JP2007021313A - Volume reduction method of sludge, method for causing bacteria group mainly comprising bacillus to dominate, and organic wastewater treatment method using the dominating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a simple volume reduction method of sludge for efficiently solubilizing the sludge, a method for easily realizing the domination of a bacteria group mainly comprising Bacillus, and an excellent organic wastewater treatment method using the above domination. <P>SOLUTION: In the volume reduction method of sludge, the method for causing the bacteria group mainly comprising Bacillus to dominate, and the organic wastewater treatment method using the dominating method, cavitation is generated in sludge fluid containing microorganisms by jetting the sludge fluid from an opening at a high speed to solubilize the microorganisms. Two or more cycles of the above jetting is carried out in the spout port and discharge port of the above fluid and a cavitation generation chamber installed between the ports, and a sludge solubilizing device installed inside of the cavitation generation chamber and having an air supply hole. Air is not supplied from the air supply hole during the first cycle, and air is supplied during the last cycle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for solubilizing microorganisms using a sludge solubilizer, a method for predominating bacteria belonging to the genus Bacillus, and a method for treating organic wastewater using the method for predominance, A method for solubilizing microorganisms, mainly consisting of the genus Bacillus, characterized in that the treatment is performed twice or more in the same sludge solubilizer, and air is not supplied at the first treatment but air is supplied at the last treatment. The present invention relates to a method for predominating bacterial groups, and a method for treating organic wastewater using the predominance method.

As represented by the activated sludge method, wastewater treatment methods using microorganisms have been widely used. In this case, how to treat surplus sludge generated in large quantities with wastewater treatment is a big problem. The method of dewatering and incinerating sludge is expensive, and there is a limit to the method of returning a part of the sludge to the treatment tank. Therefore, the sludge is solubilized and then returned, and a gas-liquid mixing device that functions as a sludge solubilizer has been developed (for example, Patent Documents 1 and 2).
Japanese Patent Publication No. 3-70540 JP 2005-28306 A

On the other hand, in recent years, it has been proposed to improve the quality of treated water, reduce the amount of excess sludge generated, and suppress bad odor by performing wastewater treatment using Bacillus bacteria (Patent Documents 3 to 5). However, when Bacillus is added to a large-capacity biological treatment tank, the concentration of the bacteria is lowered, so that the vitality of the bacteria is also lowered, and it is difficult to exert the original performance of Bacillus. In addition, microorganisms generally do not grow unless an environment such as water temperature or dissolved oxygen is prepared and the preferred food is satisfied. Therefore, even if the bacterium is added to a biological treatment tank that is not dominated by Bacillus bacteria, it is difficult for the Bacillus bacteria to proliferate and become dominant.
Japanese Patent Laid-Open No. 2001-995 JP 2001-224365 A JP 2002-18469 A

Therefore, a method has been proposed in which a tank for culturing Bacillus is newly provided, and the Bacillus cultivated in the tank is periodically transferred to a biological treatment tank (Patent Document 6). However, in order to cultivate Bacillus in a newly established tank, it is necessary to prepare an environment suitable for the growth of Bacillus and to continue to provide the preferred food, which is not only complicated but also expensive. It was. Such drawbacks are improved by performing sewage treatment in a biological treatment tank in which microorganisms other than Bacillus bacteria in sludge are selectively killed, and allowing the Bacillus bacteria to grow and dominate (Patent Document 7). However, an inexpensive method for stable operation with high efficiency has not yet been known.
JP 2002-126786 A JP 2004-275960 A

Therefore, the present inventors have conducted intensive studies on more efficiently killing bacteria other than the genus Bacillus in the sludge. As a result, the inventors have treated the same sludge solubilizer twice or more, and the first treatment is air. By supplying air at the time of the last treatment without supplying the bacteria, cells of bacteria group mainly composed of Bacillus (hereinafter referred to as Bacillus etc.) and microorganism groups other than those spores are efficiently destroyed. It is possible to easily solubilize microbial groups, and it is also easy to dominate Bacillus bacteria, etc., and it is effective for the treatment of organic wastewater to use this dominance of Bacillus bacteria, etc. As a result, the present invention has been reached.
Accordingly, a first object of the present invention is to provide a simple method for efficiently solubilizing sludge containing microorganisms.
The second object of the present invention is to provide a method capable of easily realizing the predominance of Bacillus bacteria and the like.
Furthermore, the third object of the present invention is to provide an excellent organic wastewater treatment method utilizing the predominance of the aforementioned Bacillus bacteria and the like.

