JPH0691245A - Treatment of waste - Google Patents

Abstract

PURPOSE:To efficiently treat the waste generated from a sewage treatment plant and to safely and rationally put the heat generated from a waste refuse treatment plant to practical use. CONSTITUTION:In a waste treatment method utilizing a sewage treatment system 12 performing the treatment of sewage and a carbonizing type waste refuse incinerator 10 incinerating waste refuse, the waste heat generated when waste refuse is incinerated in the carbonizing type waste refuse incinerator 10 is supplied to the sewage treatment system 12 to be utilized to generate methane gas from the sludge generated by the treatment of sewage. Next, the methane gas and malodorous exhaust gas generated during the treatment of sewage in the sewage treatment system 12 are recovered up to the carbonizing type waste refuse incinerator 10, the methane gas is used as auxiliary fuel and the malodorous exhaust gas is used as combustion air to incinerate waste refuse.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention treats municipal waste by treating waste generated after treatment of sewage which artificially removes or stabilizes pollutants of sewage including household waste and industrial waste. The present invention relates to a waste treatment method using heat generated at the time.

[0002]

2. Description of the Related Art Conventionally, sewage treatment facilities and garbage treatment facilities are
They were installed separately, and the odorous exhaust gas generated from the wastewater treatment facility was simply exhausted using an activated carbon filter.
In this case, not only the heat generated from the waste treatment facility is not effectively utilized, but it is merely discharged to the surrounding area.

[0003]

However, as in the modern times, the increase in carbon dioxide and methane gas existing in the atmosphere causes environmental problems such as global warming, and these facilities There was a situation that residents in the area were reluctant to construct due to the deterioration of the environment.

There is also a social demand that the incineration heat of waste and the heat of sewage treatment, which is said to be 85% of the exhaust heat of the city, should be recovered to make effective use of energy resources.

In view of the above facts, the present invention can obtain a waste treatment method that can efficiently treat waste generated from a wastewater treatment facility and can safely and rationally utilize heat generated from a waste treatment facility. Is the purpose.

[0006]

A waste treatment method according to claim 1 is a waste treatment method that utilizes a wastewater treatment facility for treating wastewater and a waste treatment facility for incinerating waste. Supplying the waste heat generated at the time of incineration at the facility to the sewage treatment facility and using that heat to generate methane gas from the sludge generated by the sewage treatment, and the sewage treatment facility generating during the sewage treatment The method is characterized by including a step of collecting methane gas and odorous exhaust gas to a waste treatment facility, and a step of incinerating dust using the odorous exhaust gas as combustion air using the methane gas as auxiliary fuel.

[0007]

According to the waste treatment method of the first aspect of the present invention, the wastewater that has flowed in from the ditch is treated in the wastewater treatment facility, and the waste accumulated in the waste treatment facility is incinerated. Exhaust heat generated during the incineration of the waste is supplied to a wastewater treatment facility, and the heat is used to generate methane gas from the sludge generated by the wastewater treatment. Next, the methane gas and odorous exhaust gas generated by the wastewater treatment are collected to the waste treatment facility. Then, using the recovered methane gas as an auxiliary fuel,
The odorous exhaust is used as combustion air when incinerating garbage.
Therefore, it is not necessary to exhaust methane gas or odorous exhaust gas generated during wastewater treatment to the outside air, and exhaust heat generated during waste treatment can be effectively utilized.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows an urban recycling tower 14 having a carbonized waste incinerator 10 and a sewage treatment system 12.
It is shown. This Urban Recycle Tower 14
Is equipped with a carbonized garbage incinerator 10 on the ground, a sewage treatment system 12 is installed on the underground, and an urban observation corner and a regional environment management center are also installed. It is a super high-rise building that plays a role.

