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Remediation of soils contaminated with trichloroethylene

Albergaria J. T., Alvim-Ferraz M. C. M., Delerue-Matos C. M.

Environmental Biotechnology

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2010

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Vol. 6, No. 2

37-41

EN

Soil contamination is a common problem in our society. Several activities introduce contaminants in soils affecting their quality and future utilization. In order to invert this situation and to avoid further spreading of the contaminant several remediation technologies could be used. For soils contaminated with trichloroethylene (TCE), Soil Vapor Extraction (SVE) can be an efficient remediation technology. It involves the application of vacuum to the soil matrix creating an airflow that conduce the volatized contaminant to extraction wells that lead them to the exterior of the soil where they are properly treated. This work presents the results obtained in the soil vapor experiments performed in a laboratory using soils with different water contents contaminated with TCE. These experiments aimed the study of the influence of soil water content and the airflow used in the remediation time and on the process efficiency. The results showed that in sandy soils contaminated with TCE: a) for similar levels of contamination, the increase of the soil water content from 0 to 4% created an increase of the concentration of TCE in the gas phase of the soil, in some cases by almost 50%; b) the influence of water content is not significant being overlapped by influence of the airflow rate; c) SVE performed with higher airflow rates had shorter remediation times (in some cases four times shorter) without any significant impact on the process efficiencies (fluctuations of 1 to 3%); and d) for the experimented soils, the utilization of higher airflow rates led to shorter and consequently cheaper remediation.

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Desorpcja zanieczyszczeń z gruntu wspomagana ogrzewaniem mikrofalowym

Dakiniewicz P., Araszkiewicz M., Kozioł A.

Inżynieria i Aparatura Chemiczna

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2006

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Nr 5s

32-36

EN

The paper describes experimental results of soil vapour extraction. The experiments were conducted in a specially designed semi-industrial scale apparatus. The influence of various parameters on SVE was analyzed, viz.: direction of microwave propagation, type of removed substance and soil initial moisture content.

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Symulacja rozkładów ciśnień i prędkości przepływu powietrza w procesie desorpcji próżniowej zanieczyszczeń z gruntu

Kawala Z., Dakiniewicz P., Czerniak H., Araszkiewicz M.

Ochrona Środowiska

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2002

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nr 3

15-21

EN

Soil and groundwater contamination by petroleum hydrocarbons and organic solvents has become a worldwide problem, which primarily faces high-technology countries. Soil vapor extraction (SVE) of volatile and some semivolatile compounds is rapidly being recognized as a technically and economically sound alternative to the available methods of cleaning chemically polluted soils. SVE entails the induction of an advective air phase through the contaminated vadose zone of the soil. In the unsaturated zone, the air flow can be established with combinations of withdrawal (extraction) and injection (if required) wells. Air laden with the contaminant vapors moves along the induced flow paths toward the withdrawing system, where it is subject to after-treatment. If the process is carried out for a sufficiently long time, it will be possible to remove all of the contaminants from the soil. The use of the SVE method provides continuous air flow through the vadose zone, which is a requisite for an efficient cleaning operation. A reliable assessment of the pressure distributions in the vicinity of the extraction wells, and a thorough analysis of the air flow conditions are of great importance to the design of an optimal SVE system, as well as to the determination of the major operating parameters. The present paper describes a three dimensional mathematical model which predicts the steady-state air flow through the unsaturated zone of the soil. The paper also includes the results of a computer simulation of air flow in soils, using the AIR3D software developed by loss and Baehr. With this software it was possible to examine how the properties of the soil (porosity, permeability and anisotropy) and the operating parameters of the SVE system (number and arrangement of the wells, depth and length of the filters, vacuum head in the wells) affect the pressure distribution, the mass and volumetric air flow rate, as well as the components of the air velocity vector in the soil.

4

Modelowanie wspomaganego termicznie procesu desorpcji próżniowej zanieczyszczeń z gruntu

Dakiniewicz P., Kawala Z.

Inżynieria Chemiczna i Procesowa

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2001

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T. 22, z. 3B

361--366

PL

W pracy przedstawiono równania bilansowe masy, pędu i ciepła opisujące proces desorpcji próżniowej zanieczyszczeń z gruntu. Zaprezentowano przykładowe obliczenia numeryczne przeprowadzone na podstawie powyższych równań, które porównano z wynikami badań eksperymentalnych.

EN

In article were presented equations of mass, motion and heat transfer describing process of soil vapour extraction. Results of calculations were compared with experimental measurements.