ABSTRACT
Resumen En esta investigación se desarrolló un Reactor Flujo Pistón (RFP) de lodos activados, que fue empleado para determinar el Tiempo de Retención Celular (TRC) óptimo para tratar cargas altas de lixiviado y estimar el comportamiento cinético del sistema con el fin que sirva de base para proyecciones de escalamiento y diseño de reactor de este tipo a escala real. Para ello se realizó el diseño, la construcción y puesta en marcha del RFP a nivel de laboratorio (capacidad de 50L) en condiciones de operación continua con recirculación de lodo y se utilizó como sustrato lixiviado procedente del relleno sanitario El Guayabal de la ciudad de Cúcuta. Se determinó como parámetros de control cuatro TRC diferentes entre 5 y 20 días diferenciada por etapas. Se evaluaron las variables de pH, Temperatura, Oxígeno disuelto y Sólidos Suspendidos Volátiles en el Licor Mixto (SSVLM). En cuanto al control y monitoreo de la eficiencia de remoción se escogió la Demanda Química de Oxígeno (DQO) como parámetro para medir la degradación de materia orgánica, dado que este parámetro a diferencia de la Demanda Bioquímica de Oxígeno (DBO5) puede ser calculado en un menor tiempo. El sistema biológico RFP alcanzó estabilizarse en un período de operación entre 20 y 25 días con remociones promedio mayores a 92% para TRC de 15 y 20 días mientras que TRC menores reportaron remociones promedio por debajo del 86%. Así mismo TRC de 15 permitió un Factor de carga (F/M) óptima promedio de 1.1 KgDQO/KgSSV.d. Las constantes cinéticas obtenidas en esta investigación, representativas para un sistema de RFP operado a escala laboratorio para remoción de materia orgánica carbonacea en lixiviados fueron: KS= 836.5 mg/L DQO, k=4.8123 d1, Y= 0.089 mg SSVLM/mg DQO y kd= 0.018 d-1, ajustados por regresión al modelo matemático de Lawrence y McCarty al poseer una correlación de 0.97 entre los datos experimentales obtenidos y el modelo y amplia aplicación en el campo de diseño de reactores de lodos activados.
Abstract An activated sludge processes (ASP) plug flow reactor (PFR) was developed in this research and used for determining optimal cell residence time (CRT) for treating high leachate loads and estimating the system's kinetic behaviour as a basis for scaling projections and this type of reactor design at full-scale. The RFP was designed, built and put into operation in the laboratory (50L capacity) involving continuous operation conditions with sludge recirculation; leached substrate from the city of Cúcuta's El Guayabal landfill was used. Four 5-day CRTs (ranging from 5 to 20 days) were used as control parameters. Variables were evaluated regarding pH, temperature, dissolved oxygen and mixed liquor volatile suspended solids (MLVSS). Regarding removal efficiency control and monitoring, chemical oxygen demand (COD) was chosen as a parameter for measuring organic matter degradation since COD (unlike biochemical oxygen demand (BOD5)) can be calculated in a shorter time. The RFP biological system became stabilised in a 20- to 25-day operating period, having greater than 92% average removal for 15- and 20-day CRTs, whilst lower CRTs reported lower than 86% average removal. A 15-day TRC gave an average 0.26 kgDQO/kgSSV.d optimal load factor (F/M). The representative kinetic constants obtained in this research for a laboratory-scale PFR system for the removal of carbonaceous organic matter in leachates were KS = 836mg COD / l, k = 4.8123 d1, Y = 0.089 mg SSVLM / mg COD and kd = 0.018 d-1, adjusted by regression using Lawrence and McCarty's mathematical model (having 0.97 correlation between the experimental data and the model). Such model should have broad application in the field of ASP-type PFRs.
Resumo Nesta pesquisa, um Reator de lodo ativado de Fluxo de Pistão (RFP) foi desenvolvido para determinar o Tempo de Retenção Celular (CRT) ideal para tratar altas cargas de lixiviado e estimar o comportamento cinético do sistema, a fim de servir de base para projetar o reator em escala real. Para isso, foram realizados RFP em nível de laboratório (capacidade de 50L) em condições de operação contínua com recirculação de lodo e foi utilizada como substrato lixiviado do aterro El Guayabal na cidade de Cúcuta. Usando quatro diferentes CRTs entre 5 e 20 dias como fatores de bloqueio. Foram avaliadas as variáveis pH, Temperatura, Oxigênio Dissolvido e Sólidos Suspensos Voláteis no Licor Misto (SSVLM). Em relação ao controle e monitoramento da eficiência de remoção, a Demanda Química de Oxigênio (DQO) foi escolhida como parâmetro para medir a degradação da matéria orgânica, uma vez que este parâmetro, ao contrário da Demanda Bioquímica de Oxigênio (DBO5), pode ser calculado em um tempo mais curto. O sistema biológico da RFP se estabilizou em um período de operação entre 20 e 25 dias com remoções médias superiores a 92% para TRC de 15 e 20 dias, enquanto TRC menores mostraram remoções médias abaixo de 86%. Da mesma forma, TRC de 15 dias permitiu um fator de carga ideal médio (F / M) de 0,26 KgDQO / d. As constantes cinéticas obtidas nesta pesquisa, representativas de um sistema RFP operado em escala de laboratório para remoção de matéria orgânica carbonácea em lixiviados foram: KS = 836mg COD / l, k = 4,8123 d1, Y = 0,089 mg SSVLM / mg COD e kd = 0,018 d-1, ajustado por regressão ao modelo matemático de Lawrence e McCarty, tendo uma correlação de 0,97 entre os dados experimentais obtidos e o modelo e ampla aplicação na área de projeto de reatores de lodo ativado.
