Predicting the effect of mixing on oxygen transfer and nutrient removal in activated sludge basins

Activated sludge basins (ASBs) are a key-step in wastewater treatment processes that are used to eliminate biodegradable pollution from the water discharged to the natural environment. Bacteria found in the activated sludge consume and assimilate nutrients such as carbon, nitrogen and phosphorous under specific environmental conditions. However, applying the appropriate agitation and aeration regimes to supply the environmental conditions to promote the growth of the bacteria is not easy. The agitation and aeration regimes that are applied to activated sludge basins have a strong influence on the efficacy of wastewater treatment processes. The major aims of agitation by submersible mixers are to improve the contact between biomass and wastewater and the prevention of biomass settling. They induce a horizontal flow in the oxidation ditch, which can be quantified by the mean horizontal velocity. Mean values of 0.3-0.35 m s-1 are recommended as a design criteria to ensure best conditions for mixing and aeration (Da Silva, 1994). To give circulation velocities of this order of magnitude, the positioning and types of mixers are chosen from the plant constructors' experience and the suppliers' data for the impellers. Some case studies of existing plants have shown that measured velocities were not in the range that was specified in the plant design. This illustrates that there is still a need for design and diagnosis approach to improve process reliability by eliminating or reducing the number of short circuits, dead zones, zones of inefficient mixing and poor aeration. The objective of the aeration is to facilitate the quick degradation of pollutants by bacterial growth. To achieve these objectives a wastewater treatment plant must be adequately aerated; thus resulting in 60-80% of all energetic consummation being dedicated to the aeration alone (Juspin and Vasel, 2000). An earlier study (Gillot et al., 1997) has illustrated the influence that hydrodynamics have on the aeration performance as measure by the oxygen transfer coefficient. Therefore, optimising the agitation and aeration systems can enhance the oxygen transfer coefficient and consequently reduce the operating costs of the wastewater treatment plant. It is critically important to correctly estimate the mass transfer coefficient as any errors could result in the simulations of biological activity not being physically representative. Therefore, the transfer process was rigorously examined in several different types of process equipment to determine the impact that different hydrodynamic regimes and liquid-side film transfer coefficients have on the gas phase and the mass transfer of oxygen. To model the biological activity occurring in ASBs, several generic biochemical reaction models have been developed to characterise different biochemical reaction processes that are known as Activated Sludge Models, ASM (Henze et al., 2000). The ASM1 protocol was selected to characterise the impact of aeration on the bacteria consuming and assimilating ammonia and nitrate in the wastewater. However, one drawback of ASM protocols is that the hydrodynamics are assumed to be uniform by the use of perfectly mixed, plug flow reactors or as a number of perfectly mixed reactors in series. This makes it very difficult to identify the influence of mixing and aeration on oxygen mass transfer and biological activity. Therefore, to account for the impact of local gas-liquid mixing regime on the biochemical activity Computational Fluid Dynamics (CFD) was used by applying the individual ASM1 reaction equations as the source terms to a number of scalar equations. Thus, the application of ASM1 to CFD (FLUENT) enabled the investigation of the oxygen transfer efficiency and the carbon & nitrogen biological removal in pilot (7.5 cubic metres) and plant scale (6000 cubic metres) ASBs. Both studies have been used to validate the effect that the hydrodynamic regime has on oxygen mass transfer (the circulation velocity and mass transfer coefficient) and the effect that this had on the biological activity on pollutants such as ammonia and nitrate (Cartland Glover et al., 2005). The work presented here is one part to of an overall approach for improving the understanding of ASBs and the impact that they have in terms of the hydraulic and biological performance on the overall wastewater treatment process. References CARTLAND GLOVER G., PRINTEMPS C., ESSEMIANI K., MEINHOLD J., (2005) Modelling of wastewater treatment plants ? How far shall we go with sophisticated modelling tools? 3rd IWA Leading-Edge Conference & Exhibition on Water and Wastewater Treatment Technologies, 6-8 June 2005, Sapporo, Japan DA SILVA G. (1994). Eléments d'optimisation du transfert d'oxygène par fines bulles et agitateur séparé en chenal d'oxydation. PhD Thesis. CEMAGREF Antony ? France. GILLOT S., DERONZIER G., HEDUIT A. (1997). Oxygen transfer under process conditions in an oxidation ditch equipped with fine bubble diffusers and slow speed mixers. WEFTEC, Chicago, USA. HENZE M., GUJER W., MINO T., van LOOSDRECHT M., (2000). Activated Sludge Models ASM1, ASM2, ASM2D and ASM3, Scientific and Technical Report No. 9. IWA Publishing, London, UK. JUSPIN H., VASEL J.-L. (2000). Influence of hydrodynamics on oxygen transfer in the activated sludge process. IWA, Paris - France.

