Avaliação em escala laboratorial da utilização do processo eletrolítico no tratamento de águas

Water treatment uses chlorine for disinfection causing formation of trihalomethanes. In this work, an electrolytic water pre-treatment was studied and applied to the water from a fountainhead. The action against microorganisms was evaluated using cast-iron and aluminum electrodes. Assays were made in laboratory using the electrolytic treatment. After 5 min of electrolysis the heterotrophic bacteria count was below 500 cfu/mL and complete elimination of total and fecal coliforms was observed. Using electrolytic treatment as a pretreatment of conventional tap water treatment is proposed.

Photocatalytic Degradation of Phenol by Thermal Titanium Dioxide Thin Layer Electrodes

Electrochemical processes in industrial effluents have been studied as a means to obtain higher efficiency in wastewater treatment. Heterogeneous photocatalysis appears as a low-cost alternative through the use of lower wattage lamps and thermal TiO2 films. Photocatalysis became a clean process for water treatment due to hydroxyl radicals generated on semiconductor surface. Such radicals are able to degrade several organic compounds. This study used different electrodes and analytical methods for degradation of phenol molecules to reduce treatment costs, improve efficiency, and identify compounds formed during the decomposition of phenolic molecules. Thermal growth of TiO2 film was observed on the titanium electrode in rutile form. Application of an electrical potential on the Ti/TiO2 working electrode increases efficiency in reducing concentration of phenol after photocatalytic treatment. Still, high energy radiation (UVC) showed best degradation rates in photolytic process. Different compounds formed during the degradation of phenol were also identified in the UVC-PE treatment.

Diclofenac Abatement using Modified Solar Photo-Fenton Process with Ammonium Iron(III) Citrate

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

Geofungos no Córrego do Sapateiro, Parque Municipal do Ibirapuera, São Paulo, SP, Brasil

No Córrego do Sapateiro, situado no Parque Municipal do Ibirapuera, na cidade de São Paulo, SP, Brasil, amostras de água (50 mL) na profundidade de 10 centímetros foram coletadas em locais antes (local 1) e depois (local 2) da estação de tratamento de flotação, durante os meses da estação chuvosa e quente (janeiro, fevereiro e março) e da estação seca e fria (junho, julho e agosto) de 2008. Além disso, a temperatura, oxigênio dissolvido, condutividade e pH da água foram medidos com um equipamento Horiba U10. Coliformes totais e fecais foram analisados com o kit Aquatest®. A partir de cada amostra de água, alíquotas de 1 mL foram inoculadas em meio batata-dextrose-ágar, totalizando 10 placas de Petri para cada local de coleta. Após incubação por 10 dias a 22 ºC, as colônias fúngicas foram quantificadas, purificadas e identificadas. Os parâmetros abióticos da água não foram limitantes para a presença de geofungos, sendo influenciados pelo tratamento de flotação. Nos dois locais o número de coliformes totais e fecais foi predominantemente superior a 8 NMP dL-1 durante o período estudado. Vinte e sete táxons de fungos foram obtidos, distribuídos em 136 ocorrências. de acordo com o índice de similaridade de Sörensen, a micota dos dois locais coletados foram consideravelmente diferentes, apesar da semelhança entre o número de táxons e ocorrências. Os resultados indicam que o tratamento da água do Córrego do Sapateiro pelo sistema de flotação possivelmente causa modificações na composição taxonômica e na quantidade de UFC de fungos, ao contrário do que ocorreu com os coliformes totais e fecais, cujos resultados apresentaram-se menos conclusivos.

