JP2015231589A - Elutriation treatment method of contaminated soil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an elutriation treatment method of contaminated soil which can remove volatile substances from the contaminated soil containing at least volatile substances as a pollutant efficiently and effectively.SOLUTION: In an elutriation treatment method of contaminated soil containing at least volatile substances, volatilization of the volatile substances is promoted by sieving the contaminated soil with a vibrating screen, and the volatile substances are removed from the contaminated soil.

Description

  The present invention relates to a method for purifying contaminated soil.

  Conventionally, a soil cleaning treatment method has been frequently used as one of the technologies for purifying contaminated soil. This soil cleaning treatment method is a method for purifying contaminated soil by washing contaminated soil excavated and removed from the contaminated site with a cleaning solution such as water and separating and removing the contaminant from the soil (see, for example, Patent Document 1). ).

 On the other hand, at this time, since the contaminants tend to be adsorbed on the fine particles of silt and clay, when applying the soil washing method, as shown in FIG. The contaminated soil is separated (classified) into coarse particles and fine particles on the basis of the particle size. And, from the viewpoint of purification efficiency, etc., fine particles with high pollutant concentration are taken out and disposed as concentrated contaminated soil, and the coarse particles are washed and reused after washing. I have to.

JP 2006-255515 A

  However, the conventional soil washing treatment method is generally applied to purification treatment of soil contaminated with non-volatile substances (difficult (low) volatile substances) such as heavy metals and organic pollutants other than volatile substances. Therefore, application to soil contaminated with volatile substances such as benzene, trichlorethylene, and tetrachloroethylene is considered difficult because of the need to control the volatilization of the pollutants and hence the diffusion.

  In the past, when trying to purify complex contaminated soil containing volatile substances and non-volatile substances as pollutants by the soil washing treatment method, volatilization from the contaminated soil in a separate process such as quick lime mixing treatment method is carried out in advance. The non-volatile substances are removed from the contaminated soil after the treatment in this separate process by the soil washing treatment method. For this reason, a great deal of labor and labor are required for the purification treatment of contaminated soil.

  In view of the above circumstances, the present invention provides a method for purifying contaminated soil that enables efficient and effective removal of volatile substances from contaminated soil containing at least volatile substances as contaminants. Objective.

  In order to achieve the above object, the present invention provides the following means.

  The method for purifying contaminated soil according to the present invention is a method for purifying contaminated soil containing at least a volatile substance as a pollutant, wherein the volatile substance is volatilized by sieving the contaminated soil with a vibration sieve. And the volatile substances are removed from the contaminated soil.

  In the method for purifying contaminated soil according to the present invention, the volatile substances are removed from the contaminated soil when the contaminated soil is screened as a pretreatment for cleaning the contaminated soil by a soil washing treatment method. You may do it.

  In the contaminated soil purification treatment method of the present invention, at least when contaminated soil containing volatile substances such as benzene, trichlorethylene, and tetrachloroethylene as a contaminant is purified, the contaminated soil is screened with a vibration sieve. Thus, the contaminated soil can be made into particles to increase the contact area with the air, and further, the soil particles can be treated to be stirred and mixed. Thereby, volatilization of the volatile substance (pollutant) contained in the contaminated soil can be promoted, and the volatile substance can be efficiently and effectively removed from the contaminated soil.

  In addition, conventional soil such as when soil-contaminated contaminated soil containing volatile substances and non-volatile substances (including difficult (low) volatile substances) as contaminants is subjected to purification treatment by applying the soil washing method. In the case of sieving treatment by vibration sieving of contaminated soil as a pretreatment of the washing treatment method, volatile substances are removed from the contaminated soil, so there is no need for a separate process for removing volatile substances. Volatile substances can be removed in a series of working steps. As a result, it becomes possible to efficiently and effectively purify contaminated soil containing volatile substances as contaminants by applying the soil washing treatment method.

It is a figure which shows the purification mechanism of a soil washing | cleaning processing method.