ABSTRACT
Abstract Aquaponics is a system that integrates aquaculture with plant production in which two species are benefited, and there is water saving. In this study was carried out with an aquaponic system to verify the interaction between the growth of the halophytes Batis maritime, Sarcocornia neei, and Sporobolus virginicus associated with white shrimp Litopenaeus vannamei rearing. We also investigated if there were different responses of physicochemical variables of the water in the experimental shrimp culture ponds integrated into the growth of plants and control ponds, without plants, throughout a 56-day period. The treatment experiment and control presented a statistically significant difference in total dissolved solids, salinity, total suspended solids, ammonia, orthophosphate, and nitrite. In the experimental treatment, with the presence of plants and recirculating water, a reduction of total suspended solids, ammonia and orthophosphate was observed. The rate of shrimp production was not significantly different between treatments, and the performance was similar to that of other studies. The biomass gain of the halophyte B. maritima was 876.6 grams in 0.5 m² and of S. neei was 48.8 grams in 0.16 m². All plants of the species S. virginicus died during the experiment.
Subject(s)
Animals , Water/chemistry , Chenopodiaceae/growth & development , Penaeidae/growth & development , Salt-Tolerant Plants/growth & development , Phosphates , Aquaculture , Hydroponics , Biomass , Chenopodiaceae/metabolism , Ammonia , NitritesABSTRACT
Abstract Salt water recirculation systems using automatic feeders are a new frontier for marine aquaculture. It is possible to decrease the vulnerability of the traditional fish farming in open systems and reduce wasteful feeding and discharge of effluents, as well as increase the economic returns. An experiment with common snook fingerings (4.31 ± 1.42 g and 8.4 ± 1.0 cm) was performed. Three feeding treatments were evaluated: six, twelve and eighteen feeding times per day. Each treatment had three replications. Among the three tested frequencies (fed 6, 12 and 18 times a day), the feeding frequency of 12 times per day (every two hours) showed the best values of the parameters evaluated for production performance. The final weight values, condition factor, specific growth rate and daily weight gain of the treatment 12 feeding times per day were all significantly higher than the lower and higher frequencies. Our results demonstrate that high feeding frequency is not synonymous of higher performance, but is extremely necessary to find out the best range for the target species. Besides, this relationship between feeding frequency and growth performance might change over weight range. Therefore, future studies should address higher weight ranges for comparison to our results.
Resumo Sistemas de recirculação de água salgada utilizando alimentadores automáticos são uma nova fronteira para a aquicultura marinha. Possibilitam diminuir a vulnerabilidade dos cultivos em sistemas abertos e conferir redução de desperdício de ração e lançamento de efluentes, assim como elevar o retorno econômico. Foi realizado um experimento com juvenis de Robalo-flecha (4,31 ± 1,42 g e 8,4 ± 1,0 cm). Três frequências alimentares foram avaliadas: alimentação seis vezes ao dia; doze vezes ao dia, e; dezoito vezes ao dia. Cada tratamento teve três repetições. Dentre as três frequências avaliadas a frequência alimentar de 12 vezes ao dia foi a que apresentou os melhores valores para os parâmetros zootécnicos avaliados. Os valores obtidos de peso final, fator de condição, taxa de crescimento específico e ganho de peso diário foram todos maiores para a frequência de 12 vezes ao dia do que os obtidos para as frequências maior e menor. Nossos resultados demonstram que elevadas frequências alimentares não são sinônimo de melhor desempenho produtivo, mas é extremamente importante conhecer a frequência ideal para a espécie a ser cultivada. Além disto, a relação entre frequência alimentar e crescimento pode mudar de acordo com a faixa de peso dos indivíduos. Desta forma, é extremamente importante que trabalhos futuros avaliem as frequências aqui estudadas para comparar os resultados em indivíduos maiores.
Subject(s)
Animals , Perciformes/growth & development , Aquaculture/methods , Diet/veterinary , Random Allocation , Animal Feed/analysisABSTRACT
Abstract Salt water recirculation systems using automatic feeders are a new frontier for marine aquaculture. It is possible to decrease the vulnerability of the traditional fish farming in open systems and reduce wasteful feeding and discharge of effluents, as well as increase the economic returns. An experiment with common snook fingerings (4.31 ± 1.42 g and 8.4 ± 1.0 cm) was performed. Three feeding treatments were evaluated: six, twelve and eighteen feeding times per day. Each treatment had three replications. Among the three tested frequencies (fed 6, 12 and 18 times a day), the feeding frequency of 12 times per day (every two hours) showed the best values of the parameters evaluated for production performance. The final weight values, condition factor, specific growth rate and daily weight gain of the treatment 12 feeding times per day were all significantly higher than the lower and higher frequencies. Our results demonstrate that high feeding frequency is not synonymous of higher performance, but is extremely necessary to find out the best range for the target species. Besides, this relationship between feeding frequency and growth performance might change over weight range. Therefore, future studies should address higher weight ranges for comparison to our results.
