JP3377091B2 - Method and apparatus for treating leachate at landfill site - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an incineration residue of a waste incinerator that incinerates waste such as municipal waste, and a molten residue (slag) of an ash melting furnace that melts waste incineration ash to form slag. The present invention relates to a method and a device for detoxifying leachate from a landfill site (field) at low cost and further reusing it when landfilling waste such as.

[0002]

2. Description of the Related Art As a method for treating leachate from a waste landfill site, for example, in Japanese Patent Laid-Open No. 11-188389, after leachate from a landfill site is coagulated and settled, separated water is passed through a reverse osmosis membrane. A technique for obtaining a by-product salt by introducing it into an apparatus for treatment, introducing concentrated water into a crystallization tank to precipitate salts as a solid matter, drying the solid matter containing this water, and then calcining and refining to obtain a by-product salt Have been described. In addition, JP-A-7-10828
No. 5 discloses that in order to decompose dioxins in the leachate from the landfill site, the pH-adjusted water to be treated is sent to a treatment tank and ozone is supplied under the irradiation of ultraviolet rays to perform ozone treatment and accelerated oxidation treatment. Techniques for doing are described.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
According to the method described in Japanese Patent No. 88389, heavy metals, dioxins, and environmental hormones that could not be removed by the first coagulation-sedimentation treatment are taken out as concentrated water, dried, and calcined to finally obtain a purified salt. Heavy metals that cannot be included in the purified salt. Therefore, there is a problem that it is difficult to reuse the purified salt. In addition, the above-mentioned JP-A-7-108
The method described in Japanese Patent No. 285 requires the generation of ozone, the irradiation of ultraviolet rays, the addition of hydrogen peroxide and titanium dioxide in some cases, the treatment cost is high, and the maintenance is required.

The present invention has been made in view of the above points, and an object of the present invention is to use a NF (nanofilter) filtration device and a chelate adsorption tower from a landfill leachate to make harmless mainly NaCl or KCl. Water containing high-purity salts or salts are separated, and toxic substances such as dioxins that are leaching are returned to the waste incinerator or / and ash melting furnace (facility) as concentrated water and sprayed into the furnace. (EN) Disclosed is a method and an apparatus for treating leachate of waste landfill sites, which has a low treatment cost and is decomposed.

[0005]

In order to achieve the above object, the method for treating leachate of landfill waste according to the present invention comprises:
NF (nanofilter) is used for the leachate generated at the landfill site of waste such as waste incinerator and / or ash melting furnace residue.
It is introduced into a filtration device and filtered, the permeated water of the NF filtration device is subjected to chelate adsorption treatment and then discharged, and the concentrated water of the NF filtration device is returned to an incinerator and / or an ash melting furnace to heat harmful substances in the concentrated water. It is configured to disassemble (see FIG. 1). N
As F (nanofilter), a filter having a selectively low Na ⁺ , K ⁺ , and Cl ⁻ blocking rate is adopted. Further, the permeated water is diluted as necessary and discharged.

Further, the method for treating leachate of waste landfill disposal site of the present invention is a reverse osmosis membrane for the leachate produced at the landfill site of waste such as the residue of the waste incinerator or / and the ash melting furnace. (RO membrane) It is introduced into a filtration device and filtered, the permeated water of the reverse osmosis membrane filtration device is discharged, and the concentrated water of the reverse osmosis membrane filtration device is NF.
It is introduced into a filtration device and filtered, and the permeated water of the NF filtration device is treated with chelate adsorption and then discharged. It is characterized by disassembling (see FIG. 2).

Further, the method for treating leachate of waste landfill disposal site of the present invention is an NF filtration device for treating leachate produced at landfill disposal site of waste such as waste incinerator and / or ash melting furnace residue. And filtered to permeate the permeated water of the NF filter, and then the chelate-adsorbed water is dried to evaporate water to obtain purified salt. The concentrated water of the NF filter is incinerated in an incinerator or / and It is characterized by returning to the ash melting furnace to thermally decompose harmful substances in concentrated water (see Fig. 3). The refined salt is shipped outside the facility (outside the facility).

