JP2002326071A - Method of and system for recycling circulating resource such as waste food - Google Patents

Abstract

PROBLEM TO BE SOLVED: To promote the recycling of a circulating resource such as waste food obtained by mixing garbage discharged and collected at the respective steps to manufacture, distribute and consume food or other waste food with organic sludge generated from a sewage plant or another organic liquid waste treating facility by treating the waste food as the object to be treated. SOLUTION: This system for recycling the circulating resource such as waste food is constructed (arranged side by side) between the sewage plant or the other organic waste liquid treating facility (system 1) and a biogasification cogeneration system (system 2) and operated in cooperation with system 1 and system 2 so that the waste energy is recovered and reused. In this system, slurry is prepared from the circulating resource such as waste food consisting of waste food and the concentrated organic sludge, which is then introduced into a bioreactor 6 to produce biogas. The produced biogas is supplied to the cooperated cogeneration system (Z) for supplying steam and generating power by using the supplied biogas as fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to organic waste generated from food waste, other food waste and sewage treatment plants and other organic waste liquid treatment facilities discharged and collected at each stage of food production, distribution and consumption. The present invention relates to a recycling method and a recycling system for circulating resources such as food waste for promoting recycling as recycling of circulating resources such as food waste formed by mixing sludge.

Here, the system of the present invention is positioned (co-installed) between a wastewater treatment plant and other organic wastewater treatment facilities (system 1) and a biogasification cogeneration system (system 2). This is an energy conversion system that collects and reuses waste energy by linking with the system. The cogeneration system is a common name of a co-generation system.

[0003]

2. Description of the Related Art Conventionally, most food waste and other food waste discharged and collected at each stage of food production, distribution, and consumption have been incinerated and landfilled.

On the other hand, with the spread of sewage, sludge generated from sewage treatment plants is increasing year by year, and each local government bears a large cost for its treatment. In recent years, the permissible limit of the final disposal site has been reduced and the location conditions have become strict, which has become a tight social problem.

[0005] Under these circumstances, digestion (biogasification) is known as a technique for recovering and reducing the resources of food waste (typified by garbage) or sewage sludge.

Although the digestion of garbage has been technically established, it has not been sufficiently achieved as a social system (or social capital maintenance) due to an increase in equipment costs.

[0007] In addition, in the digestion treatment of sewage sludge, it is difficult to increase the concentration of sludge, so the bioreactor becomes large.
Since heating requires a large amount of heat, high-temperature digestion is not suitable, and low-efficiency low-temperature digestion is widely used. In this case, the energy recovery rate is relatively low and the cost merit is small.

By the way, the "Law Concerning the Promotion of Recycling of Food Recyclable Resources" (commonly known as the Food Recycling Law) was enacted in May 2001, and some business-related garbage must be recycled. Was. Here, from the viewpoint of the balance of the local economy, it is required to minimize the cost of recycling.

[0009]

[Problems to be Solved by the Invention] Although there is a technical trend that a unique recycling system is constructed for each resource as before and each technical solution problem is solved,
There is a limit to distribution and cost-effectiveness in increasing (continuously expanding) processing capacity (system scale), and distributed locations that are scattered everywhere are not welcome at all. There are obstacles.

Therefore, when aiming for a recycling-oriented society in line with the legal objectives, some resources are interconnected by sharing (mutually using) raw material resources (starting substances) and target substances (products). By doing so, there is an expectation that cost merit including scale merit and energy balance can be pursued.

[0011] The present inventors have been involved in the power business,
We have been conducting research and development on systems related to waste (garbage) power generation and other effective use of energy. As one of the products, the present invention has been completed.

The present invention has been made in view of the above circumstances, and has been made in view of the above circumstances. Food waste and other food waste discharged and collected at each stage of food production, distribution and consumption, and sewage treatment plants and other organic waste liquids Recycling resources such as food waste made by mixing with organic sludge generated from treatment facilities
An object of the present invention is to provide a recycling method and a recycling system for circulating resources such as food waste, which can promote the recycling.