Resumo Sistemas de recirculação de água salgada utilizando alimentadores automáticos são uma nova fronteira para a aquicultura marinha. Possibilitam diminuir a vulnerabilidade dos cultivos em sistemas abertos e conferir redução de desperdício de ração e lançamento de efluentes, assim como elevar o retorno econômico. Foi realizado um experimento com juvenis de Robalo-flecha (4,31 ± 1,42 g e 8,4 ± 1,0 cm). Três frequências alimentares foram avaliadas: alimentação seis vezes ao dia; doze vezes ao dia, e; dezoito vezes ao dia. Cada tratamento teve três repetições. Dentre as três frequências avaliadas a frequência alimentar de 12 vezes ao dia foi a que apresentou os melhores valores para os parâmetros zootécnicos avaliados. Os valores obtidos de peso final, fator de condição, taxa de crescimento específico e ganho de peso diário foram todos maiores para a frequência de 12 vezes ao dia do que os obtidos para as frequências maior e menor. Nossos resultados demonstram que elevadas frequências alimentares não são sinônimo de melhor desempenho produtivo, mas é extremamente importante conhecer a frequência ideal para a espécie a ser cultivada. Além disto, a relação entre frequência alimentar e crescimento pode mudar de acordo com a faixa de peso dos indivíduos. Desta forma, é extremamente importante que trabalhos futuros avaliem as frequências aqui estudadas para comparar os resultados em indivíduos maiores.
ABSTRACT
Objective To investigate the feasibility of veno-venous puncture (VVP) as an alternative for temporary and long-term vascular access in hemodialysis patients. Methods A total of 84 hemodialysis patients were enrolled in this study in Fuzhou General Hospital, PLA Nanjing Military Area Command between June 2014 and June 2015. The priority order of vascular access is as follow: arteriovenous fistula (AVF)-, tunneled cuffed catheter (TCC), and VVP. Patients were divided into VVP group (n=28), TCC group (n=28) and AVF group (n=28). Dialysis adequacy, access recirculation rate and access complications were observed and compared among each group for a follow-up of 6 months. Results There were no significant differences in spKt/V. eKt/V or urea reduction ratio (URR) among the three groups at 0, 3 and 6 months after dialysis. After 6 months, the access recirculation rate in VVP group was significanlty lower than that in the other two groups (0 vs 14. 28%, 21. 43%; P<0. 05), and access dysfunction rate in VVP group was also significantly lower than that in TCC group (0 vs 21. 43%, P<0. 05), while the access-related infection rates were not significantly different among three groups. Conclusion VVP is easy to perform, with less complications and low access recirculation rate, and it might be an alternative choice for hemodialysis when AVF cannot be created or TCC cannot be placed.
ABSTRACT
Se determinó el efecto de la temperatura sobre la tasa de aclaramiento (TA), ingestión (TI) y consumo especifico de oxígeno (CEO) en individuos de Argopecten purpuratus (Lamarck, 1891) de distintos grupos de tallas. Las pruebas de TA y TI se realizaron a una concentración de Chaetoceros calcitrans de aproximadamente 1x10(6) cel.mL-1, se evaluaron dos temperaturas 17 y 22°C y se conformaron diferentes grupos de tallas promedio de 7.6 ± 0.265, 4.9 ± 0.058 y 3.7 ± 0.173 cm. En las pruebas de CEO los grupos de tallas promedio fueron 8.1 ± 0.351, 5.6 ± 0.058 y 4.3 ± 0.100 cm. Los resultados muestran un efecto significativo de la temperatura en la TA (L.h-1) y TI (cel.h-1 x 10(5)) sobre los individuos de mayor tamaño (7.6 ± 0.265 cm), observándose a 22°C un incremento promedio, respecto a 17°C, de hasta 250% para TA y 48% para TI. Además, se observó una relación directa del tamaño corporal con las TA y TI en ambas temperaturas. Se registró el efecto de la temperatura de 22°C sobre CEO en todos los grupos evaluados, con un incremento de 239.8, 165.3 y 183.4% para individuos de tallas de 8.1 ± 0.351, 5.6 ± 0.058 y 4.3 ± 0.100 respectivamente. Asimismo, los resultados muestran una relación indirecta del tamaño corporal con la CEO, en ambas temperaturas evaluadas.
The effect of temperature on the clearance rate (CR), ingestion rate (IR) and specific oxygen consumption (SOC) in individuals of Argopecten purpuratus at different size groups were determined. The CR and IR tests were performed at a concentration of approximately 1x10(6) cel.mlL-1 of Chaetoceros calcitrans, two temperatures 17 and 22 °C were evaluated and different groups of average size were formed of 7.6 ± 0.265, and 0.058 ± 4.9 3.7 ± 0.173 cm. In SOC test the average size groups were 8.1 ± 0.351, 0.058 ± 5.6 and 4.3 ± 0.100 cm. The results show a significant effect of temperature in CR (Lh-1) and IR (cel.h-1 x 10(5)) on the larger individuals (7.6 ± 0.265 cm), it was observed at 22 °C an average increase, about 17 °C, up to 250% to CR and 48% to IR. In addition, a direct relationship of body size with CR and IR in both temperatures was observed. The effect of temperature at 22 ° C on SOC in all groups was evaluated, with an increase of 239.8, 165.3 and 183.4% for size individuals of 8.1 ± 0.351, 0.058 ± 5.6 and 4.3 ± 0.100 respectively. Furthermore, in both evaluated temperatures, the results show an indirect relationship of body size with the SOC.
