Combined reverse osmosis and UV/H2O2 treatment of aqueous solutions of bisphenol A and 17α-ethinylestradiol: assessment of estrogenic activity.

Bisphenol-A (BPA) and 17α-ethinylestradiol (EE2) are considered endocrine disrupting compounds (EDC) and they may be harmful to the normal functioning of endocrine systems of humans and animals. Moreover, the presence of these compounds in superficial and groundwater may represent serious risks, even in low concentrations like ng·L-1. The objectives of this study were to remove BPA and EE2 from solutions containing a mixture of these compounds in ultrapure water at low concentrations through reverse osmosis (RO) membrane combined with a UV/H2O2 process. Furthermore, to assess the estrogenic activity reduction after such treatments, in vitro recombinant yeast-estrogen screen (YES) assay was used. The removal efficiencies of target micropollutants increased with the increase of H2O2 dosage. For RO permeate stream, they enhanced from 91% to 96% for EE2 and from 76% to 90% for BPA while, for the concentrate stream, from 70% to 81% for EE2 and 41% to 84% for BPA as the H2O2 concentration were increased from 100 to 1000 µg·L-1. The OH radicals' generation was the dominant factor in the degradation of EDC during the UV/H2O2 treatment since the photolysis itself was not enough to degrade BPA or EE2. The estrogenic activity reduction after UV/H2O2 treatment was high, ranging from 92% to 98% for the permeate stream and from 50% to 93% for the concentrate stream. The EE2 was responsible for the whole observed estrogenic activity since BPA does not present estrogenicity, by in vitro YES assay, in the concentrations observed.

Effects of pharmaceuticals compounds and calcium on granulation, microbiology, and performance of anaerobic granular sludge systems.

Granular sludge is a promising biotechnology to treat sewage contaminated with pharmaceuticals due to its increased toxicity resistance. In this context, this study evaluated the potential of Ca2+ as a granulation precursor and how pharmaceutical compounds (loratadine, prednisone, fluconazole, fenofibrate, betamethasone, 17α-ethinyl estradiol, and ketoprofen) affect granulation. Continuous and intermittent dosages of Ca2+ in the presence and absence of pharmaceuticals were evaluated. The results showed that intermittent addition of Ca2+ reduces the time for anaerobic sludge granulation, and pharmaceuticals presence did not impair granulation. 10% of the granules presented mean diameters greater than 2.11 mm within 93 days with intermittent Ca2+ dosage in the pharmaceuticals' presence. In contrast, no granules higher than 2.0 mm were observed with no precursor addition. The pharmaceuticals' toxicity may have created a stress condition for the microbial community, contributing to more EPS production and a greater potential for granulation. It was also verified that pharmaceuticals' presence did not decrease organic matter, total alkalinity, and volatile fatty acids removals. The 16S rRNA gene analysis revealed taxa resistance to recalcitrant compounds when pharmaceuticals were added. Besides, the efficiency of a granular sludge bioreactor (EGSB) was evaluated for pharmaceuticals removal, and betamethasone, fenofibrate, and prednisone were effectively removed.

Assessment of fouling mechanisms on reverse osmosis (RO) membrane during permeation of 17α-ethinylestradiol (EE2) solutions.

Fouling mechanisms are mainly caused by the deposition of organic compounds that reduce the removal efficiency on reverse osmosis (RO) membranes. It can be described by mathematical models. The aim of this study was to evaluate the membrane fouling and rejection mechanisms when aqueous solutions containing 17α-ethinylestradiol (EE2) in different concentrations are permeated at 5 and 10 bar in a bench-scale dead-end RO system. Adsorption tests were performed and the fouling mechanism was assessed by Hermia's model for solutions of EE2 at concentrations typically found in the environment (µg L-1). Fourier transform infrared spectroscopy (FTIR) has indicated the presence of EE2 on the fouled membrane surface. Membrane rejection of EE2 ranged from 90% to 98% and the main rejection mechanism was size exclusion at all experimental conditions. However, for the higher concentration of EE2 permeated at 5 and 10 bar, adsorption of 7 and 32 mg m-2, respectively, also took place. The rejection was influenced by fouling and concentration polarisation. Fouled membranes present higher rejection of hydrophobic neutral compounds and the concentration polarisation reduces rejection. Hermia's model demonstrated that the permeation values fitted better the standard blocking filtration and cake filtration equations for describing fouling mechanism. This study showed that fouling also occurs in the TFC RO membrane after permeation of EE2, which corroborates with studies using other pollutants.

