Revista Internacional de Contaminación Ambiental
Not a member yet
1371 research outputs found
Sort by
REMOVAL OF HYDROCARBONS FROM DRILL CUTTINGS USING HUMIC ACIDS IN WASHING PROCESSES
Get PDFIn petroleum exploration drilling cuttings are generated, which are toxic residues that contain significant amounts of oil. The oil levels within the cuttings are a risk for marine and terrestrial environments. This study was carried out to investigate the removal of total petroleum hydrocarbons (TPH) in perforation cuttings (OBDC) by a washing process in which humic acids (HA) were used as surfactants. The cuttings contained 114 372 mg/kg of TPH, which were washed with HA solutions, resulting in 80 % removal of OBDC contaminants, applying a washing an additional water rinse. The process effectiveness was found strongly dependent on the HA solution concentration, the highest removal rates were attained using solutions in the range of 2500 to 3000 mg/L, and lower concentrations yielded removal rates lower than 70 %. Comparing the use of HA versus synthetic surfactants, such as sodium dodecyl sulfate (SDS) and tween-20 (TW20), both resulted in lower removal efficiency than HA. An additional advantage of HA is that it is a natural material, therefore there is no risk of toxic side effects that occur with synthetic surfactants.In petroleum exploration drilling cuttings are generated, which are toxic residues that contain significant amounts of oil. The oil levels within the cuttings are a risk for marine and terrestrial environments. This study was carried out to investigate the removal of total petroleum hydrocarbons (TPH) in perforation cuttings (OBDC) by a washing process in which humic acids (HA) were used as surfactants. The cuttings contained 114 372 mg/kg of TPH, which were washed with HA solutions, resulting in 80 % removal of OBDC contaminants, applying a washing an additional water rinse. The process effectiveness was found strongly dependent on the HA solution concentration, the highest removal rates were attained using solutions in the range of 2500 to 3000 mg/L, and lower concentrations yielded removal rates lower than 70 %. Comparing the use of HA versus synthetic surfactants, such as sodium dodecyl sulfate (SDS) and tween-20 (TW20), both resulted in lower removal efficiency than HA. An additional advantage of HA is that it is a natural material, therefore there is no risk of toxic side effects that occur with synthetic surfactants
EFFECT OF RAW GLYCEROL ON PLANT SOIL SYSTEM IN CORN AND SORGHUM PLANTS
Get PDFThe raw glycerol obtained from the production of biodiesel contains salts and impurities that can generate negative impacts when applied to the soil, however, mixing them with solutions of nitrogen fertilizers could be a viable solution. The objective of this investigation was to evaluate the effect of glycerol on the system soil-plant, in two crops, corn (Zea mayz L.) and sorghum (Sorghum bicolor L.). The study was conducted in 2016 at the Sao Paulo State University UNESP- Jaboticabal, Brazil. The experiments were prepared in a design totally randomized in a factorial arrangement 2 x 3 with four repetitions. The studied factors were soil: Argisol (Hapludox) and Latosol (Haplustox) and fertilization (without fertilizer, urea and urea + glycerol). At 60 days of having applied the treatments, the electric conductivity (EC) and the dehydrogenase enzyme (DH) were measured in the soil and nitrogen accumulation in aboveground (NF) and the dry biomass (DM) in the plant. Raw glycerol increased EC values in both soils, while DH, NF and DM were higher in Latosol soil. The treatment urea + glycerin increased the EC, the DH and the DM, and the urea the NF. The DH and EC media values varied per treatment and in each studied soil. For application of crude glycerol to these crops, a systematic control of the EC of the soil should be carried out as well as the implementation of agricultural practices that mitigate the salinization impact. The raw glycerol obtained from the production of biodiesel contains salts and impurities that can generate negative impacts when applied to the soil, however, mixing them with solutions of nitrogen fertilizers could be a viable solution. The objective of this investigation was to evaluate the effect of glycerol on the system soil-plant, in two crops, corn (Zea mayz L.) and sorghum (Sorghum bicolor L.). The study was conducted in 2016 at the Sao Paulo State University UNESP- Jaboticabal, Brazil. The experiments were prepared in a design totally randomized in a factorial arrangement 2 x 3 with four repetitions. The studied factors were soil: Argisol (Hapludox) and Latosol (Haplustox) and fertilization (without fertilizer, urea and urea + glycerol). At 60 days of having applied the treatments, the electric conductivity (EC) and the dehydrogenase enzyme (DH) were measured in the soil and nitrogen accumulation in aboveground (NF) and the dry biomass (DM) in the plant. Raw glycerol increased EC values in both soils, while DH, NF and DM were higher in Latosol soil. The treatment urea + glycerin increased the EC, the DH and the DM, and the urea the NF. The DH and EC media values varied per treatment and in each studied soil. For application of crude glycerol to these crops, a systematic control of the EC of the soil should be carried out as well as the implementation of agricultural practices that mitigate the salinization impact.