[0013]

SUMMARY OF THE INVENTION In order to solve the problems, the present invention relates to food waste, other food waste and sewage treatment plants and other organic waste liquids collected and collected at each stage of food production, distribution and consumption. A method for recycling circulating resources such as food waste to promote the recycling of circulating resources such as food waste formed by mixing with organic sludge generated from a treatment facility as an object to be treated, comprising: It is characterized by including. (1) A food waste is pulverized into a slurry and used for preparation of a slurry for circulating resources such as food waste. (2) The organic sludge is concentrated and used for preparing the above-mentioned circulating resource slurry such as food waste, and the separated liquid is returned to the organic waste liquid treatment facility. (3) The circulating resource slurry such as food waste is introduced into a bioreactor to generate biogas, and the residual sludge is returned to an organic waste liquid treatment facility. (4) Connect to a cogeneration system that performs cogeneration using the biogas as fuel. (5) A sludge dryer is installed in the cogeneration system to receive heat, and a dehydration cake generated from a dehydration device of an organic waste liquid treatment facility is introduced to perform drying and weight reduction.

Further, there is provided a recycling system for circulating resources such as food waste for carrying out the above-mentioned method, wherein a system for treating an organic waste liquid (system 1) and a biogasification cogeneration system (system 2) are provided. The energy conversion system is constructed (co-located) and connected to each other to collect and reuse waste energy.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is directed to a food waste pulverizing feeder for introducing food waste, removing foreign substances and pulverizing and slurrying the food waste in the recycling system described above, and the food waste pulverizing feeder. A slurry tank for receiving crushed slurry from the plant and preparing a circulating resource slurry such as food waste, and a method for concentrating organic sludge collected in a sludge concentration tank of an organic waste liquid treatment facility and introducing piping to the slurry tank. A concentrated sludge transport line, and a separated liquid return line for returning the separated liquid to the organic waste liquid treatment facility, and a circulating resource slurry such as food waste mixed and adjusted in concentration in the slurry tank are introduced through a pulverizer. A bioreactor for methane fermentation, and an organic waste liquid treatment facility for removing residual sludge generated in the bioreactor. A residual sludge return line for pressure feeding to a dehydration device, a desulfurizer and a gas holder for desulfurizing and storing the biogas generated in the bioreactor, and a gas engine or micro fuel using the biogas introduced from the gas holder as a fuel. A gas turbine, and a sludge dryer that receives a dewatered cake generated by a dewatering device of an organic waste liquid treatment facility and that performs a drying / reducing treatment by introducing waste heat from the gas engine or the micro gas turbine; and the gas engine or Power transmission means is provided for supplying power generated by the micro gas turbine to a power load including power sales.

Here, instead of the slurry tank, a slurry supply line from a food waste pulverizing feeder to an inlet of a pulverizer or a bioreactor is provided, and a concentrated sludge transport line is joined to the slurry supply line. Alternatively, the pulverized slurry and the concentrated sludge may be mixed and adjusted in a pipeline.

Further, in place of the gas engine or the micro gas turbine, a reformer and a hydrogen fuel cell power generator can be used.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a flow sheet of the embodiment system. Each treatment amount (daily unit) added in the figure is a reference value when interconnected with an existing sewage treatment plant (organic wastewater treatment facility), and comparative costs are estimated based on this.
(See below)