ABSTRACT
Recirculating aquaculture systems allow increased productivity during larval stages due to a greater control of water quality parameters. Dorada larvae (Brycon moorei) were used 12 hours post hatching (HPE) to evaluate three planting densities with four replicates per treatment and 10, 20 and 30 larvae L-1 (T1, T2 and T3, respectively). The larvae were fed with Bocachico (Prochilodus magdalenae) larvae, Artemia salina nauplii and a 40% crude protein (CP) commercial diet for 15 days. Results showed significant differences between treatments (p<0.0001) for weight gain and specific growth rate (TCE), where T1 performed better (73.24±19 mg and 14.21±5.02%, respectively); followed by T3 (67.15±24.3 mg and 13.94±7.51%) and T2 (55.67±18.33 mg and 13.36±5.75%). Survival rate was inversely related to density, with highly significant difference (p <0.0001) (39.37±6.84%, 28.00±2.80% and 14.87±6.47%) for T1, T2 and T3, respectively. Simultaneously, cannibalism was directly related to planting density. The highest profitability was obtained with T2.
Los sistemas con recirculación para acuicultura permiten el incremento de la productividad en la etapa de larvicultura, debido al mayor control de los parámetros de calidad de agua. Larvas de dorada (Brycon moorei) de 12 horas post eclosión (HPE) fueron utilizadas para evaluar tres densidades de siembra con cuatro replicas por tratamiento, 10, 20 y 30 larvas L-1 (T1, T2 y T3, respectivamente). Las larvas fueron alimentadas durante 15 días, con larvas de bocachico (Prochilodus magdalenae), nauplios de Artemia salina y una dieta comercial de 40% de proteína cruda (PC). Al final del experimento, los resultados muestran diferencias altamente significativas entre los tratamientos (p<0.0001) para ganacia de peso y tasa de crecimento específica (TCE), obteniendo un major desempeñoen T1 (73,24±19 mg y 14,21±5,02%, respectivamente); seguido por T3 (67,15±24,3 mg y 13,94±7,51%) y T2 (55,67±18,33 mg y 13,36±5,75%). La sobrevicencia se relacionó de manera inversa con la densidad con diferencia altamente significativa (p<0.0001) (39,37±6,84%; 28,00±2,80% y 14,87±6,47%) para T1, T2 y T3, respectivamente y, simultáneamente, el canibalismo fue directamente relacionado con la densidad de siembra. Por otro lado, la mayor rentabilidad fue obtenida con T2.
Os sistemas de recirculação de aquicultura permitir o aumento da produtividade na fase de larvicultura devido ao melhor controle dos parâmetros de qualidade da água. Larvas Bream (Brycon moorei) 12 horas após a eclosão (HPE) foram utilizados para avaliar três densidades de estocagem, com quatro repetições por tratamento, 10, 20 e 30 larvas L-1 (T1, T2 e T3, respectivamente). As larvas foram alimentadas durante 15 dias com bocachico larvas (Prochilodus magdalenae), náuplios Artemia salina e uma dieta comercial de proteína bruta de 40% (CP). No final da experiência, os resultados mostraram diferenças altamente significativas entre tratamentos (p < 0,0001) para o ganho de peso e taxa específica de crecimento (TEC), obtendo-se um grande desempeño en T1 (73,24±14,21 mg e 19±5,02%, respectivamente); seguido de T3 (67,15±24,3 mg e 13,94±7,51%) e T2 (55,67±18,33 mg e 13,36±5,75%). O sobrevicencia está inversamente relacionada com a densidade, com diferença altamente significativa (p<0,0001) (39,37±6,84%; 28,00%±2,80 e 14,87±6,47%) para T1 , T2 e T3, respectivamente e, simultaneamente, o canibalismo foi diretamente relacionada à densidade de estocagem. Por outro lado, o maior rendimento foi obtido com T2.
ABSTRACT
Objective. To evaluate a water recirculation system of rainbow trout fish culture at the recirculating laboratory of the Aquaculture Engineering Production Program of the Universidad of Nariño. Materials and Methods. There were cultured 324 rainbow trout (Oncorhynchus mikyss) fries in 12 plastic tanks of 250 L capacity in a recirculation aquaculture system which treatment system was made up by a conventional sedimentation tank, a fixed bead up flow biofilter with recycled PVC tube pieces used as carrier, and a natural degassing system; the sedimentation unit effluent was pumped to a reservoir tank by a centrifugal 2 HP after passed by gravity through the biofilter and was distributed to the 12 culture units in which there were injected a constant amount of air from a blower. Results. The waste water treatment system removes 31% of the Total Suspended Solids; 9.5% of total ammonia nitrogen, and increased the dissolved oxygen to the final effluent in a 6.5%. It was calculated a biomass increase of 305% on the 75 days, the mortality percentage registered during the research period was of 4.9%. Conclusions. The wastewater treatment system maintained the physic chemical water quality parameters in the recommended values for the specie. The values of weight and size gain, food conversion, mortality and biomass production reported were between the normal values of rainbow trout fish culture in recirculating systems.