Optimization of ozonation process for organic matter and ecotoxicity removal from landfill leachate by applying rotatable central composite design (RCCD).

Ozonation process was used for leachate treatment from a landfill located in Rio de Janeiro, Brazil. The influence of pH and ozone concentration on COD (Chemical Oxygen Demand), TOC (Total Organic Carbon), Absorbance at 254 nm (ABS254nm), and True color was evaluated through RCCD (Rotatable Central Composite Design) experimental design, resulting in mathematical models that were statistically analyzed in Statistica and Design Expert software. The removals obtained was up to 26.1%, 29.9%, 56.9%, and 97.9% for COD ([COD]0=3,323 mg/L), TOC ([TOC]0=1,275 mg/L), ABS254nm (ABS0=32.2), and True color ([True color]0=3,467 mgPt-Co/L), respectively. Statistical and variance analysis of the experimental data revealed that one quadratic model obtained in Statistica was valid, ABS254nm reduction. However, by applying the Design Expert software, modified models were generated to predict the behavior of all dependent variables. Thus, the optimum point for the best response after ozonation of the landfill leachate was at the highest pH and the lowest ozone dose (9 and 2.2 mgO3/m3, respectively). Toxicity toward Allivibrio fischeri bacteria was abated at the same time that it decreased the impact of the effluent to Danio rerio fish (from 125 UT to 62 UT) on the treated leachate.

Integration of ozonation and an anaerobic expanded granular sludge bed reactor for micropollutant removal from sewage.

Conventional sewage treatment systems are generally not designed to remove micropollutants, requiring the development of new technologies, such as the combination of biological processes with advanced oxidative processes. The configuration of an anaerobic expanded granular sludge bed (EGSB) reactor stands out for its use of granular biomass and high sludge bed expansion. Ozonation is an advanced oxidative process that stands out as one of the most promising technologies for the degradation of micropollutants. Thus, the present work aimed to evaluate the removal of drugs through the application of ozonation as a polishing process for the effluent of an EGSB reactor that was fed with synthetic sewage. Ozonation was shown to be efficient in the degradation of these compounds, reaching removals above 90%. It was found that the degradation profile of each drug varied according to its chemical structure since some drugs are more susceptible to oxidation than others and since the concentrations of pharmaceuticals are also related to their removal. Moreover, the assessment of risks to the environment and human health confirmed the need to assess the best scenario for risk reduction considering all drugs, since even with almost complete removal of some compounds, the effluents still showed toxicity. Thus, the high removal efficiencies found for the evaluated micropollutants showed that this technique has the potential to be used to improve the quality of biological reactor effluents or even to be combined in effluent reuse systems.

Investigation of Biocidal Effect of Microfiltration Membranes Impregnated with Silver Nanoparticles by Sputtering Technique.

Silver nanoparticles were loaded in microfiltration membranes by sputtering technique for the development of biocidal properties and biofouling resistance. This technology allows good adhesion between silver nanoparticles and the membranes, and fast deposition rate. The microfiltration membranes (15 wt.% polyethersulfone and 7.5 wt.% polyvinylpyrrolidone in N,N-dimethylacetamide) were prepared by phase inversion method, and silver nanoparticles were deposited on their surface by the physical technique of vapor deposition in a sputtering chamber. The membranes were characterized by Field Emission Scanning Electron Microscopy, and the presence of silver was investigated by Energy-Dispersive Spectroscopy and X-ray Diffraction. Experiments of silver leaching were carried out through immersion and filtration tests. After 10 months of immersion in water, the membranes still presented ~90% of the initial silver, which confirms the efficiency of the sputtering technique. Moreover, convective experiments indicated that 98.8% of silver remained in the membrane after 24 h of operation. Biocidal analyses (disc diffusion method and biofouling resistance) were performed against Pseudomonas aeruginosa and confirmed the antibacterial activity of these membranes with 0.6 and 0.7 log reduction of viable planktonic and sessile cells, respectively. These results indicate the great potential of these new membranes to reduce biofouling effects.

