Concepção e estudo de um biofiltro para tratamento de compostos orgânicos voláteis COVs

In the last decade, biological purification of gaseous waste has become an important alternative to many conventional methods of exhaust air treatment. More recently, biofiltration has proved to be an effective and inexpensive method for the treatment of air contaminated with volatile organic compounds (VOCs). A biofilter consists in a reactor packed with a porous solid bed material, where the microorganisms are fixed. During the biofiltration process, polluted air is transported through the biofilter medium where the contaminant is degraded. Within the biofilm, the pollutants in the waste gases are energy and carbon sources for microbial metabolism and are transformed into CO2, water and biomass. The bed material should be characterized by satisfactory mechanical and physical properties as structure, void fraction, specific area and flow resistance. The aim of this research was the biofilter construction and study of the biological degradation of ethanol and toluene, as well as the modeling of the process. Luffa cylindrica is a brazilian fiber that was used as the filtering material of the present work. The parameters and conditions studied were: composition of nutrients solution; effect of microflorae strains, namely Pseudomanas putida and Rhodococcus rhodochrous; waste gas composition; air flow rate; and inlet load of VOCs. The biofilter operated in diffusion regime and the best results for remotion capacity were obtained when a microorganisms consortion of Pseudomanas putida and Rhodococcus rhodochrous,were used, with a gas flow rate of 1 m3.h-1 and molar ratio nitrogene/phosphore N/P=2 in the nutrients solution. The maximum remotion capacity for ethanol was around 90 g.m-3.h-1 and 50 g.m-3.h-1 to toluene. It was proved that toluene has inhibitory effect on the ethanol remotion When the two VOCs were present in the same waste gas, there was a decrease of 40% in ethanol remotion capacity. Luffa cylindrica does not present considerable pressure drop. Ottengraf and van Lith models were used to represent the results obtained for ethanol and toluene, respectively. The application of the transient model indicated a satisfactory approximation between the experimental results obtained for ethanol and toluene vapors biofiltration and the ones predicted it

Avaliação da eficiência de lagoas de estabilização no tratamento de resíduos esgotados de fossas sépticas

Because of disability in public policy development in mind to attend issues of sanitation in the municipalities, companies known as "clean-blue" appeared proposing to solve a simple collection and management of wastewater produced in single or multifamily residences, commercial, hospitals, etc. In the case of an activity in which there are no worries about the fate of sewage, emerged some doubts about the degree of health and environmental safety in these companies. Traditionally, most of them makes the provision of waste depleted soil or wetland, open, usually located on the outskirts of cities (MENESES, 2001). In turn, the sludge from septic tanks exhausted, provided no technical criteria - in the soil, rivers and as an agricultural fertilizer put in risk the health of the population and environmental quality. This work was entered in the search network 5 of the Notice of the Research Program in Sanitation - PROSAB-5, aimed to study the theme 'Characterization and study of alternative ways of treating sludge from septic tanks in the city of Natal, RN', proposing to evaluate the performance of the use of stabilization ponds as a system to handle waste from septic tanks exhausted. A series of lakes studied belong to one of the largest clean-pit of Natal, consisting of two anaerobic ponds, one facultative and maturation, and a tank disinfection, the wastewater being released in the Potengi River. Samples were collected between the months of October 2007 to October 2008, at six points previously defined and judged as more appropriate to what is proposed study. The analysis results in field and laboratory showed the most significant removal of COD (88.93%), total suspended solids (94.87%), organic nitrogen (66.87%) and thermotolerant coliforms (99.88%). Some results have not reached the expected because the system under study had operating problems that have undermined the efficiency of the reactors

Tecnologia eletroquímica como tratamento alternativo de efluentes têxteis sintéticos utilizando ânodos de platina e diamante