Objetivo. Evaluar un sistema de recirculación de agua para cultivo de trucha arcoiris en el laboratorio de recirculación del Programa Ingeniería en Producción Acuícola de la Universidad de Nariño. Materiales y métodos. Se cultivaron 324 alevinos de trucha arco íris (Oncorhynchus mikyss) en 12 tanques plásticos de 250 L de capacidad en un sistema de recirculación para acuacultura cuyo sistema de tratamiento estuvo constituido por un sedimentador convencional, un biofiltro de flujo ascendente con medio soporte fijo conformado por segmentos reciclados de tubos PVC, y un sistema de desgasificación natural; el efluente del sedimentador fue elevado a un tanque reservorio por medio de una bomba centrífuga de 2 HP para después pasar por gravedad a través del biofiltro y posteriormente ser distribuido a las 12 unidades de cultivo a las que de manera permanente se inyectó aire proveniente de un blówer. Resultados. El sistema de tratamiento del agua removió 31% de los sólidos suspendidos totales; 9.5% del nitrógeno amoniacal total, e incrementó el oxígeno disuelto al efluente final en un 6.5%. Se calculó un incremento de la biomasa del 345% en los 75 días, el porcentaje de mortalidad registrado durante todo el periodo de estudio fue del 4.9%. Conclusiones. El sistema de tratamiento mantuvo los parámetros físico-químicos de la calidad de agua dentro de los rangos requeridos por la especie. El incremento de peso y talla, la conversión alimenticia, la mortalidad y la producción de biomasa reportaron valores normales para producción de trucha en sistemas de recirculación.
Subject(s)
Aquaculture , Therapeutics , Trout , Virus Cultivation , Water RecirculationABSTRACT
Objetivo. Comparar la eficiencia de remoción de sólidos, turbidez y color aparente en un decantador convencional y uno de columna en un sistema de recirculación acuícola (SRA) para cultivo de tilapia. Materiales y métodos. Se cultivaron tilapias con densidad entre 30 y 33 kg/m3 en un SRA, el cual constó de: caja de nivel constante, tubería en PVC, tres tanques de cultivo, decantador convencional de flujo horizontal (D.Con), decantador de columna de flujo ascendente (D.Col), reactor de lecho fluidizado trifásico, reactor para transferencia de oxígeno, compresor, blower, electrobomba. El D.Con operó con volumen útil (VU) de 1.4 m3 y tiempo de retención hidráulica (TRH) de 2.94 h, fue vaciado una vez por semana para lavado y colecta del lodo, representando sustitución del 55% del volumen del sistema. El D.Col operó con 0.30 m3 de VU y TRH de 0.553 h. Se realizaron 3 sangrados diarios, representando sustitución semanal de 50% del volumen. Resultados. Las eficiencias promedio de remoción fueron: para sólidos totales de 34.01 y 44.44%; sólidos suspendidos 64.45% y 71.71%; sólidos volátiles 21.10 y 45.65%; para turbidez 65.51 y 62.79%; para color aparente 56.37 y 50.91%, respectivamente en el D.Con y el D.Col. Conclusiones. Ambos decantadores son útiles en la remoción de los parámetros estudiados y presentaron comportamientos semejantes en remoción de turbidez y color aparente. Sin embargo, el D.Col es más eficiente que el convencional para remoción de los sólidos, ocupa menor espacio, menor volumen y requiere menor porcentaje de renovación, mostrando viabilidad para su utilización en SRA.
Objective. To compare the removal efficiency of solids, turbidity and apparent color between a conventional and a column settling tanks in a recirculating aquaculture system (RAS) for tilapia farming. Materials and methods. Tilapia with a stocking density between 30 and 33 kg/m3 were cultured in a RAS consisting of a water level control box, PVC piping system, three plastic tanks for culture, conventional horizontal flow settling tank (Con.ST), column vertical flow settling tank (Col.ST), three phase fluidized bed reactor, oxygen transfer reactor, air compressor, air blower, centrifugal pump. The Con.ST operated at a volume of 1.4 m3 and hydraulic retention time (HRT) of 2.94 h; and was drained weekly for washing and sludge collection, representing a 55%discharge of system water volume. The Col.ST operated with a volume of 0.30 m3 and HRT of 0.553 h. Three daily partial draining operations were executed, representing a discharge of 50% of the system volume. Results. The mean solids removal efficiencies were: 34.01 and 44.44%for total solids; 64.45 and 71.71% for suspended solids; 21.10 and 45.65% volatile solids; 65.51% and 62.79% for turbidity; and 56.37 and 50.91% for apparent color, respectively for Con.ST and Col.ST. Conclusions. The two settling devices are useful on removal of the studied parameters and presented similar performance on turbidity and apparent color removal; however, the Col.ST was more efficient than Con.ST for solids removal, requires less space, less volume and requires less discharge water volume, displaying feasibility for its use on RAS.
Subject(s)
Animals , Aquaculture , Gravimetry , Tilapia , Water RecirculationABSTRACT
The main objective of this study was to evaluate the ammonia removal efficiency in the wastewater treatment system of an intensive tilapia laboratory production system with water recirculation. The system comprised of a conventional sedimentation basin and an aerobic three-phase fluidized-bed reactor with circulation, operated at hydraulic detention times of 176.4 and 11.9 minutes respectively. Granular activated carbon was used as carrier with apparent density of 1.64 g/cm³ and effective size of 0.34 mm; the carrier concentration into the reactor was maintained constant at 80 g/L. Mean removal efficiency of total ammonia nitrogen was 41.2%. The evaluated system is an effective option for water reuse in aquaculture recirculating systems. In spite of ammonium nitrogen concentration variability which average value was 0.136 mg/L, the reactor influent maintained water quality characteristics in stable conditions, with average concentrations of ammonia nitrogen of 0.079 mg/L and dissolved oxygen concentration of 6.70 mg/L, recommended for fish culture and within the permitted values by the Brazilian legislation (CONAMA Resolution No. 357 of march 5 of 2005) for the disposal of final effluent in receiving water bodies.