Remoção de substâncias húmicas por meio da oxidação com ozônio e peróxido de hidrogênio e FiME

A filtração em múltiplas etapas (FiME) se apresenta como uma alternativa para realizar o tratamento de água de comunidades de pequeno porte, entretanto, a eficiência quanto à remoção de cor verdadeira associada ao carbono orgânico dissolvido (COD) ou às substâncias húmicas, tem sido questionada ou relatada como baixa. A presente pesquisa avaliou a remoção de substâncias húmicas na FiME com pré-oxidação, com ozônio e peróxido de hidrogênio, utilizando para essa avaliação parâmetros indiretos como cor verdadeira, absorvância UV (254 nm) e COD. Foram realizados cinco ensaios, utilizando quatro filtros lentos, sendo dois com camada de carvão ativado granular (CAG). Foram ensaiadas várias alternativas de pré-oxidação com ozônio e peróxido de hidrogênio. Foram obtidos bons resultados, tendo como principal conclusão que os filtros lentos com CAG, precedidos de oxidação com ozônio e depois peróxido de hidrogênio, apresentaram remoção média de cor verdadeira de 64%, mas que o peróxido de hidrogênio afeta o desenvolvimento da camada biológica, interferindo no desenvolvimento da perda de carga, na remoção de turbidez, na remoção de coliformes e na remoção de substâncias húmicas.

Vascular effects of long-term propranolol administration after chronic nitric oxide blockade

Long-term propranolol treatment reduces arterial blood pressure in hypertensive individuals mainly by reducing peripheral vascular resistance, but mechanisms underlying their vasodilatory effect remain poorly investigated. This study aimed to investigate whether long-term propranolol administration ameliorates the impairment of relaxing responses of aorta and mesenteric artery from rats made hypertensive by chronic nitric oxide (NO) deficiency, and underlying mechanisms mediating this phenomenon. Male Wistar rats were treated with N-omega-Nitro-L-arginine methyl ester (L-NAME; 20 mg/rat/day) for four weeks. DL-Propranolol (30 mg/rat/day) was given concomitantly to L-NAME in the drinking water. Treatment with L-NAME markedly increased blood pressure, an effect largely attenuated by DL-propranolol. In phenylephrine-precontracted aortic rings, the reduction of relaxing responses for acetylcholine (0.001-10 mu M) in L-NAME group was not modified by DL-propranolol, whereas in mesenteric rings the impairment of acetylcholine-induced relaxation by L-NAME was significantly attenuated by DL-propranolol. In mesenteric rings precontracted with KCl (80 MM), DL-propranolol failed to attenuate the impairment of acetylcholine-induced relaxation by L-NAME. The contractile responses to extracellular CaCl2 (1-10 mM) were increased in L-NAME group, and co-treatment with DL-propranolol reduced this response in both preparations in most Ca2+ concentrations used. The NO2/NO3 plasma levels and superoxide dismutase (SOD) activity were reduced in L-NAME-treated rats, both of which were significantly prevented by DL-propranolol. In conclusion, propranolol-induced amplification of the relaxation to acetylcholine in mesenteric arteries from L-NAME-treated rats is sensitive to depolarization. Additional mechanisms involving blockade of Ca2+ entry in the vascular smooth muscle and increase in NO bioavailability contributes to beneficial effects of long-term propranolol treatment. (C) 2007 Elsevier B.V. All rights reserved.

Ability of bacteriophages isolated from different sources to reduce Salmonella enterica serovar enteritidis in vitro and in vivo