In this work, the treatment of synthetic wastewaters containing Remazol Red BR (RRB) and Novacron Blue C-D (NB) by anodic oxidation using boron doped diamond anodes (BDD) and Novacron Yellow (YN) using BDD and Platinum (Pt) anodes was investigated. Galvanostatic electrolyses of RRB and NB synthetic wastewaters have led to the complete decolorization removal at different operating conditions (current density, pH and temperature). The influence of these parameters was investigated in order to find the best conditions for dyestuff colour removal. According to the experimental results obtained, the electrochemical oxidation process is suitable for decolorizing wastewaters containing these textile dyes, due to the electrocatalytic properties of BDD and Pt anode. Energy requirements for removing colour during galvanostatic electrolyses of RRB, NB and YN synthetic solutions depends mainly on the operating conditions; for example for RRB, it passes from 3.30 kWh m-3 at 20 mA cm-2 to 4.28 kWh m-3 at 60 mA cm-2 (pH = 1); 15.23 kWh m-3 at 20 mA cm-2 to 24.75 kWh m-3 at 60 mA cm-2 (pH = 4.5); 10.80 kWh m-3 at 20 mA cm-2 to 31.5 kWh m-3 at 60 mA cm-2 (pH = 8) (data estimated per volume of treated effluent). In order to verify the Brazilian law regulations of NB and RRB synthetic solutions after electrochemical decolourisation treatment, Hazen Units values were determined and the total colour removal was achieved; remaining into the regulations. Finally, electrical energy cost for removing colour was estimated

Avaliação de floculante natural à base de Moringa oleifera no tratamento de água produzida na indústria do petróleo: aplicação da técnica combinada floculação/flotação

The principal effluent in the oil industry is the produced water, which is commonly associated to the produced oil. It presents a pronounced volume of production and it can be reflected on the environment and society, if its discharge is unappropriated. Therefore, it is indispensable a valuable careful to establish and maintain its management. The traditional treatment of produced water, usualy includes both tecniques, flocculation and flotation. At flocculation processes, there are traditional floculant agents that aren’t well specified by tecnichal information tables and still expensive. As for the flotation process, it’s the step in which is possible to separate the suspended particles in the effluent. The dissolved air flotation (DAF) is a technique that has been consolidating economically and environmentally, presenting great reliability when compared with other processes. The DAF is presented as a process widely used in various fields of water and wastewater treatment around the globe. In this regard, this study was aimed to evaluate the potential of an alternative natural flocculant agent based on Moringa oleifera to reduce the amount of oil and grease (TOG) in produced water from the oil industry by the method of flocculation/DAF. the natural flocculant agent was evaluated by its efficacy, as well as its efficiency when compared with two commercial flocculant agents normally used by the petroleum industry. The experiments were conducted following an experimental design and the overall efficiencies for all flocculants were treated through statistical calculation based on the use of STATISTICA software version 10.0. Therefore, contour surfaces were obtained from the experimental design and were interpreted in terms of the response variable removal efficiency TOG (total oil and greases). The plan still allowed to obtain mathematical models for calculating the response variable in the studied conditions. Commercial flocculants showed similar behavior, with an average overall efficiency of 90% for oil removal, however it is the economical analysis the decisive factor to choose one of these flocculant agents to the process. The natural alternative flocculant agent based on Moringa oleifera showed lower separation efficiency than those of commercials one (average 70%), on the other hand this flocculant causes less environmental impacts and it´s less expensive

Tecnologia eletroquímica como tratamento alternativo de efluentes derivados da indústria têxtil e petroquímica

