خيارات البحث
النتائج 881 - 890 من 1,227
Proyecto de una balsa para cultivo de albaricoque + tubería de alimentación y pozo de agua en el término municipal de Ontinyent (Valencia) النص الكامل
2017
Ferri Llopis, Javier | Pastor Pérez, Joaquín Julián
Mobilidade dos íons nitrato e amônio em área agrícola sob adubação com água residuária de bovinocultura de leite e torta de Mamona النص الكامل
2017
Silva, Jonathas Batista Gonçalves | Martinez, Mauro Aparecido | Matos, Antônio Teixeira de | Pires, Carina Soares | Terração, Geuzimar
Objetivou-se, neste trabalho, avaliar a mobilidade dos íons nitrato e amônio em um Argissolo Vermelho-Amarelo, quando aplicado água residuária de bovinocultura de leite (ARB) e torta de mamona. O experimento foi conduzido no Sistema Integrado de Produção Agroecológica, localizado no município de Seropédica, Rio de Janeiro. Na área utilizada nesse trabalho é cultivada a figueira (Ficuscarica L.), variedade Roxo de Valinhos. Diferentes lâminas de ARB foram aplicadas no solo como fonte de adubação de nitrogênio (Adubação 1- 0% de ARB e adubação complementar com torta de mamona; Adubação2- 50% da dose de N recomendada fornecida pela ARB e os outros 50% com a torta de mamona; Adubação 3- 75% da dose de N recomendada fornecida pela ARB e os outros 25% fornecido pela torta de mamona; Adubação4- 100% da dose de N recomendada fornecida pela ARB). Nas parcelas experimentais foram instalados extratores a 0,15 e a 0,60 m de profundidade. As concentrações de nitrato obtidas foram muito elevadas, com valores de até 323 mg.L -1 . No entanto, os valores do amônio na solução do solo foram baixos, com valores abaixo de 0,44 mg.L -1 . Os resultados indicam a necessidade de um rigoroso monitoramento no uso de ARB e torta de mamona em áreas agrícolas. | The aim of this study was to evaluate the mobility of nitrate and ammonium ions in an Ultisol when applied dairy cattle wastewater (ARB). The experiment was conducted in the Agroecological Production Integrated System, located in Seropédica, Rio de Janeiro. Fig (Ficuscarica L.) crop of the variety Roxo de Valinhos is grown in the area used during this work. Different blades of ARB were applied to the soil as a source of nitrogen fertilization (T1-0% of ARB and additional fertilizers with castor bean cake, T2-50% of the recommended dose of N supplied by the ARB and the other 50% with the castor bean cake, T3-75% of the recommended dose of N supplied by the ARB and the other 25% provided by the castor bean cake, T4-100% of recommended dose of N provided by the ARB). In the experimental plots, extractors were installed at 0.15 and 0.60 m of depth. Nitrate concentrations obtained were very high, with values up to 323 mg.L - 1 . However, the values of ammonium in the soil solution were low, with values below 0.44 mg L -1 . The results indicate the need for close monitoring when ARB and castor bean cake are used in agricultural areas.
اظهر المزيد [+] اقل [-]Evaluación de la efectividad de microorganismos de montaña y agua de mar en la producción de pollos de engorde, Finca Santa Rosa النص الكامل
2017
Parrales Arteaga, Reynery | Castillo Sánchez , Santos
El objetivo del presente trabajo fue evaluar el efecto del probiótico MBM y agua de mar como bioestimulante en el comportamiento productivo de pollos de engorde. Utilizándose 126 aves de un día de edad. Con un peso promedio de 47g, los cuales fueron distribuidos mediante un diseño completamente al azar en tres tratamientos con 6 repeticiones por tratamiento. Y 7 aves por repetición. Los tratamientos evaluados fueron: T1: concentrado comercial (CC), T2: CC + Microorganismo de montaña (MBM 5%), T3: concentrado comercial más agua de mar250 ml/en un galón de agua potable, y se evaluó su efecto sobre el comportamiento productivo (Consumo alimento(CA), Ganancia media Diaria (GMD), peso final (PF), Peso de la canal (PC), Rendimiento de la canal (RC), Conversión alimenticia (CAL), así como su efecto en el tracto gastrointestinal(TGI), los datos fueron analizados por el programa de análisis de varianza ANDEVA utilizando el modelo lineal general de MINITAB (MINITAB ® , VERSION 16.6 2012) con el paquete estadístico, las comparaciones de medias se realizaron por la prueba de Tuckey, cuando las diferencias entre los tratamientos eran significativas (p<0.05), sobre las variables Ganancia media diaria y Peso vivo a los 39 días. Mediante separación de medias por MINITAB se obtuvo que para la Ganancia media diaria el mayor valor lo obtuvo el T2 (MBM)con 62.43g, seguido del T3(agua de mar) con 49.74g y T1(testigo) con 47.74g. Para el peso vivo el comportamiento fue igual, presentando mayor Peso vivo el T2 con 2435g, seguido del T3 con 1940g y el T1 con 1862g. La conversión alimenticia entre los tratamientos resultó similar con valor en el T2 de 1.53 seguido del T3 con 1.52 y T1 con 2.2. El rendimiento en canal mediante agua de marsituó al T3 con el mayor valor de 74.7%, seguido del T2 con 74.4% y T1con 68.1%.Financieramente el T3aporta utilidad netas por valor de $4.25 con todo esto se denota que es factible biológicamente el uso de microorganismos de montaña y agua de mar como suplemento alimenticio para mejorar el comportamiento productivo de pollos de engorde.
