RESUMO
A sorptive slurry bioscrubber adds powdered activated carbon (PAC) to a conventional suspended-growth bioscrubber. The activated carbon increases pollutant removal from the gas phase due to adsorption on carbon. The carbon is bioregenerated in the oxidation reactor and recycled to the scrubbing column. A three-stage, conventional bioscrubber was tested with and without carbon. The experiments showed that the PAC improved the removal efficiency of the system and that bioregeneration occurred. At an inlet gas-phase acetone concentration of 50 ppmv, the steady-state removal increased from 88 to 95% when activated carbon was added to the biological slurry.
Assuntos
Acetona/metabolismo , Poluição do Ar/prevenção & controle , Solventes/metabolismo , Acetona/análise , Adsorção , Bactérias , Biodegradação Ambiental , Biomassa , Carvão Vegetal , Solventes/análiseRESUMO
A theory was developed to predict the average gamma absorbed dose rates due to a continuous Gaussian plume that meanders due to variations in the wind's direction caused by large-scale eddies. Such meandering often occurs under very stable, low-wind conditions. The theory is based on Gifford's fluctuating Gaussian plume model. Approximate calculations based on this theory were compared to traditional approaches based on an average concentration distribution.
Assuntos
Acidentes , Poluentes Radioativos do Ar , Reatores Nucleares , Radiometria/métodos , Raios gama , Modelos TeóricosRESUMO
A simple approximation for estimating the centerline gamma absorbed dose rates due to a continuous Gaussian plume was developed. To simplify the integration of the dose integral, this approach makes use of the Gaussian cloud concentration distribution. The solution is expressed in terms of the I1 and I2 integrals which were developed for estimating long-term dose due to a sector-averaged Gaussian plume. Estimates of tissue absorbed dose rates for the new approach and for the uniform cloud model were compared to numerical integration of the dose integral over a Gaussian plume distribution.
Assuntos
Poluentes Radioativos do Ar , Poluentes Atmosféricos , Doses de Radiação , Raios gama , Matemática , Modelos Teóricos , RadioisótoposAssuntos
Poluentes Radioativos do Ar , Poluentes Atmosféricos , Doses de Radiação , Radioisótopos , Acidentes , Raios gama , Humanos , Matemática , Métodos , Modelos Teóricos , Reatores NuclearesRESUMO
An exact solution is presented for the classical Gaussian cloud approximation for long-term averaged estimates of gamma absorbed dose due to a ground-level release of radioactive gases and particles. The solution is in the form of relatively simple functions and is much easier to implement than the traditional solution. Also, it is shown that the Gaussian cloud approximation predicts lower absorbed dose than the uniform cloud approximation. The difference is significant when the product of gamma attenuation coefficient and vertical dispersion coefficient is small. Since the Gaussian cloud approximation is based on a more realistic concentration distribution than the uniform cloud approximation, the calculations using the former should give more accurate estimates of the long-term averaged dose for the sector-averaged plume.
