Estudo do tratamento sequencial (adsorção e eletro-oxidação) para remediação de efluente sintético contaminado com BTX

This paper proposed the study of the treatment of a synthetic wastewater contaminated with BTX by electro-oxidation batch with the anode of Ti/PbO2, and the adsorption of BTX using expanded perlite as adsorbent material, and to evaluate the best operating conditions both methods in order to perform a sequential treatment (adsorption and electro-oxidation) and achieve greater efficiency in the removal of the compounds. The operating conditions were measured: temperature, current density and applied amount of the adsorbent material, by UV-VIS analysis and Demand Chemical oxygen demand (COD). According to the experimental results, the electro-oxidative treatment was efficient in the degradation of the compounds BTX (benzene, toluene and xylenes) in synthetic sewage due to the electrochemical properties of the anode of Ti/PbO2. The applied current density and temperature promoted increased efficiency of COD removal, reaching obtain percentages greater than 70%. In the adsorption process, the temperature increase was not a factor in the removal of organic matter, while the increase in the amount of adsorbent material led to an increase in the percentage removal, obtaining 66.30% using 2 g of adsorbent. The selected operating conditions of both treatments performed separately take into account the removal efficiency of organic matter, and the low energy consumption and operating costs, so the sequential treatment were satisfactory reaching 87.26% of COD removal using adsorption as a pretreatment. Quantification of BTX through the analysis of gas chromatography at the end of the treatments also confirmed the removal efficiency of organic compounds, giving outstanding advantages to sequential treatment.

Análise da biorremediação de compostos monoaromáticos em água através da pseudomonas aeruginosa

The monoaromatic compounds are toxic substances present in petroleum derivades and used broadly in the chemical and petrochemical industries. Those compounds are continuously released into the environment, contaminating the soil and water sources, leading to the possible unfeasibility of those hydrous resources due to their highly carcinogenic and mutagenic potentiality, since even in low concentrations, the BTEX may cause serious health issues. Therefore, it is extremely important to develop and search for new methodologies that assist and enable the treatment of BTEX-contaminated matrix. The bioremediation consists on the utilization of microbial groups capable of degrading hydrocarbons, promoting mineralization, or in other words, the permanent destruction of residues, eliminating the risks of future contaminations. This work investigated the biodegradation kinetics of water-soluble monoaromatic compounds (benzene, toluene and ethylbenzene), based on the evaluation of its consummation by the Pseudomonas aeruginosa bacteria, for concentrations varying from 40 to 200 mg/L. To do so, the performances of Monod kinetic model for microbial growth were evaluated and the material balance equations for a batch operation were discretized and numerically solved by the fourth order Runge-Kutta method. The kinetic parameters obtained using the method of least squares as statistical criteria were coherent when compared to those obtained from the literature. They also showed that, the microorganism has greater affinity for ethylbenzene. That way, it was possible to observe that Monod model can predict the experimental data for the individual biodegradation of the BTEX substrates and it can be applied to the optimization of the biodegradation processes of toxic compounds for different types of bioreactors and for different operational conditions.

Análise da biorremediação de compostos monoaromáticos em água através da pseudomonas aeruginosa

The monoaromatic compounds are toxic substances present in petroleum derivades and used broadly in the chemical and petrochemical industries. Those compounds are continuously released into the environment, contaminating the soil and water sources, leading to the possible unfeasibility of those hydrous resources due to their highly carcinogenic and mutagenic potentiality, since even in low concentrations, the BTEX may cause serious health issues. Therefore, it is extremely important to develop and search for new methodologies that assist and enable the treatment of BTEX-contaminated matrix. The bioremediation consists on the utilization of microbial groups capable of degrading hydrocarbons, promoting mineralization, or in other words, the permanent destruction of residues, eliminating the risks of future contaminations. This work investigated the biodegradation kinetics of water-soluble monoaromatic compounds (benzene, toluene and ethylbenzene), based on the evaluation of its consummation by the Pseudomonas aeruginosa bacteria, for concentrations varying from 40 to 200 mg/L. To do so, the performances of Monod kinetic model for microbial growth were evaluated and the material balance equations for a batch operation were discretized and numerically solved by the fourth order Runge-Kutta method. The kinetic parameters obtained using the method of least squares as statistical criteria were coherent when compared to those obtained from the literature. They also showed that, the microorganism has greater affinity for ethylbenzene. That way, it was possible to observe that Monod model can predict the experimental data for the individual biodegradation of the BTEX substrates and it can be applied to the optimization of the biodegradation processes of toxic compounds for different types of bioreactors and for different operational conditions.