In this work, the treatment of wastewater from the textile industry, containing dyes as Yellow Novacron (YN), Red Remazol BR (RRB) and Blue Novacron CD (NB), and also, the treatment of wastewater from petrochemical industry (produced water) were investigated by anodic oxidation (OA) with platinum anodes supported on titanium (Ti/Pt) and boron-doped diamond (DDB). Definitely, one of the main parameters of this kind of treatment is the type of electrocatalytic material used, since the mechanisms and products of some anodic reactions depend on it. The OA of synthetic effluents containing with RRB, NB and YN were investigated in order to find the best conditions for the removal of color and organic content of the dye. According to the experimental results, the process of OA is suitable for decolorization of wastewaters containing these textile dyes due to electrocatalytic properties of DDB and Pt anodes. Removal of the organic load was more efficient at DDB, in all cases; where the dyes were degraded to aliphatic carboxylic acids at the end of the electrolysis. Energy requirements for the removal of color during OA of solutions of RRB, NB and YN depends mainly on the operating conditions, for example, RRB passes of 3.30 kWh m-3 at 20 mA cm-2 for 4.28 kWh m-3 at 60 mA cm-2 (pH = 1); 15.23 kWh m-3 at 20 mA cm-2 to 24.75 kWh m-3 at 60 mA cm-2 (pH 4.5); 10.80 kWh m-3 at 20 mA cm-2 to 31.5 kWh m-3 at 60 mA cm-2 (pH = 8) (estimated data for volume of treated effluent). On the other hand, in the study of OA of produced water effluent generated by petrochemical industry, galvanostatic electrolysis using DDB led to the complete removal of COD (98%), due to large amounts of hydroxyl radicals and peroxodisulphates generated from the oxidation of water and sulfates in solution, respectively. Thus, the rate of COD removal increases with increasing applied current density (15-60 mAcm-2 ). Moreover, at Pt electrode, approximately 50% removal of the organic load was achieved by applying from 15 to 30 mAcm-2 while 80% of COD removal was achieved for 60 mAcm-2 . Thus, the results obtained in the application of this technology were satisfactory depending on the electrocatalytic materials and operating conditions used for removal of organic load (petrochemical and textile effluents) as well as for the removal of color (in the case of textile effluents). Therefore, the applicability of electrochemical treatment can be considered as a new alternative like pretreatment or treatment of effluents derived from textiles and petrochemical industries.

Estudo de métodos de tratamento de efluentes (troca iônica e eletroquímico) separados e sequenciais para eliminação de derivados de petróleo

The produce of waste and the amount of the water produced coming from activities of petroleum production and extraction has been a biggest challenge for oil companies with respect to environmental compliance due to toxicity. The discard or the reuse this effluent containing organic compounds as BTEX (benzene, toluene, ethylbenzene and xylene) can cause serious environmental and human health problems. Thus, the objective this paper was study the performance of two process (separately and sequential) in one synthetic effluent for the benzene, toluene and xylene removal (volatile hydrocarbons presents in the produced water) through of electrochemical treatment using Ti/Pt electrode and exchange resin ionic used in the adsorption process. The synthetic solution of BTX was prepared with concentration of 22,8 mg L-1, 9,7 mg L-1 e 9,0 mg L-1, respectively, in Na2SO4 0,1 mol L-1. The experiments was developed in batch with 0.3 L of solution at 25ºC. The electrochemical oxidation process was accomplished with a Ti/Pt electrode with different current density (J = 10, 20 e 30 mA.cm-2). In the adsorption process, we used an ionic exchange resin (Purolite MB 478), using different amounts of mass (2,5, 5 and 10 g). To verify the process of technics in the sequential treatment, was fixed the current density at 10 mA cm-2 and the resin weight was 2.5 g. Analysis of UV-VIS spectrophotometry, chemical oxygen demand (COD) and gas chromatography with selective photoionization detector (PID) and flame ionization (FID), confirmed the high efficiency in the removal of organic compounds after treatment. It was found that the electrochemical process (separate and sequential) is more efficient than absorption, reaching values of COD removal exceeding 70%, confirmed by the study of the cyclic voltammetry and polarization curves. While the adsorption (separately), the COD removal did not exceed 25,8%, due to interactions resin. However, the sequential process (electrochemical oxidation and adsorption) proved to be a suitable alternative, efficient and cost-effectiveness for the treatment of effluents petrochemical.