Clogging in subsurface-flow treatment wetlands:occurrence and contributing factors

Clogging is a major operational and maintenance issue associated with the use of subsurface flow wetlands for wastewater treatment, and can ultimately limit the lifetime of the system. This review considers over two decades of accumulated knowledge regarding clogging in both vertical and horizontal subsurface flow treatment wetlands. The various physical, chemical and biological factors responsible for clogging are identified and discussed. The occurrence of clogging is placed into the context of various design and operational parameters such as wastewater characteristics, upstream treatment processes, intermittent or continuous operation, influent distribution, and media type. This information is then used to describe how clogging develops within, and subsequently impacts, common variants of subsurface flow treatment wetland typically used in the U.S., U.K., France and Germany. Comparison of these systems emphasized that both hydraulic loading rate and solids loading rate need to be considered when designing systems to operate robustly, i.e. hydraulic overloading makes horizontal-flow tertiary treatment systems in the U.K. more susceptible to clogging problems than vertical-flow primary treatment systems in France. Future research should focus on elucidating the underlying mechanisms of clogging as they relate to the design, operation, and maintenance of subsurface flow treatment wetlands. © 2010 Elsevier B.V.

Determination of vertical and horizontal pathways of injected fresh wastewater into a deep saline aquifer (Florida, USA) using natural chemical tracers

Two deep-well injection sites in south Florida, USA, inject an average of 430 million liters per day (MLD) of treated domestic fresh wastewater into a deep saline aquifer 900 m below land surface. Elevated levels of NH3 (highest concentration 939 µmol) in the overlying aquifer above ambient concentrations (concentration less than 30 µmol) were evidence of the upward migration of injected fluids. Three pathways were distinguished based on ammonium, chloride and bromide ratios, and temperature. At the South District Wastewater Treatment Plant, the tracer ratios showed that the injectate remained chemically distinct as it migrated upwards through rapid vertical pathways via density-driven buoyancy. The warmer injectate (mean 28°C) retained the temperature signal as it vertically migrated upwards; however, the temperature signal did not persist as the injectate moved horizontally into the overlying aquifers. Once introduced, the injectate moved slowly horizontally through the aquifer and mixed with ambient water. At the North District Wastewater Treatment Plant, data provide strong evidence of a one-time pulse of injectate into the overlying aquifers due to improper well construction. No evidence of rapid vertical pathways was observed at the North District Wastewater Treatment Plant.

Anodic behavior of InP: film growth, porous structures and current oscillations.

We review our recent work on the anodization of InP in KOH electrolytes. The anodic oxidation processes are shown to be remarkably different in different concentrations of KOH. Anodization in 2 - 5 mol dm-3 KOH electrolytes results in the formation of porous InP layers but, under similar conditions in a 1 mol dm-3 KOH, no porous structure is evident. Rather, the InP electrode is covered with a thin, compact surface film at lower potentials and, at higher potentials, a highly porous surface film is formed which cracks on drying. Anodization of electrodes in 2 - 5 mol dm-3 KOH results in the formation of porous InP under both potential sweep and constant potential conditions. The porosity is estimated at ~65%. A thin layer (~ 30 nm) close to the surface appears to be unmodified. It is observed that this dense, near-surface layer is penetrated by a low density of pores which appear to connected it to the electrolyte. Well-defined oscillations are observed when InP is anodized in both the KOH and (NH4)2S. The charge per cycle remains constant at 0.32 C cm-2 in (NH4)2S but increases linearly with potential in KOH. Although the characteristics of the oscillations in the two systems differ, both show reproducible and well-behaved values of charge per cycle.

