JP2755083B2 - Contaminated soil cleaning method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cleaning soil contaminated with water-insoluble or hardly water-soluble organic chemicals with water.

[0002]

2. Description of the Related Art In recent years, a large number of inorganic chemicals and organic chemicals have been used in the manufacturing process of various products in the industrial world. It must be properly managed and disposed of in accordance with waste disposal and cleaning laws. However, there is an inevitable possibility of polluting the surrounding land due to a large amount of chemical spills due to troubles in the manufacturing process of products or treatment of used chemicals, and the accumulation of spilled chemicals over many years. It is a real and sometimes big problem.

[0003] When the land is contaminated with chemicals,
Conventionally, the contaminated soil is separately treated or stored in an appropriate treatment facility or storage facility, or the underground part around the contaminated land is blocked by an impermeable structure so that the contaminated water does not flow out of the contaminated land. Alternatively, there was no proper measure except relying on the natural purification power.

[0004] However, using contaminated soil treatment facilities and storage facilities is costly, and blocking contaminated land makes it impossible to reuse the contaminated land for a long time.
In addition, since it takes a long time to be able to reuse natural resources because it depends on the purification power of nature, there has been no proper cleaning method to efficiently reuse contaminated land. .

[0005]

SUMMARY OF THE INVENTION Therefore, the present invention
An object of the present invention is to provide a method for economically and efficiently cleaning soil contaminated with a water-insoluble or hardly water-soluble organic chemical such as trichlorethylene and perchlorethylene.

[0006]

According to the present invention, a plurality of drain wells are drilled in a land contaminated with a water-insoluble or poorly water-soluble organic chemical, and then clean water containing an emulsifier is conveyed from the ground to the contaminated land. While sprinkling water, the contaminated soil in the hard ground or poorly permeable ground is ground by a water jet, and contaminants are removed by contaminant treatment by adsorption or coagulation sedimentation from contaminated water passing through the soil and drained from the drain well. Contaminated soil cleaning method. Is the gist.

The present invention will be described below in detail with reference to the drawings.

[0008] The present invention is directed to a case in which pollution has progressed for a long period of time, and the pollution has penetrated into a hard ground deeply underground, a poorly permeable ground, and the like.

A description will be given with reference to FIG.

A plurality of deep wells, well points and other drainage wells 2 are drilled by vertically penetrating the contaminated soil 1 in the contaminated land. The inner diameter and the number of drain wells 2 are appropriately selected according to the size and degree of contamination of the contaminated land, the nature of the soil, the type of contaminants, etc. Tens cm to several meters is sufficient, and the number of drain wells 2 is generally about several to several tens. The arrangement of the drain wells 2 may be lattice-like, concentric, or random. Further, it is preferable that the wall of the drain well 2 has water permeability so that the contaminated water after passing through the contaminated soil 1 can flow down to the drain well 2. Alternatively, when a reinforcing material is disposed on the wall of the drain well 2, the reinforcing material is made of a water-permeable material such as a wire mesh or a porous material.

A middle part of the drain well 2 is bored, and a water jet device 8 and a pipe are inserted into the bore.

Water is sprayed on the contaminated soil 1 by operating the water jet device 8, and the contaminated soil 1 is pulverized to improve the efficiency of emulsification and dispersion of the contaminated chemicals. The apparatus 3 sprays clean water containing an emulsifier from the ground to the entire contaminated land. When this water jet device 8 is used, the water in the contaminated soil 1 fluctuates up and down in the direction of arrow B due to its action, thereby promoting the emulsification and dispersion of the contaminated chemicals.

In the case of watering, if there is a particularly highly contaminated area, it is preferable to concentrate on that area. In any case, water is sufficiently dispersed throughout the contaminated land. The sprinkled water stays in the contaminated soil 1 for a while, and the contaminants are emulsified and dispersed by the action of the emulsifier added during that time to take in the contaminated water and become contaminated water, filling the contaminated soil 1. The water contaminated in this manner is drained (arrow A) by a suitable drainage device 5 such as a drainage pump connected to the drain well 2, and the contaminated water is separately treated by a water treatment facility / equipment. Sprinkling and draining operations can generally be performed continuously or discontinuously (ie, intermittently), but during operation, the level of contaminated water filling the contaminated soil 1 is kept to a minimum. It is necessary to maintain the water level sufficiently higher than 4. Contaminated soil 1 is a clayey soil or hard ground with low water permeability and emulsification of contaminated chemicals by clean water.
Since the dispersion efficiency is low, it is preferable to repeat the intermittent operation of temporarily holding the clean water to a considerably high water level, leaving it for a certain period of time, then draining it at that water pressure, and interrupting the drainage before reaching the minimum water level of 4. . In this case, the water level of the sprinkled water fluctuates up and down near arrow B. Water treatment facilities and equipment for treating contaminated water to remove pollutants may be mobile or fixed.Fixed water treatment facilities and equipment have large-scale contamination and purify contaminated soil. It is appropriate to use it when it takes a long time. The water treatment is performed by an adsorption method using an adsorbent such as activated carbon or a coagulation precipitation method using a coagulant. It is natural that non-polluting materials are used for the emulsifier, the adsorbent, and the flocculant added to the clean water. As the water treatment method, an adsorption method using an adsorbent is preferable in terms of treatment efficiency and miniaturization of the apparatus.

In the example of FIG. 1, the surrounding of the contaminated soil 1 is not blocked by the impermeable structure from the surrounding land. However, depending on the topography, it is preferable to provide an impermeable structure to block the surrounding land. Of course.

The cleaning method of the present invention uses water containing an emulsifier as a cleansing agent while crushing contaminated soil on hard ground or poorly permeable ground with a water jet. Organic chemicals are relatively easily emulsified and dispersed in water and discharged, and the pollution degree can be reduced to a safe level at an early stage.

[0016]

According to the method for cleaning contaminated soil of the present invention,
The following effects are obtained.

(1) Contaminated land can be economically and efficiently purified, and the land can be actively recycled.

(2) Secondary pollution of surrounding rivers and the like can be promptly prevented.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an example of a state of a cleaning process according to the present invention.

[Explanation of symbols]

1 ... contaminated soil, 2 ... drain well, 3 ... sprinkler, 4 ... minimum water level, 5 ... drain, 8 ... water jet.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B09C 1/00-1/10 A62D 3/00 E02D 3/10

Claims (1)

(57) [Claims] Claims 1. After drilling a plurality of drain wells on a land contaminated with water-insoluble or poorly water-soluble organic chemicals,
While spraying clean water containing an emulsifier from the ground onto the contaminated land, the contaminated soil in the hard ground or poorly permeable ground is crushed by a water jet, and absorbed from the contaminated water passed through the soil and drained from the drain well. Alternatively, a method for cleaning contaminated soil, comprising removing contaminants by coagulation and sedimentation.