Organic waste treatment system

Abstract

[Object] To provide an organic waste treatment system in which general wastes from home, ordinary offices, and the like as well as industrial wastes including sludge, waste plastics, and the like can be subjected to treatment such as decomposition by a hydrothermal reaction under a subcritical water condition and in which treated wastes can be taken out in a dried state, sorted, and recycled.[Approach] In a waste treatment system for hydrolyzing organic wastes while stirring the wastes under a high-temperature and high-pressure environment and thermally decomposing or carbonizing the wastes in a double-walled pressure-resistant container 1, the system includes at least: water vapor supply means 9a for supplying high-heat saturated water vapor into the container 1; pressure regulating means 10 for regulating pressure in the container 1 by using an on-off valve; and stirring means 6 having a shaft 7 for stirring the charged wastes in the container 1 and provided to penetrate the container 1 and the system includes the steps of: hydrolyzing the wastes while adjusting temperature to 230° C. or higher and pressure to 3 MPa in the container 1 and stirring the wastes and thermally decomposing or carbonizing the wastes; adjusting the pressure in the container 1 to atmospheric pressure or lower and discharging the treated wastes out of the container while maintaining a dried state of the wastes; and sorting the discharged treated wastes and forming at least one of fertilizer, feed, and auxiliary fuel depending on types of the wastes.

Description

TECHNICAL FIELD[0001]The prevent invention relates to an organic waste treatment system in which general wastes from home, ordinary offices, and the like as well as industrial wastes including sludge, waste plastics, and the like can be subjected to treatment such as decomposition by a hydrothermal reaction under a subcritical water condition and in which treated wastes can be taken out in a dried state, sorted, and recycled.BACKGROUND TECHNIQUE[0002]In a prior-art organic waste treatment system, wastes to be treated are separated in advance and the separated wastes are respectively charged into treatment apparatuses designed according to types of the wastes. For example, the waste plastics are charged into and treated in a plastic-specific treatment apparatus, rubber such as waste tires is charged into and treated in a rubber-specific treatment apparatus, waste newspaper, wastepaper, and the like are charged into and treated in a treatment apparatus for paper, and garbage is charge...

AI Technical Summary

Benefits of technology

[0028]According to the present invention, by using one organic waste treatment system, it is possible to carry out treatment such as decomposition by the hydrothermal reaction under the subcritical water condition of industrial wastes such as sludge, waste plastics, wastepaper, wood waste, animal solid waste, plant and animal residue, animal feces and urine, animal carcasses, and infectious specially-controlled industrial wastes and general wastes such as general wastes from business activities, household wastes, infectious specially-controlled general wastes, separated garbage, and food residue and it is also possible to treat composite materials which cannot be separated. Therefore, it is unnecessary to provide a plurality of treatment apparatuses for respective types of the wastes as in the prior-art systems to thereby reduce the treatment cost.

[0029]Moreover, because the system of the invention can sterilize and kill the microbes and bacteria propagating in the litter and pathogens adhering to the medical wastes by the hydrothermal oxidation reaction under the high-temperature and high-pressure condition by using water vapor, it is possible to obtain a particular effect of easily treating the wastes which could not be treated before disinfection or sterilization in the prior art.

[0030]Furthermore, because the system of the invention carries out treatment such as decomposition of the organic wastes in a hermetically sealed container, it is possible to obtain an effect of not exhaling foul smells outside even during treatment of garbage, stockbreeding wastes, sludge, rotten sea food, meat, and farm produce.

[0031]Moreover, because the wastes to be treated are different depending on season and the time of day or year, the system of the invention can treat the waste plastics and waste rubber together when there are large amounts of them. It is also possible to take the treated wastes out of the pressure-resistant container in the dried state and to recycle them as auxiliary fuel. Moreover, when there are large amounts of litter, animal solid wastes, plant and animal residue, animal feces and urine, animal carcasses, sea food, and the like, it is possible to obtain an effect of treating them together, taking the treated wastes out of the pressure-resistant container in the dried state, and recycling them as feed and fertilizer.BEST MODES FOR CARRYING OUT THE INVENTION

[0032]Next, an embodiment of the present invention will be described based on the drawings. FIG. 1 is a sectional view of an example of an organic waste treatment apparatus A of a waste treatment system of the present invention. FIG. 2 is a block diagram of an example of the waste treatment system of the invention into which the treatment apparatus A of FIG. 1 is integrated.

[0033]In FIG. 1, a reference numeral A designates an organic waste treatment apparatus which is a main portion of a waste treatment system of the invention, 1 designates a double-walled heat-resistant and pressure-resistant container forming the organic waste treatment apparatus A, 1a designates an outer wall of the heat-resistant and pressure-resistant container 1, and 1b is an inner wall of the same. A proper clearance k is provided between the outer wall 1a and the inner wall 1b. In the clearance k high-temperature vapor is supplied and circulates as will be described later. As the heat-resistant and pressure-resistant container 1, a container resistant to internal temperature of 600° C. and internal pressure of 5 MPa is used here.

Problems solved by technology

However, because the treatment apparatuses are designed according to the types of the wastes and how to treat them as described above, the treatment apparatus for the waste plastics cannot be used for treatment of rubber or garbage and the treatment apparatus for making feed and fertilizer cannot be used for treatment of the waste plastics, for example.

However, it is close to impossible for local small municipalities to have so many treatment apparatuses.

Moreover, not all of wastes can be easily separated into the waste plastics, rubber, wastepaper, garbage, and the like.

Especially because composite materials are used everywhere in recent products and many of the products cannot be separated easily even by disassembly.

If they are treated by the above treatment apparatuses, the apparatuses break.

However, many of wastes collected as burnable wastes are not recommended for incineration in an incinerator.

However, microbes and bacteria propagate in such litter and they may not die but be released into the atmosphere together with smoke exhaust or remain in incineration ash if the litter is incinerated in an incinerator.

In recent years, incineration of wastes in incinerators is subjected to criticism from a viewpoint of global environment protection and the incineration of waste plastics in the incinerators may damage the incinerators or generate harmful substances such as dioxin and is therefore strictly restricted by laws, ordinances, and the like.

Because they are of a continuous type, the apparatus becomes complicated.

Because the set temperature is as high as 500° C. or higher and the set pressure is as high as 5 MPa to 22 MPa, it is difficult and expensive to develop the apparatus resistant to such temperature and pressure.

Because treatment conditions of subcritical water suitable for an oxidative decomposition reaction are temperature of 250° C. or higher and treatment pressure of 5 to 10 MPa, it is difficult and too expensive to develop the apparatus for continuously performing oxidation under these conditions.

As a result, water vapor returns to a state of water to make the treated wastes swamped and make it difficult to take the wastes out of the apparatus.

Recycling of the treated wastes requires drying of the wastes again and is too expensive.

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