Identifying the Structure and Fate of Wastewater Derived Organic Micropollutants by High-resolution Mass Spectrometry

Human activities represent a significant burden on the global water cycle, with large and increasing demands placed on limited water resources by manufacturing, energy production and domestic water use. In addition to changing the quantity of available water resources, human activities lead to changes in water quality by introducing a large and often poorly-characterized array of chemical pollutants, which may negatively impact biodiversity in aquatic ecosystems, leading to impairment of valuable ecosystem functions and services. Domestic and industrial wastewaters represent a significant source of pollution to the aquatic environment due to inadequate or incomplete removal of chemicals introduced into waters by human activities. Currently, incomplete chemical characterization of treated wastewaters limits comprehensive risk assessment of this ubiquitous impact to water. In particular, a significant fraction of the organic chemical composition of treated industrial and domestic wastewaters remains uncharacterized at the molecular level. Efforts aimed at reducing the impacts of water pollution on aquatic ecosystems critically require knowledge of the composition of wastewaters to develop interventions capable of protecting our precious natural water resources.

The goal of this dissertation was to develop a robust, extensible and high-throughput framework for the comprehensive characterization of organic micropollutants in wastewaters by high-resolution accurate-mass mass spectrometry. High-resolution mass spectrometry provides the most powerful analytical technique available for assessing the occurrence and fate of organic pollutants in the water cycle. However, significant limitations in data processing, analysis and interpretation have limited this technique in achieving comprehensive characterization of organic pollutants occurring in natural and built environments. My work aimed to address these challenges by development of automated workflows for the structural characterization of organic pollutants in wastewater and wastewater impacted environments by high-resolution mass spectrometry, and to apply these methods in combination with novel data handling routines to conduct detailed fate studies of wastewater-derived organic micropollutants in the aquatic environment.

In Chapter 2, chemoinformatic tools were implemented along with novel non-targeted mass spectrometric analytical methods to characterize, map, and explore an environmentally-relevant “chemical space” in municipal wastewater. This was accomplished by characterizing the molecular composition of known wastewater-derived organic pollutants and substances that are prioritized as potential wastewater contaminants, using these databases to evaluate the pollutant-likeness of structures postulated for unknown organic compounds that I detected in wastewater extracts using high-resolution mass spectrometry approaches. Results showed that application of multiple computational mass spectrometric tools to structural elucidation of unknown organic pollutants arising in wastewaters improved the efficiency and veracity of screening approaches based on high-resolution mass spectrometry. Furthermore, structural similarity searching was essential for prioritizing substances sharing structural features with known organic pollutants or industrial and consumer chemicals that could enter the environment through use or disposal.

I then applied this comprehensive methodological and computational non-targeted analysis workflow to micropollutant fate analysis in domestic wastewaters (Chapter 3), surface waters impacted by water reuse activities (Chapter 4) and effluents of wastewater treatment facilities receiving wastewater from oil and gas extraction activities (Chapter 5). In Chapter 3, I showed that application of chemometric tools aided in the prioritization of non-targeted compounds arising at various stages of conventional wastewater treatment by partitioning high dimensional data into rational chemical categories based on knowledge of organic chemical fate processes, resulting in the classification of organic micropollutants based on their occurrence and/or removal during treatment. Similarly, in Chapter 4, high-resolution sampling and broad-spectrum targeted and non-targeted chemical analysis were applied to assess the occurrence and fate of organic micropollutants in a water reuse application, wherein reclaimed wastewater was applied for irrigation of turf grass. Results showed that organic micropollutant composition of surface waters receiving runoff from wastewater irrigated areas appeared to be minimally impacted by wastewater-derived organic micropollutants. Finally, Chapter 5 presents results of the comprehensive organic chemical composition of oil and gas wastewaters treated for surface water discharge. Concurrent analysis of effluent samples by complementary, broad-spectrum analytical techniques, revealed that low-levels of hydrophobic organic contaminants, but elevated concentrations of polymeric surfactants, which may effect the fate and analysis of contaminants of concern in oil and gas wastewaters.