The above-mentioned objects of the present invention are a method of solubilizing microorganisms by causing a sludge fluid containing microorganisms to be ejected from an opening at high speed and generating cavitation in the sludge fluid, wherein the ejection is performed as described above. In the sludge solubilizer having two or more fluid outlets and outlets, a cavitation generation chamber provided between them, and an air supply hole provided inside the cavitation generation chamber, two or more cycles are performed, In the first cycle, air is not supplied from the air supply hole but air is supplied in the last cycle, a method for reducing sludge, a method for predominating a bacterial group mainly composed of Bacillus, And it achieved by the processing method of the organic waste_water | drain using this dominant method.
In the present invention, in particular, the temperature of the sludge fluid at the time of ejection is preferably 40 ° C. or higher, and the pH of the sludge fluid at the time of ejection is preferably 10.5 or higher.
Furthermore, when returning the fluid containing a large amount of the Bacillus bacteria and / or its spores to the biological treatment tank to treat organic wastewater, the fluid should be returned through a flow rate adjustment tank provided in the preceding stage of the biological treatment tank. It is preferable to provide a growth tank in which the Bacillus bacteria and / or spores thereof are proliferated / dominated during the returning step, and at least one of the flow rate adjustment tank, the biological treatment tank and the growth tank It is preferable to supply a nutrient source for culturing the Bacillus bacteria and / or the spores thereof to the tank. In this case, it is preferable to control the temperature of the growth tank to 5 to 40 ° C.

  According to the present invention, the sludge generated from the biological treatment tank can be easily reduced and the dominance of Bacillus bacteria can be performed at the same time, so that the organic wastewater can be treated more efficiently than before. be able to. That is, as a result of dominating Bacillus bacteria, etc., it is possible to improve the quality of treated water, suppress bad odor, shorten the sludge solubilizer operation time due to excess sludge reduction, and maintain organic wastewater treatment facilities Since management becomes easy, the cost is also reduced.

  The method for solubilizing sludge containing microorganisms of the present invention belongs to a method for solubilizing microorganisms by destroying the cells of microorganisms by ejecting a fluid containing microorganisms from an opening at high speed. The ejection is performed in a sludge solubilizer having a fluid ejection port and a discharge port, a cavitation generation chamber provided therebetween, and an air supply hole provided inside the cavitation generation chamber. As such a sludge solubilizing device, a sewage purification device described in JP-A-2005-28306 and a similar device can be used as appropriate.

  In the present invention, in particular, the sludge fluid to be treated is ejected from the same sludge solubilizer at least twice. That is, the first feature of the present invention is that the sludge fluid once ejected is again introduced into the same sludge solubilizer and is ejected again. In this case, the number of ejections is defined as the number of cycles, such as 2 cycles if the number of ejections is 2 and 3 cycles if the number is 3.

  The second feature of the present invention is that air is not supplied in the first cycle but air is supplied in the last cycle. In other cycles, air may or may not be supplied depending on the design. The sludge solubilization device is designed so that the discharge amount from the discharge port is larger than the discharge amount so that cavitation occurs in the sludge fluid when the sludge fluid is jetted without supplying air. That is, since the cavitation generation chamber is decompressed, cavitation is likely to occur. This cavitation destroys the cell membrane and cell wall of the microorganism and solubilizes the microorganism. The sludge solubilization apparatus of the present invention can solubilize microorganisms even when the diameter of the jet outlet is about 6 mm or more so that sludge clogging does not occur. In particular, the present invention sufficiently performs solubilization. And squirt at least twice.

  When the sludge fluid is ejected without supplying air, it is performed in a closed system. When air is supplied, for example, an electromagnetic valve provided in the air supply hole may be opened. In order to introduce the sludge fluid after ejection into the sludge solubilizer again, a buffer tank may be provided if necessary. One or more two-way valves or two two-way valves are arranged at the crossroads of recirculating the sludge fluid after ejection or returning it to the biological treatment tank. These valves are preferably solenoid valves.