As shown in FIG. 2, a dust carbonization conveyor 18 is installed inside the combustion chamber 16 of the carbonization type dust incinerator 10 in a state of being inclined in an upward slope to the right side of the drawing. A dust inlet 20 is provided on the left side of the combustion chamber 16, and the lower end portion 18A of the dust carbonization conveyor 18 is connected to the dust inlet 20. The dust carbonization conveyor 18 has a cylindrical outer peripheral portion 18B and a screw-shaped conveying portion 18C, and an upper end portion 18D is
Penetrating the wall 16A of the combustion chamber 16 and the condenser 22 and the pipe 22A.
Connected through. This condenser 22 is a pipe 22
It is connected to the combustion chamber 16 via C. Transport section 18C
Is connected to the power machine 19 installed at the upper end 18D. A combustion burner 24 is installed directly below the upper end portion 18D with the burner portion 24A facing the inside of the combustion chamber 16. A pipe 25 is connected to the combustion burner 24. A pipe 25A connected to the anaerobic digestion tank 80 (shown in FIG. 3) and a pipe 25B connected to the intermediate water tank 82 (shown in FIG. 3) are connected to the pipe 25. The bottom of the combustion chamber 16 is formed in a state of being inclined downwardly to the right side of the drawing, as opposed to the dust carbonization conveyor 18. As shown in FIG. 2, the combustion burner 24 is provided at the bottom of the combustion chamber 16.
An ash extraction device 16B is installed immediately below the ash extraction device 16B and collects ash in the combustion chamber 16.

A waste heat boiler 26 is installed above the combustion chamber 16, and a chimney 28 is further connected thereto. A dust collector 30 is installed in the middle of the chimney 28. Further, both ends of the pipe in the waste heat boiler 26 are connected to the pipe 3
2, 34 are connected. The pipe 32 is a pipe 32A.
It is connected to the steam header 36 via. Further, the steam header 36 is connected to a steam turbine generator 40 via a pipe 38. The steam turbine generator 40 is connected to a power transmission line 41, and is also connected to a cold / hot water generator 44 via a pipe 42. Cold / hot water generator 44
Is connected via a pipe 46 to a condensate tank 48 and a condensate pump 50.
And the pipe 34. Pipe 42 and pipe 46
Are connected via a control valve 51. The cold / hot water generator 44 is connected to the condenser 22 via a pipe 52. Further, the cold / hot water generator 44 is provided with pipes 47, 4
9 is connected.

On the other hand, at the upper part of the carbonization mist chamber 54 in which the combustion burner 24 and the pipe 25 are installed, a sorting screen 56 is attached in a downwardly sloping direction on the right side of the drawing, and the inside of the carbonization mist chamber 54 is heated. A heater 54A is installed. An outlet 58 for carbonized dust is provided in a cylindrical shape on the upper part of the sorting screen 56, and an incombustible dust crushing device (not shown) is installed inside. A cooling pipe 60 is wound around the outlet 58. Incombustible waste bin 61 on the right side of the screen of the sorting screen 56.
Is installed. One end of the cooling pipe 60 is the pipe 5
2 is connected to the cold / hot water generator 44, and the other end is connected to the residual heat exchanger 64 via the pipe 62. The residual heat exchanger 64 is connected to the condenser 22 and the cold / hot water generator 44 via the pipe 62, and is connected to the cooling water circulation pump 68 via the pipe 66. The pipes 52 and 66 are connected to the heat source 80A (shown in FIG. 3) of the anaerobic digestion tank 80.

FIG. 3 shows a system in which a carbonized waste incinerator 10 and a sewage treatment system 12 are combined. A sewage inflow section 72 is provided to connect the main body of the sewage treatment tank 70 and a pipe (not shown). The dirty water inflow portion 72 has a tubular or rectangular shape. At the inlet of the sewage inflow section 72, a screen 72A for removing the residue by primary treatment of sewage is installed. The wastewater treatment tank 70 is connected to a biological treatment tank (not shown) by an introduction pipe 74. A compressor 75 is inserted into the inlet of the introduction pipe 74.