O objetivo deste trabalho foi monitorar o desempenho de remoção de nitrogênio amoniacal no tratamento das águas residuárias da produção intensiva de tilápia nilótica em sistema com recirculação de água. O sistema foi constituído por um sedimentador convencional e um reator aeróbio de leito fluidizado trifásico com circulação, operados com tempos de detenção hidráulica de 176.4 e 11.9 minutos respectivamente. O meio suporte utilizado no reator foi o carvão ativado granular com densidade aparente de 1.64 g/cm³ e tamanho efetivo de 0.34 mm; a concentração do meio suporte no reator foi mantida constante em 80 g/L. A eficiência média de remoção do nitrogênio amoniacal total foi de 41.2%. O sistema avaliado é uma alternativa efetiva para o reuso da água em sistemas de recirculação para aqüicultura. Embora a variabilidade das concentrações do nitrogênio amoniacal afluente cujo valor médio foi de 0.136 mg/L, o efluente do reator conservou as características de qualidade da água estáveis, com concentrações médias de nitrogênio amoniacal de 0.079 mg/L e do oxigênio dissolvido de 6.70 mg/L, recomendáveis para a criação dos peixes e nas faixas de valores permitidos pela legislação Brasileira (Resolução CONAMA No. 357 de março 5 de 2005) para lançamento de efluentes finais nos corpos de água receptores.
El objetivo de este trabajo fue monitorear el desempeño de remoción de nitrógeno amoniacal en el tratamiento de las aguas residuales de producción intensiva de tilapia nilótica en un sistema con recirculación de agua. El sistema estuvo constituido por un sedimentador convencional y un reactor aerobio de lecho fluidizado trifásico con circulación, operados con tiempos de retención hidráulica de 176.4 y 11.9 minutos, respectivamente. El medio soporte utilizado en el reactor fue carbón activado granular con densidad aparente de 1.64 g/cm³ y tamaño efectivo de 0.34 mm; la concentración del medio soporte en el reactor se mantuvo constante en 80 g/L. La eficiencia media de remoción del nitrógeno amoniacal total fue de 41.2%. El sistema evaluado es una alternativa efectiva para el reuso del agua en sistemas de recirculación para acuicultura. Pese a la variabilidad de las concentraciones de nitrógeno amoniacal afluente cuyo valor promedio fue de 0.136 mg/L, el efluente del reactor mantuvo las características de calidad del agua en condiciones estables, con concentraciones promedio de nitrógeno amoniacal de 0.079 mg/L y de oxígeno disuelto de 6.70 mg/L, recomendables para el cultivo de los peces y en los valores permitidos por la legislación Brasilera (Resolución CONAMA No. 357 de marzo 5 de 2005) para lanzamiento de efluentes finales en cuerpos de agua receptores.
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O objetivo deste estudo foi avaliar o desempenho de um sistema de tratamento de lixiviado de aterro sanitário, em escala piloto, formado por três lagoas em série (L1, L2 e L3) seguidas por um filtro de pedras (FP). Foram estudadas três condições operacionais, verificando-se o efeito da recirculação do efluente da L3 para a L1: 0, 50 e 100 por cento da vazão. O sistema absorveu bem as flutuações de cargas, apresentando remoções superiores a 80 por cento para DBO F, 70 por cento para DQO T e 98 por cento para nitrogênio amoniacal. Na lagoa L2 houve nitrificação parcial, com acúmulo de nitritos. Ocorreu presença marcante do gênero Chlamydomonas nas lagoas L2 e L3 fotossintéticas. Observou-se diminuição da toxicidade do lixiviado, com reduções superiores a 95 por cento na saída do sistema. A melhor eficiência de remoção para as três condições operacionais estudadas foi obtida com 100 por cento de recirculação.
The objective of this study was to evaluate the performance of a landfill leachate treatment system, at pilot scale, formed by three in series ponds (L1, L2, and L3) followed by a rock filter. Three operational conditions were studied, assessing the effluent recirculation effect from L3 to L1: 0, 50 and 100 percent of the flow rate. The system assimilated well the load fluctuations, showing removal efficiencies over 80 percent for BOD F, 70 percent for COD T and 98 percent for ammonia. In the L2 pond there was partial nitrification with nitrite accumulation. It was observed an outstanding presence of the Chlamydomonas gender in photosynthetic ponds L2 and L3. A reduction of the toxicity from the landfill leachate was observed, with reduction of over 95 percent in the system output. The better removal efficiency for the three studied operational conditions was obtained for 100 percent of recirculation.
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To investigate the intestinal absorption of a fibrinolytic and proteolytic lumbrokinase extracted from Eisenia andrei, we used rat everted gut sacs and an in situ closed-loop recirculation method. We extracted lumbrokinase from Eisenia andrei, and then raised polyclonal antibody against lumbrokinase. Fibrinolytic activity and proteolytic activity in the serosal side of rat everted gut sacs incubated with lumbrokinase showed dose- and time-dependent patterns. Immunological results obtained by western blotting serosal side solution using rat everted gut sacs method showed that lumbrokinase proteins between 33.6 and 54.7 kDa are absorbed mostly by the intestinal epithelium. Furthermore, MALDI-TOF mass spectrometric analysis of plasma fractions obtained by in situ recirculation method confirmed that lumbrokinase F1 is absorbed into blood. These results support the notion that lumbrokinase can be absorbed from mucosal lumen into blood by oral administration.