Treatment of Bisphenol A (BPA) in water using UV/H2O2 and reverse osmosis (RO) membranes: assessment of estrogenic activity and membrane adsorption.

Removal of an endocrine disrupting compound, Bisphenol A (BPA), from water was investigated using two treatment processes, UV/H2O2 advanced oxidation (AOP) and reverse osmosis (membrane separation). Furthermore, changes in estrogenic activity using in vitro yeast estrogen screen assay as well as the adsorption of BPA by the membrane surface were evaluated. The best UV/H2O2 performance was obtained using the highest established values of all parameters, reaching 48% BPA removal. Within the investigated conditions of the AOP, when lower doses of UV were used, a higher removal efficiency was achieved at a higher initial concentration of BPA. However, the same behavior was not observed for the highest UV dose, in which the removal efficiency was not dependent on BPA initial concentration. In both cases, removal efficiency increased as H2O2 concentration increased. The formation of estrogenic by-products was observed in UV/H2O2. The membrane rejection efficiency varied from 60% to 84% and all experiments showed adsorption of BPA by the membrane surface. The RO membrane showed a greater BPA removal efficiency for samples containing 10 µg·L-1 than UV/H2O2 at the evaluated treatment conditions.

Advanced oxidative processes and membrane separation for micropollutant removal from biotreated domestic wastewater.

The presence of micropollutants in sewage is already widely known, as well as the effects caused by natural and synthetic hormones. Thus, it is necessary to apply treatments to remove them from water systems, such as advanced oxidation processes (AOPs) and membrane separation processes, which can oxidize and remove high concentrations of organic compounds. This work investigated the removal of 17ß-estradiol (E2), 17α-ethinylestradiol (EE2), and estriol (E3) from biotreated sewage. Reverse osmosis processes were conducted at three recoveries (50, 60, and 70 %). For E2 and EE2, the removals were affected by the recovery. The best results for RO were as follows: the E2 compound removal was 89 % for 60 % recovery and the EE2 compound removal was 57 % for 50 % recovery. The RO recovery did not impact the E3 removal. It was concluded that the interaction between the evaluated estrogens, and the membrane was the major factor for the hormone separation. The AOP treatment using H2O2/UV was carried out in two sampling campaigns. First, we evaluated the variation of UV doses (24.48, 73.44, 122.4, and 244.8 kJ m-2) with 18.8 mg L-1 of H2O2 in the reaction. EE2 showed considerable removals (around 70 %). In order to optimize the results, an experimental design was applied. The best result was obtained with higher UV dose (122.4 kJ m-2) and lower H2O2 concentration (4 mg L-1), achieving removal of 91 % for E3 and 100 % for E2 and EE2.

Removal of COD from a stabilized landfill leachate by physicochemical and advanced oxidative process.

This work investigated the effectiveness of a physicochemical and oxidative process for the removal of chemical oxygen demand (COD) from stabilized landfill leachates. The application of these technologies for landfill leachate treatment greatly depends on the optimal operating conditions for a specific leachate. Coagulation-flocculation followed by H2O2, Fenton and photo-Fenton processes was evaluated. Advanced oxidation processes were evaluated in the raw leachate and the leachate pretreated by coagulation-flocculation. Via the coagulation process, at 30 sec and a stirring speed of 150 rpm followed by flocculation and settling steps, 53% COD was removed at an optimal dose of 1400 mg L(-1) and pH 4.0. Moreover, from the POA evaluated, the Fenton process was determined to be the most effective process for removing COD from the leachate pretreated by coagulation-flocculation, reaching 83.3% COD removal with 1330 mg L(-1) of H2O2 and 266 mg L(-1) of Fe(2+). The photo-Fenton process applied directly to the raw effluent was effective for the removal of COD; a 75% reduction in COD was observed in tests using 2720 mg L(-1) of H2O2 and 544 mg L(-1) of Fe(2+). Due to the variability in the composition of the Gramacho landfill leachate, the combination of coagulation-flocculation and the Fenton process is an effective technology for reducing the COD in samples of this leachate.

