JPH11216500A - Solubilizing treatment of organic sludge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and homogeneously solubilize an organic sludge by stirring the organic sludge in a treating tank to increase the temp. by the frictional heat generating at this time to solubilize. SOLUTION: A change port 2 on the ceiling and a discharge port on the bottom are arranged in the treating tank 1. An the upper part and the lower part of the treating tank 1 are connected to each other through a circulating pipe 4 and the organic sludge 8 is circulated by an under water pump device 5 having an impeller. A thermocouple 6 is disposed at the upper part of the treating tank 1 and connected to the impeller type under water pump device 5 through an inverter control device 7 to control the speed of revolution of the pump device 5. In this structure, the under water pump device 5 is driven to continuously circulate the organic sludge 8. Then, the frictional heat is generated by the shearing due to the impeller of the pump device 5 to elevate the temp. of the organic sludge 8. The speed of revolution is controlled by the detected temp. of the thermocouple 6 to keep to a prescribed temp. The sludge is solubilized by this manner to improve fermentation efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for solubilizing organic sludge prior to fermenting organic sludge such as sewage sludge, septic tank sludge, kitchen waste and livestock manure.

[0002]

2. Description of the Related Art Conventionally, fermentation plants, biogas production and
In facilities that perform aerobic or anaerobic fermentation such as sludge volume reduction plants, a process called solubilization or acid fermentation, that is, a process of liquefying and reducing the molecular weight of indigestible substances such as proteins and fats contained in organic matter. And various attempts have been made.

For example, in Japanese Patent Publication No. Hei 4-70080,
Organic sludge such as sewage sludge and agricultural and marine waste is treated with alkali.
The cell wall of the microbial cells in the sludge is destroyed by adjusting to H9 to 11, and the solid matter such as the remaining cells is crushed by wet mill treatment, and then anaerobically digested.

Japanese Patent Application Laid-Open No. 55-97298 discloses a biologically difficult organic material (cell membrane, cellulose) after biological treatment.
Ozone is blown into the water to be treated, which contains carbon dioxide, thereby breaking the long carbon chain of the organic substance or generating an oxide to decompose it into an easily biologically treated organic substance, which is then subjected to biological treatment again.

JP-A-62-283100, Japanese Patent Publication No. 4-1
In No. 2198, the organic components in the sludge are solubilized and reduced in molecular weight by heating the organic sludge, and the decomposition rate in the subsequent anaerobic treatment step is increased.

[0006]

However, in the case of the above-mentioned treatment method in which alkali or ozone is applied, not only equipment costs and running costs are incurred due to the alkali agent and ozone gas, but also the latter stage due to residual alkali and residual ozone. Some measures must be taken to prevent adverse effects on biological treatment.

In the case of the heat treatment method, if the heat can be radiated to some extent, the influence on the subsequent stage is small, but since a large-capacity heater and a stirrer are required, equipment costs and running costs are increased, and the object to be treated has a high concentration. Cannot be easily stirred, and uniform solubilization is difficult.

An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a method for solubilizing organic sludge, which can solubilize organic sludge easily and uniformly.

[0009]

Means for Solving the Problems In order to solve the above problems, the method for solubilizing organic sludge of the present invention is a method for solubilizing organic sludge performed prior to fermentation. The organic sludge introduced into the inside is stirred by a blade type stirring means, and is solubilized by raising the temperature by frictional heat generated by the stirring.

[0010] Preferably, a circulation pump device for circulating organic sludge through the inside of the treatment tank and the circulation flow path outside the tank is used as the blade-type stirring means. According to the above configuration, the organic sludge is stirred and mixed while being sheared by the stirring blade, and the temperature is increased by frictional heat generated particularly at the portion of the stirring blade, and the organic sludge is uniformly solubilized by a synergistic effect of these. At this time, when the organic sludge is kept at 50 ° C. or higher, the protein of the sludge constituent substance is denatured, and the solubilization rate increases.

[0011] The circulating pump device is inevitably large in capacity regardless of whether it is an in-tank type or an out-of-tank type. Not only sludge and septic tank sludge, but also high-viscosity, for example, kitchen waste and livestock manure having a TS concentration of 1.5% or more are uniformly stirred and mixed, and heated to solubilize.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, a treatment tank 1 is provided in front of an anaerobic fermenter (not shown) for performing methane fermentation, solubilizes (ie, hydrolyzes) organic sludge, and performs acid fermentation. have.

