EE2 Removal Research Articles

Ag@helical chiral TiO2 nanofibers for visible light photocatalytic degradation of 17α-ethinylestradiol.

Ag-modified helical chiral TiO2 NFs (Ag@chiral TiO2 NFs) were fabricated and characterized by ultraviolet-visible absorption spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy. This novel material exhibited efficient photocatalytic activity for the degradation of 17α-ethinylestradiol (EE2) in water under visible light irradiation with an optimum size of deposited silver nanoparticles (Ag NPs) in the range of 12 ∼ 14 nm. The pseudo-first-order rate constant (k obs) for EE2 photodegradation by Ag@chiral TiO2 NFs increased by up to a factor of 20.1 when compared with that of pure chiral TiO2 NFs. The high photocatalytic activity can be attributed to the interactions between helical chiral TiO2 NFs and surface plasmon resonance effect of Ag NPs. The new catalyst retains its photocatalytic activity at least up to five consecutive cycles. The results clearly demonstrate the feasibility of using Ag@chiral TiO2 NFs for the photocatalytic removal of EE2 and other endocrine-disrupting chemicals from water.

UV and simulated solar photodegradation of 17α-ethynylestradiol in secondary-treated wastewater by hydrogen peroxide or iron addition

The extensive use of estrogens and their release, through various pathways, into the environment, constitutes an emerging environmental problem that poses serious threats onto public health. In this work the efficiency of UVC/H2O2 and solar/Fe2+ treatment to degrade 17α-ethynylestradiol (EE2) in environmentally relevant concentrations of 100μg/L in secondary-treated wastewater matrices was investigated. Also, photolytic treatment was performed under different irradiation sources, namely UVC, UVA and simulated solar light. The effect of H2O2 (0–20mg/L) and Fe2+ (0–15mg/L) concentration was investigated and, at optimal operating parameters, EE2 removal was 100% after 15min of UVC/H2O2 treatment, while EE2 removal reached 86% after 60min of solar/Fe2+ treatment. In addition, the effect of water matrix and pH was studied. Total organic carbon (TOC) and yeast estrogen screening (YES) measurements showed the formation of stable intermediate products during EE2 treatment and an attempt to elucidate the reaction pathways and mechanisms through the identification of transformation products (TPs) by means of UPLC–MS/MS was made. Several TPs, including quinone methide and 1,2-quinone derivatives, were identified and competing pathways were suggested, in which hydroxylation, alkylation, dealkylation, demethylation and dehydroxylation, amongst others were described as major transformation mechanisms.

Photocatalytic degradation and reactor modeling of 17α-ethynylestradiol employing titanium dioxide-incorporated foam concrete.

Photocatalytic degradation of 17α-ethynylestradiol (EE2) using TiO2 photocatalysts incorporated with foam concrete (TiO2/FC) was investigated for the first time. Scanning electron microscopy (SEM) study of the samples revealed a narrow air void size distribution on the surface of FC cubes on with 5 wt% addition of P25 TiO2, and TiO2 particles were distributed heterogeneously on the surface of TiO2/FC samples. The sorption and photocatalytic degradation of EE2 with UV-light irradiation by TiO2/FC cubes were investigated. Adsorption capacity of EE2 by the TiO2/FC and blank foam concrete (FC) samples were similar, while the degradation rates showed a great difference. More than 50 % of EE2 was removed by TiO2/FC within 3.5 h, compared with 5 % by blank FC. The EE2 removal process was then studied in a photoreactor modified from ultraviolet disinfection pool and constructed with TiO2/FC materials. An integrated model including a plate adsorption-scattering model and a modified flow diffusion model was established to simulate the photocatalytic degradation process with different radiation fields, contaminant load, and flow velocity. A satisfactory agreement was observed between the model simulations and experimental results, showing a potential for the design and scale-up of the modified photocatalytic reactor.