HAZARDOUS POLLUTANTS IN POTABLE GROUNDWATER SOURCES OF PUBLIC SCHOOLS, SOUTHERN PUNJAB (PAKISTAN)
Get PDFDrinking water quality is considered to be of vital importance for all human beings and animals but its significance is much more heightened when consumer is a teenager. In view of foregone, groundwater quality assessment of 150 public schools situated in flooded areas of Southern Punjab, Pakistan, was carried out. Analysis results revealed that 49 and 37 % water samples are contaminated with coliform and faecal coliforms, respectively. On the other hand chemicals constituents in samples, including calcium (43 %), magnesium (11 %), potassium (37 %), sodium (31 %), sulphate (39 %), hardness (31 %), total dissolved solids (TDS) (35 %) and chloride (15 %) were higher than World Health Organization (WHO) limits. The situation is more serious as fluoride, iron and arsenic were also found in high concentration in 15, 60 and 58 % samples, respectively. Health risk assessment data indicated that mean chronic daily intake (CDI) values for children and adults were 0.592 and 0.537 μg/kg/day for arsenic and 0.012 and 0.011 μg/kg/day for iron, respectively. Calculated arsenic health risk index (HRI) > 1 for 88 and 58 % water samples for children and adults respectively, which highlights possible health risks associated with intake of contaminated water.Drinking water quality is considered to be of vital importance for all human beings and animals but its significance is much more heightened when consumer is a teenager. In view of foregone, groundwater quality assessment of 150 public schools situated in flooded areas of Southern Punjab, Pakistan, was carried out. Analysis results revealed that 49 and 37 % water samples are contaminated with coliform and faecal coliforms, respectively. On the other hand chemicals constituents in samples, including calcium (43 %), magnesium (11 %), potassium (37 %), sodium (31 %), sulphate (39 %), hardness (31 %), total dissolved solids (TDS) (35 %) and chloride (15 %) were higher than World Health Organization (WHO) limits. The situation is more serious as fluoride, iron and arsenic were also found in high concentration in 15, 60 and 58 % samples, respectively. Health risk assessment data indicated that mean chronic daily intake (CDI) values for children and adults were 0.592 and 0.537 μg/kg/day for arsenic and 0.012 and 0.011 μg/kg/day for iron, respectively. Calculated arsenic health risk index (HRI) > 1 for 88 and 58 % water samples for children and adults respectively, which highlights possible health risks associated with intake of contaminated water
LIFE CYCLE ASSESSMENT OF A TRADITIONAL BRICK MANUFACTURE IMPROVEMENT
Get PDFThis research studies the application of a life cycle assessment (LCA) methodology to evaluate the environmental impacts of an improvement to traditional brick manufacture. This study case was carried out using realistic combustion gas measurements and experimental results. The traditional process and the addition of one or two hopper blower (HB) devices provided the three scenarios for this study, which were evaluated quantitatively using a set of metric indicators for potential impacts while applying a “cradle-to-gate” approach. A decreasing trend was observed for most values of the potential impact categories when the device was used. An opportunity to improve the traditional process by adding this device has been identified, as a reduction in the environmental impact categories has been observed. The study suggests that the LCA tool may be valuable for quantifying the environmental impacts of improvements in the processes.This research studies the application of a life cycle assessment (LCA) methodology to evaluate the environmental impacts of an improvement to traditional brick manufacture. This study case was carried out using realistic combustion gas measurements and experimental results. The traditional process