Furthermore, the method for treating leachate of waste landfill disposal site of the present invention is a reverse osmosis membrane for leachate produced at landfill disposal site of waste such as waste incinerator or / and residue of ash melting furnace. It is introduced into the filtration device and filtered, the permeated water of the reverse osmosis membrane filtration device is discharged, the concentrated water of the reverse osmosis membrane filtration device is introduced into the NF filtration device and filtered, and the permeated water of the NF filtration device is subjected to chelate adsorption treatment. Then, the chelate adsorption-treated water is dried to evaporate the water to obtain a purified salt, and the concentrated water of the NF filter is returned to the incinerator and / or the ash melting furnace to thermally decompose the harmful substances in the concentrated water. (See FIG. 4).

The treatment apparatus for leachate of waste landfill disposal site of the present invention is an NF for filtering leachate produced at landfill disposal site of waste such as waste incinerator and / or ash melting furnace residue. (Nanofilter) Filtration device, chelate adsorption tower for chelating adsorbed water of NF filtration device, and N
A concentrated water return line for supplying the concentrated water of the F filter device to the waste incinerator and / or the ash melting furnace (see FIG. 1).

Further, the treatment apparatus for leachate of waste landfill disposal site according to the present invention is for filtering leachate generated at landfill disposal site of waste such as residues of waste incinerator or / and ash melting furnace. Reverse osmosis membrane filtration device, an NF filtration device for filtering concentrated water of the reverse osmosis membrane filtration device, a chelate adsorption tower for chelating and adsorbing permeated water of the NF filtration device, and N.
A concentrated water return line for supplying the concentrated water of the F filter device to the waste incinerator and / or the ash melting furnace is featured (see FIG. 2).

Further, the treatment apparatus for leachate of waste landfill disposal site of the present invention is for filtering leachate produced in waste landfill disposal site such as residue of waste incinerator or / and ash melting furnace. NF filter device, a chelate adsorption tower for chelating and adsorbing permeated water of the NF filter device, and a concentrated water return line for supplying concentrated water of the NF filter device to a waste incinerator and / or an ash melting furnace. And a dryer for introducing the treated water from the chelate adsorption tower and evaporating the water to obtain a purified salt (see FIG. 3).

Further, the treatment apparatus for leachate of waste landfill disposal site of the present invention is for filtering leachate generated at landfill disposal site of waste such as waste incinerator or / and residue of ash melting furnace. Reverse osmosis membrane filtration device, an NF filtration device for filtering concentrated water of the reverse osmosis membrane filtration device, and a chelate adsorption tower for chelating and adsorbing permeated water of the NF filtration device.
A concentrated water return line for supplying the concentrated water of the NF filter to the waste incinerator and / or the ash melting furnace, and a drying process for introducing the treated water from the chelate adsorption tower to evaporate the water and obtain a purified salt. And a machine (see FIG. 4).

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments, and can be appropriately modified and implemented. FIG. 1 shows a waste landfill leachate treatment apparatus according to a first embodiment of the present invention. Reference numeral 10 denotes an incinerator or an ash melting furnace, and the residue (incineration residue or melting residue) discharged from the furnace 10 is conveyed to a landfill disposal site 12. Note that FIG. 1 shows a case where waste is treated as an example of an incineration product.