Remediation of 17-α-ethinylestradiol aqueous solution by photocatalysis and electrochemically-assisted photocatalysis using TiO2 and TiO2/WO3 electrodes irradiated by a solar simulator

TiO2 and TiO2/WO3 electrodes, irradiated by a solar simulator in configurations for heterogeneous photocatalysis (HP) and electrochemically-assisted HP (EHP), were used to remediate aqueous solutions containing 10 mg L−1 (34 μmol L−1) of 17-α-ethinylestradiol (EE2), active component of most oral contraceptives. The photocatalysts consisted of 4.5 μm thick porous films of TiO2 and TiO2/WO3 (molar ratio W/Ti of 12%) deposited on transparent electrodes from aqueous suspensions of TiO2 particles and WO3 precursors, followed by thermal treatment at 450 °C. First, an energy diagram was organized with photoelectrochemical and UV–Vis absorption spectroscopy data and revealed that EE2 could be directly oxidized by the photogenerated holes at the semiconductor surfaces, considering the relative HOMO level for EE2 and the semiconductor valence band edges. Also, for the irradiated hybrid photocatalyst, electrons in TiO2 should be transferred to WO3 conduction band, while holes move toward TiO2 valence band, improving charge separation. The remediated EE2 solutions were analyzed by fluorescence, HPLC and total organic carbon measurements. As expected from the energy diagram, both photocatalysts promoted the EE2 oxidation in HP configuration; after 4 h, the EE2 concentration decayed to 6.2 mg L−1 (35% of EE2 removal) with irradiated TiO2 while TiO2/WO3 electrode resulted in 45% EE2 removal. A higher performance was achieved in EHP systems, when a Pt wire was introduced as a counter-electrode and the photoelectrodes were biased at +0.7 V; then, the EE2 removal corresponded to 48 and 54% for the TiO2 and TiO2/WO3, respectively. The hybrid TiO2/WO3, when compared to TiO2 electrode, exhibited enhanced sunlight harvesting and improved separation of photogenerated charge carriers, resulting in higher performance for removing this contaminant of emerging concern from aqueous solution.

Simultaneous removal of estrogens and pathogens from secondary treated wastewater by solar photocatalytic treatment

<p>Recently, the fate of emerging compounds in environmentally relevant samples has attracted considerable attention. Solar semiconductor photocatalysis may offer an appealing methodology to treat such contaminants. At the same time the use of solar photocatalysis for water and wastewater disinfection is a topic well-documented in the literature. In this respect, the simultaneous degradation of synthetic estrogen 17α-ethynylestradiol (EE2) and <em>Escherichia coli </em>removal employing simulated solar radiation and TiO<sub>2</sub> as the photocatalyst was investigated. In general, the more complex the water matrix is the slower <em>E. coli</em> removal becomes, while the presence of <em>E. coli</em> in the reaction mixture did not obstruct EE2 removal.</p> <div> <p>Although EE2 removal occurred relatively fast, overall estrogenic activity was only partially removed. This implies that other species inherently present in the effluent and/or some photocatalytic transformation by-products may be proportionately more estrogenic than EE2. Overall, the use of solar radiation can constitute an advantageous treatment strategy for the simultaneous removal of micro-pollutants and pathogens from secondary treated effluent.</p> </div> <p> </p>

Photocatalytic degradation of 17α-ethinylestradiol (EE2) in the presence of TiO2-doped zeolite

Current design limitations and ineffective remediation techniques in wastewater treatment plants have led to concerns about the prevalence of pharmaceutical and personal care products (PPCPs) in receiving waters. A novel photocatalyst, TiO2-doped low-silica X zeolite (TiO2-LSX), was used to study the degradation of the pharmaceutical compound, 17α-ethinylestradiol (EE2). The catalyst was synthesized and characterized using XRD, BET surface analysis, SEM-EDAX, and ICP-OES. The effects of different UV light intensities, initial EE2 concentrations, and catalyst dosages on the EE2 removal efficiency were studied. A higher EE2 removal efficiency was attained with UV-TiO2-LSX when compared with UV-TiO2 or UV alone. The EE2 degradation process followed pseudo-first-order kinetics. A comprehensive empirical model was developed to describe the EE2 degradation kinetics under different conditions using multiple linear regression analysis. The EE2 degradation mechanism was proposed based on molecular calculations, identification of photoproducts using HPLC–MS/MS, and reactive species quenching experiments; the results showed that oxidative degradation pathways initiated by hydroxyl radicals were predominant. This novel TiO2-doped zeolite system provides a promising application for the UV disinfection process in wastewater treatment plants.

