950 resultados para Diatomite and effluent


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

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The problems caused by the residual effluents of wine distilleries for alcohol production are well known. The effluent effects in soil and groundwater are being researched in an area with sugar cane culture which receives, yearly, vinasse by dispersion. Samples are being collected from the soil, the groundwater and the existing creeks in the area. Four sub-areas are being monitored separately with a vinasse application of 300 m 3/ha year. Experimentation periods in each area have been 0, 5, 10 and 15 years. In the unsaturated zone, samples are being collected at depths of 25, 75 and 150 cm. The chemical analyses include macro and micro nutrients, organic matter and pH. Physical analyses give the soil water retention, hydraulic conductivity and soil particle distribution. These measurements permit the evaluation of nitrogen absorption and fertility changes of the soil. A tendency for the maintenance of soil fertility can be observed but with an elevation of nitrate concentration in groundwater.

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Several studies are being conducted to assess the toxicity and cytotoxicity of water bodies receiving industrial and domestic effluents, using the Allium cepa test. To assess the toxicity and mutagenicity of water possibly contaminated with chromium, derived from tannery activities, seasonal water samplings were performed in 2001 and 2002 at five different sites along the Sapucaizinho river, Municipality of Patrocinio Paulista, State of São Paulo, Brazil. A. cepa seeds were used as the test material and were submitted to germination in waters from the different collection sites, in Milli-Q water (negative control) and in aqueous solution of chromium (positive control). For the determination of cell division rates and mitotic irregularities, slides were prepared with root tip cells according to the standard Feulgen methodology. The results showed that the collection sites most heavily compromised by chromium emission presented low mitotic indices and a higher frequency of mitotic changes such as irregular anaphases (disorganized, multipolar, laggard), cells with chromosomal adherences, cells with micronuclei, and binucleate and/or multinucleate cells. © 2004 The Japan Mendel Society.

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The comet assay technique has been considered to be more efficient in the biomonitoring of aquatic environments that the micronucleus and sister chromatid exchange techniques. The comet assay has been used to determine breaks in the DNA strands of organisms exposed to pollutants with a genotoxic potential. The comet technique was applied to CHO-K1 cells in order to evaluate the genotoxic potential of the waters of the Sapucaizinho River (Municipality of Patrocínio Paulista, State of São Paulo, Brazil), which receive tannery effluents and therefore are contaminated with chromium. The results indicated high genotoxicity of the waters collected at sites located downstream from the emission of tannery effluents, where the concentration of chromium was found to be high.

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The presence of Staphylococcus aureus in the nasal cavities and pericatheter skin of peritoneal dialysis patients put them at high risk of developing peritonitis. However, it is not clear whether the presence of coagulase-negative staphylococci (CNS) in the nasal passages and skin of patients is related to subsequent occurrence of peritoneal infection. The aim of the present study was to verify the relationship between endogenous sources of S. aureus and CNS and occurrence of peritonitis in patients undergoing peritoneal dialysis. Thirty-two patients on peritoneal hemodialysis were observed for 18 months. Staphylococcus species present in their nasal passage, pericatheter skin and peritoneal effluent were identified and compared based on drug susceptibility tests and dendrograms, which were drawn to better visualize the similarity among strains from extraperitoneal sites as well as their involvement in the causes of infection. Out of 288 Staphylococcus strains isolated, 155 (53.8%) were detected in the nasal cavity, 122 (42.4%) on the skin, and 11 (3.8%) in the peritoneal effluent of patients who developed peritonitis during the study. The most frequent Staphylococcus species were CNS (78.1%), compared with S. aureus (21.9%). Among CNS, S. epidermidis was predominant (64.4%), followed by S. warneri (15.1%), S. haemolyticus (10.7%), and other species (9.8%). Seven (64%) out of 11 cases of peritonitis analyzed presented similar strains. The same strain was isolated from different sites in two (66%) out of three S. aureus infection cases. In the six cases of S. epidermidis peritonitis, the species that caused infection was also found in the normal flora. From these, two cases (33%) presented highly similar strains and in three cases (50%), it was difficult to group strains as to similarity. Patients colonized with multidrug-resistant S. epidermidis strains were more predisposed to infection. Results demonstrated that an endogenous source of S. epidermidis could cause peritonitis in peritoneal dialysis patients, similarly to what has been observed with S. aureus.