Subject(s)
Animals , Rats , Administration, Oral , Blotting, Western , Endopeptidases , Intestinal Absorption , Intestinal Mucosa , Oligochaeta , Plasma , ProteinsABSTRACT
PURPOSE: We intended to evaluate myocardial oxygen consumption (MVO2) by applying recirculation correction and modified one-compartment model to have a reference range of MVO2 in normal young population and to reveal the effect of recirculation on time-activity curve (TAC). Materials and METHODS: In nine normal male volunteers with mean age of 26.3+/-4.0, MVO2 was estimated with 925 MBq (25mCi) of 11C-Acetate (Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon, Korea) and PET/CT (Biograph 6, Siemens Medical Solution, Germany). Analysis software such as MATLAB(R) v7.1 (Mathworks, Inc., United States), Excel(R) 2007 (Microsoft, United States), and SPSS(R) v12.0 (Apache Software Foundation, United States) were used. Twenty three frames were of 12 x 10, 5 x 60, 3 x 120, 2 x 300's duration, respectively. The modified one-compartmental model and the recirculation correction method were applied. Statistical analysis was performed by using Test of Normality, ANOVA and Post-Hoc (Scheffe's) analysis, and p-value less than 0.05 was considered as significant. RESULTS: The normal reference ranges of MVO2 were presented as 3.18-4.64 x 10(-4) ml/g/sec, 1.91-3.94 x 10(-4) ml/g/sec, 4.31-6.40 x 10(-4) ml/g/sec, 2.84-4.53 x 10(-4) ml/g/sec and 3.42-5.00 x 10(-4) ml/g/sec in the septum, the inferior wall, the lateral wall, the anterior wall and the entire wall, respectively. In addition, it was noted that the dual exponentiality of the clearance curve is due to the recirculation effect and that the characteristic of the curve is essentially mono-exponential. CONCLUSION: 11C-Acetate is a radiotracer worthwhile to assess MVO2. Re-circulated 11C can influence TAC of 11C in myocadia and so the recirculation correction must be considered when measuring MVO2.
Subject(s)
Humans , Male , Academies and Institutes , Acetates , Carbon , Oxygen , Oxygen Consumption , Positron-Emission Tomography , Reference ValuesABSTRACT
BACKGROUND: To assess the adequacy of dialysis, serial urea kinetic modeling (single-pool Kt/V) is used. The main problems that lead to impaired delivery of dialysis prescriptions are inadequate blood flow, reduced treatment time and recirculation. If it is true that the shorter distance between two needles induces the more recirculation, short needle distance would reduce Kt/V. But, usually there is no access recirculation, because upstream access supply exceeds the demand of the blood pump. So we have a question about the relationship between recirculation and needle distance. METHODS: Thirty five chronic dialysis patients were enrolled. We measured access recirculation (a two-needle, slow/stop flow method) and Kt/V with needle distance of 2 cm, 5 cm, and 11 cm in each patient. Three dialysis session were done with each needle distance. Treatment time, dialyzer and blood flow rate were fixed during the study period. RESULTS: Access recirculation with needle distance of 2 cm was 5.37+/-7.53%, with needle distance of 5 cm, 4.26+/-5.69%, and with needle distance of 11 cm, 4.30+/-5.69%. There was no difference of recirculation between three distance. Kt/V with needle distance of 2 cm was 1.27+/-0.19, with needle distance of 5 cm was 1.26+/-0.19, and with needle distance of 11 cm was 1.23+/-0.18. There was no difference of Kt/V between three distance. CONCLUSION: There is no relationship between access recirculation and needle distance. We suggest that short distance between two needles does not increase recirculation and may not a cause of impaired delivery of dialysis prescription.
Subject(s)
Humans , Dialysis , Needles , Prescriptions , Renal Dialysis , UreaABSTRACT
Aim The nasal absorption of furosemide and promotion action of l_menthol was examined. Methods In situ nasal recirculation methods was used to study the does_effect relationship of nasal absorption of furosemide and the effect of l_menthol on nasal absorption of furosemide in rats. Results When the concentration of furosemide in circulation liquid was respectively(4.66?0.33) ?(9.76?0.45) and (18.83?1.89) ?g?ml-1,the absorption rate constant k(min-1) of nasal in situ was correspondingly 0.0067?0.0011,0.0134?0.0024 and 0.0163?0.0037;and urine liquid appearing time was (73.33?1.53)?(52.67?7.02) and (47.00?4.58) min.But the larger the concentration of l_menthol, the little the absorption rate constant k. Conclusion Furosemide can be absorbed through the nasal mucous, and l_menthol can promote its absorption.
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Objective: To study the application of glucose infusion test (GIT) in assaying the vascular access recirculation rate in hemodialysis patients. Methods: Access recirculation was assayed by both urea test (UT) and GIT in 82 hemodialysis patients, and 17 patients were also examined by Doppler ultrosonics method. The results of the Doppler ultrosonics were compared with those of UT and GIT. Results: Thirty-seven (45.12%) patients showed positive results with GIT and 29 patients (35.36%) with UT.All 17 patients had recirculation confirmed by Doppler ultrosonics and all had positive results by GIT (100%), but only 9 (52.94%) of the 17 patients had positive results by UT. Conclusion: Comapared with UT, GIT is more sensitive, more ecnomical,and simpler in determining vascular access recirculation, and can be used as a new method for screening vascular access recirculation.