As shown, the embodiment system (X)
Is a food waste pulverizing feeder (1) that inputs food waste, removes foreign substances, and performs pulverization slurry processing.
And a slurry tank (2) for receiving the pulverized slurry from the food waste pulverizing feeder (1) to prepare a circulating resource slurry such as food waste, and an organic waste liquid treatment facility [hereinafter referred to as a sewage treatment plant. ] The organic sludge collected in the sludge thickening tank (20) of (Y) is concentrated via the concentration / separation means (3) (dehydrator or centrifugal separator shown in the figure) and introduced into the slurry tank (2) by piping. Sludge tank (2) and a concentrated sludge transport line (4), and a separated liquid return line (5) for returning a separated liquid (or filtrate) to a sewage treatment plant (Y). A bioreactor (6) for introducing circulating resource slurries such as food waste through a crusher (61) and subjecting it to methane fermentation, and a dewatering device for a residual sludge generated in the bioreactor (6) at a sewage treatment plant (Y) Residual sludge return line for transport to (21) (7)
A desulfurizer [not shown] and a gas holder (8) for desulfurizing and storing biogas generated from the bioreactor (6); and a gas engine (10) using biogas introduced from the gas holder (8) as fuel. ) And sewage treatment plant (Y)
The sludge dryer (11) that receives the dewatered cake generated by the dewatering device (21), introduces waste heat from the gas engine (10), and performs drying and weight reduction processing, and the power generated by the gas engine (10) Power supply means (12) for supplying power to a power load including power selling. Here, the gas engine (10) is a micro gas turbine (not shown).
May be substituted. Note that equipment downstream of the gas engine (10) may be considered to belong to the system of the cogeneration system (Z).

Further, instead of the slurry tank (2), a slurry supply line (not shown) from the food waste crushing feeder (1) to the inlet of the crusher (61) or the bioreactor (6) is provided. The concentrated sludge transport line (4) may be joined to the slurry supply line to mix the pulverized slurry with the concentrated sludge and adjust the concentration in the pipeline. (Not shown)

Furthermore, a case where a reformer and a hydrogen fuel cell power generator are used instead of the gas engine (10) or the micro gas turbine may be considered. (Not shown)

To summarize the processing flow, first, garbage and other food waste discharged and collected at each stage of food production, distribution, and consumption are collected, foreign matter is removed, and the slurry is formed into a pulverized slurry. The sludge stored in a tank and conveyed by piping from a sewage treatment plant is concentrated, and is then charged into a slurry tank to adjust the slurry concentration.

The slurry (circulated resource slurry such as food waste) is transported to a bioreactor and subjected to methane fermentation treatment to generate biogas. The biogas is desulfurized to generate electric power and heat as a fuel for a cogeneration system. .

Further, the residual sludge generated in the bioreactor is transported to a sewage treatment plant by pipes, mixed with a coagulant, and then converted into a dewatered cake through a dewatering device. Simultaneously generated sewage is treated at a sewage treatment plant.

The electric power generated by the cogeneration system is used as a power source in the recycling system, the heat is used (consumed) as a heat source for heating the bioreactor and for drying / reducing the dewatered cake, and the surplus energy is used for the local (system). Outside)
(Supply). Significant cost reduction can be expected by connecting these systems.

FIGS. 2 (a) and 2 (b) show the comparison between the effects of the existing sewage sludge treatment and the effect of the amount reduction treatment by the embodiment system.
Along with this, the annual cost of incineration and composting of the current treatment can be significantly reduced by digestion and drying of the embodiment system. Of course, the equipment cost (initial investment amount) of the embodiment system must be separately considered,
The annual cost of current processing is every year, and the running cost of the system of the embodiment is extremely low in consideration of the energy balance, so it is estimated that the facility cost can be recovered in about 10 years.

[0028]

According to the present invention, there is no need for a wastewater treatment device required for the treatment of garbage, and a high-concentration mixed slurry of garbage and sewage sludge is subjected to high-temperature digestion. As a result, efficient recycling can be achieved in terms of energy balance, reduction and other recyclability of circulating resources such as food waste.

Since the entire amount of the sewage sludge currently incinerated and landfilled can be recycled, the load on the final disposal site can be reduced.

