JP2000334498A - Treatment of night soil and waste plastic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To utilize the heat generated when waste plastic is subjected to gasification cracking and combustion as a part of the energy necessary for a night soil treatment and to decrease the amount of the waste which is generated by the night soil treatment and waste plastic treatment and for which final disposition needed is zero. SOLUTION: In an energy regeneration system 30, the waste plastic 32 and the extraneous materials 31 removed in a water treatment system are subjected to the gasification cracking by dry distillation in a gasification cracking furnace 33. The dry distillation gas generated in the gasification cracking furnace 33 is combusted in a combustion furnace 34 and the combustion gases generated in the combustion furnace 34 are supplied as heating fluid to a waste heat boiler 35. The steam generated in the waste heat boiler 35 is supplied as drive fluid to a steam turbine 36. The waste steam discharged from the steam turbine 36 is supplied as a heat source to a drying machine 23 of a sludge recycling system 20. The carbide generated in the gasification cracking furnace 33 is supplied as a fermentation sub-material to a fermentation tank 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating human waste and waste plastic by effectively using energy generated by exposing human waste, sludge regeneration and waste plastics to each other.

[0002]

2. Description of the Related Art Conventionally, human waste treatment equipment is composed of a main treatment, an advanced treatment, a sludge treatment, and a deodorization treatment. The discharged residues are incinerated, and the incinerated ash is finally landfilled. On the other hand, waste plastics as municipal waste, when incinerated as incineration at incineration plants, can cause the furnace temperature to rise excessively and damage the furnace body. In many cases, harmful substances such as dioxins are generated, and in many cases, they are separated and collected as non-burnable refuse, and finally disposed at landfill sites.

[0003]

The above-mentioned human waste treatment facility consumes a large amount of heavy oil or kerosene as an electric power and auxiliary heat source, and has a drawback that the utility cost is high. In addition, waste plastic has a low bulk density if not reduced in volume, and requires a large volume for landfill disposal.This shortens the life of the final disposal site early, making it difficult for local governments to secure new disposal sites. Safe and effective disposal of waste plastic is an important issue.

In such a situation, a technique of heating waste in a low-concentration environment with no or no oxygen to gasify organic matter and then burning the waste has been put into practical use in recent years as a gasification cracking furnace, a carbonization furnace or the like. ing. As an example of this technology, in the case of an internal combustion type carbonization furnace, an internal combustion tube through which a high-temperature gas flows as a heating medium is arranged in the furnace, and the waste put into the furnace is indirectly heated by the internal combustion tube, and is also placed in the furnace. Steam is supplied to expel air from the furnace and carbonize waste in a reducing atmosphere to prevent the generation of dioxins.

[0005] If this technique is used, it is possible to safely dispose of waste plastic that has been conventionally separated and collected as non-burnable waste. The present invention utilizes the heat generated when gasifying and decomposing waste plastics to burn it as a part of the energy required for human waste processing, and also requires final disposal generated in the processing of human waste and waste plastic processing. It is an object of the present invention to provide a method for treating human waste and waste plastic to reduce the amount of waste to zero.

[0006]

Means for Solving the Problems To solve the above-mentioned problems, a method for treating human waste and waste plastic according to the present invention is directed to a water treatment system for biologically treating human waste and septic tank sludge as a pretreatment of human waste and septic tank sludge. In a sludge recycling system that removes contaminants and composts excess sludge generated in the biological treatment in a fermenter, the excess sludge is dewatered with a dehydrator as a pretreatment, and then dried with a dryer. In an energy regeneration system for energy conversion, waste plastics and the contaminants are carbonized in a gasification cracking furnace, the carbonized gas generated in the gasification cracking furnace is burned in a combustion furnace, and the combustion gas generated in the combustion furnace is heated fluid. As a waste heat boiler,
The steam generated in the waste heat boiler is supplied to the dryer as a heating fluid, and the carbide generated in the gasification cracking furnace is supplied to the fermenter.