Taken together, my work represents significant progress in the characterization of polar organic chemical pollutants associated with wastewater-impacted environments by high-resolution mass spectrometry. Application of these comprehensive methods to examine micropollutant fate processes in wastewater treatment systems, water reuse environments, and water applications in oil/gas exploration yielded new insights into the factors that influence transport, transformation, and persistence of organic micropollutants in these systems across an unprecedented breadth of chemical space.

Evaluation of semi-passive treatment technologies for septic lagoon capacity expansion

In Canada, increases in rural development has led to a growing need to effectively manage the resulting municipal and city sewage without the addition of significant cost- and energy- expending infrastructure. Storring Septic Service Limited is a family-owned, licensed wastewater treatment facility located in eastern Ontario. It makes use of a passive waste stabilization pond system to treat and dispose of waste and wastewater in an environmentally responsible manner. Storring Septic, like many other similar small-scale wastewater treatment facilities across Canada, has the potential to act as a sustainable eco-engineered facility that municipalities and service providers could utilize to manage and dispose of their wastewater. However, it is of concern that the substantial inclusion of third party material could be detrimental to the stability and robustness of the pond system. In order to augment the capacity of the current facility, and ensure it remains a self-sustaining system with the capacity to safely accept septage from other sewage haulers, it was hypothesized that pond effluent treatment could be further enhanced through the incorporation of one of three different technology solutions, which would allow the reduction of wastewater quality parameters below existing regulatory effluent discharge limits put in place by Ontario’s Ministry of the Environment and Climate Change (MOECC). Two of these solutions make use of biofilm technologies in order to enhance the removal of wastewater parameters of interest, and the third utilizes the natural water filtration capabilities of zebra mussels. Pilot-scale testing investigated the effects of each of these technologies on treatment performance under both cold and warm weather operation. This research aimed to understand the important mechanisms behind biological filtration methods in order to choose and optimize the best treatment strategy for full-scale testing and implementation. In doing so, a recommendation matrix was elaborated provided with the potential to be used as a universal operational strategy for wastewater treatment facilities located in environments of similar climate and ecology.

Microbial phylogenetic and functional responses within acidified wastewater communities exhibiting enhanced phosphate uptake

Acid stimulated accumulation of insoluble phosphorus within microbial cells is highly beneficial to wastewater treatment but remains largely unexplored. Using single cell analyses and next generation sequencing, the response of active polyphosphate accumulating microbial communities under conditions of enhanced phosphorus uptake under both acidic and aerobic conditions was characterised. Phosphorus accumulation activities were highest under acidic conditions (pH 5.5 > 8.5), where a significant positive effect on bioaccumulation was observed at pH 5.5 when compared to pH 8.5. In contrast to the Betaproteobacteria and Actinobacteria dominated enhanced biological phosphorus removal process, the functionally active polyP accumulators at pH 5.5 belonged to the Gammaproteobacteria, with key accumulators identified as members of the families Aeromonadaceae and Enterobacteriaceae. This study demonstrated a significant enrichment of key polyphosphate kinase and exopolyphosphatase genes within the community metagenome after acidification, concomitant with an increase in P accumulation kinetics.

Electrochemical Oxidation of N - p -Toluenesulfinamides

Contrasting and interesting electrochemical behavior is observed in anodic oxidation of N-substituted p-toluenesulfinamides under controlled current conditions. For sulfinamides derived from secondary alkylamines and primary arylamines, the N-sulfinyl group is removed and the corresponding amines are formed; for sulfinamides derived from primary alkylamines, sulfur oxidation yields the corresponding sulfonamides in good yields.