In the present invention, in order to promote the solubilization of microorganisms, the pH of the sludge fluid at the time of ejection is preferably 10.5 or more, and particularly preferably 11 or more. The pH may be adjusted using a known alkali, but usually an inexpensive sodium salt or calcium salt is used. In addition, the solubilization of the microorganism can be promoted by heating the sludge fluid before jetting together with the pH adjustment or in place of the pH adjustment. In particular, when the temperature of the sludge fluid before jetting is 40 ° C. or higher, bacteria other than Bacillus bacteria and the like are killed, and Bacillus bacteria and / or their spores survive, which is particularly effective for purification of organic waste water. It is possible to make dominant Bacillus and the like selectively dominant.
Incidentally, Bacillus bacteria and the like can easily become spores and can withstand impact, alkali, or high temperature, and therefore Bacillus bacteria and the like can be easily dominated by the method of the present invention.

  In the present invention, the sludge fluid in which microorganisms other than Bacillus bacteria and the like in the sludge are selectively solubilized is biologically treated again in the biological treatment tank, but cell walls and cell membranes which are dead bodies of solubilized microorganisms Is a bait for Bacillus, etc., so that Bacillus can be proliferated and predominated in the biological treatment tank. However, since the sludge fluid just discharged from the sludge solubilizer to be returned to the biological treatment tank contains many spores such as Bacillus bacteria, the above spores are grown before being put into the biological treatment tank, and the Bacillus bacteria and the like are favored. It is preferable to make it occupied. Therefore, in the present invention, it is preferable that the sludge fluid after the solubilization treatment is not directly returned to the biological treatment tank, but is returned to the biological treatment tank through a flow rate adjustment tank that is usually provided in front of the biological treatment tank. In this case, the flow rate adjustment tank functions as a growth tank for Bacillus bacteria or the like.

  In this invention, you may provide a separate growth tank in the middle of the return process of the sludge fluid after the said solubilization process with the said flow volume adjustment tank or replacing with a flow volume adjustment tank. The temperature of the growth tank including the flow rate adjustment tank functioning as the growth tank is preferably 5 to 40 ° C. suitable for the growth of Bacillus bacteria, etc., and supplements nutrients that are insufficient with only the dead bodies of solubilized microorganisms. It is preferable to do. The growing tank is neutralized as necessary.

  In addition, the biological treatment tank used in the present invention is an aerobic aeration tank, but the tank does not need to be a single tank, and also includes a floating activated sludge, a contact filter bed, a treatment method using a fluid carrier, etc. The organic wastewater is not particularly limited as long as it is a biological treatment system. When the biological treatment tank is a multi-tank, it is possible to give the tank a function as a growth tank by reducing the volume of the first tank.

Hereinafter, the present invention will be further described with reference to the drawings.
FIG. 1 is a conceptual diagram illustrating the organic wastewater treatment method of the present invention. In the figure, organic waste water 1 is sent to a biological treatment tank 2 and biologically treated. The treated organic waste water 1 is sent to a solid-liquid separation tank 3 such as a sedimentation tank or a membrane separation tank for solid-liquid separation, and divided into supernatant water and sedimented sludge. The supernatant water is discharged out of the system as treated water 4, and the settled sludge is divided into return sludge 5 and surplus sludge 6. Return sludge 5 is solubilized by sludge solubilizer 7, and after solubilization treatment The sludge fluid 8 is returned to the biological treatment tank 2 or a flow rate adjustment tank (not shown) provided in front of the biological treatment tank via a growth tank provided as necessary. It is discharged out of the system.

  Bacillus bacteria have the ability to grow by using solubilized cell walls and cell membranes, which are contained in activated sludge and are not easily decomposed by normal microorganisms. Therefore, the sludge fluid solubilized as described above is supplied to the biological treatment tank 2 or a flow rate adjustment tank (not shown) provided in front of the biological treatment tank via a growth tank provided as necessary. By returning, the inside of the biological treatment tank 2 is dominated by Bacillus bacteria and the like, so that the organic wastewater is efficiently treated without causing malodor due to Bacillus bacteria and the like.

  As mentioned above, Bacillus bacteria and the like have the ability to decompose odor components, and thus cause odors such as ammonia and hydrogen sulfide that are generated under conditions of low DO (dissolved oxygen) during wastewater treatment. In order to decompose the component which becomes, the malodor which may generate | occur | produce at the time of organic waste water treatment is also suppressed.

  Further, when the organic waste water 1 contains a large amount of starch, fat and the like, it is often contained in the treated water 4 as it is untreated because there are few microorganisms that decompose and remove these in a normal biological treatment. However, since Bacillus bacteria have the ability to decompose and remove these starches and fats, the quality of the treated water 4 can be improved.

