂ photocatalyst could enhance photocatalytic degradation of organic contaminants in aqueous solutions. This study characterized the photocatalytic activities of TiO₂-Fe and TiO₂-rGO nanocomposites immobilized on optical fibers synthesized by polymer assisted hydrothermal deposition method. The photocatalysts presented a mixture phase of anatase and rutile in the TiO₂-rGO and TiO₂-Fe nanocomposites. Doping Fe into TiO₂ particles (2.40eV) could reduce more band gap energy than incorporating rGO (2.85eV), thereby enhancing utilization efficiency of visible light. Incorporating Fe and rGO in TiO₂ decreased significantly the intensity of TiO₂ photoluminescence signals and enhanced the separation rate of photo-induced charge carriers. Photocatalytic performance of the synthesized nanocomposites was measured by the degradation of three pharmaceuticals under UV and visible light irradiation, including carbamazepine, ibuprofen, and sulfamethoxazole. TiO₂-rGO exhibited higher photocatalytic activity for the degradation of pharmaceuticals under UV irradiation, while TiO₂-Fe demonstrated more suitable for visible light oxidation. The results suggested that the enhanced photocatalytic performance of TiO₂-rGO could be attributed to reduced recombination rate of photoexcited electrons-hole pairs, but for TiO₂-Fe nanocomposite, narrower band gap would contribute to increased photocatalytic activity.

Desorption of micropollutant from spent carbon filters used for water purifier

In this study, to examine the accumulated micropollutants in the spent carbon filter used in the water purifier, first, the method to desorb micropollutant from the activated carbon was developed and optimized. Then, using this optimized desorption conditions, we examined which micropollutants exist in spent carbon filters collected from houses in different regions in Korea where water purifiers were used. A total of 11 micropollutants (caffeine (CFF), acetaminophen (ACT), sulfamethazine (SMA), sulfamethoxazole (SMZ), metoprolol (MTP), carbamazepine (CBM), naproxen (NPX), bisphenol-A (BPA), ibuprofen (IBU), diclofenac (DCF), and triclocarban (TCB)) were analyzed using LC/MS-MS from the spent carbon filters. CFF, NPX, and DCF had the highest detection frequencies (>60%) in the carbon filters (n = 100), whereas SMA, SMZ, and MTP were only detected in the carbon filters, but not in the tap waters (n = 25), indicating that these micropollutants, which exist less than the detection limit in tap water, were accumulated in the carbon filters. The regional micropollutant detection patterns in the carbon filters showed higher levels of micropollutants, especially NPX, BPA, IBU, and DCF, in carbon filters collected in the Han River and Nakdong River basins where large cities exist. The levels of micropollutants in the carbon filter were generally lower in the regions where advanced oxidation processes (AOPs) were employed at nearby water treatment plants (WTPs), indicating that AOP process in WTP is quite effective in removing micropollutant. Our results suggest that desorption of micropollutant from the carbon filter used can be a tool to identify micropollutants present in tap water with trace amounts or below the detection limit.