A membrane filtration separation tank 76 is installed downstream of the sewage treatment tank 70. In the membrane filtration separation tank 76, several membrane filtration devices (not shown) are installed. The membrane filtration device is a combination of two mesh-shaped membranes. next,
A sludge storage tank 78, an anaerobic digestion tank 80, and a medium water tank 82 are installed on the left side of the drawing. A sludge removal pump 80B is connected to the anaerobic digestion tank 80, and a heater 80C connected to a heat source 80A is laid. The sludge extraction pump 80B is connected to the dust inlet 20 of the carbonized waste incinerator 10 via a pipe 81. A sprinkler 82B connected to the blower 82A is laid in the middle water tank 82, and a middle water pump 82C is connected to the middle water tank 82. The middle water pump 82C is connected to the residual heat exchanger 64 via a pipe 84. A middle water tank return pipe 86 is further connected to the residual heat exchanger 64 so that the middle water returns to the middle water tank 82 again.

The operation of this embodiment will be described below.
The municipal waste collected by the garbage carrier 88 is put into the dust inlet 20. Garbage can also be collected using an underground physical distribution system that uses linear orbital transportation. Further, the sludge generated in the anaerobic digestion tank 80 of the sewage treatment system 12 is put into the dust inlet 20 from the pipe 81 by using the pump 80B. In particular, since the sewage treatment system 12 is constantly operating, the sludge in the anaerobic digestion tank 80 is continuously supplied.

Next, the dust and sludge (hereinafter simply referred to as "dust") put into the dust inlet 20 is transferred to the lower end portion 18 of the dust carbonization conveyor 18 by using the screw-shaped conveying portion 18C.
It is conveyed from A to the dust carbonization conveyor 18 in the combustion chamber 16. At that time, the load speed of the dust is controlled by the power unit 19. Since the diameter of the outer peripheral portion 18B of the dust carbonization conveyor 18 and the diameter of the transport portion 18C are substantially the same, it is difficult for air to enter from the inlet 18E of the dust carbonization conveyor 18. Therefore, the inside of the dust carbonization conveyor 18 is cut off from the air, and the dust is carbonized without being completely burned. When the dust is carbonized, the moisture contained in the dust becomes vapor and rises up along the outer peripheral portion 18B of the gradient to be collected in the condenser 22. The condenser 22 uses the cooling water supplied from the cold / hot water generator 44 to convey the waste carbonization conveyor 1
The steam blown out from 8 is condensed. After that, the water generated by the condensation is once sent to a waste liquid treatment facility (not shown) from the pipe 22B, where harmful substances that interfere with biological treatment are removed and then discharged to the sewage treatment system 12. Needless to say, when a substance that is harmful to biological treatment due to a carbonized substance is not contained, it is directly discharged to the sewage treatment system 12. Further, the gas remaining in the condenser 22 is discharged from the pipe 22C to the combustion chamber 16 by using a discharge device (not shown). Since the amount of this residual gas is very small, the discharge device is also small in scale and the harmful substances contained can be easily removed.

On the other hand, the dust carbonized at a high temperature falls from the outlet 58 onto the sorting screen 56. Non-burnable dust such as glass is crushed by the non-burnable dust crushing device installed inside the outlet 58 and then falls. Further, the outlet 58 is cooled by the cooling water supplied from the cold / hot water generator 44 to the cooling pipe 60, and the sorting screen 56
To prevent the fire. In the sorting screen 56, carbonized combustible dust is misted, so 20
It passes through a mesh of mm and falls into the carbonized mist chamber 54. Since the incombustible dust is solid, it cannot pass through the mesh of the sorting screen 56 and falls into the incombustible waste bin 61. In this way, the incombustibles and combustibles are selected after incineration, so that the dust collecting operation can be performed more easily than when the incombustibles are selected before incineration.

