961 resultados para water treatment plant


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Channel catfish ponds are treated with salt (sodium chloride) to increase chloride concentration and prevent nitrite toxicity in fish. A survey indicated that most farmers try to maintain chloride concentration of 50 to 100 mg/L in ponds by annual salt applications. Averages and standard deviations for selected water quality variables in salt-treated ponds were as follows: chloride, 87.2 ± 37.5 mg/L; total dissolved solids (TDS), 336 ± 96 mg/L; specific conductance, 512 ± 164 μmhos/cm. Maximum values were 189 mg/L for chloride, 481 mg/L for TDS, and 825 μmhos/cm for specific conductance. Good correlations between specific conductance values and both chloride and TDS concentrations suggest that specific conductance can be a rapid method for estimating concentrations of these two variables in surface water. The maximum limit for chloride concentration in Alabama streams allowed by the Alabama Department of Environmental Management is 230 mg/L. The usual recommended upper limit of TDS for protection of aquatic life in freshwater streams is 1,000 mg/L. Based on the observed relationship between TDS concentration and specific conductance in Alabama catfish ponds, 1,000 mg/L TDS corresponds to 1,733 μmhos/cm specific conductance. It is unlikely that effluents from salt-treated catfish ponds would violate the in-stream chloride standard of 230 mg/L or harm aquatic life in streams. Nevertheless, chloride concentrations in ponds should be measured before salt application as a safe guard against excessive salt application and chloride concentrations above the in-stream chloride standard.

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Salting have been a very utilized fish conservation method, however only in the last years the basic mechanism involved in salting fish has been understood. The objectives of this study were determine the addition in brine salt of rosemary leaves, rosemary extracts and tocopherol, and your action in the followed parameters: water activity (Aw), moisture, ash, salt content and TBARS. The results showed that the addition of antioxidants was difficulted the salt absorption, however didn't have differences between rosemary or tocopherol use. In the salting time of 3 hours the values of Aw and salt levels, was respectively: 0.77±0.01 and 14.42±1.69. for control treatment; 0.85±0.02 and 9.09±1.39for rosemary filtrate; 0.78±0.03 and 10.63±0.69 rosemary without filtrating and 0.85±0.02 and 11.96±1.78 tocopherol, showed that didn't grow indigenous bacterias. Lipid oxidation was evaluated by TBARS and the results showed the oxidative effect of salt and the pro oxidant effects of alls antioxidants used in brine salting.

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It was aimed to extend the postharvest conservation of 'Tommy Atkins' mango fruits harvested in break maturity stage. Fruits were submitted at the following treatments: hot water treatment (55°C for 5 minutes) and benomyl 1,000 mg.L-1; irradiation with 0,8 or 1,0 kGy; irradiation associated at carnaúba wax; and control. The fruits were stored at 10°C and 85 - 90%RH during 21 days, and then removed to ambient temperature (25,7±0,7°C and 87,1±2,2%RH). Through the storage time, the evolution of fresh weight, color, rottenness, total soluble solids (TSS), total titratable acidity (TTA), and TSS/TTA ratio were measured. 'Tommy Atkins' mango fruits can have shelf life notably increased, when they were submitted to hot water treatment (55°C for 5 minutes) or γ radiation (0,8 and 1,0 kGy), associated with carnaúba wax application, before cold storage. These treatments increased the fruit resistance at refrigerated storage, and improved shelflife after transferring to ambient temperature.

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In this study, we report the efficiency of photocatalytic and photoelectrochemical treatment using titanium dioxide as semiconductor and its applications in water disinfection. It was compared the efficiency of the two methods on the killing of E.coli cells. The photoelectrochemical treatment with electric field enhancement showed a good result and could be a new technology to water treatment.

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The objective of this study was to determine the influence of five different water levels on the crop development of Calla. The crop parameters evaluated were leaf area and evapotranspiration. The study was conducted in glass greenhouse with 50% of sunlight reduction. The plants were grown in PVC pots with 150 mm diameter, which were filled with substrate. The plant tubers weighed from 10 g to 12 g. The pots were placed within containers, under water level constant automatically.. The table water levels used were 10, 17, 24, 31 and 38 cm. Nine evaluations during the growth cycle checked the growth development. The evaporation varied from 26.89 to 46.14 L.plant-1 for 38 and 10 cm water levels, respectively and leaf area per plant showed 1011.6 to 2016.3 for the same levels. The substrate water was more available in the treatment 24 cm, with more restrictions in the upper and lower treatments. There was positive correlation between leaf area and evapotranspiration at the final of the culture.