  According to the present invention, the sludge generated from the biological treatment tank can be easily reduced and the dominance of Bacillus bacteria can be performed at the same time, so that the organic wastewater can be treated more efficiently than before. be able to. That is, as a result of dominating Bacillus bacteria, etc., it is possible to improve the quality of treated water, suppress bad odor, shorten the sludge solubilizer operation time due to excess sludge reduction, and maintain organic wastewater treatment facilities Since management becomes easy and the cost is reduced, it is very significant in industry.

It is a conceptual diagram for demonstrating the processing method of the organic waste_water | drain of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Organic waste water 2 Biological treatment tank 3 Solid-liquid separation tank 4 Treated water 5 Return sludge 6 Excess sludge 7 Sludge solubilizer 8 Sludge fluid after solubilization treatment

Claims (13)

  A method of solubilizing the microorganisms by causing a sludge fluid containing microorganisms to be ejected from an opening at high speed and generating cavitation in the sludge fluid, wherein the ejection comprises an ejection outlet and an outlet of the fluid, and these In the sludge solubilizer having an air supply hole provided inside the cavitation generation chamber and the inside of the cavitation generation chamber. The sludge reduction method is characterized in that air is not supplied and air is supplied in the last cycle.   The sludge reduction method according to claim 1, wherein a temperature of the sludge fluid at the time of ejection is 40 ° C. or more.   The method for reducing sludge according to claim 1 or 2, wherein the pH of the sludge fluid at the time of ejection is 10.5 or more.   A sludge fluid containing microorganisms is ejected from the opening at high speed, and the microorganisms are solubilized by generating cavitation in the sludge fluid, and then a residual bacteria group mainly composed of Bacillus and / or its spores are grown. , A method for predominating a bacterial group mainly comprising Bacillus genus, wherein the jet is a jet port and a discharge port of the fluid, a cavitation generating chamber provided therebetween, and an inside of the cavitation chamber In the sludge solubilizer having an air supply hole provided in the above, two cycles or more are made, and air is not supplied from the air supply hole in the first cycle, and air is supplied in the last cycle. A method of dominating a bacterial group mainly composed of the genus Bacillus.   The method according to claim 4, wherein the temperature of the sludge fluid at the time of ejection is 40 ° C or higher.   The method for predominating a bacterial group mainly composed of Bacillus according to claim 4 or 5, wherein a pH of the sludge fluid at the time of ejection is 10.5 or more.   Using a waste water treatment apparatus having at least a biological treatment tank comprising aeration tank containing microorganisms and a solid-liquid separation tank, sludge fluid separated in the solid-liquid separation tank is ejected at high speed from an opening, and cavitation is performed in the sludge fluid An organic wastewater treatment method for returning a fluid containing a large amount of residual bacteria and / or spores mainly composed of the genus Bacillus to the biological treatment tank, Two or more cycles of jetting in the sludge solubilizer having the fluid outlet and outlet, the cavitation generation chamber provided therebetween, and the air supply hole provided inside the cavitation generation chamber In addition, air is not supplied from the air supply hole in the first cycle, and air is supplied in the last cycle. Method of treating organic waste water according to symptoms.   The processing method of the organic waste_water | drain according to claim 7 whose temperature of the sludge fluid at the time of the said ejection is 40 degreeC or more.   The method for treating organic waste water according to claim 7 or 8, wherein a pH of the sludge fluid at the time of ejection is 10.5 or more.   10. The fluid according to claim 7, wherein a fluid containing a large amount of residual bacteria or a spore thereof mainly comprising the genus Bacillus is returned to the biological treatment tank through a flow rate adjustment tank provided in a preceding stage of the biological treatment tank. Of treated organic wastewater.   In the middle of the step of returning a fluid containing a large amount of the residual bacteria group or spore mainly composed of the genus Bacillus to the biological treatment tank, a growth tank for growing and predominating the bacteria group and / or the spore is provided. Item 10. An organic wastewater treatment method according to any one of Items 7 to 10.   The method for treating organic wastewater according to any one of claims 7 to 11, wherein a nutrient source for culturing the bacterial group and / or spore thereof is supplied to the biological treatment tank and / or growth tank. The method for treating organic waste water according to claim 11 or 12, wherein the temperature of the growth tank is controlled to 5 to 40 ° C.

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