JPH0671278A - Septic tank - Google Patents

Abstract

PURPOSE:To efficiently aerate the aerobic treating chamber of a septic tank provided with a membrane separator. CONSTITUTION:The liq. treated in a second aerobic treating chamber 6 is supplied to the primary side of a membrane separator 15 by a pump 14, the concd. liq. not permeated through the membrane is returned to a first aerobic treating chamber 5 through a return pipe 17, and a part of the concd, liq. is passed through an ejector 20 and returned to the second aerobic treating chamber 6. Air is entrained by the concd. liq. in this case, and the second aerobic treating chamber 6 is aerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a septic tank for purifying and discharging sewage from a toilet, washroom, bath, kitchen or the like.

[0002]

2. Description of the Related Art A septic tank for wastewater discharged from toilets, toilets, baths, kitchens, etc. has an aerobic treatment chamber downstream of the anaerobic treatment chamber for aeration with an aeration device. A sedimentation separation chamber is provided downstream of this aerobic treatment chamber, where organic substances in wastewater are decomposed by anaerobic bacteria in the anaerobic treatment chamber, and nitrate nitrogen in the treated water is decomposed into nitrogen gas by the action of denitrifying bacteria. , In the aerobic treatment chamber, the organic substances are decomposed by aerobic bacteria and the nitrifying bacteria act to convert ammoniacal nitrogen in the treated water into nitrate nitrogen.
There is a system in which the nitrate nitrogen is returned to the anaerobic treatment chamber and the sludge generated by these treatments and purified treated water are separated in a sedimentation separation chamber.

In the above-mentioned septic tank, the separation in the sedimentation separation chamber is not sufficient, sludge flows out, and the salt concentration and solid concentration in the separated clean treated water are not sufficiently lowered. is there. Therefore, Japanese Patent Publication No. 64-9074 or Japanese Patent Application Laid-Open No. 3-98697 discloses a technique in which a membrane separation device is provided in place of the sedimentation separation chamber to enhance the solid-liquid separation function.

[0004]

In each of the above-mentioned conventional devices, an aeration device is provided in the aerobic treatment chamber, and aeration is performed to supply air (oxygen) to aerobic bacteria. For this reason, a blower or the like dedicated to the aeration device is required, the size of the entire device is increased, and extra power is required.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, according to the present invention, a membrane separation device is arranged on the downstream side of an aerobic treatment chamber of a septic tank, and concentration is performed in the middle of a return pipe led out from the membrane separation device. An ejector for mixing air into the treated water and introducing it into the aerobic treatment chamber was provided.

[0006]

[Function] The concentrated treated water passes through the return pipe and the ejector by the power of the pump required to give a differential pressure to the membrane surface of the membrane separation device, and entrains air when passing through the ejector, which acts as aeration. To do.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a longitudinal sectional view of the septic tank according to the present invention, FIG. 2 is a plan sectional view of the septic tank, FIG. 3 is a sectional view taken along the line AA of FIG. 1, and FIG. 4 is a sectional view of the ejector.

In the septic tank, the inside of the main body 1 made of FRP or the like is divided by the partition walls 2 ... In order from the upstream side, the first anaerobic treatment chamber 3, the second anaerobic treatment chamber 4, the first aerobic treatment chamber 5, and the second aerobic treatment. It is divided into a processing chamber 6 and a final processing chamber 7.

In the first anaerobic treatment chamber 3 and the second anaerobic treatment chamber 4, a filter bed 8 to which anaerobic bacteria including methane bacteria and denitrifying bacteria are adhered is arranged, and the first aerobic treatment chamber 5 and the first aerobic treatment chamber 5 and 2 Inside the aerobic treatment chamber 6, a filter bed 9 to which aerobic bacteria including nitrifying bacteria adhere is arranged. Then, the first anaerobic treatment chamber 3 and the second anaerobic treatment chamber 4 are connected by a communication hole 10 formed in the partition wall 2, and the second anaerobic treatment chamber 4 and the first aerobic treatment chamber 5 are connected to the partition wall 2. The communication hole 11 formed is connected, and the first aerobic treatment chamber 5 and the second aerobic treatment chamber 6 are connected by a communication hole 12 formed in the partition wall 2.

Further, in the final processing chamber 7, a pump 14 and a membrane separation device 15 are provided on a support 13 so that the processing liquid in the second aerobic processing chamber 6 sucked through the pipe 16 by the pump 14 can be used. It is sent to the membrane separation device 15 and is separated by the separation membrane into a concentrated liquid containing sludge and a clean permeated liquid.

A return pipe 17 for returning the concentrated liquid to the first anaerobic treatment chamber 3 is led out from the primary side of the membrane separation device 15, that is, the side where the concentrated liquid remains. And this return pipe 1
In the middle of 7, a downward branch pipe 18 is provided in an upper portion of the second aerobic treatment chamber 6, and the ejector 2 is attached to the branch pipe 18.
0 is attached.