اظهر المزيد [+] اقل [-]Formulación del plan de manejo ambiental para el hotel Agua Blanca (Puente Nacional-Santander), teniendo en cuenta los lineamientos de la Norma NTS-TS 002 | Formulation of the environmental management plan for the Agua Blanca hotel (Puente Nacional-Santander), taking into account the guidelines of the standard NTS-TS 002 النص الكامل
2017
Ovelencio Ballén, Luisa Fernanda | Figueroa Fernández, Alberto | Pardo Masmela, Yhonathan Werney
La pasantía fue realizada con el objetivo de realizar la formulación de un plan de manejo ambiental en el hotel campestre Agua Blanca, (Ubicado en el municipio de Puente Nacional, Santander), con el fin de identificar y evaluar los impactos ambientales significativos y proponer una serie de medidas en aras de prevenir, controlar, mitigar y/o compensar los impactos ambientales significativos de la prestación del servicio de hospedaje, teniendo en cuenta los lineamientos de la Norma Técnica Sectorial NTS-TS 002. La metodología se compone de tres etapas; la primera contempla la revisión y diagnóstico ambiental inicial; la segunda contempla la identificación y evaluación de impactos ambientales y la tercera contempla la formulación de medida de manejo ambiental y la formulación del plan para la preparación y respuesta ante emergencia. | The internship was carried out with the objective of formulating an environmental management plan at the hotel campestre Agua Blanca, (Located in the municipality of Puente Nacional, Santander), in order to identify and evaluate significant environmental impacts and propose a series of measures in order to prevent, control, mitigate and/or compensate the significant environmental impacts of the provision of lodging services, taking into account the guidelines of the sectoral technical standard NTS-TS 002. The methodology consists of three stages; the first contemplates the initial environmental review and diagnosis; the second contemplates the identification and evaluation of environmental impacts; and the third contemplates the formulation of environmental management measures and the formulation of the plan for emergency preparedness and response. | Hotel campestre Agua Blanca
اظهر المزيد [+] اقل [-]Participación de mujeres en el uso, manejo y conservación de los recursos naturales y gobernanza del agua en la microcuenca río Marcala, Honduras النص الكامل
2017
Joya R., Crisly M. | Suazo, Laura | Tercero, José | Trejos, Bernardo
El estudio analizó la participación de la mujer en el uso y manejo de los recursos naturales y toma de decisiones en la gobernanza de agua de la Microcuenca río Marcala, La Paz, Honduras. Los objetivos del estudio buscaron describir prácticas de usos y manejo de los recursos naturales realizadas por mujeres, determinar la participación y toma decisiones de la mujer en la gobernanza de agua, identificar oportunidades y limitaciones para la participación de la mujer en la gobernanza de agua e identificar oportunidades de creación de microempresas a partir de recursos locales. La metodología aplicada fue mixta mediante encuestas, entrevistas semiestructuradas y grupos focales. Este estudio demostró que la relación entre la mujer y los recursos naturales es extractiva. Las mujeres se preocupan por la conservación de los recursos naturales, sin embargo, por factores culturales, falta de capacitaciones y sobrecarga de labores domésticas, muy pocas reportaron realizar actividades de conservación. Para las mujeres del estudio la toma de decisiones en la gobernanza de agua es limitada debido a tener una baja autoestima y sobrecarga de labores domésticas. Sin embargo, todas las informantes consideran que deben de ser involucradas en la toma de decisiones para tener equidad de género y ayudar al desarrollo de su comunidad. Todas las informantes estuvieron anuentes a la creación de microempresas en sus aldeas. Se considera que se debe apoyar los procesos organizativos donde las mujeres puedan tomar decisiones y desarrollar su liderazgo