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Many plants, even without scientific confirmation, are used in Brazil as hypoglycemic. The objective of the present work was to study the influence of the Allium sativum treatment, plant known popularly as garlic, on characteristic biochemical parameters in streptozotocin-induced diabetic rats. Female Wistar rats were injected with 40 mg kg-1 streptozotocin (STZ). Oral administration of an aqueous extract of A. sativum was given to the diabetic animals in 2 doses: 200 and 400 mg kg-1 (n=6 animals/group). Diabetic rats given distilled water constituted the control group. After 28 days of treatment, the female rats were anesthetized and died by decapitation for collection of the blood for biochemical determinations and retreat of liver samples for hepatic glycogen dosage. The treatment with Allium sativum in the doses of 200 and 400 mg kg-1 alter no concentrations of total proteins, hepatic glycogen, triglycerides and VLDL, but it promoted reduction in the total cholesterol rate (control=280.5 ± 30.9; 200 mg kg-1 A. sativum =169.9 ± 19.5 and 400 mg kg-1 A. sativum =148.4 ± 26.6 mg dL-1) and LDL (control=128.8± 25.3; 200 mg kg-1 A. sativum = 41.4 ± 16.2 and 400 mg kg-1 A. sativum=42.0 ± 26.0 mg dL-1). The extract presented beneficial effect because it decreased 13.0% of glycemia in the highest dose. Therefore, the of garlic extract reduced the HDL concentration in two tested doses (control= 81.4 ± 30.2; 200 mg kg-1 A. sativum=49.6 ± 14.3 and 400 mg kg-1 A. sativum=41.7 ± 16.1 mg dL -1), presenting impaired effect. Thus, the garlic extract showed efficiency in the analyzed experimental conditions, and it could be used as complementary therapy to diabetic patients.

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This review focuses on the heterogeneous photocatalytic treatment of organic dyes in air and water. Representative studies spanning approximately three decades are included in this review. These studies have mostly used titanium dioxide (TiO2) as the inorganic semiconductor photocatalyst of choice for decolorizing and decomposing the organic dye to mineralized products. Other semiconductors such as ZnO, CdS, WO3, and Fe2O3 have also been used, albeit to a much smaller extent. The topics covered include historical aspects, dark adsorption of the dye on the semiconductor surface and its role in the subsequent photoreaction, semiconductor preparation details, photoreactor configurations, photooxidation kinetics/mechanisms and comparison with other Advanced Oxidation Processes (e.g., UV/H2O2, ozonation, UV/O3, Fenton and photo-Fenton reactions), visible light-induced dye decomposition by sensitization mechanism, reaction intermediates and toxicity issues, and real-world process scenarios. © 2008 Elsevier B.V. All rights reserved.

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The good efficiency in a sewage treatment plant (WWTP) is a great importance to the environment. The management of electromechanical equipment installed in these stations is a major challenge due to the fact that they are installed on areas of difficult access and maintenance unhealthy and making the time for the correction of any faults is extended. This paper proposes the development of a Wireless Sensor Network (WSN), in order to monitor electromechanical equipment, allowing the Concessionaire a predictive control in real time. The design of a wireless sensors network for monitoring equipment requires not only the development and assembly of the sensor modules, but must also include the development of software for managing the data collected. Thus, this work includes a Zigbee WSN, small, adapted for monitoring of electromechanical equipment and environmental conditions of a WWTP, type stabilization pond, installed in an area of approximately 0.15 km 2 and the average flow of 320 liters of treatment per second. The experimental results show that this monitoring system can perform with the collection of parameters of performance and quality assessment at the station.