and the addition of one or two hopper blower (HB) devices provided the three scenarios for this study, which were evaluated quantitatively using a set of metric indicators for potential impacts while applying a “cradle-to-gate” approach. A decreasing trend was observed for most values of the potential impact categories when the device was used. An opportunity to improve the traditional process by adding this device has been identified, as a reduction in the environmental impact categories has been observed. The study suggests that the LCA tool may be valuable for quantifying the environmental impacts of improvements in the processes
APROVECHAMIENTO DE ALMIDÓN DE CEBADA DE MALA CALIDAD PARA LA PRODUCCIÓN DE ENZIMAS AMILOLÍTICAS POR Aureobasidium pullulans
Get PDFLow quality barley that has been rejected for the malt production process can be used to produce value added products, particularly enzymes. Hence, in this work the starch was extracted and used to produce amylolytic enzymes by Aureobasidium pullulans. Using 50 g/L of barley raw starch, glucoamylase, α-amylase, α glucosidase and β-glucosidase enzymes were produced with maximum activities of 193, 7.4, 8.1 and 8.5 U/mL, respectively. After 30 h of fermentation a crude extract was obtained, which was used as enzymatic source for the saccharification of starch from three sources at 10 g/L: barley, soluble (from potato) and corn. First, two reaction solvents (water and acetate buffer) and the addition of calcium (Ca2+) were evaluated. Afterwards, starch gelatinization was evaluated and finally experiments varying the starch concentration (from 50 to 400 g/L) were conducted. Using water as solvent and the Ca2+ addition had a positive effect, resulting in a maximum glucose concentration of 3.84, 0.84 and 0.4 g/L from barley, soluble and corn starches, respectively. In the other hand, starch gelatinization was positive for soluble and corn starches, enhancing hydrolysis in 23 and 25 %, respectively. Increasing the starch concentration to 50 g/L was the best condition, enhancing hydrolysis in 3.2, 40 and 42 % from barley, soluble and corn starches, respectively. This work demonstrates that low quality raw barley starch can be used for the production of value added products such as enzymes.La cebada de baja calidad rechazada para el proceso de producción de malta puede ser utilizada para la obtención de productos de valor agregado, particularmente enzimas. En este trabajo se extrajo almidón de cebada y se usó para producir enzimas amilolíticas por Aureobasidium pullulans. Utilizando 50 g/L de almidón, se produjeron glucoamilasa, α-amilasa, α-glucosidasa y β-glucosidasa con actividades máximas de 193, 7.4, 8.1 y 8.5 U/mL, respectivamente. A las 30 h de fermentación se obtuvo un extracto enzimático crudo que se utilizó para sacarificar almidón de tres fuentes a 10 g/L: cebada, soluble (papa) y maíz. Primero, fueron evaluados dos medios de reacción (agua y solución tampón de acetato) y la adición de calcio (Ca2+). Posteriormente, se evaluó la gelatinización del almidón y finalmente se realizaron experimentos aumentando la concentración de almidón (50 a 400 g/L). El agua y la adición de Ca2+ tuvieron un efecto positivo, resultando una concentración máxima de glucosa de 3.84, 0.84 y 0.4 g/L para almidón de cebada, soluble y de maíz, respectivamente. La gelatinización del almidón fue positiva para el almidón soluble y de maíz, aumentando la hidrólisis en 23 y 25 %, respectivamente. El incremento de la concentración de almidón a 50 g/L fue la mejor condición; aumentó la hidrólisis en 3.2, 40 y 42 % para almidón de cebada, soluble y de maíz, respectivamente. Este trabajo demuestra que el almidón de cebada de baja calidad puede ser aprovechado para la obtención de productos de valor agregado, como las enzimas
VARIACIÓN DE LOS NIVELES DE BUTIRILCOLINESTERASA DE UNA POBLACIÓN MEXICANA EN DISTINTOS PERIODOS DE CONTROL DE Aedes SPP.