اظهر المزيد [+] اقل [-]Dinámica espacio-temporal (2004-2017) en el parque ecológico Distrital de humedal Capellanía en Bogotá a partir de parámetros de calidad de agua النص الكامل
2017
Pérez Tovar, Gabriel Andrés | Luna Acosta, Andrea
Con base a datos de calidad de agua suministrados por la Empresa de Agua y Alcantarillado de Bogotá (EAAB) se evaluaron en el humedal Capellanía, el índice de contaminación para sólidos suspendidos (ICOSUS), el índice de eutrofización (ICOTRO), el índice de pH (ICOpH), el índice de demanda biológica de oxígeno (DBO) y el índice de Coliformes Totales, del 2004 al 2017. Se observó una disminución significativa de estos índices, entre los años iniciales de estudio (2004-2006) y los años finales (2014 y 2017), lo cual sugiere una mejora de la calidad del agua. Por otra parte, se realizaron mapas de transformación de cobertura de la cuenca aferente, y se encontró un mayor crecimiento urbanoindustrial del 2004 al 2011, que del 2011 al 2017. Junto con los resultados de calidad de agua, la transformación de cobertura de la cuenca aferente no parece afectar de manera directa la calidad del agua del humedal.También se investigaron las estrategias llevadas a cabo en la recuperación y mantenimiento del humedal por la EAAB y se evidenciaron avances del 2008 hasta la actualidad, y los cuales de acuerdo a los resultados del primer objetivo, parecen estar teniendo efectos positivos en la calidad del agua del humedal. Por último, se ejecutó un análisis de componentes principales y una prueba de correlación de Spearman donde se observó una correlación positiva significativa entre coliformes totales, DBO, y fósforo, sugiriendo mismas fuentes de contaminación. Se podrían reducir las concentraciones de estos parámetros corrigiendo más conexiones erradas, y realizando una adecuación hidrogeomorfológica. | Based on the water quality data provided by the Bogota Water and Sewerage Agency (EAAB), Suspended Solids Contamination Index (ICOSUS), Eutrophication Index (ICOTRO), pH Index (ICOpH), Biological Oxygen Demand (DBO) and Total Coliforms Index were evaluated from 2004 to 2017 in Capellania Wetland. The values of these indexes diminished significantly, between the early years of study (2004-2006) and the late years (2014 and 2017). In addition to this, coverage transformation maps were made, and it was observed a greater urbanindustrial growth from 2004 to 2011, in comparison to 2011-2017. Together with the results of water quality, the transformation of afferent basin coverage does not seem to directly affect the water quality in the wetland. Also, EAAB strategies used for wetland maintenance and recovery were investigated, and a progress was observed between 2008 and 2017, which, according to the first objective, appears to have a positive effect on the water quality of the wetland. Finally, a principal component analysis and a Spearman correlation test were executed, and it was found that the variables of total colifomrs, DBO and phosphorus have a high-significantpositive correlation, suggesting the same sources of contamination. | Ecólogo (a) | Pregrado
اظهر المزيد [+] اقل [-]Modelagem e simulação aplicadas à avaliação dos impactos da perda de solo e dos dejetos de suínos na qualidade da água de microbacias. النص الكامل
2017
CRESTANA, S. | MINOTI, R. T. | NEVES, F. F.