Considering the location as an infrastructure facility of the local community (including the widening of the area), it is useful in returning excess energy to the local community, and can be expected to contribute to the formation of a recycling-based society.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing one embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a comparison between the effects of a current sewage sludge treatment and an effect of a reduction treatment of an example system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Food waste feeder 2 Slurry tank 3 Dehydrator (concentration separation means) 4 Condensed sludge transport line 5 Separated liquid return line 6 Bioreactor 61 Crusher 7 Residual sludge return line 8 Gas holder 10 Gas engine 11 Sludge dryer 12 Power transmission means 20 Sludge thickening tank 21 Dehydrator X Recycling system Y Sewage treatment plant (organic wastewater treatment facility) (Z) Cogeneration system

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C12M 1/00 F02C 6/00 E F02C 3/28 6/18 Z 6/00 7/22 D 6/18 F02G 5 / 02 A 7/22 5/04 H F02G 5/02 H01M 8/00 Z 5/04 B09B 3/00 D H01M 8/00 ZABZ C (72) Inventor Hidehiko Shimizu 4-33 Komachi, Naka-ku, Hiroshima City, Hiroshima Prefecture F-term (reference) in Chugoku Electric Power Co., Inc.

Claims (4)

[Claims] 1. A mixture of garbage and other food waste discharged and collected at each stage of food production, distribution and consumption, and organic sludge generated from a sewage treatment plant and other organic waste liquid treatment facilities. A method for recycling circulating resources such as food waste, comprising the following processing steps in order to promote recycling of circulating resources such as food waste as objects to be treated. (1) The food waste is pulverized into a slurry to provide a slurry for circulating resources such as food waste. (2) The organic sludge is concentrated and used for the preparation of a circulating resource slurry such as the food waste, and the separated liquid is returned to the organic waste liquid treatment facility. (3) The circulating resource slurry such as food waste is introduced into a bioreactor to generate biogas, and the residual sludge is returned to an organic waste liquid treatment facility. (4) Connect to a cogeneration system that performs cogeneration using the biogas as fuel. (5) A sludge dryer is installed in the system of the cogeneration system to receive heat supply, and a dehydration cake generated from a dehydration device of an organic waste liquid treatment facility is introduced to perform drying and weight reduction processing. 2. Mixing garbage and other food waste discharged and collected at each stage of food production, distribution and consumption with organic sludge generated from a sewage treatment plant and other organic waste liquid treatment facilities. This is a recycling system for food waste and other circulating resources to promote the recycling of food waste and other circulating resources as objects to be treated. And a slurry tank for receiving crushed slurry from the food waste crush feeder and preparing a circulating resource slurry such as food waste, and concentrating organic sludge collected in a sludge concentration tank of an organic waste liquid treatment facility. And a separated liquid return line for returning the separated liquid to the organic waste liquid treatment facility. And a bioreactor for introducing a circulating resource slurry such as food waste mixed and adjusted in concentration in the slurry tank through a pulverizer to perform methane fermentation, and treating residual sludge generated in the bioreactor with an organic waste liquid treatment. A line for returning sludge to be transported to a dehydrator of the facility, a desulfurizer and a gas holder for desulfurizing and storing biogas generated in the bioreactor, and a gas engine using biogas introduced from the gas holder as fuel Or a micro gas turbine, and a sludge dryer for receiving a dewatered cake generated by a dewatering device of an organic waste liquid treatment facility, drying and reducing the amount by introducing waste heat from the gas engine or the micro gas turbine, and the gas Electricity load including electric power generated by engine or micro gas turbine Recycling system for food waste recyclable resources, characterized by comprising a power transmission means for supplying. 3. A slurry supply line from a food waste pulverizing feeder to an inlet of a pulverizer or a bioreactor is provided in place of the slurry tank, and a concentrated sludge transport line is joined to the slurry supply line. 3. The recycling system for circulating resources such as food waste according to claim 2, wherein the crushed slurry and the concentrated sludge are mixed and the concentration is adjusted in the pipeline. 4. The recycling system for circulating resources such as food waste according to claim 2, wherein a reformer and a hydrogen fuel cell power generator are used instead of said gas engine or micro gas turbine.