JP3485450B2 - Resource recovery landfill method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to landfill technology for final disposal sites for general waste, industrial waste, etc., and is a resource recovery type landfill disposal for recovering valuable materials in waste to shorten the closing period. The purpose is to provide a method.

[0002]

2. Description of the Related Art The quantity of leachate at the final disposal site depends on the quality of landfill, weather conditions such as rainfall, landfill structure, size of landfill, size of catchment area, landfill period, elapsed time of landfill, etc. The characteristics peculiar to the landfill can be seen. For example, organic pollutants in leachate have high concentrations at the beginning of landfill, but they decrease over time and biodegradable after several years.
Or difficult organic matter remains. In addition, when landfilling incineration residues and non-combustible waste, since there are many inorganic substances, SS and inorganic salts derived from these are included. Also, if the incineration residue and often easy organic matter biodegradation noncombustible during garbage, BOD, COD, T-N , NH 4 + -N and the like is relatively high concentrations.

[0003]

The leachate treatment facility for treating leachate comprises a first coagulation sedimentation treatment facility, a biological treatment facility,
It is equipped with a second coagulation-sedimentation treatment facility, sand filtration treatment facility, activated carbon adsorption treatment facility, and the like. The first coagulation-sedimentation treatment equipment removes calcium in the raw water of the leachate to prevent scaling of pipes and pumps, and performs alkali coagulation-sedimentation treatment in combination with a calcium removing agent. The biological treatment equipment adopts the catalytic oxidation type cyclic denitrification method, which uses microorganisms on the surface of the packing material to decompose organic substances in the raw water and remove nitrogen components. The second coagulation-sedimentation treatment facility coagulates pollutants in biologically treated water by chemicals and removes them by gravity sedimentation, and performs weak acid coagulation-sedimentation treatment effective for removing COD and chromaticity components. The sand filtration equipment captures and removes fine suspended matter remaining in the coagulation-sedimentation-treated water with a filter medium composed of anthracite and silica sand. The activated carbon adsorption treatment device removes COD, chromaticity components, etc. due to the strong adsorption ability of activated carbon. Treated water is discharged after sterilization treatment.

In the above-mentioned treatment of leachate, heavy metals and salts in the leachate are treated as useless harmful components, but heavy metals and salts are originally valuable materials and are recovered and recycled. Is required from the viewpoint of resource reuse and effective use.

The present invention is intended to solve the above-mentioned problems, and recovers valuable substances eluted from leachate from waste,
An object of the present invention is to provide a resource recovery type landfill disposal method for shortening the closing period of a landfill disposal site.

[0006]

In order to solve the above-mentioned problems, the resource recovery type landfill disposal method of the present invention desalinates the leachate leached from the landfill disposal site and concentrates it in the desalination process. By separating water with a bipolar membrane separator, acid and alkali are generated, the generated acid is returned to the landfill waste at the landfill disposal site, and the waste metal is decomposed by acid to dissolve the heavy metal in the leachate. , It stabilizes the properties of waste materials at an early stage.

The acid and alkali produced in the bipolar membrane separator are used as a pH adjuster in water treatment. The concentrated water generated in the desalination treatment is electrolyzed to generate sodium hypochlorite, and the generated sodium hypochlorite is used as a disinfectant in water treatment.

The treated water treated in the desalination treatment is used as gas cooling water in a refuse incineration facility.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In Fig. 1, the landfill disposal site 1 forms a landfill by covering the waste layer 2 of the landfilled waste with the cover soil 3, and the rainwater falling on the landfill penetrates the cover soil 3 and the waste layer 2 and becomes leachate. Outflow. This leachate passes through the drainage / drainage distribution pipe 4 communicating with the bottom layer of the landfill, and the leachate storage tank 5
Flow into. The leachate storage tank 5 temporarily stores leachate, and the leachate in the leachate storage tank 5 is sent to the valuable resource recovery facility 8 through a water supply pipe system 7 equipped with a pump 6.

The valuable resource recovery facility 8 comprises a pretreatment step, a desalting step, a bipolar membrane separation step and an electrolytic treatment step. In the pretreatment step, calcium in the leachate is separated by sedimentation 9 and the separated water is subjected to a membrane separation type biological treatment 10 and B
Remove OD, etc. The calcium precipitated in the settling separation 9 is sludge dewatered 11 and the calcium sludge 12 is exhausted.
It is used as the cleaning 13 and the neutralizer 14.

In the desalination treatment step, the treated water of the membrane separation type biological treatment 10 is desalted in the electrodialyzer 15 and the desalted treated water is subjected to a dioxin removing treatment 16. This treated water should be discharged or used as gas cooling water in a refuse incineration facility.

In the bipolar membrane separation step, the concentrated water generated in the desalting process is used as the bipolar membrane separation device 17
Acid 18, alkali 1 by separation treatment in
9 is generated. The generated acid 18 is returned to the landfill of the landfill disposal site 1, the waste of the landfill is decomposed by acid to dissolve the heavy metal in the leachate, and the properties of the waste are stabilized early. As a result, the closing period required from the start of the operation of the landfill disposal site 1 to the closing thereof will be shortened. Bipolar membrane separator 17
Both of the acid 18 and the alkali 19 produced in step 2 can be used as pH adjusters in water treatment.

The concentrated water generated in the desalting process is converted into sodium hypochlorite 21 in the electrolysis 20, and the generated sodium hypochlorite 21 is used as a disinfectant in the water treatment.

[0014]

As described above, according to the present invention, an acid and an alkali are produced in a bipolar membrane separation apparatus from concentrated water of desalted water, and the produced heavy acid dissolves heavy metals in waste. By doing so, the properties of the waste can be stabilized at an early stage, and acid and alkali can be added in water treatment.
It can be used as an H conditioner, can generate sodium hypochlorite by electrolysis from desalted concentrated water, and can use sodium hypochlorite as a disinfectant in water treatment. Treated water treated in desalination treatment. Since it can be used as gas cooling water in a refuse incineration facility, it is possible to collect valuable materials that are eluted from the waste into the leachate and shorten the closing period of the landfill disposal site.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a landfill disposal method according to an embodiment of the present invention.

[Explanation of symbols]

1 landfill disposal site 5 Leachate storage tank 8 Valuable material recovery equipment 15 Electrodialysis device 17 Bipolar membrane separator

Continuation of the front page (56) Reference JP-A-4-78479 (JP, A) JP-A-10-5714 (JP, A) JP-A-5-277465 (JP, A) (58) Fields investigated (Int .Cl. ⁷ , DB name) B09B 1/00-5/00

Claims (4)

(57) [Claims] 1. Leachate leached from a landfill site is desalted, and concentrated water generated in the desalination process is separated in a bipolar membrane separator to generate an acid and an alkali, and the generated acid is removed. A resource recovery type landfill disposal method characterized by returning the landfilled waste at a landfill disposal site, decomposing the acid with acid to dissolve heavy metals in the leachate, and stabilizing the properties of the waste at an early stage. 2. The acid and alkali produced in the bipolar membrane separation apparatus according to claim 1 are added to p in water treatment.
A resource recovery type landfill disposal method characterized by being used as an H regulator. 3. The concentrated water generated in the desalting treatment according to claim 1 is electrolyzed to generate sodium hypochlorite, and the generated sodium hypochlorite is used as a disinfectant in water treatment. A resource recovery type landfill disposal method characterized by the above. 4. A resource recovery type landfill disposal method, wherein the treated water treated in the desalination treatment according to claim 1 is used as gas cooling water in a refuse incineration facility.