Uso de argilominerais e diatomita como adsorvente de fenóis em águas produzidas na indústria de petróleo

The oil production in Brazil has been increasing each year. Consequently, increasing volumes of water produced are generated with large quantities of contaminants, which brings many problems in disposing of these waters. The concern that the concentrations of contaminants in water produced meet existing laws for disposal of effluents, has been extremely important for the development of different techniques for treatment of water produced. The study of clay minerals as adsorbents of organic contaminants has grown considerably so in order to combine the low cost with the efficiency of environmental preservation and health issues. Thus, this study aims to understand the characteristics of vermiculite clay, sodium bentonite, calcium bentonite and diatomite and evaluate their performance as adsorbents for phenol in the water produced. Through adsorption isotherms it was possible to observe the behavior of these adsorptive clay and diatomite for adsorption of phenol, the main phenolic compound found in water produced. Different concentrations of synthetic solutions of phenol were put in touch with these adsorbents under same conditions of agitation and temperature. The adsorbents were composted adsorptive favorable, but the vermiculite and diatomite showed little capacity for absorption, being suggested for absorbs small concentrations of phenol in the balance isothermal

Rejeito de xisto como adsorvente para remoção de fenol em águas produzidas na indústria de petróleo

Produced water is the main effluent linked to the activity of extraction of oil and their caring management is necessary due to the large volume involved, to ensure to minimize the negative impacts of discharges of these waters in the environment. This study aimed to analyze the use of retorted shale, which is a reject from the pyrolysis of pirobituminous shale, as adsorbent for the removal of phenols in produced water. The material was characterized by different techniques (grain sized analysis, thermal analysis, BET, FRX, FT-IR, XRD and SEM), showing the heterogeneity in their composition, showing its potential for the removal of varied compounds, as well as the phenols and their derivatives. For the analysis of the efficiency of the oil shale for the adsorption process, assays of adsorption balance were carried through, and also kinetic studies and dynamics adsorption, in the ETE of the UTPF of Petrobras, in Guamaré-RN. The balance assays shown a bigger conformity with the model of Langmuir and the kinetic model more adjusted to describe the adsorption of phenols in retorted shale was of pseudo-second order. The retorted shale presented a low capacity of adsorption of phenols (1,3mg/g), when related to others conventional adsorbents, however it is enough to the removal of these composites in concentrations presented in the produced water of the UTPF of Guamaré. The assays of dynamics adsorption in field had shown that the concentration of phenol in the effluent was null until reaching its rupture (58 hours). The results showed the possibility of use of the reject for removal of phenols in the final operations of the treatment process, removing as well, satisfactorily, the color and turbidity of the produced water, with more than 90% of removal

Estudo de adsorvente obtido de terras diatomáceas para remoção de metais pesados em águas produzidas: processamento, caracterização e dinâmica em leito fixo

