Laboratory testing, soil decontamination

Fig. 15.31. One-dimensional laboratory test apparatus. (Reprinted from R. J. Gale, Soil Decontamination Using Electrokinetic Processing, in Environmental Oriented Electrochemistry, C. A. C. Sequeira, ed., Fig. 4, p. 362, copyright 1994. Reproduced with kind permission of Elsevier Science-NL, Sara Burgerhartstraat 25, 1055 KV Amsterdam, The Netherlands.)...

Laboratory and field testing determined the effectiveness of a new decontamination process for soils containing 2,4-D/2,4,5-T and traces of dioxin. The process employs three primary operations - thermal desorption to volatilize the contaminants, condensation and absorption of the contaminants in a solvent, and photochemical decomposition of the contaminants. Bench-scale experiments established the relationship between desorption conditions (time and temperature) and treatment efficiency. Laboratory tests using a batch photochemical reactor defined the kinetics of 2,3,7,8-TCDD disappearance. A pilot-scale system was assembled to process up to 100 pounds per hour of soil. Tests were conducted at two sites to evaluate treatment performance and develop scale-up information. Soil was successfully decontaminated to less than 1 ng/g... 

Many earlier geotechnical studies exist of the electroosmotic effect in soils and clays with an emphasis on dewatering in this chapter we limit the discussion to the more recent activities aimed at decontamination of pollutants. Most laboratory tests have used a onedimensional geometry and inert carbon electrodes. 

Interest in soil decontamination by electrokinetic processing has been increasing steadily, as shown by the volume of scientific studies. There have been two workshop/conferences dedicated to this topic in the U.S. in recent years [86,87] and a number of companies now have offered specialized services in this area. The technology is an emerging one and it is not yet fully mature. There exists a need to conduct further basic and applied studies before it achieves its full potential. In environmental remediation, the site chemistry before and after any application of technical processes need to be fully evaluated. It is recommended that bench scale, laboratory tests be undertaken prior to any site work to help optimize the process parameters. Although the... 

Applying this soil remediation technology requires special expertise this chapter describes the technology and its applications, indicating the materials and decontamination methods that can be used and how the system should be initiated and controlled. It also specifies the samples that need to be taken in order to monitor the decontamination process. Before remediation can commence, however, it is first necessary to clarify where contamination is present in the area of soil concerned and in what form. It is furthermore necessary to perform electrokinetic laboratory tests with one or preferably more representative soil samples. Finally, it is explained how the data are analyzed and used for carrying out the design of the remediation system. 

Most of the studies done, by Munnecke were small scale laboratory studies. The efficacy of parathion hydrolase has not been tested under field conditions. It was the major objective of our study to determine the usefulness of parathion hydrolase for the decontamination of high concentrations of formulated diazinon in soil under greenhouse conditions. A secondary, but very important, objective was to determine if the enzyme could be handled in a practical fashion as would be done in the field and retain its ability to degrade diazinon. 

Comparison of Laboratory and Field Test Data in the Chemical Decontamination of Dioxin-Contaminated Soils... 

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