Reproductive biology of the freshwater drum Aplodinotus grunniens in Tabasco, Mexico/Biología reproductiva del tambor de agua dulce Aplodinotus grunniens en Tabasco, México النص الكامل
2017
Raúl Enrique Hernández-Gómez | Wilfrido Miguel Contreras-Sánchez | Martha Alicia Perera-García
Reproductive biology of the freshwater drum Aplodinotus grunniens in Tabasco, Mexico/Biología reproductiva del tambor de agua dulce Aplodinotus grunniens en Tabasco, México النص الكامل
2017
Raúl Enrique Hernández-Gómez | Wilfrido Miguel Contreras-Sánchez | Martha Alicia Perera-García
Aplodinotus grunniens supports a sustained artisanal shery in the Usumacinta River; however, there are few studies to understand the population dynamics of the species. Relevant aspects of the reproductive biology were documented over an annual cycle, using 593 specimens captured with seine nets. The results indicate that females had a median TL of 32.05 cm, while males had 29.71 cm. The estimated sex ratio was 1.2:1 (males: females). The length-weight relationship showed signicant dierence between sexes, observing an allometric-type growth represented by TW=0.0013(TL)3.5985 with 89.17 % of the data variability explained by the model. Gonadosomatic index (GSI) in females was higher in September (4.29), with males displaying a higher GSI in October (1.02). The highest HSI increase in females was observed in October (1.0). The estimated relative fecundity was 138.74 (± 74.30) oocytes/g of female weight. The macroscopic analysis of gonads indicates that the highest frequency of mature females occurs in June (75 %), while in males it takes place in March and June (35 %). The estimated L50 for females was 31.89 cm (TL) and 28.78 cm (TL) for males. Though A. grunniens reproduces throughout the year, reproductive peaks coincide with the period when the river level decreases, and shing increases considerably. Hence, preventive measures must be applied in regards to the size of the species at capture and the exploitation volumes of this resource.
اظهر المزيد [+] اقل [-]Reproductive biology of the freshwater drum Aplodinotus grunniens in Tabasco, Mexico النص الكامل
2017
Hernández-Gómez,Raúl Enrique | Contreras-Sánchez,Wilfrido Miguel | Perera-García,Martha Alicia
ABSTRACT: Aplodinotus grunniens supports a sustained artisanal fishery in the Usumacinta River; however, there are few studies to understand the population dynamics of the species. Relevant aspects of the reproductive biology were documented over an annual cycle, using 593 specimens captured with seine nets. The results indicate that females had a median TL of 32.05 cm, while males had 29.71 cm. The estimated sex ratio was 1.2:1 (males: females). The length-weight relationship showed significant difference between sexes, observing an allometric-type growth represented by TW=0.0013(TL)3.5985 with 89.17 % of the data variability explained by the model. Gonadosomatic index (GSI) in females was higher in September (4.29), with males displaying a higher GSI in October (1.02). The highest HSI increase in females was observed in October (1.0). The estimated relative fecundity was 138.74 (± 74.30) oocytes/g of female weight. The macroscopic analysis of gonads indicates that the highest frequency of mature females occurs in June (75 %), while in males it takes place in March and June (35 %). The estimated L50 for females was 31.89 cm (TL) and 28.78 cm (TL) for males. Though A. grunniens reproduces throughout the year, reproductive peaks coincide with the period when the river level decreases, and fishing increases considerably. Hence, preventive measures must be applied in regards to the size of the species at capture and the exploitation volumes of this resource.
اظهر المزيد [+] اقل [-]Determinación de la calidad fisicoquímica del agua del humedal El Juncal y su reconocimiento como ecosistema estratégico dentro de la educación básica primaria النص الكامل
2017
Espejo Cruz, María Eliana | Ruiz Sepúlveda, José Efrain