Estudo da eficiência eletroquímica para tratamento de chorume gerado em aterro sanitário brasileiro

This work was performing effluent degradation studies by electrochemical treatment. The electrochemical oxidation (EO) hydroquinone (H2Q) was carried out in acid medium, using PbO2 electrode by galvanostatic electrolysis, applying current densities of 10 and 30 mA/cm2 . The concentration of H2Q was monitored by differential pulse voltammetry (DPV). The experimental results showed that the galvanostatic electrolysis process performance significantly depends on the applied current density, achieving removal efficiencies of 100% and 80 % and 10 applying 30 mA/cm2 , respectively. Furthermore, the electroanalytical technique was effective in H2Q be used as a detection method. In order to test the efficiency of PbO2 electrode, the electrochemical treatment was conducted in an actual effluent, leachate from a landfill. The liquid waste leachate (600ml effluent) was treated in a batch electrochemical cell, with or without addition of NaCl by applying 7 mA/cm2 . The efficiency of EO was assessed against the removal of thermo-tolerant coliforms, total organic carbon (TOC), total phosphorus and metals (copper, cobalt, chromium, iron and nickel). These results showed that efficient removal of coliforms was obtained (100%), and was further decrease the concentration of heavy metals by the cathode processes. However, results were not satisfactory TOC, achieving low total removal of dissolved organic load. Because it is considered an effluent complex were developed other tests with this effluent to monitor a larger number of decontamination parameters (Turbidity, Total Solids, Color, Conductivity, Total Organic Carbon (TOC) and metals (barium, chromium, lithium, manganese and Zinc), comparing the efficiency of this type of electrochemical treatment (EO or electrocoagulation) using a flow cell. In this assay was compared to electro streaming. In the case of the OE, Ti/IrO2-TaO5 was used as the anode, however, the electrocoagulation process, aluminum electrodes were used; applying current densities of 10, 20 and 30 mA/cm2 in the presence and absence of NaCl as an electrolyte. The results showed that EO using Ti/IrO2–TaO5 was anode as efficient when Cl- was present in the effluent. In contrast, the electrocoagulation flow reduces the dissolved organic matter in the effluent, under certain experimental conditions.

Aplicação da oxidação eletroquímica no tratamento de efluentes contendo corantes reativos utilizando Ti/Pt e Ti/Pt-SnSb

The textile effluents are a complex mixture of many pollutants that contain high organic loads, severe color and toxic compounds. The high concentration of the textile effluent may cause increased chemical demand (COD) and biochemical (BOD) of oxygen, elevated temperature, acidity or alkalinity, causing damage and environmental problems. In addition to representing a serious threat to human health such effluent is also quite toxic to most aquatic organisms. And for this reason, one must meet the concentration limits for emission sources and sewage system. This study aimed to investigate the performance of electrochemical treatment of a textile effluent for the removal of color, turbidity, dissolved oxygen (DO) and dissolved organic matter by investigating the influence of experimental parameters such as the electrocatalyst materials (Ti/Pt and Ti/Pt-SnSb) and current density in order to compare their efficiency, energy consumption and cost. The dye Novacron Blue CD (NB) was employed in synthetic solution, while the dyes Remazol Yellow 3RS (RY 3RS) Remazol Red RR Gran (RR-RR Gran) and Navy Blue CL-R (NB CL-R) were used to generate simulated textile effluent laboratory. The results showed that the application of electrochemical oxidation process favors the elimination of color effectively independent the electrocatalytic material and current used, as well as treated effluent. However, the influence of electrocatalytic material was crucial to reduction of the organic matter in all cases.

Estudo comparativo dos processos eletroquímicos oxidativos avançados (PEOAs) no tratamento de efluentes contendo corantes orgânicos de difícil degradação

Organic dyes have been widely used in various branches of dyeing industries. These compounds are known to be very toxic, mutagenic, cancinogenic only cause aesthetic pollution and irreversible damage to aquatic ecosystems and human health. Are recalcitrant contaminants due to its high stability and resistance to photobleaching and bio. Given this context, the search for technologies that can minimize the effects of such pollutants is required. In recent decades the Electrochemical Oxidation Process Advanced (PEOAs) based on the generation of strongly oxidizing species (radicals ●OH) offer promising approaches for the prevention of problems caused by industrial effluents. This study analyzed the degradation and mineralization of textile dyes and the study of a real effluent in order to assess the feasibility of PEOAs: Electro-Fenton (EF), Photo Electro-Fenton (PEF) and anodic oxidation (AO), and these methods still was studied the Solar Fotoelectro-Fenton (SPEF) in a pre-pilot plant, in order to study the electrochemical treatment on an industrial scale. In the study has compared the effect of PEOAs in the removal of color, TOC and decay kinetics of degradation of the compounds, and also for using the Congo Red (CR) SPEF studies were performed mineralization current efficiency (MCE). The best results are given to the treatment of the PEF for all the studied dyes. From the results it was possible to choose the PEF as the most effective and promising for application of treatment when compared to other methods of treatment, and prove from SPEF that the process can be used in industrial scales, since this method PEF has been improved and solar irradiation replaced the UVA lamp.