The acceleration of industrial growth in recent decades on all continents aroused the interest of the companies to counter the impacts produced on the environment, spurred primarily by major disasters in the petroleum industry. In this context, the water produced is responsible for the largest volume of effluent from the production and extraction of oil and natural gas. This effluent has in its composition some critical components such as inorganic salts, heavy metals (Fe, Cu, Zn, Pb, Cd, ), presence of oil and chemicals added in the various production processes. In response to impact, have been triggered by research alternative adsorbent materials for water treatment and water produced, in order to removing oils and acids and heavy metals. Many surveys of diatomaceous earth (diatomite) in Brazil involve studies on the physico-chemical, mineral deposits, extraction, processing and applications. The official estimated Jazi are around 2.5 million tonnes, the main located in the states of Bahia (44%) and Rio Grande do Norte (37,4%). Moreover, these two states appear as large offshore producers, earning a prominent role in research of adsorbents such as diatomite for treatment of water produced. Its main applications are as an agent of filtration, adsorption of oils and greases, industrial load and thermal insulator. The objective of this work was the processing and characterization of diatomite diatomaceous earth obtained from the municipality of Macaíba-RN (known locally as tabatinga) as a low cost regenerative adsorbent for removal of heavy metals in the application of water produced treatment. In this work we adopted a methodology for batch processing, practiced by small businesses located in producing regions of Brazil. The characterization was made by X-ray diffraction (XRD), scanning electron microscopy (SEM) and specific surface area (BET). Research conducted showed that the improvement process used was effective for small volume production of diatomite concentrated. The diatomite obtained was treated by calcination at temperature of 900 oC for 2 hours, with and without fluxing Na2CO3 (4%), according to optimal results in the literature. Column adsorption experiments were conducted to percolation of the in nature, calcined and calcined fluxing diatomites. Effluent was used as a saline solution containing ions of Cu, Zn, Na, Ca and Mg simulating the composition of produced waters in the state of Rio Grande do Norte, Brazil. The breakthrough curves for simultaneous removal of copper ions and zinc as a result, 84.3% for calcined diatomite and diatomite with 97.3 % for fluxing. The calcined fluxing diatomite was more efficient permeability through the bed and removal of copper and zinc ions. The fresh diatomite had trouble with the permeability through the bed under the conditions tested, compared with the other obtained diatomite. The results are presented as promising for application in the petroleum industry

Avaliação preliminar da contaminação por BTEX, em água subterrânea de poços tubulares, no município de Natal-RN

Among the different types of pollutants typically attributed to human activities, the petroleum products are one of the most important because of its toxic potential. This toxicity is attributed to the presence of substances such as benzene and its derivatives are very toxic to the central nervous system of man, with chronic toxicity, even in small concentrations. The area chosen for study was the city of Natal, capital of Rio Grande do Norte, where samples were collected in six different areas in the city, comprising 10 wells located in the urban area, being carried out in three distinct periods March/2009, December / June/2010 and 2009, and were evaluated for contamination by volatile hydrocarbons (BTEX - benzene, toluene, ethylbenzene and xylenes), so this work aimed to assess the quality of groundwater wells that supply funding for public supply and trade in the urban area of the city of Natal, in Rio Grande do Norte, contributing to the environmental assessment of the municipality. The analysis of BTEX in water was performed according to EPA Method 8021b. Was used the technique of headspace (TriPlus TP100) coupled to high resolution gas chromatography with selective photoionization detector (PID) and flame ionization (FID) - model Trace GC Ultra, Thermo Electron Corporation brand. The procedure adopted allowed the detection of concentrations of the order of μg.L-1. Data analysis with respect to BTEX in groundwater in the area monitored so far, shows that water quality is still preserved, because it exceeds the limits imposed by the potability Resolution CONAMA Nº. 396, April 2008

Avaliação de HPA e BTEX no solo e água subterrânea, em postos de revenda de combustíveis: estudo de caso na cidade de Natal -RN