Get PDFThe impact of organophosphate and carbamate pesticides used to control the Aedes spp. mosquito in sanitary campaigns was determined by measuring serum butirylcholinesterase activity in dry and rainy seasons. Differences in levels and their trend over time were analyzed, finding statistically significant differences between both seasons (men: dry season = 5272 U/L; rainy season = 4854 U/L; p < 0.05), with a decrease of 92 U/L each month. The decrease in men was 92 U/L each month. The enzymatic inhibition may be due to exposure to these anticholinesterase insecticides, and protective measures must be taken against the related health risks.Se determinó el impacto de insecticidas organofosforados y carbamatos usados para el combate del mosquito Aedes spp. en campañas sanitarias, a través de la medición de la actividad de butirilcolinesterasa sérica en la temporada seca y de lluvias. Se analizaron las diferencias en los niveles y su tendencia en el tiempo, encontrando diferencias estadísticamente significativas entre ambas temporadas (hombres: temporada seca = 5272 U/L; temporada de lluvias = 4854 U/L; p < 0.05), con una disminución de 92 U/L cada mes. La disminución en los hombres fue de 92 U/L cada mes. La inhibición enzimática encontrada puede ser consecuencia de la exposición a estos insecticidas anticolinesterásicos y deben tomarse medidas de protección contra los riesgos sanitarios relacionados
REDUCCIÓN DE LA FERTILIZACIÓN INORGÁNICA MEDIANTE MICORRIZA ARBUSCULAR EN SORGO
Get PDFThe role of arbuscular mycorrhizal fungi (AMF) has been emphasized in the fields of conservation and soil fertility. The objective of this study was to explore the response of sorghum DKS60 in 2011 and 83G19 in 2016—with respect to plant physiology and productivity—to AMF (Rhizophagus intraradices) alone or combined with half of inorganic fertilizer (IF50 %), compared with conventional fertilization (120N-40P-00K; IF100 %). Profitability was estimated through grain yield with a benefit-cost (b/c) indicator. All treatments exceeded significantly the control with respect to chlorophyll index (SPAD), plant height, stem diameter, panicle length and grain yield, although overall the highest values were recorded with IF100 % and IF50 % + AMF. However, the benefit-cost relationship demonstrated that IF50 % + HMA and AMF alone obtained 1.45 and 1.5 b/c, respectively, higher than the profitability obtained with IF-100 % (1.3). This, although AMF alone recorded 852 kg/ha less than the average of IF100 % and IF50 % + AMF. Reduction or replacement of inorganic fertilization through AMF may represent a viable practice promoting greater profitability, as well as the conservation of agro-ecological production systems.Dentro de la conservación y la fertilidad de los suelos se ha destacado el papel de los hongos micorrízicos arbusculares (HMA). El objetivo del presente estudio fue conocer la respuesta de los sorgos DKS60 en 2011 y 83G19 en 2016, en cuanto a características fisiológicas y productivas, inoculado con HMA (Rhizophagus intraradices) solo o en combinación con la mitad de la fertilización inorgánica (FI50 %), comparada con la fertilización convencional (120N-40P-00K; FI100 %). Con el rendimiento del grano se estimó la rentabilidad de la producción mediante el indicador beneficio-costo (b/c). Todos los tratamientos superaron significativamente al testigo respecto de índice de clorofila (SPAD), altura de planta, diámetro de tallo, longitud de panoja y rendimiento del grano, aunque en general los mayores valores se registraron con FI100 % y FI50 % + HMA. No obstante, en el b/c se demostró que FI50 % + HMA y HMA sólo obtuvieron 1.45 y 1.5 b/c, respectivamente, superiores a la rentabilidad obtenida con FI100 % (1.3). Lo anterior, a pesar de que el HMA registró 852 kg/ha menos que el promedio de FI100 % y FI50 % + HMA. La reducción o sustitución de la fertilización inorgánica a través de HMA puede representar una práctica viable que promueva mayor rentabilidad, así como la conservación agroecológica de los sistemas de producción
REMOCIÓN DE TENSOACTIVOS Y COLIFORMES EN AGUAS RESIDUALES DOMÉSTICAS MEDIANTE PROCESOS FENTON
