US 20030210956A1 (19) United States (12) Patent Application Publication (10) Pub. No.: US 2003/0210956A1 Tanaka et al. (43) Pub. Date: Nov. 13, 2003 (54) METHOD FOR PURIFYING ALAYER OF Publication Classification CONTAMINATED SOIL AND APPARATUS (51) Int. Cl." ....................................................... B09C 1/02 (75) Inventors: Takeshi Tanaka, Tokyo (JP); Hisashi (52) U.S. Cl. ................................... 405/128.25; 405/128.5 Nirei, Chiba (JP); Kenji Nanba, Chiba (JP); Mio Takeuchi, Ibaragi (JP); Asuka Takahashi, Tokyo (JP); Masato (57) ABSTRACT Owaki, Ibaragi (JP) A method for purifying a layer of contaminated Soil is Correspondence Address: provided, including the following steps: (a) preparing an ARMSTRONG.WESTERMAN & HATTORI, injection well for injecting a fluid which has a purification LLP capability utilizing one of physical action, chemical reac 1725 KSTREET, NW tion, metabolism of microbes and promotion thereof and SUTE 1000 highly pressurized washing into the layer and (b) injecting WASHINGTON, DC 20006 (US) the fluid under a high pressure at which one of the physical (73) Assignee: TANAKA KANKYO-KAHATSU action, chemical reaction, metabolism of microbes and pro CO., Tokyo (JP) motion thereof and highly pressurized Washing can be controlled, through injection nozzles provided on a first wall (21) Appl. No.: 10/337,381 or a first bottom of the injection well. The method has features that the injected fluid Stirs and washes the layer to (22) Filed: Jan. 7, 2003 Separate or decompose contaminants and the contaminants (30) Foreign Application Priority Data are eliminated by collecting the fluid containing an unde composed portion of the contaminants in the layer through May 10, 2002 (JP)...................................... 2002-136126 a plurality of collection wells. 4 TO THEATMOSPHERE 8- 10m >3SLEC2 X ge 7 Y 79%Y72 !e IL 22b | 22 LAYER OF SOL Patent Application Publication Nov. 13, 2003 Sheet 1 of 8 US 2003/0210956A1 aa 1P a rete 12 ce. e Sec 5at as5 - to as at ec 92 as S 912 Sisa ses is sa EeES S3as S. Patent Application Publication Nov. 13, 2003 Sheet 2 of 8 US 2003/0210956A1 Z~SIDI–|| /E7/D/,/ ZZ}CIZZ TIOSHOHB)\WT 2.---T-~SA-T-S. I-AØ TOE:A£4,ZWZ Patent Application Publication Nov. 13, 2003 Sheet 3 of 8 US 2003/0210956A1 FIG 3 Patent Application Publication Nov. 13, 2003 Sheet 4 of 8 US 2003/0210956A1 Patent Application Publication Nov. 13, 2003 Sheet 5 of 8 US 2003/0210956A1 FIG5 S1 TO FRACTUREALAYER S2 TO CREATE ASATURATED ZONE TO RECYCLE THE FLUID S3 TO LIFT AFLUED WITH PRESSURIZED AIR S4 S5 S6 S7 Patent Application Publication Nov. 13, 2003 Sheet 6 of 8 US 2003/0210956A1 FIG.6 (K) ( C. |- 1C 2m 2m 2m 2m <-- - - Patent Application Publication Nov. 13, 2003 Sheet 7 of 8 US 2003/0210956A1 FI G. 7 START S11 TODRILL WELS INAGRID S12 TO ASSIGN WELLY IN THE CENTER OF CONTAMINATED AREAFOR ANNECTION WELL S13 TO ASSIGN OTHER WELLSA-XFOR COLLECTION WELS S4 TO MEASURE THE CONCENTRATION OF CONTAMINANTS FOREACH COLLECTION WELL S15 TO ASSIGN WELLS Q, R, S, T, U, W, WANDX RIGHT NEARTHEINJECTION WELLY FOR COLLECTION WELLS S16 TO ROTATE THENJECTION WELL FROMY TOX S17 TO ASSIGN WELLSP, Q, R. Y. W. W. N., AND ORIGHT NEARTHENJECTION WELLXFOR COLLECTION WELS S18 TO ROTATE THE INJECTION WELL FROMX TOW, V, U, T, S, R, Q SEQUENTIALLY S 19 TOREPEAT THE STEPSASSIGNING AWELL OF NCOMPLETEPURIFICATION FORTHENJECTION COMPLETION OFPURIFICATION NO YES CEND D Patent Application Publication Nov. 13, 2003 Sheet 8 of 8 US 2003/0210956A1 s WWOOuu09 WWOO uuOg s: S. US 2003/0210956 A1 Nov. 13, 2003 METHOD FOR PURIFYING ALAYER OF augmentation, is likely to cause undesired diffusion of CONTAMINATED SOIL AND APPARATUS bacteria into a Surrounding layer of Soil, thereby resulting in harmful side effects. It would therefore be difficult to adopt FIELD OF THE INVENTION this method publicly for fear of Secondary contamination. 0001. The present invention relates to a method and an 0008. In a conventional vacuum extraction method, a apparatus thereof for purifying in situ a layer of Soil (Soil level of groundwater rises due to pressure reduction in a layer, bedrock and groundwater) contaminated by harmful layer of contaminated Soil. This will lead to a reduction in a chemical materials. Zone from which contaminants can be extracted by vacuum extraction in a case where the contaminants are VOCs BACKGROUND OF THE INVENTION described above, thereby resulting in low efficiency of 0002 Contamination of a layer of soil by not only purification. To be more specific, Since it is difficult to well-known heavy metals but also volatile organochlorine volatilize VOCs, which exist in water in a layer of contami chemical materials (hereinafter referred to as VOCs), for nated Soil deep in a Zone of Saturation under the level of example organic Solvents Such as trichloroethylene and groundwater, only a portion of the layer of contaminated Soil tetrachloroethylene, has recently posed a Serious Social above the level of groundwater can be purified. Therefore, problem. An apparatus for purifying a