The retail fuel stations are partially or potentially polluters and generators of environmental accidents, potentially causing contamination of underground and surface water bodies, soil and air. Leaks in fuel retail stations´ underground storage systems are often detected in Brazil and around the world. Monoaromatic hydrocarbons, BTEX (benzene, toluene, ethylbenzene and xylenes) and polycyclic aromatic hydrocarbons (PAHs) are an indication of the presence of contamination due to its high toxicity. This paper presents a case study of contamination in a Fuel Retail Station by petroleum derivative products in the city of Natal. For identification and quantification of the hydrocarbons, EPA analytical methods were used. The values of benzene quantified by EPA method 8021b CG-PID/FID, ranged from 1.164 to 4.503 mg.Kg-1 in soil samples, and from 12.10 to 27,639 μg.L-1 in underground water samples. Among the PAHs, naphthalene and anthracene showed the most significant results in soil samples, 0.420 to 15.46 mg.Kg-1 and 0.110 to 0,970 mg.Kg-1, respectively. In underground water samples, the results for Naphthalene varied between 0.759 and 614.7 μg.L-1. PAHs were quantified by EPA Method 8270 for GCMS. All of the results for the chemical analysis were compared with the values for the CONAMA 420/2009 resolution. The results for benzene (27,639 μg.L-1) showed levels highly above the recommended by the CONAMA 420 resolution, wherein the maximum permissible for underground water is 5 μg.L-1. This is a worrying factor, since underground water makes up 70% of the city of Natal´s water supply

Tratamento eletroquímico de efluente proveniente de caixas separadoras de água e óleo de postos revendedores de combustíveis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Aplicação de técnicas eletroquímicas na determinação do potencial de corrosividade de ligas de alumínio em água produzida

The resistance of aluminum and their alloys, to the corrosion phenomenon, in aqueous solutions, is a result of the oxide layer formed. However, the corrosion process in the aluminum alloy is associated with the presence a second phase of particles or the presence of chloride ions which promote the disruption of the oxide layer located producing the corrosion process. On the other hand, the term water produced is used to describe the water after the separation of the oil and gas in API separators. The volumes of produced water arrive around 5 more times to the volume of oil produced. The greatest feature of the water is the presence of numerous pollutants. Due to the increased volume of waste around the world in the current decade, the outcome and the effect of the discharge of produced water on the environment has recently become an important issue of environmental concern where numerous treatments are aimed at reducing these contaminants before disposal. Then, this study aims to investigate the electrochemical corrosion behavior of aluminum alloy 6060 in presence of water produced and the influence of organic components as well as chloride ions, by using the electrochemical techniques of linear polarization. The modification of the passive layer and the likely breakpoints were observed by atomic force microscopy (AFM). In the pit formation potential around -0.4 to -0.8 V/EAg/AgCl was observed that the diffusion of chloride ions occurs via the layer formed with the probable formation of pits. Whereas, at temperatures above 65 °C, it was observed that the range of potential for thepit formation was -0.4 to -0.5 V/EAg/AgCl. In all reactions, the concentration of Al(OH)3 in the form of a gel was observed

Estudo do efeito dos metabólitos do benzeno e tolueno sobre as mitocôndris cerebrais e hepáticas de ratos

Aim: The aim of this work was to investigate the hypothesis that catechol and 3MC inhibit FADH2-linked basal respiration in mitochondria isolated from rat liver and brain homogenates. Moreover, catechol ability to induce DNA damage in rat brain cells through the comet assay (alkaline single-cell gel electrophoresis assay) was also observed. Methods: Two different catechols were evaluated: pirocatechol (derived from benzene) and 3-methylcatechol (derived from toluene); rat liver and brain homogenates were incubated with 1mM catechol at pH 7.4 for up to 30 minutes. After that, mitochondrial fractions were isolated by differential centrifugation. Basal oxygen uptake was measured using a Clark-type electrode after the addition of 10 mM sodium succinate for a period of 12 minutes. In additional experiments, rat brain cells were treated with 1, 5 and 10mM pirocatechol for up to 20 minutes at 37º C, and submitted to electrophoresis. Results: Catechols (pirocatechol and 3methylcatechol) induced a time-dependent partial inhibition of FADH2-linked basal mitochondrial respiration. Indeed, pirocatechol was able to produce a dosedependent DNA oxidative damage in rat brain cells by 2 and 4 injury levels. These results suggest that reactive oxygen species generated by the oxidation of catechols, induced an impairment on mitochondrial respiration and a DNA damage, which might be related to their citotoxicity. Conclusion: Catechols produced an inhibition of basal respiration associated to FADH2 in isolated liver and brain mitochondria; 3-methylcatechol, at the same concentration, produced similar toxicity in the mitochondrial model. Indeed, pirocatechol induced a DNA damage in rat brain cells, mainly observed in comets formation and consequent DNA degradation