Salmonella enterica serovar Enteritidis-lysing bacteriophages isolated from poultry or human sewage sources were used to reduce Salmonella Enteritidis in vitro and in experimentally infected chicks. Cocktails of 4 different bacteriophages obtained from commercial broiler houses (CB4O) and 45 bacteriophages from a municipal wastewater treatment plant (WT45O) were evaluated. In experiment 1, an in vitro crop assay was conducted with selected bacteriophage concentrations (105 to 101 pfu/mL) to determine ability to reduce Salmonella Enteritidis in the simulated crop environment. Following 2 h at 37 degrees C, CB40 or WT45O reduced Salmonella Enteritidis recovery by 1.5 or 5 log, respectively, as compared with control. However, CB40 did not affect total SE recovery after 6 h, whereas WT45O resulted in up to a 6-log reduction of Salmonella Enteritidis. In experiment 2, day-of-hatch chicks were challenged orally with 3 x 103 cfu /chick Salmonella Enteritidis and treated cloacally with 1 X 109 WT45O pfu/chick I h postchallenge. One hour later, chicks were treated or not with a commercially available probiotic (Floramax-B11). Both treatments significantly reduced Salmonella Enteritidis recovery from cecal tonsils at 24 h following vent lip application as compared with controls, but no additive effect was observed with the combination of bacteriophages and probiotic. In experiment 3, day-of-hatch chicks were challenged orally with 9 x 103 cfu/chick Salmonella Enteritidis and treated via oral gavage with I X 108 CB40 pfu/chick, 1.2 x 108 WT45O pfu/chick, or a combination of both, I h postchallenge. All treatments significantly reduced Salmonella Enteritidis recovered from cecal tonsils at 24 h as compared with untreated controls, but no significant differences were observed at 48 h following treatment. These data suggest that some bacteriophages can be efficacious in reducing SE colonization in poultry during a short period, but with the bacteriophages and methods presently tested, persistent reductions were not observed.

Effect of TiO2 surface modification in Rhodamine B photodegradation

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

Amino Acids on Mango Yield and Fruit Quality at Submedio Sao Francisco Region, Brazil

Farmers of the Submedio Sao Francisco Region (Brazil) have been spraying amino acids on mango trees with the objective of increasing panicle length and improving fruit retention and quality. This study, done in two experiments, tested the effect of amino acids sprayings at concentrations of 0.0%; 0.02%; 0.04% and 0.06%, on mango plants, 'Tommy Atkins', on the budding phase (panicles with 5 cm), fruit set and fruit growth (5 cm diameter). They were carried out from June to October in 2003, that is the natural period for harvest in the region, and from January to May, in 2004. There were no statistical differences in the first experiment among treatments regarding panicle length and fruit production, probably due to an appropriate management of nutrition, water and plant growth regulators, besides climatic conditions, mainly temperature and solar radiation. In the second experiment, significant increments in the panicle length of 13.37%, 11.70% and 21.4% were observed with amino acids concentrations, compared to the control. Increasing amino acids doses also enhanced the number of fruits per plant, thirty days before the harvest, in 16.17%, 45.32% and 37.38%, respectively, compared to the control, but there were no significant statistical differences. Characteristics of fruit quality during storage, as weight loss, total soluble solids, total titratable acidity and pulp firmness were not significantly affected by amino acids spraying. Changes on those variables were registered as a consequence of fruit ripening. Amino acids sprays lightly delayed the evolution of skin luminosity and Hue of pulp, but the differences could not be visually identified. The concentrations of amino acids were not efficient for improving the natural concentrations of these substances in the leaves, which could be the reason for the non significant effects on the variables analyzed.

Heterogeneous Fenton reactants: a study of the behavior of iron oxide nanoparticles obtained by the polymeric precursor method

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Wetland projects developed in Brazil

The first studies with constructed wetlands undertaken in Brazil were the result of observations made from the Amazon flood plains. The first attempt to use this capacity to change the quality of the water, in the sense of purification performed in Brazil using constructed wetland systems, was made by Salati et al. After that, new technologies were developed in a focused attempt to increase the efficiency of the system and reduce investments. Over these 18 years, persuading the Brazilian scientific community as well as the environmental control agencies to give due attention to this kind of research has required endless efforts. Only in recent years have major institutions responsible for sewage treatment and potable water supply been concerned with this type of technology for solving real problems. These institutions are as follows: SABESP (Basic Sanitation Company of Sao Paulo State), SANEPAR (Sanitation Company of Parana State) and CESP (Electric Company of Sao Paulo State). One of the private institutions that has systematically worked in the design and projects of constructed wetlands is the Institute of Applied Ecology. This institution has enhanced and developed a water depuration system based on the purifying capacity of the soil. The wetlands with filtering soils are systems formed by overlapping layers of crushed stone, gravel and soil planted with rice. This technology has been used in sewage treatment and also in water supply systems.