Further, the steam generated in the waste heat boiler is supplied to a steam turbine as a driving fluid, and the waste steam discharged from the steam turbine is supplied to a dryer as a heating fluid. Further, electric power generated by driving the generator by the steam turbine is supplied for power consumption in a water treatment system, a sludge recycling system, and an energy regeneration system.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a water treatment system 1 includes a receiving tank 3 for receiving human waste and septic tank sludge 2, and a screen and the like for pretreating the human waste and septic tank sludge supplied from the receiving tank 3 by a crushing pump 4 to remove foreign substances. Object removal device 5
A storage tank 6 for storing a pretreatment liquid from which impurities have been removed,
Biological treatment equipment 8 for biologically treating the pretreatment liquid transferred by the pump 7, advanced treatment equipment 9 for highly treating treated water with activated carbon, etc., and disinfection equipment 1 for disinfecting highly treated water
0.

The sludge recycling system 20 includes a dehydrator 22 for dehydrating excess sludge (activated sludge) 21 generated in the biological treatment facility 8 and a drier 23 for reducing the water content of the dehydrated dewatered sludge.
And a fermenter 24 for fermenting sludge whose moisture is adjusted in a dryer 23 to form a compost, and an automatic bagging machine 25 for bagging the compost taken out from the fermenter 24 by a fixed amount.

The energy regeneration system 30 includes a gasification cracking furnace 33 for gasifying and cracking the contaminants 31 and waste plastics 32 removed by the contaminant removal device 5 and a gasification cracking furnace 3.
3, a combustion furnace 34 for burning the carbonization gas generated in the combustion furnace 3, a waste heat boiler 35 for generating steam using the combustion gas generated in the combustion furnace 34 as a heating fluid, and a rotary drive using the steam generated in the waste heat boiler 35 as a driving fluid. Steam turbine 36,
And a generator 37 driven by a steam turbine 36.

The operation of the above configuration will be described below. In the water treatment system 1, as a pretreatment, impurities in the night soil and septic tank sludge 2 are removed by the impurity removing device 5, and the impurities 3 are removed.
The pretreatment liquid from which 1 has been removed is biologically treated in the biological treatment facility 8 to remove BOD and nitrogen.
This treated water is discharged after removing the chromaticity and the like in the advanced treatment facility 9 and disinfecting it in the disinfection facility 10. The removed contaminants 31 are supplied to a gasification cracking furnace 33 of the energy regeneration system 30 and surplus sludge (activated sludge) generated in the biological treatment equipment 8.
21 is supplied to the dehydrator 22 of the sludge recycling system 20.

In the sludge recycling system 20, the excess sludge 21 is dewatered by a dehydrator 22 to make dewatered sludge having a water content of about 85%. This dewatered sludge is not suitable for fermentation because of its high moisture content and poor air permeability. For this reason, the dewatered sludge is dried by the dryer 2
By drying in step 3, it is dried to about 65%, and the water in the dewatered sludge is adjusted to a water suitable for fermentation. Waste heat of the steam turbine 36 is used as a heat source of the dryer 23. It is also possible to use other excess steam. The dryer 23 is of an indirect heating type, and this type generates a small amount of odor due to drying and can easily treat the odor.

The sludge whose moisture has been adjusted is composted in an aerobic fermentation treatment in a fermenter 24. The compost taken out from the fermenter 24 is quantitatively bagged by the automatic bagging machine 25 and shipped as a high-quality compost product. In the energy regeneration system 30, waste plastics 32 and impurities 31 are charged into a gasification cracking furnace 33, and carbonized by carbonization in an environment at 300 to 500 ° C. and no oxygen or a low oxygen concentration, and carbonized. And carbonization gas is generated. The carbonization gas is supplied to the combustion furnace 34, and the combustion air is blown into the combustion furnace 34 to 800-120.
The fuel is burned at 0 ° C., and the generated combustion gas is supplied to the waste heat boiler 35 as a heating fluid. The high-temperature steam generated in the waste heat boiler 35 is supplied as a driving fluid to a steam turbine 36, and the steam turbine 36 drives a generator 37 to generate electric power.