A comparison of various rural wastewater treatment processes for the removal of endocrine-disrupting chemicals (EDCs)

The removal of six endocrine-disrupting chemicals (EDCs), including estrone (E1), 17β-estradiol (E2), estriol (E3), 17α-ethinyl estradiol (EE2), bisphenol A (BPA) and 4-nonylphenol (NP), was investigated in 20 rural wastewater treatment facilities (WWTFs) located in a county of Zhejiang Province, China. These WWTFs adopted one of the four treatment processes: activated sludge (AS), constructed wetland (CW), stabilization pond (SP), and micro-power biofilm reactor (MP). Results indicate that all the six EDCs were detected in wastewater samples with NP showing a maximum detection frequency (97%) and a maximum influent concentration (5002ngL−1). After biological treatment, the concentrations of E2, E3 and NP decreased remarkably, while E1, EE2 and BPA exhibited varying removal efficiencies that depended on the specific treatment process and sampling season. In general, the centralized AS process outperformed those decentralized processes (i.e., CW, SP and MP) and a higher removal of E1, EE2, NP and BPA in the AS process was observed in summer (>70%) than in winter. Among the three decentralized processes, the removal of EDCs in the SP process was limited, especially for E1, EE2 and BPA (18–46%) in winter. Due to an incomplete removal, the total concentration of target EDCs increased obviously in the mixing and downstream sections of a local river receiving the effluent from a typical WWTF (practicing AS). This study reveals that the design and operation of rural WWTFs should be optimized if an effective removal of EDCs is to be achieved.

Sludge Retention Time as a Suitable Operational Parameter to Remove Both Estrogen and Nutrients in an Anaerobic–Anoxic–Aerobic Activated Sludge System

Estrogen in wastewater are responsible for a significant part of the endocrine-disrupting effects observed in the aquatic environment. The effect of sludge retention time (SRT) on the removal and fate of 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) in an anaerobic-anoxic-oxic activated sludge system designed for nutrient removal was investigated by laboratory-scale experiments using synthetic wastewater. With a hydraulic retention time of 8 h, when SRT ranged 10-25 days, E2 was almost completely removed from water, and EE2 removal efficiency was 65%-81%. Both estrogens were easily sorbed onto activated sludge. Distribution coefficients (Kd) of estrogens on anaerobic sludge were greater than those on anoxic and aerobic sludges. Mass balance calculation indicated that 99% of influent E2 was degraded by the activated sludge process, and 1% remained in excess sludge; of influent EE2, 62.0%-80.1% was biodegraded; 18.9%-34.7% was released in effluent; and 0.88%-3.31% remained in excess sludge. Optimal SRT was 20 days for both estrogen and nutrient removal. E2 was almost completely degraded, and EE2 was only partly degraded in the activated sludge process. Residual estrogen on excess sludge must be considered in the sludge treatment and disposal processes. The originality of the work is that removal of nutrients and estrogens were linked, and optimal SRT for both estrogen and nutrient removal in an enhanced biological phosphorus removal system was determined. This has an important implication for the design and operation of full-scale wastewater treatment plants.

Removal of bisphenol A and 17α-ethinyl estradiol by combined coagulation and adsorption using carbon nanomaterials and powdered activated carbon

In this study, combined coagulation–adsorption treatment using single-walled carbon nanotubes (SWCNTs), multiwalled carbon nanotubes (MWCNTs), and powdered activated carbon (PAC) was employed for the removal of endocrine disrupting chemicals (EDCs) from various water sources. Bisphenol A (BPA) and 17α-ethinyl estradiol (EE2) were the target EDCs used in this study. Natural surface water (BRW) was obtained from Broad River in Columbia, South Carolina. Synthetic seawater (SW) and brackish water (BW) were produced to reflect the typical composition observed in previously published literature. Synthetic landfill leachates were created to replicate the characteristics of leachate produced in young landfills (YLs) and old landfills (OLs). The adsorption capacity of the SWCNTs was greater for EE2 than for BPA for the majority of the aqueous solutions with the exceptions of BW and BRW. The adsorption capacity for BPA observed the following trend: BRW (log Kf=3.18)>SW (log Kf=3.01)>YL (log Kf=2.32)>BW (log Kf=1.96)>OL (log Kf=1.25), while the adsorption capacity of EE2 followed a different trend: SW (log Kf=3.41)>YL (log Kf=3.38)>BRW (log Kf=3.14)>OL (log Kf=2.09)>BW (log Kf=1.38). Molecular modeling was also conducted to determine the binding energies between the EDCs and the SWCNTs in both the gas phase and the liquid phase. The results showed higher binding energies between EE2 and the SWCNTs than between BPA and the SWCNTs in the gas phase and the aqueous phase, which support the higher removal of EE2 than BPA found using adsorption isotherm modeling. Jar testing was conducted with each adsorbent to simulate the combined coagulation–adsorption treatment process. The sole use of coagulation yielded small percentages of BPA removal (<10%) in each aqueous solution but higher percentages of EE2 removal. However, the removal percentages using the combined coagulation–adsorption process were similar to those achieved using only the adsorbent. In these processes, the SWCNTs outperformed the MWCNTs for each combination, while PAC often outperformed both the SWCNTs and the MWCNTs, with more than 90% removal of both BPA and EE2.