The treatment tank 1 has an inlet 2 formed in the top part, an outlet 3 formed in the lower part, and a circulation pipe 4 communicating the lower part and the upper part in the tank. The lower end of the circulation pipe 4 is connected to a discharge port of a submersible pump device 5 having an impeller (not shown).

A thermocouple 6 for measuring the temperature of the organic sludge in the tank is provided at the upper part of the treatment tank 1. The thermocouple 6 is electrically connected to the thermocouple 6 and the submersible pump device 5 to form a thermocouple. Vs. 6
There is provided an inverter control device 7 for controlling the rotation speed of the pump device 5 based on the temperature data from.

The operation of the above configuration will be described. Organic sludge 8 is charged into the acid fermentation tank 1 through the inlet 2, and is continuously circulated through the circulation pipe 4 by the submersible pump device 5 inside and outside the tank.

Thus, the organic sludge 8 is agitated and mixed while being sheared by the impeller of the submersible pump device 5, and the temperature is increased by frictional heat generated particularly in the impeller.

At this time, the temperature of the organic sludge 8 is continuously or intermittently measured by the thermocouple 6, and based on the temperature data transmitted from the thermocouple 6, the organic sludge 8 is The rotation speed of the submersible pump device 5 is controlled so as to be maintained within a predetermined temperature range.

While the operation is continued, the organic sludge 8 is gradually solubilized and undergoes acid fermentation. Therefore, the sludge is taken out from the discharge port 3 at an appropriate time and sent to the anaerobic fermenter. As described above, the sewage sludge was solubilized at 50 ° C. for 24 hours and then anaerobic fermented (15 days). As a result, the organic matter decomposition rate became 50% or more. On the other hand, when the same sludge was not solubilized, the organic matter decomposition rate was about 40%.
%, Indicating a clear difference in the fermentation efficiency.

The treatment conditions for solubilization may be appropriately determined according to the properties of the organic sludge to be treated. For example, 70 ° C. for 3 hours, 50 ° C. for 12 hours, 50 ° C. for about 24 hours, tank To stay inside. It is also possible to solubilize only urine sludge which is hardly oxidatively decomposed, mix with garbage which is relatively easily oxidatively decomposed, and ferment.

The blade-type stirring means may be of a relatively large capacity corresponding to the properties of sludge and the amount of sludge. The use of a submersible pump as described above has a high solubilization efficiency. As shown in FIG.
May be used, or a cutter pump having a crushing function may be selected. A similar effect can be obtained by the blade-type stirring device 10 installed in the tank as shown in FIG.

In the above description, the solubilization treatment is performed prior to the anaerobic fermentation. However, even if such a solubilization treatment method is performed before the aerobic fermentation, the fermentation efficiency is naturally improved.

[0022]

As described above, according to the present invention, the organic sludge can be sheared and heated with sufficient stirring and mixing by a single means of the blade type stirring means, and the efficiency can be easily and uniformly increased. The solubilization treatment can be performed well, the influence on the subsequent stage is small, and the equipment cost can be reduced as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a schematic configuration of a treatment tank in which a method for solubilizing organic sludge according to a first embodiment of the present invention is performed.

FIG. 2 is a sectional view showing a schematic configuration of a treatment tank in which a method for solubilizing organic sludge according to a second embodiment of the present invention is performed.

FIG. 3 is a cross-sectional view illustrating a schematic configuration of a treatment tank in which a method for solubilizing organic sludge according to a third embodiment of the present invention is performed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Processing tank 4 Circulation pipe 5 Submersible pump device 8 Organic sludge 9 Pump device 10 Blade type stirring device

Continuation of front page (72) Inventor Toshiyuki Shibata 2-47 Shishitsu Higashi 1-chome, Naniwa-ku, Osaka-shi, Osaka Kubota Corporation

Claims (2)

[Claims] 1. A method for solubilizing organic sludge carried out prior to fermentation, wherein organic sludge introduced into a treatment tank is stirred by a blade type stirring means, and friction heat generated by the stirring is used. A method for solubilizing organic sludge, wherein the method is solubilized by raising the temperature. 2. The organic sludge according to claim 1, wherein the blade type stirring means is a circulation pump device for circulating the organic sludge through the inside of the treatment tank and the circulation passage outside the tank. Solubilization method.