  Hereinafter, a purification treatment method for contaminated soil according to an embodiment of the present invention will be described.

  In the contaminated soil purification treatment method of the present embodiment, at least contaminated soil containing volatile substances such as benzene, trichlorethylene, and tetrachloroethylene as a contaminant is subjected to a sieving process using a vibration sieve. For example, the contaminated soil is screened into fine particles and coarse particles using a sieve having a sieve size of about 0.5 mm.

  Here, when the contaminated soil containing a volatile substance is generally stirred by using a backhoe bucket or the like, volatilization of the volatile substance is promoted by the aeration action by the stirring of the soil, and the purification treatment can be performed to some extent.

  For this reason, as described above, when contaminated soil containing volatile substances is screened with a vibration sieve, the contaminated soil becomes particles and the contact area with the air increases, and the soil particles are further agitated and mixed. Volatilization of volatile substances contained in the soil is promoted.

  Accordingly, the volatile substances are efficiently and effectively removed from the contaminated soil by performing the sifting process on the contaminated soil with the vibration sieve as in the method for purifying the contaminated soil of the present embodiment.

  At this time, in order to prevent the volatile substances volatilized from the contaminated soil from diffusing outside, it is desirable to surround the vibrating screen with a hood or the like (outer body). Then, the internal air of the hood is appropriately sucked, and the volatile substances in the air are adsorbed and removed with activated carbon, so that the air is discharged to the outside in a clean state containing no pollutants.

  Furthermore, volatile substances may be removed from the contaminated soil when the contaminated soil is screened as a pretreatment for cleaning the contaminated soil by a soil cleaning treatment method.

  Specifically, contaminated contaminated soil containing volatile substances and non-volatile substances such as heavy metals (including difficult (low) volatile substances) as contaminants is purified by applying the soil washing treatment method. In this case, in the case of the sieving process by the vibration sieving of the contaminated soil performed as the pretreatment of the conventional soil cleaning treatment method, the volatile substances are removed from the contaminated soil together with the sieving process by the vibration sieving as described above. Accordingly, the volatile substance can be removed within a series of work steps of the soil washing treatment method without requiring another process such as a quick lime mixing method for removing the volatile substance.

  Therefore, in the method for purifying contaminated soil according to the present embodiment, when the contaminated soil containing at least a volatile substance as a contaminant is purified, the contaminated soil is subjected to a sieving process using a vibration sieve, so that the contaminated soil becomes particles. To increase the contact area with the air, and further, the soil particles can be processed to be stirred and mixed. Thereby, volatilization of the volatile substance (pollutant) contained in the contaminated soil can be promoted, and the volatile substance can be efficiently and effectively removed from the contaminated soil.

  In addition, vibration of contaminated soil that is performed as a pretreatment of conventional soil cleaning treatment methods, such as when soil-contaminated contaminated soil containing volatile substances and non-volatile substances as contaminants is purified by applying the soil cleaning treatment method. During sieving by sieving, volatile substances are removed from contaminated soil, eliminating the need for a separate volatile substance removal process and eliminating volatile substances within a series of work steps in the soil cleaning process. be able to. In other words, it becomes possible to purify the contaminated soil contaminated with complex contamination only by the soil washing treatment method. As a result, it becomes possible to efficiently and effectively purify contaminated soil containing volatile substances as contaminants by applying the soil washing treatment method.

  As mentioned above, although one Embodiment of the purification processing method of the contaminated soil which concerns on this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning, it can change suitably.

Claims (2)

A method for purifying contaminated soil containing at least a volatile substance as a contaminant,
A method for purifying contaminated soil, wherein the contaminated soil is screened with a vibration sieve to promote volatilization of the volatile substances to remove the volatile substances from the contaminated soil. In the purification treatment method of the contaminated soil according to claim 1,
The method for purifying contaminated soil, wherein the volatile substances are removed from the contaminated soil when the contaminated soil is screened as a pretreatment for cleaning the contaminated soil by a soil cleaning treatment method. .

Images