En la vereda El Cortés localizada en el municipio de Bojacá – departamento de Cundinamarca se encuentra ubicado el humedal El Juncal, declarado reserva hídrica mediante el Acuerdo N° 47 del 20 de noviembre de 2006 por la Corporación Autónoma Regional de Cundinamarca (CAR), razón por la cual se debe velar por su recuperación, rehabilitación y/o restauración. Sin embargo, pese a dicho reconocimiento éste presenta signos de contaminación que hacen pensar que su deterioro más que por factores naturales obedece a presiones antrópicas. Por lo anterior, el presente trabajo tuvo como objetivo caracterizar el cuerpo de agua a través del uso de parámetros fisicoquímicos en cinco puntos distintos, efectuándose para ello cuatro muestreos, tres de ellos durante los meses de febrero, marzo y mayo de 2016 y uno en febrero de 2017, abarcando el período de transición de aguas bajas a altas (IDEAM 2012). Se analizaron veinte variables de importancia de acuerdo con las actividades de pastoreo, agricultura y vertimiento de la planta de tratamiento de aguas residuales del municipio, presentes en la zona y se calcularon los índices de contaminación (ICOMI, ICOSUS e ICOTRO), observándose que el humedal presentó una condición crítica relacionada con alta carga de materia orgánica de acuerdo con los valores obtenidos para la DBO5, DQO y COT, concluyéndose que la actividad de mayor impacto correspondió a las aguas residuales domésticas municipales provenientes de Bojacá y Cartagenita (Facatativá), y cuyo afluente se localizó en el punto P2 e incumpliendo con la normatividad nacional (Decreto 1594 de 1984 del Ministerio de Salud, Resolución 631 de 2015 del Ministerio de Ambiente y Desarrollo Sostenible) al hallarse valores por encima de los límites máximos permisibles para varios de sus parámetros. A nivel pedagógico se implementara una estrategia que permita ampliar la información acerca del humedal y multiplicarla a toda la comunidad educativa de la IED Nuestra Señora de la Gracia, (cd interactivo, volumen N° 2 Cartilla “Amigos del Humedal el Juncal”, talleres), en pro de su recuperación. | "Nota: Documento confidencial por 16 meses por solicitud del autor" | In the footpath Cortes which is located in the Municipality of Bojacá – Department of Cundinamarca, It is the Wetland el Juncal, which was declared as a water reserve by agreement N 47 of November 20, 2006 for the Autonomous Regional Corporation of Cundinamarca (CAR), reason for which it is necessary to look over Its recovery, rehabilitation and/or restoration. Nevertheless, despite the above-mentioned recognition, this one presents signs of contamination that makes think that its deterioration more that for natural factors, it obeys to anthropogenic pressures. For the previous thing, the present work had as objective to characterize the water in the physical and chemical way, in five different points, four samplings being carried out for it, three of them during February, March and may, 2016 and one in February, 2017, covering the period of transition from low to high waters (IDEAM 2012). Twenty variables of importance, were analyzed in accordance with the present activities in the zone, and there were calculated the indexes of contamination (ICOMI, ICOSUS and ICOTRO),observing that the wetland presented critical condition associated with load in accordance with the values obtained for the DBO5, DQO and COT, it was concluded, that the activity of major impact corresponded to the municipal domestic water from Bojacá and Cartagenita (Facatativá), and whose affluent was located at point P2 and not complying with national regulations (Decree 1594 of 1984 of the Ministry of Health, Resolution 631 of 2015 of the Ministry of Environment and Sustainable Development) being found values above the maximum limits Allowable for several of its parameters. At the pedagogical level, the proposal will be presented, which will implement the strategies to enrich the existing information about the wetland, expand it and multiply it to the entire educational community of the Our Lady of Grace (Interactive CD, volume N ° 2 "Friends of the Wetland" The Juncal ", workshops). | Magister en Ciencias Ambientales
اظهر المزيد [+] اقل [-]Emprego da tecnologia de adsorção em leito fixo de carvão ativado granular para a remoção de agrotóxicos carbamatos da água de abastecimento público النص الكامل
2017
Alves, Alcione Aparecida de Almeida | Sens, Mauricio Luiz | Universidade Federal de Santa Catarina