layer of contaminated the deepest portion of a well for vacuum extraction has not Soil, which makes an in Situ purification feasible by utilizing been used efficiently biodegradation of microbes in addition to a chemical approach, has been under way Such that these heavy metals SUMMARY OF THE INVENTION and VOCs (hereinafter also referred to as contaminants) can 0009. The items which are required for treatment of a be eliminated to be harmless effectively and efficiently. layer of Soil contaminated by harmful chemical materials 0003. Also a method, a combination of physical/chemical will now be described. method and biological one, which can provide an easy 0010 First, a purification method is required, which treatment for organochlorine compound in a shorter period enables not only complete in Situ purification for a layer of of time, has been attracting attention. Hopes have been put contaminated Soil but also prevention of the spread of on these methods for purifying a layer of contaminated Soil Secondary environmental contamination. Technique which in Situ, which do not require large-scale drilling of Soil can exert purification on the deepest layer of contaminated containing contaminants, transportation or burying back Soil and prevent Side effects caused by chemical materials thereof, thereby making it feasible to perform purification at and/or microbes is necessary for this method, when a fluid a low cost. having a purification capability utilizing one of physical 0004 Specifically, some examples for the method for action, chemical reaction, metabolism of microbes and purification utilizing physical/chemical method and micro highly pressurized Washing is injected through a well. biological method (bioremediation) are known. One method can provide treatment for contaminated water, which is 0011 Second, when the fluid is injected through a well collected and protected against diffusion by a water collect and collected through another well, it is required that puri ing unit located downstream the flow of contaminants, fication be performed uniformly and efficiently for a wide utilizing a groundwater vein. One method, which also has an area of layer of contaminated Soil including contamination area for treating contaminated water downstream the flow, caused by heavy metals as well. treats contaminants passing therethrough. The other method, 0012. Third, a method that can provide high solidifying which adopts injection of microbes and nutrients upstream purification for all the contaminants including heavy metals the flow of contaminants (VOCs) and diffusing of them in a is necessary. contaminated area, provides treatment for the contaminants. 0005. However, the aforementioned methods for purify 0013 Fourth, an optimization should be implemented ing a layer of contaminated Soil utilizing groundwater are Such that highly effective destruction of a layer of contami relatively a passive approach and depend on the flow of nated Soil can be achieved while the cost for associated groundwater. They can be applied only to treatment for the facilities is minimized. contaminants flowing out into the groundwater, and other 0014 Fifth, a method of highly efficient collection of wise require a large amount of time when they are applied Volatile contaminants is required, which enables elimination to purification of all the contaminants by forcing them out of Volatile contaminants remaining in a layer of Soil by from throughout the layer of contaminated Soil. Since the utilizing forced purification So that a high level of purifica flow of groundwater is neither constant nor uniform, it is tion can be achieved. difficult to collect and treat the contaminants completely. Also it is very unlikely that the injected chemical materials, 0015. When contaminants are volatilized from a layer of microbes and nutrients diffuse throughout the layer of con contaminated Soil and the air containing the contaminants is taminated Soil. extracted by a vacuum pump for purification of VOCs, a level of groundwater in a Saturated Zone rises since the 0006 Further, it has commonly occurred that the chemi preSSure in the layer is reduced by the pump. Since it is cal materials used for purification develop another contami difficult to volatilize the VOCs existing in water in the layer nation adversely due to complicated layer Structure. of contaminated Soil under the level of groundwater in the 0007 Among the aforementioned methods related to Saturated Zone, only contaminated Soil above the level is bioremediation, a method which introduces bacteria having purified, thereby resulting in remarkably low efficiency of a high decomposition capability for contaminants, biological purification. US 2003/0210956 A1 Nov. 13, 2003 0016 For this reason, it is required that the level of the contaminants are eliminated by collecting the fluid groundwater be lowered for the purification of VOCs as containing an undecomposed portion of the contaminants in described later. the layer through a plurality of collection wells.