Biodegradation of 17α-ethinylestradiol by heterotrophic bacteria

The presence of the synthetic estrogen 17α-ethinylestradiol (EE2) in the environment is of increasing concern due to the endocrine disruption of aquatic organisms. Incomplete removal from wastewater (WW) is one of the main sources of EE2 in aquatic ecosystems, thus improving processes like biological WW treatment/activated sludge (AS) is becoming significantly important. There are opposing results regarding EE2 biodegradability by AS; one discrepancy is the efficacy of heterotrophic bacteria. This research demonstrated the ability of heterotrophs commonly present in AS (B. subtilis, P. aeruginosa, P. putida, R. equi, R. erythropolis, R. rhodochrous, R. zopfii) to remove EE2. R. rhodochrous was the most successful with no detectable EE2 after 48 h; the other bacteria achieved 21%–61% EE2 removal. No additive or synergistic effects were observed due to the combination of the bacterial cultures with maximum EE2 removals of 43% after 300 h.

Case study of treatment of waste water for 17α-ethinylestradiol and microorganisms with UV and photocatalysis in an on-going process of introducing AOP techniques in the Danish water sector

Failure to obtain a sufficient disinfection of waste water, initiated an investigation of the use of UV light and photocatalysis with TiO2 for treating the waste water. Furthermore, the ability of such a system to degrade endocrine disrupting chemicals was investigated through experiments with the estrogen 17α-ethinylestradiol (EE2). This study found LP UV lamps to be the optimal solution for disinfection, while photocatalysis with TiO2 was found to be the best method for removal of EE2. The experiments were carried out in a mobile test unit with solution volumes of 30 L. By use of data from the real UV system, the effect found in the experiments were extrapolated and used to evaluate the efficiency of the current system.

Mechanistic Study of 17α-Ethinylestradiol Biodegradation by Pleurotus ostreatus: Tracking of Extracelullar and Intracelullar Degradation Mechanisms

The white rot fungus Pleurotus ostreatus is able to completely remove the synthetic hormone 17α-ethinylestradiol (EE2, 200 μg in 20 mL) from a liquid complex or mineral medium in 3 or 14 days, respectively. Its efficiency has also been documented in the removal of estrogenic activity that correlated with the EE2 degradation. A set of in vitro experiments using various cellular and enzyme fractions has been performed and the results showed that EE2 was degraded by isolated laccase (about 90% within 24 h). The degradation was also tested with concentrated extracellular liquid where degradation reached 50% mainly due to the laccase activity; however, after a supplementation with H₂O₂ and Mn²⁺, residual manganese-dependent peroxidase activities (40 times lower than Lac) raised the degradation to 100%. Moreover, the intracellular fraction and also laccase-like activity associated with fungal mycelium were found to be efficient in the degradation too. Isolated microsomal proteins appeared to also be involved in the process. The degradation was completely suppressed in the presence of cytochrome P-450 inhibitors, piperonylbutoxide and carbon monoxide, indicating a role of this monooxygenase in the degradation process. Attention was also paid to monitoring of changes in the estrogenic activity during these particular in vitro experiments when mainly degradations related to ligninolytic enzymes were found to decrease the estrogenic activity with EE2 removal proportionally. Several novel metabolites of EE2 were detected using different chromatographic method with mass spectrometric techniques (LC-MS, GC-MS) including also [¹³C]-labeled substrates. The results document the involvement of various different simultaneous mechanisms in the EE2 degradation by P. ostreatus by both the ligninolytic system and the eukaryotic machinery of cytochromes P-450.

