JPH03213128A - Wastewater treatment equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to wastewater treatment equipment for organic wastewater such as septic tank sludge, domestic wastewater sludge, and human waste.

2. Description of the Related Art Conventionally, membrane separation systems have been used as equipment for treating organic wastewater such as septic tank sludge, domestic wastewater sludge, and human waste. In this method, a membrane separator is immersed in a treatment tank such as a nitrification tank, and a suspension such as a mixed liquid is separated into solid and liquid by the membrane separator, and the permeate is extracted as treated water. By aerating air into the treatment tank, the oxygen necessary for oxidizing the wastewater contained in the wastewater is supplied, and the membrane surface of the membrane separator is cleaned by the upward stirring flow generated by the air lift effect. was going on.

Problems to be Solved by the Invention However, in the above configuration, if the aeration intensity is increased in order to increase the cleaning power of the upward agitation flow on the membrane surface, the sludge flocs in which microorganisms live will be destroyed, and the biological treatment capacity will be reduced. As a result, it is not possible to sufficiently wash and remove gels and other substances that adhere to the membrane surface with the upward agitation flow alone, and it is necessary to periodically take the membrane separation device out of the processing tank for cleaning, which reduces operating efficiency. This was seen as a problem in raising the level.

The present invention solves the above problems, and aims to provide wastewater treatment equipment that can reliably clean the membrane surface without destroying sludge flocs.

Means for Solving the Problems In order to solve the above problems, the present invention provides a wastewater treatment facility in which a membrane separation device is immersed in a biological treatment tank.
The structure includes an ultrasonic cleaning device that applies ultrasonic vibration to the membrane surface of the membrane separator.

Operation With the above-described configuration, organic matter contained in the raw water stored in the biological treatment tank is digested by activated sludge organisms of sludge flocs staying in the tank. Further, the raw water is subjected to solid-liquid separation in a membrane separator, and the permeated water that has passed through the filtration membrane of the membrane separator is extracted as treated water, and the solid content captured by the filtration membrane remains in the tank. Then, ultrasonic vibration is applied to the membrane surface of the filtration membrane of the membrane separation device using an ultrasonic cleaning device to clean the gel layer and other deposits that have adhered to the membrane surface due to the vibration of the membrane surface and the interference between the vibrating membrane surface and raw water. Remove. Therefore, when cleaning the membrane surface, the membrane surface is reliably cleaned without affecting the sludge flocs and without deteriorating the biological treatment capacity due to destruction of the sludge flocs.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
In the figure, a denitrifying rosewood 1 is sealed and formed in an anaerobic environment, and a supply pipe 3 for raw water 2 is communicated with the denitrifying rosewood 1 via a contaminant/diaphragm separation device 4. Further, the denitrifying rosewood 1 is provided with a discharge device 6 for discharging floating matter floating and separating on the water surface of the mixed liquid 5. And denitrifying rosewood 1
A water pipe 7 is opened at a suitable depth below the water, and the water pipe 7 communicates with a nitrification tank 8. This nitrification tank 8 has a membrane separator 9 immersed therein.
The negative pressure side of is connected to the suction pump IO. The separation membrane II of this membrane separation device 9 is formed of UF or MF.

An ultrasonic terminal section I2 is attached to the membrane separation device 9, and the ultrasonic terminal section 12 is connected to an ultrasonic oscillator I3. Further, an aeration pipe 14 is arranged at the bottom of the nitrification tank 8, and the aeration pipe 14 communicates with the discharge side of the blower 15. The nitrification tank 8 is equipped with a sludge suction pump for discharging excess sludge 16! 7 is excess sludge discharge pipe I8
A circulation pump 20 for circulating the nitrification circulating liquid 19 is connected via a circulation pipe 21 , and the tip of the circulation pipe 21 communicates with the denitrification rosewood 1 .

Hereinafter, the effects of the above configuration will be explained.

The raw water 2 flowing into the denitrifying rosewood 1 from the supply pipe 3 is the denitrifying rosewood 1.
is mixed with the activated sludge that stays inside to form a mixed solution 5, and the organic matter supplied together with the raw water 2 is oxidized and decomposed by nitrate respiration and nitrite respiration of denitrifying bacteria cultured in the activated sludge.

The mixed liquid 5 is then sent to the nitrification tank 8 through the water pipe 7. In the nitrification tank 8, the air supplied from the blower 15 is diffused into the mixed liquid 5 using an aeration pipe, and the nitrogen compounds contained in the mixed liquid 5 are converted into nitrate compounds and nitrogen by the nitrifying bacteria cultured in the activated sludge. Oxidized to nitrate compounds. Furthermore, the nitrate compounds and nitrite compounds in the nitrification tank 8 are removed from the nitrification circulating fluid 1.
As 9, the activated sludge is returned to the denitrifying rosewood 1 through the circulation pipe 21 by the circulation pump 20, and is reduced to nitrogen gas and nitrogen oxide gas by the nitric acid respiration and nitrite respiration of the denitrifying bacteria.

Then, the mixture 5 circulated through the denitrification rosewood 1 and the nitrification tank 8
is separated into solid and liquid by being sucked through the membrane separator 9 by a suction pump, and the permeate that has passed through the separation membrane 11 is extracted as treated water 22. The activated sludge captured by the il membrane 11 and remaining in the nitrification tank 8 is returned to the denitrification rosewood 1 together with the nitrification circulating fluid 19 as return sludge. Further, the surplus sludge is discharged to the outside of the nitrification tank 8 by the sludge suction pump 17 through the surplus sludge discharge pipe 18.

Then, the upward agitation flow generated by the air lift effect of the air diffused from the aeration tube 14 washes away the gel layer and the like attached to the membrane surface of the separation membrane 11. Further, the ultrasonic waves generated by the ultrasonic oscillator 13 constituting the ultrasonic cleaning device are transmitted from the ultrasonic terminal section 12 to the membrane separation device 9, and ultrasonic vibrations are applied to the membrane surface of the filtration membrane 11 of the membrane separation device 9. , the gel layer and other deposits adhering to the membrane surface due to the vibration of the membrane surface of the filtration 1 μl and the interference between the vibrating membrane surface and the mixed liquid 5 are washed and removed.

Therefore, when cleaning the membrane surface, the membrane surface is reliably cleaned without affecting the sludge flocs and without deteriorating the biological treatment capacity due to destruction of the sludge flocs.

Effects of the Invention As described above, according to the present invention, by applying ultrasonic vibration to the membrane surface of a filtration membrane of a membrane separation device using an ultrasonic cleaning device, vibration of the membrane surface and interference between the vibrating membrane surface and raw water are reduced. The gel layer and other deposits on the membrane surface can be washed and removed, and the cleaning of the membrane surface does not have any effect on the sludge flocs, resulting in a decrease in biological treatment capacity due to destruction of the sludge flocs, etc. The membrane surface can be reliably cleaned without any problems.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. 8... Nitrification tank, 9... Membrane separation device, 11... Separation membrane, 12... Ultrasonic terminal section, 13... Ultrasonic oscillator.

Claims (1)

[Claims] 1. A wastewater treatment facility in which a membrane separator is immersed in a biological treatment tank, characterized in that it is equipped with an ultrasonic cleaning device that applies ultrasonic vibrations to the membrane surface of the membrane separator.