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Objective:To research the rule of melatonin nasal absorption.Methods: The stability of melatonin in rat nasal wash was studied, after that the in situ rat nasal recirculation methods were used as experimental animal model to study the rule of melatonin nasal absorption.Results:Melatonin was stable in rat nasal wash, its absorption in nasal cavity accorded with first order kinetic equation. The absorption rate constants did not vary with melatonin concentrations.Conclusion:The mechanism of melatonin nasal absorption is passive diffusion, the average absorption rate constant is 1.054?10 -2 min -1 .
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It has been known that access recirculation is positively related to dialyzer blood flow and is negatively related to access blood flow in the vascular access in hemodialysis patients. The present study was designed to examine whether an increase in access recirculation generated by an increase in dialyzer blood flow is related to access blood flow. All patients had native end-to-side arteriovenous anastomoses at the radial site. We measured access recirculation at two different dialyzer blood flow rates (85 and 170 ml/min) using a three-needle technique. Access blood flow rates (mean 668 ml/min ranging from 493 to 1038 ml/min) were measured using Doppler ultrasound sonography. We confirmed that an increase in dialyzer blood flow rate led to an increase in access recirculation (5.4±1.1 vs. 9.9±1.9%, p<0.05), and that access recirculation was negatively related to the access blood flow rate (y=-30.78x+972.20, r=-0.79, p<0.05). We further found a negative correlation between the increase in access recirculation generated by the increase in dialyzer blood flow rate and access blood flow rate (y=-33.88x+821.57, r=-0.75, p<0.05). These results suggested that dialyzer blood flow less affects access recirculation when access blood flow is higher.
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Blood recirculation in hemodialysis access is one of the factors decreasing dialysis efficiency. The purpose of this study was to evaluate access recirculation by the site of veins, length of catheters using the low-flow two-needle method in recently inserted temporary central vein catheterization used for hemodialysis in patients with chronic renal failure, and evaluate the reproducibility of low-flow method. A total of 56 measurements were performed in 15 chronic renal failure patients harboring 25 different catheters. Mean blood recirculation for the 56 measurements was 11.1+/-7.9%, it was significantly higher in the femoral catheters than in the subclavian catheters, reaching respective means of 17.9+/-6.5%, 5.2+/-2.3%. Blood recirculation rate was not different between 13.5cm and 19.5cm long subclavian catheters(5.3+/-2.7%, versus 5.5+/-1.7%), but was significantly higher in 13.5cm than in 19.5cm long femoral catheters(20.3+/-6.1% versus 13.3+/-4.8%, P=0.0067). Mean URR for the 56 dialysis sessions was 52.7+/-10.3%, it was significantly higher for sessions performed with subclavian than with femoral catheters(56.0+/-9.8% versus 48.8+/-9.7%, P=0.0088). An overall weak negative correlation of -0.42 was observed between blood recirculation and URR; the correlation was stronger for the sub-group of 19.5cm long femoral catheters, reaching -0.63. The obtained results were reproducible with a mean difference between two measurements in 18 cases of only 3.62+/-5.3% and a correlation of 0.68. The difference between blood recirculation rates in temporary femoral and subclavian catheters may be consequent to an anatomical factor. It may relate to the size of the vein, the blood probably having less possibility to recirculate near the tip of the catheter in a wider vein. In conclusion, femoral catheters particularily the shorter ones, are associated with significantly higher blood recirculation, and thus may consequently reduce the dialysis efficiency. In patients for whom dialysis dose is a priority, such as cases of intoxication for whom rapid and efficient toxic substance removal is mandatory, we think the subclavian catheters may become a first choice.
Subject(s)
Humans , Catheterization , Catheters , Dialysis , Kidney Failure, Chronic , Renal Dialysis , VeinsABSTRACT
OBJECTIVES: Recirculation is one of the factors preventing effective hemodialysis(HD) and one of the methods which can detect vascular access stenosis. We analyzed the possible clinical risk factors and relationship between the recirculation rate(R) and adequacy of hemodialysis. Also, we attempted to find out whether vascular access stenosis actually exist in the high R group. METHODS: We examined the period of hemodialysis, the presence of diabetes mellitus(DM), use of artificial grafts, the venous pressure(VP) during HD, the difference(deltaKt/V) between prescribed Kt/V(Kt/V') and delivered Kt/V(Kt/V") in 113 patients(22 DM, 39 artifical graft patients) receving maintenence HD. R was obtained by two needle slow flow method. Fistulogram was performed in the high R group(R>10%) and if significant stenosis was found, surgical correction was performed followed by repeated R, VP, Kt/V" measurement. RESULTS: As a whole R was 5.6%(+/-8.8), VP was 92mmHg(+/-44), the duration of hemodialysis was 36 months(+/-25) and Kt/V" was 1.20 (+/-0.29). The VP of the group with artificial graft was higher than that of the group with native fistula, but there was no relationship between R and duration of HD, Kt/V", deltaKt/V as a whole. The VP and deltaKt/V of group with high R(>10%) were significantly higher than the group with low R(or=100mmHg) than in the group with low VP(<100mmHg) as well as in patients with diabetes or prosthetic grafts, CONCLUSION: We believe recirculation should be measured during maintenance HD especially when the patient has diabetes, artificial graft or high venous pressure during HD. When the recirculation rate is high, reconstructive vascular surgery with proprer mediacl management may lead to better dialysis adequacy.