Get PDFIn many developing countries, domestic wastewater is one of the major pollution sources to water bodies, and advanced oxidation processes appear nowadays as a promising solution to this problem. In this work, the conventional Fenton process, and the chelate-modified Fenton process with citric acid, were tested for surfactants and fecal coliforms removal from an effluent of a domestic wastewater treatment plant located in Quito city, Ecuador. The best conditions (agitation requirements, H2O2 concentration and Fe2+:H2O2 molar ratio) for the conventional Fenton process were found. These conditions were applied to the chelate-modified Fenton process with citric acid. For this process, two Fe2+:citrate molar ratios (1:1 and 1:1.25) were tested at four pH values (2.80, 4.50, 6.00, and 7.84). The best results were achieved with a H2O2 concentration of 56.33 mM, a Fe2+:citrate:H2O2 molar ratio of 1:1:9, continuous stirring and a pH value of 6. The application of these conditions allowed a complete removal of fecal coliforms, a 97 % reduction of surfactants and an 89 % decrease in chemical oxygen demand in 15 min of treatment. The resulting treated waters complied with water quality standards for discharge to water bodies according to the Ecuadorian legislation. This work provides valuable data on the effectiveness of these treatments, thus presenting them as potential solutions for the problematic of domestic wastewater treatment.En varios países en desarrollo, el agua residual doméstica es una de las mayores fuentes de contaminación de cuerpos de agua, y los procesos de oxidación avanzada aparecen en la actualidad como una solución promisoria a dicha problemática. En este trabajo se probaron los procesos Fenton convencional y modificado con el agente quelante ácido cítrico para la remoción de tensoactivos y la inactivación de coliformes fecales del efluente de una planta de tratamiento de aguas residuales domésticas localizada en la ciudad de Quito, Ecuador. Se encontraron las mejores condiciones (requerimiento de agitación, concentración de H2O2 y relación molar Fe2+:H2O2) para el proceso Fenton convencional. Estas condiciones fueron aplicadas en el Fenton modificado con ácido cítrico. Para este proceso, se probaron dos relaciones molares Fe2+:citrato (1:1 y 1:1.25) a cuatro valores de pH (2.80, 4.50, 6.00 y 7.84). Los mejores resultados se alcanzaron al emplear una concentración de H2O2 de 56.33 mM, una relación molar 1:1:9 de Fe2+:citrato:H2O2, agitación continua y pH 6. La aplicación de dichas condiciones permitió una remoción completa de coliformes fecales, una reducción de tensoactivos del 97 % y la disminución de la demanda química de oxígeno en 89 % en 15 min de tratamiento. Las aguas tratadas resultantes cumplieron con los estándares estipulados en la legislación ecuatoriana para descargas a un cuerpo de agua dulce. Este trabajo provee datos valiosos de la efectividad de los procesos Fenton y los postula como solución potencial para la problemática que implica el tratamiento de aguas residuales domésticas
CALIDAD MICROBIOLÓGICA Y USOS DEL AGUA SUBTERRÁNEA EN ESTABLECIMIENTOS AGROPECUARIOS DEL CENTRO-SUR DE CÓRDOBA, ARGENTINA
Get PDFThe productive systems intensification (agricultural or livestock) has caused groundwater shifts mainly due to the introduction of exogenous and contaminating microorganisms. The microbial quality of water must be considered as an essential parameter when defining the suitability of the groundwater for animals or rural human consumption, as well as for cleaning the facilities of the dairy. In this study, the objectives were: (1) to determine the microbiological quality of the groundwater in agricultural or livestock farms and, (2) to establish in the studied area the relationship between the land use and groundwater quality. The microbial analyses were performed using several indicators such as: i) aerobic mesophilic bacteria counts, ii) total and fecal coliforms count, and iii) detection of Escherichia coli and Pseudomonas aeruginosa in groundwater samples obtained from agricultural farms (EA; n = 28) or livestock/dairy farms (EG; n = 34) located in south-central area of Córdoba province, Argentina. At least one microbial indicator over the acceptable limit for human drink or for cleaning dairy farm facilities was detected in the 58 % of studied samples (n = 62). The 12 % of the EG demonstrated to have deficient water quality for animal consumption. By bivariate statistical analysis, a scarce relationship was observed between land uses and microbiological water