Food and fuel microalgae applications: insights from portuguese experience [Resumo]

Microalgae have a wide range of application fields, from food to fuels, to pharmaceuticals & fine chemicals, aquaculture and environmental bioremediation, among others. Spirulina and Chlorella have been used as food sources since ancient times, due to their high and balanced nutritional value. Our research group in Lisbon has developed a range of food products (emulsions, gelled desserts, biscuits and pastas) enriched with freshwater and marine microalgae (Spirulina, Chlorella, Haematococcus, Isochrysis and Diacronema). The developed products presented attractive and stable colours, high resistance to oxidation and enhanced rheological properties. Some of these products will be prepared at the Post-Congress Course “Functional Foods Development” at the University of Antofagasta. More recently, a great interest has arisen on using microalgae for biofuel production. The same group has also been exploring several marine and freshwater species for biofuel production (e.g., biodiesel, bioethanol, biohydrogen and biomethane) within a biorefinery approach, in order to obtain high and low-value co-products using integral biomass maximizing the energy revenue. Namely, supercritical fluid extraction of Nannochloropsis sp. allowed the recovery of valuable carotenoids and lipids, prior to bioH2 production through dark fermentation of the residual biomass. Also, Scenedesmus obliquus residues after sugars (for bioethanol) and lipids (for biodiesel) extraction has been anaerobically digested attaining high biomethane yields. Regarding sustainability issues, the current trend of our group is now focused on using liquid effluents and high CO2 levels for low cost microalgae growth, contributing to a lower water demand, primary energy consumption and global warming potential by reducing the need for potable water and fertilizers (P, N) and increasing CO2 mitigation. Microalgae biomass has been successfully used for urban wastewater treatment with subsequent bioH2 production, in a biorefinery approach. Presently, ammonium-rich raw effluents from piggeries and poultry industry are being effectively used for microalgae growth avoiding any pre-treatment step.

Estudo e desenvolvimento de um capacitor eletrolítico de nióbio

It seeks to find an alternative to the current tantalum electrolytic capacitors in the market due to its high cost. Niobium is a potential substitute, since both belong to the same group of the periodic table and because of this have many similar physical and chemical properties. Niobium has several technologically important applications, and Brazil has the largest reserves, around 96%. There are including niobium in reserves of tantalite and columbite in Rio Grande do Norte. These electrolytic capacitors have high capacitance specifies, ie they can store high energy in small volumes compared to other types of capacitors. This is the main attraction of this type of capacitor because is growing demand in the production of capacitors with capacitance specifies increasingly high, this because of the miniaturization of various devices such as GPS devices, televisions, computers, phones and many others. The production route of the capacitor was made by powder metallurgy. The initial niobium powder supplied by EEL-USP was first characterized by XRD, SEM, XRF and laser particle size, to then be sieved into three particle size, 200, 400 e 635mesh. The powders were then compacted and sintered at 1350, 1450 and 1550°C using two sintering time 30 and 60min. Sintering is one of the most important parts of the process as it affects properties as porosity and surface cleaning of the samples, which greatly affected the quality of the capacitor. The sintered samples then underwent a process of anodic oxidation, which created a thin film of niobium pentóxido over the whole porous surface of the sample, this film is the dielectric capacitor. The oxidation process variables influence the performance of the film and therefore the capacitor. The samples were characterized by electrical measurements of capacitance, loss factor, ESR, relative density, porosity and surface area. After the characterizations was made an annealing in air ate 260ºC for 60min. After this treatment were made again the electrical measurements. The particle size of powders and sintering affected the porosity and in turn the specific area of the samples. The larger de area of the capacitor, greater is the capacitance. The powder showed the highest capacitance was with the smallest particle size. Higher temperatures and times of sintering caused samples with smaller surface area, but on the other hand the cleaning surface impurities was higher for this cases. So a balance must be made between the gain that is achieved with the cleaning of impurities and the loss with the decreased in specific area. The best results were obtained for the temperature of 1450ºC/60min. The influence of annealing on the loss factor and ESR did not follow a well-defined pattern, because their values increased in some cases and decreased in others. The most interesting results due to heat treatment were with respect to capacitance, which showed an increase for all samples after treatment