Tese (doutorado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Ambiental, Florianópolis, 2017. | Em virtude da detecção de agrotóxicos carbamatos após o tratamento convencional de potabilização da água e considerando os seus efeitos deletérios à saúde humana, o desempenho da tecnologia de adsorção em leito fixo de carvão ativado granular (CAG) na remoção de carbaril, metomil e carbofurano da água de abastecimento público foi investigado neste estudo. Para descrever a dinâmica de funcionamento da coluna de adsorção em leito fixo de carvão ativado granular (CALF-CAG) realizaram-se três procedimentos experimentais (PE) e um procedimento analítico de validação do método cromatográfico. Na validação do procedimento de medição (VPM) em cromatografia líquida de alta eficiência com derivatização pós-coluna foram atendidas as exigências das aplicações analíticas quanto à seletividade, linearidade, intervalo, precisão, exatidão, limite de detecção (LD) e limite de quantificação (LQ) destes carbamatos em águas de abastecimento público. A VPM foi considerada linear (0,5 a 100 µg L-1), precisa (desvio padrão relativo < 5 %), exata (98,6 % a 103,6 %), específica e seletiva (não houve sobreposição de picos cromatográficos). Os LD e LQ corresponderam a 0,0082 µg L-1 e 0,0273 µg L-1 (carbaril), 0,0472 µg L-1 e 0,0157 µg L-1 (metomil), 0,0042 µg L-1 e 0,0140 µg L-1 (carbofurano), respectivamente. No PE I, a caracterização do CAG referente à área superficial (754,00 m2 g-1), tamanho médio de poros (20,79 Å), volume médio de poros (0,392 g cm-3), teor de cinzas (11,32 % ± 1 %), densidade aparente (0,47 ± 0,01 g cm-3), pH (10,01 ± 0,02), pH do ponto de carga zero (7,49 ± 0,01), teor de materiais voláteis (7,36 % ± 0,5 %), teor de umidade (2,22 % ± 0,1 %), índice de iodo (837,0 ± 4,92 mg g-1), índice de azul de metileno (113,5 ± 1,57 mg g-1) e as imagens do CAG obtidas por meio da micrografia eletrônica de varredura confirmaram que este adsorvente possui características físico-químicas e estruturais favoráveis à adsorção de carbamatos. Por meio da comparação da saturação da CALF-CAGDIP para determinas a difusividade intrapartícula predominante (DIP) em relação ao teste rápido em coluna de escala reduzida (TRCER) sob difusividade constante (DC) e ao TRCER sob difusividade proporcional (DP) confirmou-se que a DIP foi a DC. Desta forma, puderam-se estimar as condições operacionais da CALF-CAG em escala real, sendo estas: de 1 a 1,410 mm de diâmetro do CAG; relação entre o diâmetro interno da CALF e o diâmetro do CAG = 50; tempo de contato de leito vazio de 3 min e taxa de aplicação superficial (TAS) de 240 m3 m-2 d-1. No PE II, os ensaios de adsorção entre o CAG e os carbamatos foram realizados em reator batelada e CALf-CAGDIP. Os resultados demonstraram que os dados de equilíbrio monocomponente e multicomponente foram melhores ajustados à isoterma de Langmuir-Freundlich. A cinética de adsorção foi descrita mais precisamente pelo modelo de pseudo-segunda ordem. E, os valores negativos dos parâmetros termodinâmicos de entropia (?S° ads (-16,2, -9,8, -0,5)), entalpia (?H°ads (-9,2, -6,7, -4,1)) e energia livre Gibbs (?G°ads (-4,583, -3,841, -4,021)) condizentes ao carbaril, ao metomil e ao carbofurano, respectivamente, confirmaram um processo de adsorção exotérmico, de natureza física e espontâneo. No PE III, a CALF-CAG operou sob as seguintes condições: 1 mm de granulometria do CAG; 2,35 m de altura; 40 mm de diâmetro interno; 1 m de altura do leito fixo de CAG; 15 cm de camada suporte; 6 min TCLV; 240 m3 m-2 d-1 de TAS e concentração inicial de 25 µg L-1 de carbamatos na água abastecimento público. De acordo com os resultados obtidos, a microfiltração (MF) da água previamente a adsorção favoreceu a remoção máxima dos carbamatos (100 %) devido à menor competição por sítios ativos do CAG. O procedimento de retrolavagem contribuiu para a recuperação parcial do desempenho da filtragem hidráulica e possibilitou identificar a saturação em 108 h na CALF-CAG e em 240 h na CALF-CAG precedida por MF. Considerando os resultados de remoção de carbamatos na CALF-CAG e MF seguida da CALF-CAG comprovou-se por meio da análise estatística que estas diferem entre si com um nível de siginificância de 95 %. Ao comparar os resultados obtidos em relação à remoção dos carbamatos em água de abastecimento público sob distintas condições operacionais (PE I, II e III) identificou-se a maior eficiência quando a CALF-CAG operou com MF previamente a adsorção, retrolavagem periódica, 240 m3 m2 d-1 de TAS, 1 mm de granulometria média do CAG. Estas condições operacionais foram consideradas como alternativas promissoras para a maximização da remoção de carbaril, metomil e carbofurano por meio da tecnologia de adsorção em leito fixo de CAG. | Abstract : Due to the detection of pesticides carbamates after conventional water treatment and considering their deleterious effects on human