Next, the combustible dust that has fallen into the carbonized mist chamber 54 (hereinafter referred to as "carbonized mist") is heated by the heater 54A in order to increase the combustion efficiency, and thereafter,
By cooling and exhausting heat, it is dehumidified and atomized into pulverized coal which is sucked into the combustion burner 24. The heater 54A uses hot water generated by the cold / hot water generator 44 and supplied via the pipe 52 as a heat source. The combustion burner 24 uses methane gas supplied from the pipe 25A as auxiliary fuel, and uses odorous exhaust gas supplied from the pipe 25B as combustion air. The methane gas and the odorous exhaust gas are sucked into the combustion burner 24 together with the carbonized mist supplied from the carbonized mist chamber 54, mixed there, and burned in the combustion chamber 16. This methane gas is generated in the anaerobic digestion tank 80 of the sewage treatment system 12 described later, and the odorous exhaust gas is similarly generated from the sewage treatment system 12. As a result, it is not necessary to use a conventionally used exhaust treatment filter, and waste such as methane gas and odorous exhaust generated in the wastewater treatment system 12 can be safely and economically treated. Further, unlike the conventional refuse incinerator, the combustion chamber 16 completely burns the dry pulverized coal, so that the generation of soot and the smoke generation phenomenon due to steam can be prevented, and the dust collector 3
The burden of zero can be reduced. Therefore, the installation space of the device can be saved, the construction cost and the operating cost can be reduced, and since the device is simple, the operation management can be facilitated and the management staff can be rationalized.

When the pulverized coal is burned in the combustion chamber 16, the high pressure steam is recovered in the waste heat boiler 26. The high-pressure steam is collected by the steam header 36 and reaches the steam turbine generator 40. The steam turbine generator 40 uses this high-pressure steam to generate electric power, and supplies electric power from the power transmission line 41 to each consumer. After this high-pressure steam is used for power generation, it becomes low-pressure steam, is used as a heat source of the cold / hot water generator 44, is condensed, and is supplied to the waste heat boiler 26 again via the condensate tank 48 and the condensate pump 50. To be done. At this time, the amount of steam supplied to the cold / hot water generator 44 can be adjusted by the control valve 51.

The cold / hot water generator 44 receives supply of residual heat steam of the steam turbine generator 40 from the pipe 42, utilizes it as an evaporation heat source, and through the pipe 52, the condenser 22 and the outlet 58.
The warm water generated in the above is recovered and heated by the heater 54A as described later.
Supply warm water to. Further, the surplus cold water generated by the cold / hot water generator 44 is supplied from the pipe 47 to the unillustrated tap water, or when the tap water is insufficient, the tap water is supplied from the tap water through the pipe 49. To do.

Next, the operation of the sewage treatment system 12 of this embodiment will be described. As shown in FIG. 3, the sewage flowing out of the unillustrated conduit passes through the sewage inflow section 72. At that time, the screen 72A performs the primary treatment for separating the suspended solids and the liquid in the dirty water, and when the residue is accumulated on the screen 72A, the residue is removed from the screen 72A. Sewage that has passed through the screen 72A is
It is once stored in the sewage treatment tank 70 in the state of a completely mixed liquid which is not completely separated from the microorganisms, organic and inorganic suspended matters, and circulates in the direction of arrow A.

The sewage in the state of the completely mixed liquid stored in the sewage treatment tank 70 (hereinafter referred to as "completely mixed liquid") flows into the biological treatment tank (not shown) from the introduction pipe 74. In the biological treatment tank, when the completely mixed liquid is sufficiently aerated and stirred, aerobic microorganisms and organic and inorganic suspended matter are aggregated to generate activated sludge. At that time, air is sent from the compressor 75 to help the production of activated sludge. Activated sludge has a strong cohesive and oxidative power for organic matter, and its growth and repeated contact with a complete mixed solution with sufficient agitation adsorb organic matter with great force, and microbial oxidization and assimilation action results in wastewater treatment. I do. Further, since the biological treatment tank is installed at a position deeper than about 40 meters, it has a characteristic that the water pressure is high and oxygen is easily dissolved. Therefore, the activity of aerobic microorganisms can be promoted.