Catalytic oxidative degradation of 17α-ethinylestradiol by FeIII-TAML/H2O2: Estrogenicities of the products of partial, and extensive oxidation

The oxidative degradation of the oral contraceptive 17α-ethinylestradiol (EE2) in water by a new advanced catalytic oxidation process was investigated. The oxidant employed was hydrogen peroxide in aqueous solution and the catalyst was the iron tetra-amido macrocyclic ligand (FeIII-TAML) complex that has been designated Na[Fe(H2O)(B*)] (FeIII-B*). EE2 (10 μM) was oxidised rapidly by the FeIII-B*/H2O2 (5 nM/4 mM) catalytic oxidation system at 25 °C, and for reactions at pH 8.40–11.00, no unchanged EE2 was detected in the reaction mixtures after 60 min. No oxidation of EE2 was detected in blank reactions using either H2O2 or FeIII-B* alone. The maximum rate of EE2 loss occurred at pH 10.21. At this pH the half-life of EE2 was 2.1 min and the oxidised products showed around 30% estrogenicity removal, as determined by the yeast estrogen screen (YES) bioassay. At pH 11.00, partial oxidation of EE2 by FeIII-B*/H2O2 (5 nM/4 mM) was studied (half-life of EE2 was 14.5 min) and in this case the initial intermediates formed were a mixture of the epimers 17α-ethynyl-1,4-estradiene-10α,17β-diol-3-one (1a) and 17α-ethynyl-1,4-estradiene-10β,17β-diol-3-one (1b) (identified by LC-ToF-MS and 1H NMR spectroscopy). Significantly, this product mixture displayed a slightly higher estrogenicity than EE2 itself, as determined by the YES bioassay. Upon the addition of further aliquots of FeIII-B* (to give a FeIII-B* concentration of 500 nM) and H2O2 (to bring the concentration up to 4 mM assuming the final concentration had dropped to zero) to this reaction mixture the amounts of 1a and 1b slowly decreased to zero over a 60 min period as they were oxidised to unidentified products that showed no estrogenicity. Thus, partial oxidation of EE2 gave products that have slightly increased estrogenicity, whereas more extensive oxidation by the advanced catalytic oxidation system completely removed all estrogenicity. These results underscore the importance of controlling the level of oxidation during the removal of EE2 from water by oxidative processes.

Removal mechanisms of 17β-estradiol and 17α-ethinylestradiol in membrane bioreactors

The fate and behavior of natural and synthetic estrogens in wastewater treatment processes is currently of increasing concern all over the world. In this study, the removal mechanisms of a natural estrogen, 17β-estradiol (E2), and a synthetic estrogen, 17α-ethinylestradiol (EE2) were investigated in membrane bioreactors (MBRs) with and without powdered activated carbon (PAC) addition. The experimental results showed that the average removal rates of E2 and EE2 by the MBR without PAC addition were 89.0 and 70.9%; PAC addition in the MBR increased the removal rate of E2 and EE2 by 3.4 and 15.8%, respectively. The greater impact of PAC dosing on EE2 removal was due to its greater hydrophobic property. Adsorption played a more important role in the removal mechanisms of EE2 than E2. Biodegradation was the dominant mechanism for the removal of E2 and EE2 in MBRs. Unlike their adsorption behavior, the biodegradation rates of both E2 and EE2 were not significantly different between the MBRs with and without PAC addition.

Removal of ethinylestradiol (EE2) from water via adsorption on aliphatic polyamides

This study demonstrates the use of aliphatic polyamides (PAs) as efficient adsorbents for the removal of ethinylestradiol (EE2), a synthetic hormone and high-potency estrogenic contaminant, from water via strong adsorptive interactions. PA612 and PA12 showed significantly higher adsorption capacities than PA6 for EE2 adsorption from water. Isothermal adsorption studies showed that PA612 had an adsorption capacity for EE2 comparable to the benchmark macroreticular polymeric adsorbent, AMBERLTIE XAD4 (XAD4), despite its nonporous structure and far smaller surface area. The substantial adsorption of EE2 on PA612 is predominantly driven by Lewis acid-base interactions between EE2 and PA612 amide functionalities and facilitated by the hydrophobic partitioning of EE2 solutes in water. Rapid column adsorption tests demonstrated efficient removal of EE2 from water on a continuous flow basis. With an empty bed contact time of 0.8–1.0 min, the fixed-bed column with 1.0 g PA612 particles removed the EE2 from 24.1 L of 30 μg L−1 EE2 spiked solution to non-detectable levels by HPLC analysis. Regeneration was readily effected by rinsing the exhausted column with 4 wt.% NaOH solution at room temperature. Regenerated PA612 particles showed consistent performance to fresh PA612 particles in subsequent batch and column adsorption studies.