Remoção de óleo da água de produção por flotação em coluna utilizando tensoativos de origem vegetal

In the petroleum industry, water is always present in the reservoir formation together with petroleum and natural gas and this fact provokes the production of water with petroleum, resulting in a great environmental impact. Several methods can be applied for treatment of oily waters, such as: gravitational vases, granulated media filtration systems, flotation process, centrifugation process and the use of hydrocyclones, which can also be used in a combined way. However, the flotation process has showed a great efficiency as compared with other methods, because these methods do not remove great part of the emulsified oil. In this work was investigated the use of surfactants derived from vegetable oils, OSS and OGS, as collectors, using the flotation process in a glass column with a porous plate filter in its base for the input of the gaseous steam. For this purpose, oil/water emulsions were prepared using mechanical stirring, with concentrations around 300 ppm. The air flow rate was set at 700 cm3/min and the porous plate filter used for the generation of the air bubbles has pore size varying from 16 to 40 Pm. The column operated at constant volume (1500mL). A new methodology has been developed to collect the samples, where, instead of collecting the water phase, it was collected the oil phase removed by the process in the top of the flotation column. It has been observed that it is necessary to find an optimum surfactant concentration to achieve enhanced removal efficiency. Being for OSS 1.275 mmol/L and for OGS 0.840 mmol/L, with removal efficiencies of 93% and 99%, respectively, using synthetic solutions. For the produced water, the removal in these concentrations was 75% for OSS and 65% for OGS. It is possible to remove oil from water in a flotation process using surfactants of high HLB, fact that is against the own definition of HLB (Hydrophile-Lipophile Balance). The interfacial tension is an important factor in the oil removal process using a flotation process, because it has direct interference in the coalescence of the oil drops. The spreading of the oil of the air bubble should be considered in the process, and for the optimum surfactant concentrations it reached a maximum value. The removal kinetics for the flotation process using surfactants in the optimum concentration has been adjusted according to a first order model, for synthetic water as for the produced water.

Aperfeiçoamento no projeto de um protótipo de misturador-decantador à inversão de fases visando aplicação na indústria do petróleo

In the oil industry the mixture oil/water occurs in the operations of production, transportation and refining, as well as during the use of its derivatives. The amount of water produced associated with the oil varies and can reach values of 90% in volume in the case of mature phase of the production fields. The present work deals with the development of new design of the Mixer Settler based on Phase Inversion (MDIF) in a laboratory scale. We envisage this application in industrial scale so the phases of project, construction and operation are considered. The modifications most significant, in comparison with the original prototype, include the materials of construction and the substitution of the equipment used in the mixing stage of the process. It was tested the viability of substitution of the original system of mechanical mixing by a static mixer. A statistical treatment by means of an experimental design of composed central type was used in order to evaluate the behavior of the main variables of the separation process as function of the efficiency of separation for the new device. This procedure is useful to delimit an optimal region of operation with the equipment. The variables of process considered on the experimental design were: oil concentration in the feeding water (mg/L); Total volumetric flow rate (L/h); Ratio organic/water on volumetric basis (O/A). The separation efficiency is calculated by comparison of the content of oil and greases in the inlet and outlet of the equipment. For determination of TOG (Total Oil and Grease), the method used was based in the absorption of radiation in the infra-red region. The equipment used for these determinations was InfraCal® TOG/TPH Model HATR-T2 of the Wilks Enterprise, Incorporation. It´s important to stand out that this method of measure has being used by PETROBRAS S.A. Results of global efficiency of separation oil/water varied from 75.3 to 97.7% for contaminated waters containing up to 1664,1 mg/L of oil. By means of tests carried out with a real sample of contaminated water supplied by PETROBRAS we have got an effluent specified in terms of the legal standards required for discharging. Thus, the new design of equipment constitutes a real alternative for the conventional systems of treatment of produced water in the oil industry