Estudo comparativo dos processos eletroquímicos oxidativos avançados (PEOAs) no tratamento de efluentes contendo corantes orgânicos de difícil degradação

Organic dyes have been widely used in various branches of dyeing industries. These compounds are known to be very toxic, mutagenic, cancinogenic only cause aesthetic pollution and irreversible damage to aquatic ecosystems and human health. Are recalcitrant contaminants due to its high stability and resistance to photobleaching and bio. Given this context, the search for technologies that can minimize the effects of such pollutants is required. In recent decades the Electrochemical Oxidation Process Advanced (PEOAs) based on the generation of strongly oxidizing species (radicals ●OH) offer promising approaches for the prevention of problems caused by industrial effluents. This study analyzed the degradation and mineralization of textile dyes and the study of a real effluent in order to assess the feasibility of PEOAs: Electro-Fenton (EF), Photo Electro-Fenton (PEF) and anodic oxidation (AO), and these methods still was studied the Solar Fotoelectro-Fenton (SPEF) in a pre-pilot plant, in order to study the electrochemical treatment on an industrial scale. In the study has compared the effect of PEOAs in the removal of color, TOC and decay kinetics of degradation of the compounds, and also for using the Congo Red (CR) SPEF studies were performed mineralization current efficiency (MCE). The best results are given to the treatment of the PEF for all the studied dyes. From the results it was possible to choose the PEF as the most effective and promising for application of treatment when compared to other methods of treatment, and prove from SPEF that the process can be used in industrial scales, since this method PEF has been improved and solar irradiation replaced the UVA lamp.

Potencialidade do tratamento eletroquímico oxidativo associado à adsorção para remediação de corantes têxteis

This study aimed to evaluate the potential of oxidative electrochemical treatment coupled with adsorption process using expanded perlite as adsorbent in the removal of textile dyes, Red Remazol and Novacron Blue on synthetic effluent. Dyes and perlite were characterized by thermogravimetry techniques (TG), Differential Scanning Calorimetry (DSC), Spectroscopy infrared (IR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Electrochemical treatments used as anodes, Ti/Pt and Pb/PbO2 under different conditions: 60 minutes, current density 20, 40 e 60 mAcm-2, pH 1, 4.5 e 8 and temperature variation 20, 40 e 60 ºC. In the case of adsorption tests, contact time of 30 minutes for the Remazol Red dye and 20 minutes for Novacron Blue were established, while pH 1, 4.5 e 8, 500 mg adsorbent and temperature variation 20, 40 e 60 ºC were used for both treatments. The results indicated that both treatments, electroxidation/adsorption and the adsorption/electroxidation, were effective for removing color from synthetic solutions. The consumption of electricity allowed to evaluate the applicability of the electrochemical process, providing very acceptable values, which allowed us to estimate the cost. Total organic carbon (TOC) and Gas Chromatography linked mass spectrometer (GC-MS) analyzes were performed, showing that the better combination for removing organic matter is by Pb/PbO2 and perlite. Meanwhile, GC-MS indicated that the by-products formed are benzoic acid, phthalic acid, thiocarbamic acid, benzene, chlorobenzene, phenol-2-ethyl and naphthalene when Remazol Red was degraded. Conversely, aniline, phthalic acid, 1, 6 - dimethylnaphthalene, naphthalene and ion hidroxobenzenosulfonat was detected when Novacron Blue was studied. Analyses obtained through atomic absorption spectrometry showed that there was release of lead in the electrochemical oxidation of analyzes that were performed with the anode Pb/PbO2, but these values are reduced by subjecting the effluent to adsorption analysis. According to these results, sequential techniques electroxidation/adsorption and adsorption/electroxidation are to treat solutions containing dyes.