The waste steam discharged from the steam turbine 36 is supplied to the dryer 23 as a heating fluid, and the char generated in the gasification cracking furnace 33 is supplied to the fermenter 24 to promote fermentation.
In other words, since the carbide has no moisture, it can be used as an auxiliary material that contributes to the improvement of the permeability of the sludge in the fermenter 24, and the properties of the compost are improved to produce a high-quality compost. In addition, since the carbide has a slight odor adsorption ability, it is effective in reducing the odor in the fermenter 24.

The electric power generated by the generator 37 is supplied to the water treatment system 1
Various pumps (not shown) and stirrers (not shown) used in the crushing pump 4, the pump 7 and the biological treatment equipment 8 in the above, the sludge recycling system 20, or the gasification cracking furnace 33 in the energy regeneration system 30, It is supplied for power consumption of operating equipment such as a blower (not shown) used in the combustion furnace 34.

By processing about 10 t / day of waste plastic, it is possible to generate almost all of the power consumed by the night soil treatment facility of about 100 kL / day and the power consumed by the gasification cracking furnace 33 and the combustion furnace 34. . Furthermore, the dryer 23
Can supply the entire amount of heat consumed in reducing the water content of the dewatered sludge from 85% to about 65%.

[0017]

As described above, according to the present invention, impurities in night soil and septic tank sludge are gasified and decomposed into fuel in an energy regeneration system, and carbonized in the energy regeneration system is fermented in a sludge recycling system. By throwing it into the tank and using it as a secondary material for the fermentation treatment, it is possible to reduce the amount of waste requiring final disposal to zero. In addition, the energy generated by the energy regeneration system is used as power for operating equipment in each facility, and the waste steam from the steam turbine that is discharged in the process is used as a heat source for the dryer in the sludge recycling system. Can be improved.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a method for treating human waste and waste plastic in an embodiment of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 water treatment system 2 night soil and septic tank sludge 3 receiving tank 4 crushing pump 5 foreign matter removing device 6 storage tank 7 pump 8 biological treatment facility 9 advanced treatment facility 10 disinfection facility 20 sludge recycling system 21 excess sludge (active sludge) ) 22 Dehydrator 23 Dryer 24 Fermenter 25 Automatic bagging machine 30 Energy regeneration system 31 Contaminants 32 Waste plastic 33 Gasification cracking furnace 34 Combustion furnace 35 Waste heat boiler 36 Steam turbine 37 Generator

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4D003 BA02 CA02 CA08 FA07 FA10 4D004 AA07 AC04 BA03 CA26 CA27 CA28 CA42 CC02 4D059 AA05 BA01 BA29 BA56 BD00 BE00 BK11 BK17 CA06 CA11 CB27 CC01 DA61 4F301 AA30 CA09 CA25 CA26

Claims (3)

[Claims] In a water treatment system for biologically treating human waste and septic tank sludge, impurities in human waste and septic tank sludge are removed as a pretreatment, and excess sludge generated in the biological treatment is composted in a fermenter. In a sludge recycling system, in an energy regeneration system that dehydrates excess sludge as a pretreatment by dehydrating it with a dehydrator and then drying it with a dryer, turning waste plastic into energy
Waste plastics and the contaminants are carbonized in a gasification cracking furnace, the carbonized gas generated in the gasification cracking furnace is burned in a combustion furnace, and the combustion gas generated in the combustion furnace is supplied to a waste heat boiler as a heating fluid, A method for treating human waste and waste plastics, comprising supplying steam generated in a waste heat boiler to the dryer as a heating fluid, and supplying carbide generated in a gasification cracking furnace to the fermenter. 2. The human waste according to claim 1, wherein the steam generated in the waste heat boiler is supplied as a driving fluid to a steam turbine, and the waste steam discharged from the steam turbine is supplied to a dryer as a heating fluid. And waste plastic treatment methods. 3. The power generator according to claim 2, wherein electric power generated by driving the generator by the steam turbine is supplied for power consumption in a water treatment system, a sludge recycling system, and an energy regeneration system. How to treat human waste and waste plastic.