1000 resultados para TRATAMENTO DE ÁGUAS RESIDUÁRIAS


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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

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With water pollution increment at the last years, so many progresses in researches about treatment of contaminated waters have been developed. In wastewaters containing highly toxic organic compounds, which the biological treatment cannot be applied, the Advanced Oxidation Processes (AOP) is an alternative for degradation of nonbiodegradable and toxic organic substances, because theses processes are generation of hydroxyl radical based on, a highly reactivate substance, with ability to degradate practically all classes of organic compounds. In general, the AOP request use of special ultraviolet (UV) lamps into the reactors. These lamps present a high electric power demand, consisting one of the largest problems for the application of these processes in industrial scale. This work involves the development of a new photochemistry reactor composed of 12 low cost black light fluorescent lamps (SYLVANIA, black light, 40 W) as UV radiation source. The studied process was the photo-Fenton system, a combination of ferrous ions, hydrogen peroxide, and UV radiation, it has been employed for the degradation of a synthetic wastewater containing phenol as pollutant model, one of the main pollutants in the petroleum industry. Preliminary experiments were carrier on to estimate operational conditions of the reactor, besides the effects of the intensity of radiation source and lamp distribution into the reactor. Samples were collected during the experiments and analyzed for determining to dissolved organic carbon (DOC) content, using a TOC analyzer Shimadzu 5000A. The High Performance Liquid Chromatography (HPLC) was also used for identification of the cathecol and hydroquinone formed during the degradation process of the phenol. The actinometry indicated 9,06⋅1018 foton⋅s-1 of photons flow, for 12 actived lamps. A factorial experimental design was elaborated which it was possible to evaluate the influence of the reactants concentration (Fe2+ and H2O2) and to determine the most favorable experimental conditions ([Fe2+] = 1,6 mM and [H2O2] = 150,5 mM). It was verified the increase of ferrous ions concentration is favorable to process until reaching a limit when the increase of ferrous ions presents a negative effect. The H2O2 exhibited a positive effect, however, in high concentrations, reaching a maximum ratio degradation. The mathematical modeling of the process was accomplished using the artificial neural network technique

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At the cashew nut processing industry it is often the generation of wastewaters containing high content of toxic organic compounds. The presence of these compounds is due mainly to the so called liquid of the cashew nut (CNSL). CNSL, as it is commercially known in Brazil, is the liquid of the cashew nut. It looks like an oil with dark brown color, viscous and presents a high toxicity index due to the chemical composition, i.e. phenol compounds, such as anacardic acid, cardol, 2-methyl cardol and monophenol (cardanol). These compounds are bio resistant to the conventional treatments. Furthermore, the corresponding wastewaters present high content of TOC (total organic carbon). Therefore due to the high degree of toxicity it is very important to study and develop treatments of these wastewaters before discharge to the environmental. This research aims to decompose these compounds using advanced oxidative processes (AOP) based on the photo-Fenton system. The advantage of this system is the fast and non-selective oxidation promoted by the hydroxyl radicals (●OH), that is under determined conditions can totally convert the organic pollutants to CO2 and H2O. In order to evaluate the decomposition of the organic charge system samples of the real wastewater od a processing cashew nut industry were taken. This industry was located at the country of the state of Rio Grande do Norte. The experiments were carried out with a photochemical annular reactor equipped with UV (ultra violet) lamp. Based on preliminary experiments, a Doehlert experimental design was defined to optimize the concentrations of H2O2 and Fe(II) with a total of 13 runs. The experimental conditions were set to pH equal to 3 and temperature of 30°C. The power of the lamps applied was 80W, 125W and 250W. To evaluate the decomposition rate measures of the TOC were accomplished during 4 hours of experiment. According to the results, the organic removal obtained in terms of TOC was 80% minimum and 95% maximum. Furthermore, it was gotten a minimum time of 49 minutes for the removal of 30% of the initial TOC. Based on the obtained experimental results, the photo-Fenton system presents a very satisfactory performance as a complementary treatment of the wastewater studied

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The technology of anaerobic reactors for sanitary wastewater treatment has been extensively developed in Brazil, and today it is practically consolidated. They present several advantages, such as low construction and operating costs, and low sludge production, the anaerobic reactors are an attractive alternative to minimize problematic lack of basic sanitation in urban areas, and also of the rural areas. The anaerobic filters have been widely used in Brazil. It produces an effluent with low concentration of organic matter and solids suspended, besides conserving the nutrients, therefore, it is good for use in irrigation, but the practice must be associated with knowledge of the pathogens presence. The main objective of this study was to evaluate the efficiency of anaerobic filters in removal faecal coliforms and helminth eggs, and to verify if the effluent can be used for agricultural purposes, according to the World Organization of Health (WHO, 1989). The protocol used to enumerate helminths eggs was the modified Bailenger method, (Ayres and Mara, 1996) recommended by WHO for evaluation of raw effluent and treated effluent. The membrane filtration method was utilized to determine the concentrations of faecal coliforms. Three different systems of sewer treatment composed by anaerobic filters were analyzed. The results, in a general analysis, showed that all the researched systems reached a larger removal than 93% to helminth eggs, resulting in an effluent with smaller average than 1 egg/L. One of these systems, Sistema RN, reached a larger removal than 99%, confirming the good performance of the anaerobic filters in removal helminths eggs. Even with low concentrations of eggs in the influent, the filters were capable to remove this parameter efficiently. About faecal coliforms, it was observed for all the researched systems an effluent with 106 CFU/100mL. The high concentrations to faecal coliforms in the effluent just allow reuse for restricted irrigation, in agreement with the guidelines of WHO. Although the researched systems have not removed faecal coliforms efficiently, the results indicated a good efficiency of the anaerobic filters in removal helminth eggs