Modulation of the pharmacological effects of enzymatically-active PLA2 by BTL-2, an isolectin isolated from the Bryothamnion triquetrum red alga.

BACKGROUND: An interaction between lectins from marine algae and PLA2 from rattlesnake was suggested some years ago. We, herein, studied the effects elicited by a small isolectin (BTL-2), isolated from Bryothamnion triquetrum, on the pharmacological and biological activities of a PLA2 isolated from rattlesnake venom (Crotalus durissus cascavella), to better understand the enzymatic and pharmacological mechanisms of the PLA2 and its complex. RESULTS: This PLA2 consisted of 122 amino acids (approximate molecular mass of 14 kDa), its pI was estimated to be 8.3, and its amino acid sequence shared a high degree of similarity with that of other neurotoxic and enzymatically-active PLA2s. BTL-2 had a molecular mass estimated in approximately 9 kDa and was characterized as a basic protein. In addition, BTL-2 did not exhibit any enzymatic activity. The PLA2 and BTL-2 formed a stable heterodimer with a molecular mass of approximately 24-26 kDa, estimated by molecular exclusion HPLC. In the presence of BTL-2, we observed a significant increase in PLA2 activity, 23% higher than that of PLA2 alone. BTL-2 demonstrated an inhibition of 98% in the growth of the Gram-positive bacterial strain, Clavibacter michiganensis michiganensis (Cmm), but only 9.8% inhibition of the Gram-negative bacterial strain, Xanthomonas axonopodis pv passiflorae (Xap). PLA2 decreased bacterial growth by 27.3% and 98.5% for Xap and Cmm, respectively, while incubating these two proteins with PLA2-BTL-2 inhibited their growths by 36.2% for Xap and 98.5% for Cmm.PLA2 significantly induced platelet aggregation in washed platelets, whereas BTL-2 did not induce significant platelet aggregation in any assay. However, BTL-2 significantly inhibited platelet aggregation induced by PLA2. In addition, PLA2 exhibited strong oedematogenic activity, which was decreased in the presence of BTL-2. BTL-2 alone did not induce oedema and did not decrease or abolish the oedema induced by the 48/80 compound. CONCLUSION: The unexpected results observed for the PLA2-BTL-2 complex strongly suggest that the pharmacological activity of this PLA2 is not solely dependent on the presence of enzymatic activity, and that other pharmacological regions may also be involved. In addition, we describe for the first time an interaction between two different molecules, which form a stable complex with significant changes in their original biological action. This opens new possibilities for understanding the function and action of crude venom, an extremely complex mixture of different molecules.

Isolation of a new L-amino acid oxidase from Crotalus durissus cascavella venom.

A novel l-amino acid oxidase (LAO) (Casca LAO) from Crotalus durissus cascavella venom was purified to a high degree of molecular homogeneity using a combination of molecular exclusion and ion-exchange chromatography system. The purified monomer of LAO presented a molecular mass of 68 kDa and pI estimated in 5.43, which were determined by two-dimensional electrophoresis. The 71st N-terminal amino acid sequence of the LAO from Crotalus durissus cascavella presented a high amino acid sequence similarities with other LAOs from Colloselasma rhosostoma, Crotalus adamanteus, Agkistrodon h. blomhoffi, Agkistrodon h. halys and Trimeresurus stejnegeri. LAO displayed a Michaelis-Menten behavior with a kilometer of 46.7 microM and an optimum pH for enzymatic activity of 6.5. Casca LAO induced a dose-dependent platelet aggregation, which was abolished by catalase and inhibited by indomethacin and aspirin. These results suggest that the production of H2O2 is involved in subsequent activation of inflammatory enzymes, such as thromboxane. Casca LAO also inhibited the bacterial growth of Gram-negative (Xanthomonas axonopodis pv passiflorae) and Gram-positive (S. mutans) strains. Electron microscopy assessments of both bacterial strains suggest that the hydrogen peroxide produced by LAO induce bacterial membrane rupture and consequently loss of cytoplasmatic content. This LAO exhibited a high antileishmanic activity against the promastigote of Leishmania amazonensis in vitro, its activity was dependent on the production of hydrogen peroxide, and the 50% inhibitory concentration was estimated in 2.39 microg/ml.