Desenvolvimento de um destilador solar para tratamento de águas de produção de petróleo com vistas a sua utilização na agricultura e geração de vapor

The production of petroleum is frequently accomplished with great volumes of water, that it is carried of the underground with the oil. It is a challenge of the present century the development of technologies that allow the use of waste water for purposes that consume great amounts of water and don't demand as rigid as the one of the drinking water requirements. The solar distillation has been configuring as an alternative of clean technology for desalination of brine and saline. Besides causing the minimum possible damage to the environment, it takes advantage of an abundant and free energy source: the solar energy. That study aims to develop a Solar Distillator for treatment of the produced water of the oil wells, to obtain an efluent to use in agriculture and vapor generation. The methodology for collection, conservation and analysis of the physical-chemical parameters obeyed the norms in APHA (1995). The sampling was of the composed type. Experiments were accomplished in the solar distillation pilot and simulation in thermostatic bathing. The operation was in batch system and for periods of 4, 6 and 12 h. The developed Distillator is of the type simple effect of two waters. It was still tested two inclination angles for covering; 20º and 45º. The Distillator presented minimum of 2,85 L/m2d revenues and maximum of 7,14 L/m2d. The removals of salts were great than 98%. The removal of TOC in the simulation was great than 90%. In agreement with the data of energy and mass balance, it was verified that the developed solar Distillator presented compatible revenues with those found in literature for similar types. It can be inferred that the obtained distilled water assists to the requirements CONAMA in almost all the points and could be used for irrigation of cultures such as cotton and mamona. As the distilled water has characteristics of fresh water it can be used in the generation of vapor

Remoção conjugada de metais e óleo de água produzida

Petroleum can be associated or not with natural gas, but in both cases water is always present in its formation. The presence of water causes several problems, such as the difficulty of removing the petroleum from the reservoir rock and the formation of waterin-oil and oil-in-water emulsions. The produced water causes environmental problems, which should be solved to reduce the effect of petroleum industry in the environment. The main objective of this work is to remove simultaneously from the produced water the dispersed petroleum and dissolved metals. The process is made possible through the use of anionic surfactants that with its hydrophilic heads interacts with ionized metals and with its lipophilic tails interacts with the oil. The studied metals were: calcium, magnesium, barium, and cadmium. The surfactants used in this research were derived from: soy oil, sunflower oil, coconut oil, and a soap obtained from a mixture of 5wt.% coconut oil and 95wt.% animal fat. It was used a sample of produced water from Terminal de São Sebastião, São Paulo. As the concentration of the studied metals in produced water presented values close to 300 mg/L, it was decided to use this concentration as reference for the development of this research. Molecular absorption and atomic absorption spectroscopy were used to determine petroleum and metals concentrations in the water sample, respectively. A constant pressure filtration system was used to promote the separation of solid and liquid phases. To represent the behavior of the studied systems it was developed an equilibrium model and a mathematical one. The obtained results showed that all used surfactants presented similar behavior with relation to metals extraction, being selected the surfactant derived from soy oil for this purpose. The values of the partition coefficients between the solid and liquid phases " D " for the studied metals varied from 0.2 to 1.1, while the coefficients for equilibrium model " K " varied from 0.0002 and 0.0009. The removal percentile for oil with all metals associated was near 100%, showing the efficiency of the process