A water blocking sheet made of plastic is laid in the landfill disposal site 12, and the leachate is extracted by a water collecting pipe provided in the water blocking sheet. This leachate is introduced into the pretreatment device 14 to remove a part of heavy metals, calcium content, etc. in the leachate. As the pretreatment device 14, for example, a coagulating sedimentation tank by a lime soda method is used. The pretreated leachate is introduced into the NF filter 16, and mainly monovalent ions Na ⁺ , K ⁺ , and Cl ⁻ are collected on the permeate side. The NF filtration device 16 is a device provided with a nano filter (NF) as a permeable membrane.
The F membrane can remove salts in the leachate, particularly salts of divalent or more negative ions, to the concentrated water side, and can remove most of organic substances to the concentrated water side. NF
To further explain the decomposition characteristics of the above, in the separation of ions by NF, not only anions but also cations can be supplemented with divalent or higher valent ions on the concentrated water side. Conceptually, it has the following separation tendency. Actually, various tendencies are seen depending on the material of the film, its charge and combination, and therefore the following is not always the case. Cation permeated water side Na ⁺ , K ⁺ concentrated water side Ca ²⁺ , Mg ²⁺ , Fe ³⁺ , Mn ⁴⁺ , Pb ²⁺ and other heavy metals anions Permeated water side Cl ⁻ , NO ₃ ⁻ , F ⁻ Concentrated water side SO ₄ ^2- , CO ₃ ^2- , BO ₃ ^3- Other permeated water side Concentrated water side Dioxins, environmental hormones, SiO ₂

The permeated water (filtrate) of the NF filter 16 is introduced into the chelate adsorption tower 18 to remove boron, fluorine, trace amounts of heavy metals and the like. As the chelating agent, polymer resin bodies having functional groups such as iminodiacetic acid type, aminophosphoric acid type, amidoxime type, glucamine type, special metal supporting type, polyamine type, thiourea type and dithiocarbamic acid type are used. To be By these treatments, chelated water has very little impurities and harmful substances, NaC
1 and treated water containing salts mainly containing KCl. Therefore, there is no problem if this treated water is discharged to public sewers or sea areas, and if it is dried to form a purified salt as described later, it can be easily reused in the soda industry.

The concentrated water of the NF filter 16 contains divalent ions and larger components, mainly harmful substances such as high molecular weight organic substances and dioxins, environmental hormones, and heavy metals. This concentrated water is returned by the concentrated water return line 20.
The wastewater from the incinerator or the ash melting furnace 10 is sent to the wastewater treatment device 22, and after being treated there, it is returned to the incinerator or the ash melting furnace 10 and sprayed into the furnace to remove harmful substances such as dioxins. Pyrolytically detoxifies. As a result, the leachate treatment according to the present embodiment does not require the steps such as the accelerated oxidation treatment for removing dioxins as in the prior art. In addition, as the discharge processing device 22, 2
Coagulation sedimentation treatment + sand filtration treatment system, coagulation sedimentation treatment + sand filtration treatment + activated carbon adsorption treatment system, or coagulation sedimentation treatment + biological treatment + coagulation sedimentation treatment + sand filtration treatment + chelate treatment + activated carbon treatment system Used. The treated water obtained by NF-filtering the leachate and subjecting it to chelate adsorption is discharged, but in this case, it may be discharged from the waste landfill disposal facility 26, or may be discharged from the incineration or ash melting facility 24. Select the most suitable discharge destination according to each site condition and drainage standard. The incineration or ash melting facility 24 is composed of an incinerator or ash melting furnace 10, an emission treatment device 22, and the like, and a waste landfill disposal facility 26 is a landfill disposal site 12, pretreatment device 1.
4, an NF filter 16, a chelate adsorption tower 18, and the like.