As shown in FIG. 4, the ejector 20 is composed of a nozzle 21, an air introduction pipe 22 and a venturi pipe 23. The negative pressure when the concentrated liquid flows from the nozzle 21 into the venturi pipe 23 causes the ejector 20 to exit from the air introduction pipe 22. Air is entrained and this air is supplied to the filter bed 9 in the second aerobic treatment chamber 6 to perform aeration (aeration). Further, a metering valve 19 is provided midway in the return pipe 17 on the downstream side of the ejector 20, and a fixed amount of the concentrated liquid is returned to the first anaerobic treatment chamber 3 to enter.

On the other hand, the permeated liquid that has permeated the separation membrane of the membrane separation device 15 and has exited to the secondary side is passed through the pipe 30 to the final treatment chamber 7.
It is sent to the measuring box 31 arranged in the upper part of the inside, and a certain amount of permeated liquid is supplied to the disinfection tank 32 by the weir provided in the measuring box 31, and then discharged to the outside. The remaining permeate sent to the measuring box 31 is returned to the inside of the second aerobic treatment chamber 6 via the pipe 33.

In the above, the treatment liquid supplied to the first anaerobic treatment chamber 3 is decomposed into organic matter by the action of anaerobic bacteria in the first anaerobic treatment chamber 3 and the second anaerobic treatment chamber 4 to be reduced in molecular weight. . A part or all of the nitrogen component becomes ammonia nitrogen, and a part of the carbon component is decomposed into methane gas or carbon dioxide gas by the action of methane bacteria and the like, and is released into the atmosphere through the opening 34 or the like provided in the ceiling portion of the main body 1. . Next, in the treatment liquid, organic substances are decomposed by the action of aerobic bacteria in the first aerobic treatment chamber 5 and the second aerobic treatment chamber 6, and the ammonia nitrogen in the treatment liquid is converted into nitrate nitrogen by the action of nitrifying bacteria. To be done. The nitrate nitrogen is returned to the first anaerobic treatment chamber 3 by the return pipe 17 and is converted into nitrogen gas in the first and second anaerobic treatment chambers 3 and 4 by the action of denitrifying bacteria.

The treatment liquid which has been treated in the second aerobic treatment chamber 6 is supplied to the primary side of the membrane separation device 15 by the pump 14, and the permeated liquid which has permeated the separation membrane is measured box 31 as described above. Sent to the outside through the disinfection tank 32, the remaining permeate is returned to the second aerobic treatment chamber 6, while the concentrated liquid that does not permeate the separation membrane is returned to the return pipe 17 Is returned to the first anaerobic treatment chamber 3 via.

Then, when a part of the concentrated liquid returned to the first anaerobic treatment chamber 3 passes through the ejector 20 and is returned to the second aerobic treatment chamber 6, air is entrained and the second aerobic treatment chamber is evacuated. Aerate 6

In the illustrated example, the membrane separation device is incorporated into the main body 1 of the septic tank, but the membrane separation device may be separated from the main body 1. Further, the membrane separation device may be provided in the aerobic treatment chamber, and further, the sedimentation separation chamber may be provided between the membrane separation device and the aerobic treatment chamber.

[0018]

As described above, according to the present invention, an ejector is provided in the middle of the return pipe for returning the treated water concentrated in the membrane separator to the anaerobic treatment chamber or the aerobic treatment chamber. Since air is mixed into the treated water concentrated in step 1 and the concentrated liquid mixed with air is introduced into the aerobic treatment chamber, aeration can be performed without the need for an aeration device, and a membrane separation device is used. Compared to the conventional septic tank, the power source is reduced by one.

Further, in the conventional septic tank using the membrane separation device, the power of the pump for giving a differential pressure between the primary side (concentration side) and the secondary side (permeation side) of the membrane is once the differential pressure. Although it has not been effectively used after being given, according to the present invention, the power of the pump entrains air in the ejector, so that the power can be effectively used.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a septic tank according to the present invention.

FIG. 2 is a plan sectional view of the septic tank.

FIG. 3 is a view on arrow AA of FIG.

FIG. 4 is a sectional view of the ejector.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Septic tank main body, 3 ... 1st anaerobic treatment chamber, 4 ... 2nd anaerobic treatment chamber, 5 ... 1st aerobic treatment chamber, 6 ... 2nd aerobic treatment chamber, 7 ... Final treatment chamber, 14 ... Pump , 15 ... Membrane separation device, 17 ... Return pipe, 20 ... Ejector.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Shimodera Kenichi Shimodera 2-1-1 Nakajima, Kokurakita-ku, Kitakyushu City, Fukuoka Prefecture Totoki Kikai Co., Ltd. (72) Isao Miura, Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka 2-1, 1-1 Totoki Equipment Co., Ltd.

Claims (1)

[Claims] 1. A septic tank in which treated water treated in an anaerobic treatment chamber is introduced into an aerobic treatment chamber, and treated water treated in the aerobic treatment chamber is supplied to a membrane separation device by a pump, From the membrane separator, we led out a return pipe that returned the concentrated treated water to the anaerobic treatment chamber or the aerobic treatment chamber,
A septic tank characterized in that an ejector for mixing air into the concentrated treated water and introducing it into the aerobic treatment chamber is provided in the middle of the return pipe.