health, the performance of adsorption technology in fixed bed of granular activated carbon (CAG) in the removal of carbaryl, methomyl and carbofuran from water supply was investigated. In order to describe the dynamics of the in fixed bed adsorption column of granular activated carbon (FBCA-GAC), three experimental procedures (EP) and an analytical procedure for the validation of the chromatographic method were performed. In the validation of the measurement procedure (VMP) in high performance liquid chromatography with post-column derivatization, the requirements of the analytical applications for selectivity, linearity, range, accuracy, detection limit (DL) and quantification (QL) of carbamates in public water supply. The VMP was considered linear (0.5 to 100 µg L-1), accurate (relative standard deviation < 5 %), exact (98.6 % to 103.6 %), specific and selective (there was no overlap of chromatographic peaks). The DL and QL corresponded to 0.0082 µg L-1 and 0.0273 µg L-1 (carbaryl), 0.0472 µg L-1 and 0.0157 µg L-1 (methomyl), 0.0042 µg L-1 and 0.0140 µg L-1 (carbofuran), respectively. In the EP the characterization of the CAG relative to the surface area (754.00 m2 g-1), pore size (20,79 Å), pore volume (0,392 g cm-3), ash contente (11.32 % ± 1 %), density (0.47 ± 0.01 g cm-3), pH (10.01 ± 0.02), zero charge point pH (7.49 ± 0.01) , content of volatile materials (7.36 % ± 0.5 %), moisture content (2.22 % ± 0.1 %), iodine number (837.0 ± 4.92 mg g-1), methylene blue number (113.5 ± 1.57 mg g-1) and adsorbent images obtained by scanning electron micrograph confirmed that CAG has physicochemical and structural characteristics favorable to the adsorption of carbamates. By comparing the saturation of FBCA-GACPID (predominant intraparticle diffusivity) in relation to rapid small-scale column test (RSSCT) test under constant diffusivity (CD) and to the RSSCT under proportional diffusivity (PD), it was confirmed that PID was to CD. In this way, the operational conditions of the FBCA-GAC in real scale could be estimated, being these: from 1 to 1,410 mm of CAG diameter; relation between the internal diameter of the FBCA-GAC and the diameter of the CAG = 50; time of empty bed contact time (EBCT) of 3 min and surface application rate (SAR) of 240 m3 m-2 d-1. In EP II, batch reactor adsorption assays were performed in the results showed that the single-component and multicomponent equilibrium data were better fitted to the Langmuir-Freundlich isotherm. The adsorption kinetics were described more precisely by the pseudo-second order model. And the negative values of the thermodynamic entropy parameters (?S°ads (-16.2, -9.8, -0.5)), enthalpy (?H°ads (-9.2, -6.7, -4,1)) and free energy Gibbs (?G°ads (-4.583, -3.841, -4.021)) corresponding to the carbaryl, methomyl and carbofuran, respectively, confirmed an exothermic adsorption process, of a physical and spontaneous nature. In EP III, the main design parameters of FBCA-GAC were: 1 mm CAG granulometry; 2.35 m high; 40 mm internal diameter; 1 m height of the fixed bed of CAG; 15 cm of support layer; 6 min EBCT; 240 m3 m-2 d-1 of SAR and initial concentration of carbamates of 25 µg L-1 in water. According to the results, microfiltration (MF) of water previously adsorbed favored the maximum removal of carbamates (between 80 and 100%) due to the reduced competition for active sites of CAG. The backwashing procedure contributed to the partial recovery of the hydraulic filtration performance and made it possible to identify saturation at 108 h in FBCA-GACand at 240 h in the FBCA-GAC preceded by MF. Considering a significance level of 95 % (p < 0.05), the true and apparent color parameters, turbidity and removal of carbaryl, methomyl and carbofuran presented p < 0.05, attesting that there is a statistical difference between the means of the results of FBCA-GAC compared to FBCA-GAC with prior MF. When comparing the results obtained in relation to the removal of the carbamates in public water under different operating conditions (EP I, II and III), it was identified that the higher efficiency of CAG fixed bed adsorption technology occurred when FBCA-GAC was run with MF before adsorption, periodic backwashing, 240 m3 m2 d-1 of TAS, 1 mm of mean CAG granulometry. These operating conditions were considered as promising alternatives for maximizing the removal of carbaryl, methomyl and carbofuran by CAG fixed bed adsorption technology.
اظهر المزيد [+] اقل [-]