Photodegradation of dichloroacetic acid and 2,4-dichlorophenol by ferrioxalate/H2O2 system

The photo-Fenton process using potassium ferrioxalate as a mediator in the photodegradation reaction of organochloride compounds in an aqueous medium was investigated. The influence of parameters such as hydrogen peroxide and ferrioxalate concentrations and initial pH, was evaluated using dichloroacetic acid (DCA) as a model compound under black-light lamp irradiation. An upflow annular photoreactor, operating in a single pass or recirculating mode was used during photodegradation experiments with artificial light. The extent of the release of chloride ions was used to evaluate the photodegradation reaction. The optimum pH range observed was 2.5-2.8. The efficiency of DCA dechlorination increased with increasing concentrations of H2O2 and potassium ferrioxalate, reaching a plateau after the addition of 6 and 1.5 mmol/L of those reagents, respectively. The total organic carbon (TOC) content in DCA and 2,4-dichlorophenol (DCP) solutions was compared with the chloride released after photodegradation. The influence of natural solar light intensity, measured at 365 nm, was evaluated for the dechlorination of DCA on typical summer's days showing a linear dependency. The photodegradation of DCA using black-light lamp and solar irradiation was compared.

Behavior of bromide in the photoelectrocatalytic process and bromine generation using nanoporous titanium dioxide thin-film electrodes

In this study, the photoelectrocatalytic behavior of bromide and generation of bromine using TiO2 was investigated in the separate anode and cathode reaction chambers. Our results show that the generation of bromine begins around a flatband potential of -0.34 V vs. standard calomel electrode (SCE) at pH 3.0 under UV illumination and increases with an increase in positive potential, finally reaching a steady-state concentration at 1.0 V vs. SCE. Maximum bromine formation occurs over the range of pH 4-6, decreasing sharply at conditions where the pH > 7. © 2003 Elsevier Ltd. All rights reserved.

Uso racional de nutrientes no cultivo hidropônico de amorperfeito

The objective of this work was to evaluate different concentrations of nutritional solution in the hydroponic cultivation of Viola x wittrockiana Gams. The experiment was conducted in DFT hydroponic system, in a completely randomized design with a 5×4 factorial scheme and five nutrient solution concentrations (50, 75, 100, 125 and 150%), four evaluation periods with three replications of three plants for each treatment. Plant height, root length, number of leaves, flowers and floral buttons; fresh and dry weight of shoot and root were determined. The results were submitted to variance analysis, Tukey's test for evaluation periods and regression analysis for nutrient solution. A decrease in the development of the shoot and root was observed with an increase of the number of cultivation days; the greatest number of floral buttons occurred in the third week of cultivation. A reduction in the plant height, root system length, the number of leaves and the fresh and dry weight of shoot was observed generally with the increase of nutrient solution concentration.

Concentração de flúor nas águas de abastecimento público de municípios da região noroeste do estado de São Paulo, Brasil

It may be difficult for small and medium cities to obtain information about the fluoride content of public water, because of the lack of equipments and technicians. This study aimed to analyze the fluoride levels of the water supplied by the public treatment stations of 40 cities situated in the northwest region of São Paulo State, during a period of 6 months, to verify if fluoridation occurs in a continuous manner and if the fluoride levels are within the recommended. Maps of the water distribution system were obtained from the water treatment companies and utilized to randomize the addresses of the collection sites, so that they included all regions with treated water sources. One water sample by month was collected and analyzed in duplicate using an ion-specific-electrode. Samples with 0.6 to 0.8 mgF/L were considered acceptable. In the 38 cities that regularly provided the samples in the 6 months of the study, water from 144 collection sites was collected and a total of 864 samples were analyzed, of which 61.81 percent were classified as unacceptable. It was observed that 33 cities performed fluoridation but in 78.79 percent of these cities there were variations in the fluoride level among the sites and in the same site during the period of study. One can conclude that most of these cities do not control the fluoride levels in the public water, since fluoridation occurs in a discontinuous manner and in most of the situations not within the recommended concentrations.