Photocatalytic degradation of 17α‐ethynylestradiol in environmental samples by ZnO under simulated solar radiation

AbstractBACKGROUND: Recently, the fate of emerging micro‐contaminants in environmentally relevant samples has attracted considerable attention. Semiconductor photocatalysis may offer an appealing methodology to treat such contaminants; in this respect, the degradation of synthetic estrogen 17α‐ethynylestradiol (EE2) employing simulated solar radiation and ZnO as the photocatalyst was investigated.RESULTS: A factorial design approach was adopted to evaluate the effect of estrogen concentration (100–500 µg L−1), ZnO concentration (50‐500 mg L−1 in suspension), treatment time (2‐10 min), photon flux (4.93 × 10−7–5.8 × 10−7 einstein L−1 s−1) and the water matrix (ultrapure water and treated wastewater) on EE2 removal. The first four variables had a statistically important, positive effect on degradation, while the water matrix introduced a negative effect presumably due to the competition between EE2 and the effluent organic and inorganic matter for hydroxyl radicals and other oxidizing species. Moreover, second‐order interactions of estrogen concentration with time and the water matrix were also significant. EE2 degradation follows first‐order kinetics with the respective rate constants in wastewater and water being 9.2 ± 0.7 × 10−2 and 41 ± 8 × 10−2 min−1 at the maximum ZnO concentration and photon flux. On the other hand, the removal rate of effluent's overall estrogenicity (as assessed by the yeast estrogen screening bioassay) was an order of magnitude lower than that of EE2, implying the presence of persistent estrogenic compounds in the photocatalyzed effluent.CONCLUSIONS: An effective treatment process is demonstrated which benefits from the use of renewable energy and a stable and highly active photocatalyst. Copyright © 2012 Society of Chemical Industry

Fate and removal of selected endocrine‐disrupting compounds in sewage using activated sludge treatment

AbstractThe variation and fate of four endocrine‐disrupting compounds (EDCs) composed of 4‐n‐nonylphenol (4‐n‐NP), bisphenol A (BPA), 17β‐estradiol (E2) and 17α‐ethinylestradiol (EE2) were investigated along treatment units in a sewage treatment plant (STP), China with anaerobic, anoxic and aerobic activated sludge processes. The mean concentrations were 64.8 ng/L (E2), 115.3 ng/L (4‐n‐NP), 171.5 ng/L (EE2), and 920.7 ng/L (BPA) in the influents, and 22.8 ng/L (E2), 50.9 ng/L (4‐n‐NP), 49.9 ng/L (EE2), and 84.3 ng/L (BPA) in the effluents. The biological treatment was more effective in removing NP, BPA and E2 from the aqueous phase than the primary treatment, while the latter could effectively remove EE2. Their possible removal mechanisms during the biological treatment with activated sludge were further explored through spiked batch experiments under three oxygen‐supplying conditions (anaerobic, anoxic and aerobic). The batch experiments showed that 4‐n‐NP, E2 and BPA were removed from the aqueous phase through biodegradation. The combination of sludge sorption and biodegradation accounted for the removal of EE2. Anoxic activated sludge showed the most rapid degradation of 4‐n‐NP, while E2 could be removed most effectively by aerobic activated sludge, and sludge sorption had a remarkable effect on its removal within the initial 15 min of the experiments under three oxygen‐supplying conditions.