FIG. 2 shows a treatment apparatus for waste landfill leachate according to a second embodiment of the present invention. In the present embodiment, the leachate that has been pretreated by the pretreatment device 14 is introduced into a reverse osmosis membrane (RO) filtration device 28 and filtered, the permeated water is discharged, and the concentrated water is incinerator or ash melting furnace 10. It is sent to the pretreatment device 30 such as a coagulating sedimentation tank together with the discharge from the tank. Reverse osmosis membrane is a semi-permeable membrane that can be filtered at the molecular level when a pressure higher than osmotic pressure is applied.In addition to phosphorus, organic substances, nitrogen, salts such as calcium, sodium and potassium,
Dioxins, environmental hormones (for example, bisphenol A, organic chlorine-based substances, etc.), heavy metals, etc. can be separated on the concentrated liquid side. Then, the pretreated water is N
The permeated water is introduced into the F filtration device 16 and the permeated water is the chelate adsorption tower 1
After being subjected to the chelate adsorption treatment in 8, the concentrated water is discharged, and the concentrated water is returned to the incinerator or the ash melting furnace 10 by the concentrated water return line 20a and sprayed in the furnace to thermally decompose toxic substances such as dioxins. In the present embodiment, the incineration or ash melting facility 24a includes the incinerator or ash melting furnace 10 and the pretreatment device 3
0, an NF filter 16, a chelate adsorption tower 18, etc., and the waste landfill disposal facility 26a is a landfill disposal site 12,
It comprises a pretreatment device 14, a reverse osmosis membrane filtration device 28, and the like. As described above, according to the present embodiment, the leachate is filtered by the reverse osmosis membrane to discharge the permeate, and the concentrated water is finally NF.
It is what is filtered. Other configurations and operations are similar to those of the first embodiment.

FIG. 3 shows a waste landfill leachate treatment system according to a third embodiment of the present invention. In the present embodiment, the treated water that has been subjected to the chelate adsorption treatment is introduced into a drier 32 and dried to evaporate the water to obtain a purified salt. Waste landfill disposal facility 26b is landfill disposal site 1
2. A pretreatment device 14, an NF filtration device 16, a chelate adsorption tower 18, a dryer 32, and the like. As the dryer 32, a vacuum rotary drum type, a spray type, a ventilation band type, an air flow type, a fluidized bed type, an infrared type, a high frequency type, or the like is used. Other configurations and operations are similar to those of the first embodiment. In the present embodiment, the treated water that has been subjected to the chelate adsorption treatment after NF filtration is harmless, so that when the treated water is dried, the treatment of exhaust gas (mainly steam) is unnecessary, or a simple device is used. Just enough.

FIG. 4 shows a waste landfill leachate treatment system according to a fourth embodiment of the present invention. In this embodiment, after the leachate is pretreated by the pretreatment device 14, the leachate is introduced into the reverse osmosis membrane filtration device 28 to be filtered, and the permeated water is discharged. The configuration and operation of these are similar to those of the second embodiment. The concentrated water of the reverse osmosis membrane filtration device 28 is introduced into the NF filtration device 16 for filtration treatment, the permeated water is introduced into the chelate adsorption tower 18, and the concentrated liquid is drained together with the wastewater from the furnace 10 through the concentrated water return line 20. After being sent to the processing device 22, processed there, it is returned to the furnace 10. The configuration and operation of these are similar to those of the first embodiment. The treated water that has been subjected to the chelate adsorption treatment is introduced into the dryer 32 and dried to evaporate the water content to obtain a purified salt. This configuration,
The operation is similar to that of the third embodiment. The waste landfill disposal facility 26c includes a landfill disposal site 12, a pretreatment device 14, a reverse osmosis membrane filtration device 28, an NF filtration device 16, a chelate adsorption tower 18, a dryer 32, and the like.

[0020]

Since the present invention is configured as described above, it has the following effects. (1) Treated water containing salts mainly consisting of NaCl and KCl can be obtained from landfill leachate by using an NF filter and a chelate adsorption tower. In this case, impurities mixed in the salts are small, so public sewer It is harmless if released into the sea. Further, when the treated water is dried to obtain a purified salt, it is easy to reuse because of its high purity. (2) Hazardous substances such as dioxins in landfill leachate can be easily pyrolyzed in the existing incinerator and / or ash melting furnace, eliminating the need for special decomposition equipment as in the past. Therefore, cost reduction can be achieved.

[Brief description of drawings]

FIG. 1 is a systematic schematic configuration diagram of a treatment device for leachate of waste landfill disposal site according to a first embodiment of the present invention.