Remoção de ibuprofeno de águas por oxidação catalítica

A ocorrência e destino de fármacos no ambiente aquático tem vindo a ser reconhecido como um problema emergente em química ambiental. Alguns compostos são resistentes à degradação nas estações de tratamento de águas residuais, ETARs, enquanto que outros, ainda que sofram degradação parcial, continuam a ser lançados nos meios aquáticos em quantidades apreciáveis. O Ibuprofeno, IB, um dos anti­ inflamatórios mais consumidos por todo o mundo, é um dos fármacos mais detectados no meio hídrico. Apesar dos sistemas de tratamento convencionais utilizados nas ETARs removerem até 90% do IB das águas residuais, é frequente o efluente descarregado conter ainda quantidades significativas deste poluente. A presença destes compostos no ambiente deve ser avaliada dado que possuem actividade biológica, mesmo a baixas concentrações. Os processos avançados de oxidação com peróxido de hidrogénio, na presença de catalisadores heterogéneos, permitem melhorar significativamente a remoção deste tipo de compostos em águas. Assim, foi objectivo deste trabalho o estudo da utilização de peróxido de hidrogénio como agente oxidante na remoção de IB em soluções aquosas, na presença de complexo de acetilacetonato de Ni (II) disperso em PDMS ou encapsulado em zeólitos NaY. Para o doseamento do fármaco em solução foi necessário desenvolver um método analítico consistindo de separação cromatográfica por HPLC e detecção e quantificação por UV-Vis. Não houve necessidade de recorrer a um passo de pré­ concentração de amostras por extracção em fase sólida (SPE) devido ao facto das concentrações de IB medidas ao longo do trabalho se terem sempre encontrado acima do LOQ (811 g L-1) do método analítico por injecção directa. Deste estudo pode concluir-se que o catalisador que apresentou melhor actividade catalítica e consequentemente maior remoção do IB em solução, foi o complexo de acetilacetonato de Ni (II), disperso em PDMS. Foi avaliada a influência, na conversão do IB, de diferentes parâmetros como a concentração inicial de peróxido de hidrogénio adicionada, quantidade de catalisador utilizada na mistura reaccional e temperatura. Os resultados permitiram concluir que os aumentos destes parâmetros conduzem a um aumento da actividade catalítica da reacção. A estabilidade catalítica do acetilacetonato de Ni (II)/PDMS, foi avaliada em ensaios consecutivos com a mesma amostra e nas mesmas condições, tendo-se observado que, após 8 utilizações, o catalisador perde ligeiramente a actividade (cerca de 11% do seu valor inicial). ABSTRACT: The presence and fate of pharmaceuticals in the aquatic environment is an emergent issue in environmental chemistry. Some compounds are poorly removed in wastewater treatment plants (WWTPs) while others, in spite of being partially removed, are still present in the WWTPs effluents and discharged in the receiving water bodies. Ibuprofen, IB, a non-steroid anti-inflammatory drug, is one of the most used and also one of the most frequently detected pharmaceutical contaminants in aquifers worldwide. Its removal by conventional wastewater treatment processes used in most WWTPs is usually high (up to 90% of incoming IB may be removed), but duet the high loads present in the influents, still significant amounts of IB usually leave the WWTPs in the treated effluents. The presence of these compounds in the environment must be evaluated considering that they may have some biological activity even at low concentrations. Advanced oxidation processes using hydrogen peroxide, in the presence of heterogeneous catalysts, provide a significantly improved removal of this type of substances from waters. Therefore, it was the aim of this work to study the use of hydrogen peroxide as an oxidizing agent in the removal of IB from aqueous solutions, in the presence of the catalyst nickel (II) acetylacetonate dispersed in PDMS or encapsulated in the NaY zeolite. For the quantification of the pharmaceutical in aqueous solution it was necessary to develop an analytical methodology based in chromatographic separation by HPLC and with UV-Vis detection and quantification. There was no need for a pre­concentration step of the samples by solid phase extraction (SPE) as the IB concentrations measured were always above the limit of quantification (811 bL1 of) the analytical method. The results from this study have shown that the catalyst which presented the best catalytic activity and the highest IB removal in solution was nickel (II) acetylacetonate dispersed in PDMS.