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In the urban areas of the cities a larger problem of destiny of effluents of the treatment stations is verified due to the junction of the sewages in great volumes. This way the hidroponic cultive becomes important, for your intensive characteristic, as alternative of reuse. This work presents as objective the improvement of the relation hidric-nutritious of the hidroponic cultive of green forage (FVH) using treaty sewage. The production of forage was with corn (Zea mays L.), using double hybrid AG1051, in the experimental field of the Federal University of Rio Grande do Norte (UFRN), in the city of Natal-RN-Brazil. The treated effluent essentially domestic had origin of anaerobic reactor, type decant-digester of two cameras in series followed by anaerobic filters drowned. The hidroponic experimental system was composed of 08 stonemasons, with limited contours for masonry of drained ceramic brick, measuring each one 2,5 meters in length for 1,0 meter of width, with inclination of 4% (m/m) in the longitudinal sense, leveled carefully, in way to not to allow preferential roads in the flow. These dimensions, the useful area of Isow was of 2 square meters. The stonemasons of cultive were waterproof (found and lateral) with plastic canvas of 200 micres of thickness, in the white color. Controlled the entrance and exit of the effluente in the stonemasons, with cycles of 12,68 minutes, it being water of 1,18 minutes. The treatments were constituted of: T1 - 24 hours/day under it waters with flow of 2 L/min; T2 - 12 hours/day under waters with flow of 4 L/min; T3 - 12 hours/day under waters with flow of 2 L/min; and T4 - 16 hours/day under waters with flow of 3 L/min. There were evaluations of the evapotranspirometric demand, of hidroponic system affluent and effluent seeking to characterize and to monitor physical-chemical parameters as: pH, temperature, Electric Conductivity and Fecal Coliforms. This last one was analyzed to the 11 days after isow (DAS) and to the 14 DAS. The others were analyzed daily. I sow it was accomplished in the dates of February 21, 2007, first experiment, and April 10, 2007, second experiment. The density of Isow was of 2 kg of seeds, germinated before 48 hours, for square meter of stonemason. The statistic delineament was it casual entirely with two repetitions, in two experiments. It was applied Tukey test of average to five percent of probability. The cultivation cycle was of 14 DAS with evapotranspirometric demand maximum, reached by T1, of 67,44 mm/day. The analyzed parameters, as mass of green matter - Kg, productivity-Kg/m2 and reason of production of seed FVH/Kg used in Isow, the best result was presented by T1, obtaining value of up to 19,01 Kg/m2 of cultive. Without significant difference, the T4 presented greats values with 16 hours under cycle of water. The Treatments 2 and 3 with 12 hours under cycle of water, they obtained inferior results to the other Treatments. As treatment system, came efficient in the reduction of the salinity. T1 obtained reduction medium maxim of 62,5%, to the 7 DAS, in the amount of salts that enter in the system in they are absorbed in the cultivation. The cultivation FVH acted reducing the microbiologic load. Significant percentile of reduction they were reached, with up to 90,23% of reduction of Units of Colonies (UFC), constituting, like this, the Hidroponic System as good alternative of treatment of effluents of Reactors of high Efficiency

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The improper disposal of nitrogen in receiving water courses causes problems such as toxicity to living beings through the consumption of oxygen to meet the nitrogen demand, eutrophication and nitrate contamination of aquifers. For this reason it is often necessary to be carried out complementary treatment of wastewater to eliminate or reduce the concentration of this compound in the wastewater. The objective of this study is to evaluate the biological removal of nitrogen compounds using submerged aerated and anoxic filters as post-treatment of an anaerobic system, with low cost and innovative technology, which in previous studies has shown high removal efficiency of organic matter and great potential biological nitrogen compounds removal. The simple design with perforated hoses for air distribution and filling with plastic parts proved to be very efficient in relation to organic matter removal and nitrification. The system presented, in the best stage, efficiency in converting ammonia to nitrate by 71%, and produced a final effluent concentration below 10 mg / L of NH3-N. In addition, carbon concentration was removed by 77%, producing final effluent with 24 mg/L COD. However, denitrification in anoxic filter was not effective even with the addition of an external carbon source. There was a reduction of up to 56% of nitrogen caused by the process of simultaneous nitrification and denitrification (SND). The high voids space presented by this type of support material coupled with direct aeration of the sludge, allows the respiration of biomass retained between the endogenous phase, increased cell retention time and sludge retention capacity, producing a final effluent with turbidity less than 5 UT and total suspended solids around 5.0 mg/L

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The Ji-Paraná city (RO) it doesn't possess public system of collection and treatment of sewers, being the waters residuárias produced by the local population thrown at sewages. Traditionally, many inhabitants use wells amazon extracted underground water or tubular shallow in the urban zone. The study accomplished in the Nova Brasília neighborhood for Silva (2009) revealed that the local aquifer is strongly contaminated for nitrate, originated of the decomposition of the organic matter deposited at the sewages local maidservants. With the objective of detecting areas with high concentrations originating from organic compositions of septic sewages, geophysical risings were accomplished, later related with analyses physical-chemistries in samples of groundwaters obtained in several wells installed in the Nova Brasília neighborhood, besides of soil samples descriptions in zone not saturated obtained in wells. The results obtained by the geophysical rehearsals they reveal that the polluting feather not migrates through the zone saturated, arriving with relative easiness to the aquifer, reaching in some points, superior depth to 34 m reached by the geoelectrical profiling.

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Pós-graduação em Agronomia (Energia na Agricultura) - FCA

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)