FIG. 2 is a systematic schematic configuration diagram of a treatment device for leachate of waste landfill disposal site according to a second embodiment of the present invention.

FIG. 3 is a systematic schematic configuration diagram of a treatment device for leachate of waste landfill disposal site according to a third embodiment of the present invention.

FIG. 4 is a systematic schematic configuration diagram of a treatment device for leachate of waste landfill disposal site according to a fourth embodiment of the present invention.

[Explanation of symbols]

10 Incinerator or ash melting furnace 12 Landfill disposal site 14,30 Pretreatment equipment 16 NF filtration device 18 Chelate adsorption tower 20, 20a Concentrated water return line 22 Wastewater treatment equipment 24, 24a Incineration or ash melting facility 26, 26a, 26b, 26c Waste landfill disposal facility 28 Reverse osmosis membrane filtration device 32 dryer

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI C02F 9/00 C02F 9/00 502E 502F 502H 503 503C 503G 504 504B 504E // B09B 1/00 B09B 1/00 A C02F 1/02 C02F 1/02 B 1/04 1/04 C 1/28 1/28 B L Z F23G 5/02 ZAB F23G 5/02 ZABE 5/027 ZAB 5/027 ZABZ 7/00 102 7/00 102C ZAB ZAB ( 72) Inventor Kozo Nagayasu 1-1 Kawasaki-cho, Akashi City, Hyogo Prefecture Kawasaki Heavy Industries Ltd., Akashi Factory (56) References JP-A-11-188389 (JP, A) JP-A-5-26427 (JP, A) JP 2000-61422 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C02F 1/44 B01D 61/00-65/10 B01D 9/00-9/04 C02F 9 / 00-9/00 504 B09B 1/0 0

Claims (4)

(57) [Claims] 1. Leachate generated at a landfill site of waste such as waste incinerator or / and ash melting furnace residue is introduced into an NF filter and filtered, and permeated water of the NF filter is chelated. Adsorption treatment, then chelate adsorption treatment water is dried to evaporate water to obtain purified salt, and concentrated water of NF filter is returned to incinerator and / or ash melting furnace to thermally decompose harmful substances in concentrated water. A method for treating leachate from a waste landfill site, which comprises: 2. The reverse osmosis membrane filtration device is provided with the leachate generated at the landfill disposal site of the waste such as the residue of the waste incinerator or / and the ash melting furnace, which is introduced into the reverse osmosis membrane filtration device to be filtered. The permeated water is discharged, the concentrated water of the reverse osmosis membrane filtration device is introduced into the NF filtration device and filtered, the permeated water of the NF filtration device is subjected to chelate adsorption treatment, and then the chelate adsorption treated water is dried to evaporate the water content. A method for treating leachate of landfill waste, which comprises refining salt to obtain purified salt and returning the concentrated water of the NF filter to an incinerator and / or an ash melting furnace to thermally decompose harmful substances in the concentrated water . 3. An NF filtration device for filtering leachate generated at a landfill site of waste such as residues of a waste incinerator or / and an ash melting furnace, and chelate adsorption of permeated water of the NF filtration device. Chelate adsorption tower for processing, concentrated water return line for supplying concentrated water of NF filter to waste incinerator and / or ash melting furnace, and introducing treated water from chelate adsorption tower to evaporate water An apparatus for treating leachate of landfill waste, comprising a drier for producing purified salt. 4. A reverse osmosis membrane filtration device for filtering leachate generated in a landfill of waste such as waste incinerator or / and ash melting furnace residue, and concentration of the reverse osmosis membrane filtration device. NF filtration device for filtering water, chelate adsorption tower for chelate adsorption treatment of permeated water of NF filtration device, and supply of concentrated water of NF filtration device to waste incinerator and / or ash melting furnace The equipment for treating leachate of landfilled waste land, characterized by comprising: a concentrated water return line of the above, and a dryer for introducing the treated water from the chelate adsorption tower and evaporating the water to obtain purified salt. .