Potencialidade do tratamento eletroquímico oxidativo associado à adsorção para remediação de corantes têxteis

This study aimed to evaluate the potential of oxidative electrochemical treatment coupled with adsorption process using expanded perlite as adsorbent in the removal of textile dyes, Red Remazol and Novacron Blue on synthetic effluent. Dyes and perlite were characterized by thermogravimetry techniques (TG), Differential Scanning Calorimetry (DSC), Spectroscopy infrared (IR), Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Electrochemical treatments used as anodes, Ti/Pt and Pb/PbO2 under different conditions: 60 minutes, current density 20, 40 e 60 mAcm-2, pH 1, 4.5 e 8 and temperature variation 20, 40 e 60 ºC. In the case of adsorption tests, contact time of 30 minutes for the Remazol Red dye and 20 minutes for Novacron Blue were established, while pH 1, 4.5 e 8, 500 mg adsorbent and temperature variation 20, 40 e 60 ºC were used for both treatments. The results indicated that both treatments, electroxidation/adsorption and the adsorption/electroxidation, were effective for removing color from synthetic solutions. The consumption of electricity allowed to evaluate the applicability of the electrochemical process, providing very acceptable values, which allowed us to estimate the cost. Total organic carbon (TOC) and Gas Chromatography linked mass spectrometer (GC-MS) analyzes were performed, showing that the better combination for removing organic matter is by Pb/PbO2 and perlite. Meanwhile, GC-MS indicated that the by-products formed are benzoic acid, phthalic acid, thiocarbamic acid, benzene, chlorobenzene, phenol-2-ethyl and naphthalene when Remazol Red was degraded. Conversely, aniline, phthalic acid, 1, 6 - dimethylnaphthalene, naphthalene and ion hidroxobenzenosulfonat was detected when Novacron Blue was studied. Analyses obtained through atomic absorption spectrometry showed that there was release of lead in the electrochemical oxidation of analyzes that were performed with the anode Pb/PbO2, but these values are reduced by subjecting the effluent to adsorption analysis. According to these results, sequential techniques electroxidation/adsorption and adsorption/electroxidation are to treat solutions containing dyes.

Projeto, construção e análise de um prototipo vibracional em escala de bancada aplicável ao tratamento de água de produção de petróleo bruto, mediante inovadora operação híbrida de adsorção e auto-flotação

A self-flotator vibrational prototype electromechanical drive for treatment of oil and water emulsion or like emulsion is presented and evaluated. Oil production and refining to obtain derivatives is carried out under arrangements technically referred to as on-shore and off-shore, ie, on the continent and in the sea. In Brazil 80 % of the petroleum production is taken at sea and area of deployment and it cost scale are worrisome. It is associated, oily water production on a large scale, carrier 95% of the potential pollutant of activity whose final destination is the environment medium, terrestrial or maritime. Although diversified set of techniques and water treatment systems are in use or research, we propose an innovative system that operates in a sustainable way without chemical additives, for the good of the ecosystem. Labyrinth adsor-bent is used in metal spirals, and laboratory scale flow. Equipment and process patents are claimed. Treatments were performed at different flow rates and bands often monitored with control systems, some built, other bought for this purpose. Measurements of the levels of oil and grease (OGC) of efluents treaty remained within the range of legal framework under test conditions. Adsorbents were weighed before and after treatment for obtaining oil impregna-tion, the performance goal of vibratory action and treatment as a whole. Treatment technolo-gies in course are referenced, to compare performance, qualitatively and quantitatively. The vibration energy consumption is faced with and without conventional flotation and self-flotation. There are good prospects for the proposed, especially in reducing the residence time, by capillary action system. The impregnation dimensionless parameter was created and confronted with consecrated dimensionless parameters, on the vibrational version, such as Weber number and Froude number in quadratic form, referred to as vibrational criticality. Re-sults suggest limits to the vibration intensity