JPH04290590A - Membrane separator in septic tank - Google Patents

Abstract

PURPOSE:To provider a membrane separator capable of sufficiently preventing clogging with a small horsepower and capable of being easily maintained and inspected in a septic tank. CONSTITUTION:A separation membrane module 2 obtained by vertically arranging many tubular external pressure-type microporous separation membranes 2A at regular intervals in parallel is erected on the bottom 3 of a septic tank, a supply pipe 4 for water to be treated having many water passage ports 4A in its peripheral wall is arranged in the central vertical space 2B of the module, and a pump 6 for supplying the water W to be treated in the sepatic tank through an intake ejector 5 is provided to the supply pipe 4. As a result, the release of the foreign matter deposited on the surface of the module is promoted by the water current mixed with air and injected in the radial direction.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a membrane separation device for a septic tank.

0002

[Prior Art] Conventionally, as a sewage septic tank, a sewage septic tank that purifies sewage through biological treatment using anaerobic microorganisms and aerobic microorganisms has been widely known. It is known to have a treatment tank using aerobic activated sludge.

[0003] This aerobic activated sludge treatment tank has the advantage that the contact rate between the treated water and the activated sludge is very high and that it can purify the sewage efficiently, but it is necessary to prevent the activated sludge from flowing out when discharging the treated water. Therefore, activated sludge treatment tanks are sometimes equipped with a separation membrane module that filters and discharges only the treated water.

0004

[Problems with the Prior Art] However, if filtration is performed in treated water in which activated sludge is dispersed, the separation membrane module is likely to become clogged, making maintenance management extremely troublesome. However, as a means to prevent such clogging, an air diffuser is used to generate an upward flow containing air bubbles with a large shear force at the bottom of a horizontally arranged separation membrane module. In order to generate an upward flow, an air supply device with extremely large power is required, which increases the cost of the device or hinders its miniaturization.

[0005]

[Problems to be Solved by the Invention] In view of the above-mentioned problems, the present invention aims to provide a membrane separation device for a septic tank that can sufficiently prevent clogging with a small horsepower and that can be easily maintained and inspected. It has been done.

That is, in the membrane separation device for a septic tank of the present invention, a separation membrane module consisting of a large number of tubular external pressure type microporous separation membranes collected at regular intervals in parallel in the vertical direction is installed upright at the bottom of the septic tank, and the separation A tank liquid supply pipe having a large number of water holes on the peripheral wall is arranged in the central vertical space of the membrane module,
The present invention is characterized in that a pump for supplying the liquid in the septic tank is connected to the tank liquid supply pipe via an ejector for mixing air.

[0007]

[Example] Next, an example of the present invention will be described. FIG. 1 is a sectional view of an embodiment of the invention. A membrane separation device 1 for a septic tank according to the present invention has a separation membrane module 2 formed by collecting a large number of tubular external pressure type microporous separation membranes 2A...2A in parallel in the vertical direction at regular intervals for use in a septic tank, for example, an aerobic activated sludge treatment tank. A tank liquid supply pipe 4 is installed vertically on the inner bottom 3 and has a large number of water passage ports 4A...4A on the peripheral wall in the central vertical space 2B of the separation membrane module 2.
A pump 6 for supplying the liquid W in the septic tank via an ejector 5 for mixing air is connected to the septic tank. The method can also be used in contact aeration tanks.

Reference numeral 7 in the figure indicates a suction pump that sucks filtrate from the separation membrane module 2 made of a tubular external pressure type microporous separation membrane 2A, and is connected to a pipe 7A that discharges the filtrate to the outside. Further, reference numeral 8 in the figure indicates an air intake pipe to the ejector 3.

[0009]

[Operation] In the above, when the suction pump 7 is driven to filter and discharge treated water, the pump 6 is driven to supply the liquid W in the septic tank into the central vertical space 2B of the separation membrane module 2. At this time, air is mixed in from the ejector 5 as the water flows, and the air-mixed liquid W is transferred to the water inlet 4A of the tank liquid supply pipe 4...
It ejects more forcefully than 4A. On the other hand, the drive of the suction pump 6 creates a negative pressure inside the membrane of the separation membrane module 2, causing filtration from the outside of the membrane to the inside, and suspended matter such as activated sludge adheres to the membrane surface, but inside the central vertical space 2B. Due to the force of the air-mixed liquid W that is blown out, a water flow is generated on the outer surface of the membrane in the direction shown by the arrow, and the attached foreign matter is likely to be peeled off. Also,
Oxygen is also supplied at the same time.

0010

Effects of the Invention As explained above, the present invention has a membrane separator arranged vertically, generates water flow from the center to the outside in the radial direction, and at the same time takes in air from the ejector to mix in many air bubbles. Foreign matter adhering to the outer surface is efficiently removed and clogging is prevented for a long period of time. Furthermore, since the membrane separator is vertically arranged, it is easy to take out and insert, and subsequent maintenance and inspection work is also facilitated.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the invention.

[Explanation of symbols]

1 Membrane separation device 2 Separation membrane module 2A Tubular external pressure type microporous separation membrane 2B
Central vertical space 3 Septic tank inner bottom 4 Tank liquid supply pipe 4A Water inlet 5 Ejector 6 Pump W Tank liquid

Claims (1)

[Claims] Claim 1: A separation membrane module comprising a large number of tubular external pressure type microporous separation membranes arranged vertically in parallel at regular intervals is installed at the bottom of the septic tank, and a peripheral wall is provided in the central vertical space of the separation membrane module. A tank liquid supply pipe having a large number of water holes is disposed in the tank, and a pump for supplying the liquid in the septic tank is connected to the tank liquid supply pipe via an air mixing ejector. Membrane separation equipment in septic tanks.