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This research aimed at studying the oxidation process, to verify the effectiveness of coliform inactivation and to evaluate the formation of ozonation disinfection byproducts (DBP) in anoxic sanitary wastewater treated with ozone/hydrogen peroxide applied at doses of 2.6 mg O3 L-1 and 2.0 mg H2O2 L-1 with contact time of 10 min and 8.1 mg O3 L-1 and 8.0 mg H2O2 L-1 with contact time of 20 min. The mean chemical oxygen demand (COD) reductions were 7.50 and 9.40% for applied dosages of 2.5-2.8 and 6.4-9.4 mg O3 L-1 + 2.0 and 8.0 mg H2O2.L-1, respectively. The Escherichia coli (E. coli) inactivation range was 2.98-4.04 log10 and the total coliform inactivation range was 2.77-4.01 log10. The aldehydes investigated were formaldehyde, acetaldehyde, glyoxal and methylglyoxal. It was observed only the formation of acetaldehyde that ranged 5.53 to 29.68 μg L-1.

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Water pollution found in major rivers in Brazil has its origin from urban sewage discharges and industrial effluent, carried out by small streams and rivers crossing cities. Therefore, studies related to hydrographic micro-basins offer the opportunity to establish environmental management strategies for restoring water resources, based on diagnosis of the water quality. Despite this understanding, few studies in urban and rural areas have been performed in a systematic manner in Brazilian micro-basins. The main goal of this research was to diagnose the water resources in micro-basins in the region of the district of Americana, São Paulo state, Brazil, through the quantification of metals in water and sediment. The methodology was based on the investigation of metals (Ba, Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn), in four micro-basins, determined by inductively coupled plasma optical emission spectrometry (ICP-OES). The most significant result showed high concentration levels of chromium (969 μg L-1), downstream of the discharge of sewage from the city of Nova Odessa. This concentration in the river was above the allowed limit of Brazilian regulation agency (50 μg L-1 for Cr). Also high levels of Cr were found in the sediment (98.9 μg g-1) collected at the same monitored site. These results are important indicators of environmental performance and anthropogenic activities to help the government establish environmental management strategies aimed at the reduction of water pollution. © 2013 WIT Press.

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This work describes the efficiency of photoelectrocatalysis based on Ti/TiO2 nanotubes in the degradation of the azo dyes Disperse Red 1, Disperse Red 13 and Disperse Orange 1 and to remove their toxic properties, as an alternative method for the treatment of effluents and water. For this purpose, the discoloration rate, total organic carbon (TOC) removal, and genotoxic, cytotoxic and mutagenic responses were determined, using the comet, micronucleus and cytotoxicity assays in HepG2 cells and the Salmonella mutagenicity assay. In a previous study it was found that the surfactant Emulsogen could contribute to the low mineralization of the dyes (60% after 4h of treatment), which, in turn, seems to account for the mutagenicity of the products generated. Thus this surfactant was not added to the chloride medium in order to avoid this interference. The photoelectrocatalytic method presented rapid discoloration and the TOC reduction was ≥87% after 240min of treatment, showing that photoelectrocatalysis is able to mineralize the dyes tested. The method was also efficient in removing the mutagenic activity and cytotoxic effects of these three dyes. Thus it was concluded that photoelectrocatalysis was a promising method for the treatment of aqueous samples. © 2013 Elsevier Ltd.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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The multi stage filtration (MSF) is an alternative that permits to enlarge the spectrum of application of the slow sand filtration as for the effluent quality and run duration. In this research the use of MSF technology associated to a granular activated carbon (GAC) column as polishing mechanism of the final effluent was evaluated; in the slow sand filters GAC was used as an intermediate layer and non-woven synthetic fabrics were utilized as a first layer of the filter media. Five different tests were conducted, where the systems subjected to the treatment were: water from the Ipe Lake (Ilha Solteira, Sao Paulo, Brazil); water from the lake with water from a recreational fish pond; water from the lake with a phytoplankton and cyanobacteria overload simulation, with and without the use of the pre-filters as a stage of the treatment. The synthetic fabrics and GAC use resulted in the best turbidity removal and an efficient apparent and true color removal; in spite that the polishing columns reported similar results for those parameters. The utilization of GAC as an intermediate layer contributed to a better organic matter removal and the fabrics improved chlorophyll-a removal. The pre-filtration columns made an efficient algae and cyanobacteria removal, a function that was completed by the filters and reached >98% efficiency. The synthetic non-woven fabrics and GAC inclusion in MSF operation improved performance of this technology with ease of application and operation.

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

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)