Calculation methods to perform mass balance of endocrine disrupting compounds in a submerged membrane bioreactor: fate and distribution of estrogens during the biological treatment

The purpose of this paper is to report the study of the fate and distribution of three endocrine disrupting compounds (estrogens); Estrone (E1), 17β-estradiol (E2), and 17α-ethinylestradiol (EE2) in a laboratory scale submerged membrane bioreactor (SMBR). For this matter, both aqueous and solids phases were analyzed for the presence of E1, E2 and EE2. The outcome of this study was that three SMBRs showed enhanced elimination of estrogens in different operational conditions; the estrogen removal was close to 100% in SMBR. Additionally, E1, E2 and EE2 were detected in SMBR sludge at concentrations of up to 41.2, 37.3 and 36.9 ng g(-1) dry weight, respectively. The estrogen removal in the SMBRs was directly influenced by a combination of simultaneous biodegradation-adsorption processes, indicating that the main removal mechanism of the estrogens in the SMBRs is the biodegradation process. The E1, E2 and EE2 were biologically degraded in the SMBR (87-100%). The sorption of estrogens onto activated sludge was from 2%. Therefore, a high potential for estrogen removal by biodegradation in the SMBR was observed, allowing less estrogen concentration in the dissolved phase available for the adsorption of these compounds onto biological flocs. Two different methods were carried out for mass balance calculations of estrogens in SMBR. For the first method, the measured data was used in both liquid and solid phases, whereas for the second one, it was in aqueous phase and solid-water distribution coefficients (K(d)) value of E1, E2 and EE2. The purpose of these methodologies is to make easier the identification of the main mechanisms involved in the removal of E1, E2 and EE2 in a SMBR. Both methods can be applied in order to determine the mechanism, fate and distribution of estrogens in a SMBR.

Degradation of 17α-ethinylestradiol by ozonation — Identification of the by-products and assessment of their estrogenicity and toxicity

The presence of the synthetic estrogen 17α-ethinylestradiol (EE2) in waters at low levels is a concern due to its ability to act as an endocrine disruptor. Ozone (O 3) is commonly used in water treatment and reacts with EE2 to form by-products having characteristics that are mostly unknown. The aim of this study was to identify the by-products of E2 and EE2 ozonation and determine their estrogenicity and toxicity relative to the parent compound. Ozonation by-products were identified via LC–MS analysis. The estrogenicity was measured using the YES assay, and toxicity was determined by monitoring effects on histology of fetal rat testes and testosterone secretion by these tissues. Two EE2 by-products were identified with open phenolic ring structures (masses 302 and 344 u). The Yeast Estrogen Screening (YES) assay showed a decreased but incomplete removal of estrogenicity after ozonation of EE2. Histological analysis of fetal testes revealed that neither E2 nor EE2, with or without ozonation, had any effect on seminiferous cord formation; however, a remarkable negative effect on testosterone secretion was observed, with EE2 by-products after ozonation showing the most rapid and extensive inhibition. These results show that the removal of EE2 via reaction with O 3 resulted in the formation of by-products that are less estrogenic (as demonstrated by the YES assay), but have a greater negative impact on testosterone secretion. Thus, the disappearance of the parent compound is not a sufficient endpoint, as the by-products created may be more toxic. Care should be taken when implementing oxidation applications such as ozone during waste water treatment.

Removal of endocrine disrupting chemicals in a large scale membrane bioreactor plant combined with anaerobic-anoxic-oxic process for municipal wastewater reclamation

The removal of eight typical endocrine disrupting compounds (EDCs) in a full scale membrane bioreactor combined with anaerobic-anoxic-oxic process (A(2)/O-MBR) for municipal wastewater reclamation located in Beijing was investigated. These EDCs, including 4-octylphenol (4-OP), 4-n-nonylphenol (4-n-NP), bisphenol A (BPA), estrone (E1), 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), estriol (E3) and 17α-ethinylestradiol (EE2), were simultaneously analyzed by gas chromatography/mass spectrometry after derivatization. The concentrations of eight EDCs were also measured in sludge of anaerobic, anoxic, oxic and membrane tanks to measure sludge-water distribution coefficients (K(d) values) as the indicator of adsorption propensity of target compound to sludge. The removal efficiencies of EDCs reached above 97%, except for 4-n-NP removal efficiency of 72%, 4-OP removal efficiency of 75% and EE2 removal efficiency of 87% in the A(2)/O-MBR process. The high K(d) values indicated that the sludge had a large adsorption capacity for these EDCs, and significantly contributed to removal of EDCs. Yeast estrogen screen assay was performed on samples to assess the total estrogenic activity by measuring the 17β-E2 equivalent quantity (EEQ), expressed in ng-EEQ/L. The measured EEQ value was markedly reduced from 72.1 ng-EEQ/L in the influent to 4.9 ng-EEQ/L in the effluent. Anoxic tank and anaerobic tank contributed to 80% and 37% in total EEQ removal, respectively.