quality indicating that bacterial contamination source is unspecific and probably due to intrinsic factors of the area. La intensificación de los sistemas productivos (agrícolas o ganaderos) ha provocado una alteración en la calidad del agua subterránea debido, entre otras causas, a la introducción de microorganismos contaminantes. La calidad microbiológica del agua debe considerarse como un parámetro elemental para definir su aptitud para diferentes usos: consumo de la población rural, consumo del ganado bovino o limpieza de instalaciones de ordeñe. Los objetivos de este estudio fueron: (1) conocer la calidad microbiológica del agua subterránea en establecimientos agropecuarios para definir aptitudes de uso y (2) evaluar la relación entre el uso del suelo y la calidad del agua subterránea de la región. Se realizaron análisis microbiológicos utilizando como indicadores: i) recuento de bacterias aerobias mesófilas, ii) detección de coliformes totales y fecales, y iii) presencia de Escherichia coli y Pseudomonas aeruginosa en muestras de agua obtenidas de perforaciones de establecimientos agrícolas (EA; n = 28) o ganaderos/lecheros (EG; n = 34) ubicados en la región centro-sur de la provincia de Córdoba, Argentina. En el 58 % de las muestras analizadas (n = 62) se detectó la presencia de al menos un indicador de contaminación que supera los parámetros para consumo humano o higiene de instalaciones de ordeñe. El 12 % de los EG poseen agua de calidad deficiente para el consumo del ganado bovino. Mediante análisis bivariados se encontró una escasa asociación entre el uso del suelo y la calidad microbiológica del agua, por lo que el origen de la contaminación observada responde a múltiples factores que inciden en la región.
PARTICLE IMAGE VELOCIMETRY AND NUMERICAL STUDIES OF ARTIFICIAL UPWELLING VIA DIFFERENTIAL HEATING IN OPEN SURROUNDINGS
Get PDFArtificial upwelling is considered as a promising technology to recover the marine environment, especially for fishery environment recovery. This paper studied basic characteristics of “differential-heating- liquid- upwelling” (DHLU) in open surroundings with PIV and numerical analysis. Flow field of upwelling under typical condition was measured with particle image velocimetry (PIV), and a reasonable numerical model was built on the base of experimental data to study the key characteristics of DHLU system by numerical simulations. Results show that the upwelling in DHLU is mainly driven by the masses with high ascending speed. It is reasonable to choose k-ε turbulence model to study the flow field of DHLU in simulation. All of the three important parameters such as characteristic ascending speed, the cross-sectional area of upwelling stream and the upwelling’s flow rate are all increase firstly and then decreases while the height from the heating source increases. But the position of maximum value for characteristic ascending speed is much lower than the other two parameters. The drop of ambient temperature is not favorable for the production of upwelling. A flow rate as high as 95.9 cm3/s was reached in studied cases in this paper.Artificial upwelling is considered as a promising technology to recover the marine environment, especially for fishery environment recovery. This paper studied basic characteristics of “differential-heating- liquid- upwelling” (DHLU) in open surroundings with PIV and numerical analysis. Flow field of upwelling under typical condition was measured with particle image velocimetry (PIV), and a reasonable numerical model was built on the base of experimental data to study the key characteristics of DHLU system by numerical simulations. Results show that the upwelling in DHLU is mainly driven by the masses with high ascending speed. It is reasonable to choose k-ε turbulence model to study the flow field of DHLU in simulation. All of the three important parameters such as characteristic ascending speed, the cross-sectional area of upwelling stream and the upwelling’s flow rate are all increase firstly and then decreases while the height from the heating source increases. But the position of maximum value for characteristic ascending speed is much lower than the other two parameters. The drop of ambient temperature is not favorable for the production of upwelling. A flow rate as high as 95.9 cm3/s was reached in studied cases in this paper