Tempo de vida útil da represa velha da microbacia do córrego da barrinha, pirassununga, sp, brasil

ABSTRACT Conservation of continental waters is becoming increasingly necessary due to the growing negative environmental impacts and the acceleration of its scarcity. In the Center of Research and Management of Continental Fishing Resources (CEPTA/IBAMA), city of Pirassununga, SP, Brazil, located in the Velha dam. The lifespan of this dam was determined by sedimentation rate, comparing two different methodologies. One was the bathymetry with a hydrometric and other hydrometric using sedimentation chambers. The samples collections in these last ones had occurred in the water column the 50 cm above the sediment, in the dry and rainy periods, during twelve months. With this methodology can be calculated the sediment rate of 7.0 mg.cm-2day-1 and 0.66 mg.cm-3 annual density. The calculation of lifetime for the Velha dam was 7.5 years. Through the bathymetry was determined the loss of depth along the entire length of this dam, with an average, of 0.07 m.year-1. It was concluded it will take 72 years for this dam to be completely silted up, this time can be reduced if no mitigating actions for the current impacts and planning to avoid others who may possibly occur.

RESUMO Conservação das águas continentais torna-se cada vez mais necessária devido aos crescentes impactos ambientais negativos e ao aumento acelerado da sua escassez. No Centro de Pesquisa e Gestão de Recursos Pesqueiros Continentais (CEPTA/IBAMA), no Município de Pirassununga, SP, localiza-se a represa Velha. O tempo de vida útil desta represa foi determinado por meio da taxa de sedimentação, comparando-se duas metodologias distintas. Uma delas consistiu na batimetria com guincho hidrométrico e a outra utilizando câmaras de sedimentação. As coletas das amostras nestas últimas ocorreram na coluna de água a 50 cm acima do sedimento, nos períodos de seca e chuvoso, durante doze meses. Com esta metodologia pode-se calcular a taxa de sedimento de 7,0 mg.cm-2dia-1 e a densidade anual de 0,66 mg.cm-3. O cálculo do tempo de vida útil para a represa Velha foi de 7,5 anos. Por meio da batimetria foi determinada a perda da profundidade ao longo de toda a extensão desta represa, sendo em média, de 0,07 m.ano-1. Concluiu-se que serão necessários 72 anos para que esta represa possa ser totalmente assoreada, este tempo podendo ser reduzido se não houver ações mitigadoras dos impactos atuais e planejamento para evitar outros que possivelmente poderão ocorrer.

Electrolytic treatment of wastewater containing n-phenyl-n'-1,3-dimethylbutyl-p-phenylenediamine.

This study investigated the effects of electrolytic treatment using Dimensionally Stable Anode (DSA, 70%TiO2/30%RuO2) type electrodes in simulated wastewater containing aromatic amine n-phenyl-n'-1,3-dimethylbutyl-p-phenylenediamine (Flexzone 7P). A low direct current density of 0.025 A cm(-2) was applied for periods up to 60 minutes and a 52.6% decrease in Flexzone 7P concentration was observed. Ultraviolet-visible spectra, gas chromatography, toxicity and biodegradation tests were carried out with the aim of verifying the toxic by-products that were formed. Ultraviolet-visible spectra of simulated wastewater exhibited changes in the aromatic amine's molecular structure. Additionally, based on the S. cerevisiae toxicity test, it was observed that detoxification of the wastewater occurred after 15 minutes of electrolysis. It was also observed that five minutes of treatment were sufficient to improve the biodegradation rate, determined through the respirometric Bartha method.

Solarização de água contaminada por leveduras: saccharomyces cerevisiae e candida albicans

ABSTRACT This study the analyzed the cellular feasibility of Saccharomyces cerevisiae and Candida albicans in water suspension packed in glass flasks and in colorless (clear) and green bottles made of polyethylene terephthalate PET exposed to direct solar radiation, and with yeast cells added to the water obtained from the public supply system after neutralization of chlorine by sodium thiosulfate. The resulting cellular suspension was distributed in the different kinds of receptacles, which were placed on support trays covered with aluminum foil to increase the incidence of light. At the time intervals of 0; 8; 24; 28; 32; 48; 56; 72 and 76 hours (counting the night period) samples were taken and the cellular feasibility was calculated in a Neubauer chamber. Results showed that direct sun radiation was effective for the cellular elimination of S. cerevisiae and C. albicans present in the water suspension. Results also showed that exposure of water placed in flasks of glass and in colorless (clear) and green bottles made of polyethylene terephthalate for human consumption can be used to diminish water-transmitted disease risks.

RESUMO A fim de analisar a viabilidade celular de Saccharomyces cerevisiae e Candida albicans mantidas em suspensão aquosa acondicionada em frascos de vidro e garrafas de politereftalato de etileno PET incolores e verdes expostas à radiação solar direta, utilizaram-se células das leveduras para contaminar água de abastecimento público após neutralização do cloro por ação do tiossulfato de sódio. A suspensão celular resultante da contaminação foi distribuída nos diferentes tipos de frascos, os quais foram colocados sobre folhas de alumínio que revestiam bandejas utilizadas como suporte de modo a receberem máxima incidência luminosa. Nos intervalos temporais de 0, 8, 24, 28, 32, 48, 56, 72 e 76 horas (computando o período noturno) foram retiradas alíquotas e a viabilidade celular quantificada em câmara de Neubauer. Os resultados indicaram a eficiência da solarização da água para a eliminação celular de S. cerevisiae e C. albicans presentes em suspensão aquosa e evidenciaram que a exposição à radiação solar da água de consumo humano, acondicionada em frascos de vidro e garrafas PET, pode ser utilizada para diminuir o risco de enfermidades de veiculação hídrica.