After that, as the sewage newly flows in from the pipe, the complete mixed liquid is pushed up, passes through the introduction pipe 74, and reaches the sewage treatment tank 70 again. On the other hand, a part of the complete mixed solution temporarily stored in the head tank 15 passes through the introduction pipe 74 and again flows into the biological treatment tank according to the new inflow of wastewater, and is recirculated. After such recirculation is repeated, a part of the complete mixed solution that has reached the wastewater treatment tank 70 reaches the inlet of the membrane filtration separation tank 76. Of this complete mixture, the one that can pass through the mesh-shaped membrane of the membrane filtration device is
Only the clear water, which is a liquid. Therefore, when the completely mixed liquid passes through the membrane filtration device, it is separated into supernatant water and activated sludge. Thus, the supernatant water that has passed through the membrane filtration separation tank 76 is
Since the specific gravity is light, it passes above the bifurcated entrance 77. The passed clear water reaches the intermediate water tank 82 as intermediate water and is stored therein. On the other hand, the treated water containing a large amount of activated sludge having a large specific gravity passes below the inlet 77 and reaches the sludge storage tank 78. In the sludge storage tank 78, activated sludge having a high specific gravity is precipitated and separated from the treated water. A part of the settled sludge that has been separated by settling is stored in the anaerobic digestion tank 80. Anaerobic digester 8
The inside of 0 is the heater 80 laid in the anaerobic digestion tank 80.
It is warmed by C, and the settled sludge is anaerobically decomposed to generate methane gas. As described above, this methane gas is sent to the pipe 25 via the pipe 25A. Moreover, a part of the settled sludge is extracted by using the sludge pump 80B. On the other hand, in the intermediate water tank 82, air is sent using the blower 82A provided in the intermediate water tank 82.

The wastewater treated by the wastewater treatment system 12 is supplied from the pipe 84 using the wastewater pump 82C to the residual heat exchanger 64.
Supply to. Next, from the residual heat exchanger 64 to the cold / hot water generator 4
The intermediate water is supplied to the pipe 4 through the pipe 62. This intermediate water is supplied as cooling water from the cold / hot water generator 44 to the carbonized dust outlet 58 through the pipe 62 as described above. Cold / hot water generator 44
As described above, hot water is supplied to the heat source 80A of the anaerobic digestion tank 80 to raise the temperature of the anaerobic digestion tank 80 to promote the generation of methane gas. When the temperature of the hot water decreases, it is sent from the pipe 66 to the residual heat exchanger 64 by using the circulation pump 68. As a result, the heat generated in the carbonized waste incinerator 10 can be used for the generation of methane gas, and the methane gas can also be used for the fuel of the combustion burner 24.

[0024]

As described above, in the waste treatment method according to the present invention, the methane gas and odorous exhaust gas generated by wastewater treatment are used in the incineration of waste, and the exhaust heat generated in the incineration of waste is used. Since it is configured to be used as a heat source when methane gas is generated, it has an excellent effect that the exhaust gas generated from the sewage treatment facility and the waste treatment facility can be easily treated and the generated heat can be effectively used.

[Brief description of drawings]

FIG. 1 Carbonized garbage incinerator 10 and sewage treatment system 1
FIG. 3 is a partial cross-sectional view showing an urban recycling tower 14 having two.

FIG. 2 is a schematic view of a carbonized waste incinerator 10.

FIG. 3 Carbonized garbage incinerator 10 and sewage treatment system 1
It is a schematic diagram showing the state where 2 was incorporated.

[Explanation of symbols]

 10 Carbonized waste incinerator 12 Sewage treatment system

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kohei Kagami 8-21-1 Ginza, Chuo-ku, Tokyo Stock company Takenaka Corporation Tokyo main store (72) Inventor Kenji Odawara 8-21 Ginza, Chuo-ku, Tokyo No. 1 Stock Company Takenaka Corporation Tokyo Main Store

Claims (1)

[Claims] 1. A waste treatment method using a sewage treatment facility for treating sewage and a trash treatment facility for incinerating trash, comprising:
Supplying waste heat generated at the time of incineration of waste in the waste treatment facility to the wastewater treatment facility and using the heat to generate methane gas from sludge generated by wastewater treatment; and wastewater treatment at the wastewater treatment facility. And a step of recovering methane gas and odorous exhaust gas generated in the waste gas to a waste treatment facility, and a step of incinerating the waste gas by utilizing the odorous exhaust gas as combustion air with the methane gas as an auxiliary fuel. Material processing method.