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Agroindustrial by-products and residues from treatment of sewage sludge have been recently recycled as soil amendments. This study was aimed at assessing toxic potential of biosolid, obtained from a sewage treatment plant (STP), vinasse, a by-product of the sugar cane industry, and a combination of both residues using Allium cepa assay. Bioprocessing of these samples by a terrestrial invertebrate (diplopod Rhinocricus padbergi) was also examined. Bioassay assembly followed standards of the Brazilian legislation for disposal of these residues. After adding residues, 20 diplopods were placed in each terrarium, where they remained for 30 days. Chemical analysis and the A. cepa assay were conducted before and after bioprocessing by diplopods. At the end of the bioassay, there was a decrease in arsenic and mercury. For the remaining metals, accumulation and/or bioavailability varied in all samples but suggested bioprocessing by animals. The A. cepa test revealed genotoxic effects characterized by different chromosome aberrations. Micronuclei and chromosome breaks on meristematic cells and F1 cells with micronuclei were examined to assess mutagenicity of samples. After 30 days, the genotoxic effects were significantly reduced in the soil + biosolid and soil + biosolid + vinasse groups as well as the mutagenic effects in the soil + biosolid + vinasse group. Similar to vermicomposting, bioprocessing of residues by diplopods can be a feasible alternative and used prior to application in crops to improve degraded soils and/or city dumps. Based on our findings, further studies are needed to adequately dispose of these residues in the environment. © 2013 Springer Science+Business Media Dordrecht.

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luoridation of the public water supplies is recognized as among the top ten public health achievements of the twentieth century. However, the positive aspects of this measure depend on the maintenance of fluoride concentrations within adequate levels. Objective: To report the results of seven years of external control of the fluoride (F) concentrations in the public water supply in Bauru, SP, Brazil in an attempt to verify, on the basis of risk/ benefit balance, whether the levels are appropriate. Material and Methods: From March 2004 to February 2011, 60 samples were collected every month from the 19 supply sectors of the city, totaling 4,641 samples. F concentrations in water samples were determined in duplicate, using an ion-speciflc electrode (Orion 9609) coupled to a potentiometer after buffering with TISAB II. After the analysis, the samples were classified according to the best risk-benefit adjustment. Results: Means (±standard deviation) of F concentrations ranged between 0.73±0.06 and 0.81±0.10 mg/L for the different sectors during the seven years. The individual values ranged between 0.03 and 2.63 mg/L. The percentages of the samples considered low risk for dental fluorosis development and of maximum benefit for dental caries prevention (0.55-0.84 mg F/L) in the first, second, third, fourth, fifth, sixth, and seventh years of the study were 82.0, 58.5, 37.4, 61.0, 89.9, 77.3, and 72.4%, respectively, and 69.0% for the entire period. Conclusions: Fluctuations of F levels were found in the public water supply in Bauru during the seven years of evaluation. These results suggest that external monitoring of water fluoridation by an independent assessor should be implemented in cities where there is adjusted fluoridation. This measure should be continued in order to verify that fluoride levels are suitable and, if not, to provide support for the appropriate adjustments.

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Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been recovered from a wide variety of environmental sources. Here, we applied the photoelectrocatalytic technique using a Ti/TiO2-Ag photoanode to inactivate mycobacteria. For a mycobacteria population of 5 × 108 CFU mL-1, we achieved 99.9 and 99.8% inactivation of Mycobacterium kansasii and Mycobacterium avium with rate constant of 6.2 × 10-3 and 4.2 × 10-3 min-1, respectively, after 240 min. We compared the proposed method with the photolytic and photocatalytic methods. Using a mycobacteria population of 7.5 × 104 CFU mL-1, the proposed Ti/TiO2-Ag photoanode elicited total mycobacteria inactivation within 3 min of treatment; the presence of Ag nanoparticles in the electrode provided 1.5 larger degradation rate constant as compared with the Ti/TiO2 anode (1.75 × 10-2 for M. kansassi and 1.98 × 10-2 for M. avium). We monitored the degradation of the metabolites released during cellular lysis by TOC removal, sugar release, chromatography, and mass spectrometry measurements; photoelectrocatalysis and Ti/TiO2-Ag photoanodes furnished the best results. © 2013 Elsevier Ltd. All rights reserved.

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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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Pós-graduação em Química - IQ