Solvent regeneration of activated carbon mixed-matrix membranes for the removal of micropollutants from wastewater

The constantly increasing demand of clean water has become challenging to deal with over the past years, water being an ever more precious resource. In recent times, the existing wastewater treatments had to be integrated with new steps, due to the detection of so-called organic micropollutants (OMPs). These compounds have been shown to adversely affect the environment and possibly human health, even when found in very low concentrations. In order to remove OMPs from wastewater, one possible technique is a hybrid process combining filtration and adsorption. In this work, polyethersulfone multi-channel mixed-matrix membranes with embedded powdered activated carbon (PAC) were tested to investigate the membrane’s adsorption and desorption performance. Micropollutants retention was analyzed using the pharmaceutical compounds diclofenac (DCF), paracetamol (PARA) and carbamazepine (CBZ) in filtration mode, combining the PAC adsorption process with the membrane’s ultrafiltration. Desorption performance was studied through solvent regeneration, using seven different solvents: pure water, pure ethanol, mixture of ethanol and water in different concentration, sodium hydroxide and a mixture of ethanol and sodium hydroxide. Regeneration experiments were carried out in forward-flushing. At first regeneration efficiency was investigated using a single-solute solution (diclofenac in water). The mixture Ethanol/Water (50:50) was found to be the most efficient with long-term retention of 59% after one desorption cycle. It was, therefore, later tested on a membrane previously loaded with a multi-solute solution. Three desorption cycles were performed after which, retention (after 30 min) reached values of 87% for PARA and 72% for CBZ and 55% for DCF, which indicates decent regenerability. A morphological analysis on the membranes confirmed that, in any case, the regeneration cycles did not affect either the membranes’ structure, or the content and distribution of PAC in the matrix.

Aplicações de cromatografia líquida de alta eficiência para o estudo de poluentes orgânicos emergentes

Emerging organic pollutants (EOP) include many environmental contaminants based on commercial products such as pharmaceuticals, personal care products, detergents, gasoline, polymers, etc. EOP may be candidates for future regulation as they offer potential risk to environmental and human health due to their continual entrance into the environment and to the fact that even the most modern wastewater treatment plants are not able to totally transform / remove these compounds. High performance liquid chromatography is recommended to separate emerging organic pollutants with characteristics of high polarity and low volatility, especially pharmaceuticals, from environmental matrices.

Identification of new ozonation disinfection byproducts of 17 beta-estradiol and estrone in water

Estrogens are a class of micro-pollutants found in water at low concentrations (in the ng L(-1) range), but often sufficient to exert estrogenic effects due to their high estrogenic potency. Disinfection of waters containing estrogens through oxidative processes has been shown to lead to the formation of disinfection byproducts, which may also be estrogenic. The present work investigates the formation of disinfection byproducts of 17 beta-estradiol (E2) and estrone (E1) in the treatment of water with ozone. Experiments have been carried out at two different concentrations of the estrogens in ground water (100 ng L(-1) and 100 mu g L(-1)) and at varying ozone dosages (0-30 mg L(-1)). Detection of the estrogens and their disinfection byproducts in the water samples has been performed by means of ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with a triple quadrupole (QqQ) and a quadrupole-time of flight (QqTOF) instrument. Both E2 and El have been found to form two main byproducts, with molecular mass (MM) 288 and 278 in the case of E2, and 286 and 276 in the case of El, following presumably the same reaction pathways. The E2 byproduct with MM 288 has been identified as 10epsilon-17beta-dihydroxy-1,4-estradieno-3-one (DEO), in agreement with previously published results. The molecular structures and the formation pathways of the other three newly identified byproducts have been suggested. These byproducts have been found to be formed at both high and low concentrations of the estrogens and to be persistent even after application of high ozone dosages. (C) 2011 Elsevier Ltd. All rights reserved.