JPH04371218A - Liquid supply system for membrane separation equipment - Google Patents

Abstract

PURPOSE:To prevent clogging of a separation membrane and a raw water passage of membrane separation equipment. CONSTITUTION:Part of raw water introduced to membrane separation equipment 4 is led to a torque meter 7 which detects viscosity. This detected value is input to a controller 10 through a converter 9. When the detected value of the torque meter becomes a prescribed one or more, the controller 10 stops a liquid supply pump 2. Thereby there is a correlation between the detected value of the torque meter and SS concentration in the raw water: when the SS concentration in the raw water exceeds a certain value, the detected value of the torque meter is increased suddenly. Therefore, the raw water of high SS concentration that may cause clogging of the separation membrane of the membrane separation equipment is prevented from flowing into the membrane separation equipment, so that clogging of the separation membrane and the raw water passage is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid supply device for a membrane separation device, and more particularly to a fluid supply device for a membrane separation device suitable for use in a secondary treatment system or advanced treatment system of biological treatment. .

0002

[Prior Art] As is well known, membrane separation equipment supplies liquid under pressure to one side of a separation membrane and extracts permeated water from the other side. When there are many SS components in liquid (raw water) such as sludge, clogging of the separation membrane and its raw water flow path (hereinafter referred to as separation membrane clogging) is likely to occur.

0003

[Problems to be Solved by the Invention] Particularly, in the tubular type membrane separation apparatus, when the separation membrane becomes clogged, it is not possible to take measures such as opening the frame and cleaning it, and the separation membrane must be completely replaced. It is also expected that clogging of separation membranes can be prevented in membrane separation devices other than tubular types, such as flat plate types and hollow fiber types.

0004

[Means for Solving the Problems] A liquid supply device for a membrane separator according to the present invention includes: a pump that supplies liquid to the membrane separator; a torque meter that measures the viscosity of the liquid supplied to the membrane separator; The pump includes a control device that stops the pump when the detected value of the torque meter exceeds a predetermined value.

[0005]

[Function] The present inventors have conducted various studies and found that as the SS concentration in raw water increases, the viscosity (detected by a torque meter) gradually increases, and in particular, when the SS concentration in raw water increases, the viscosity (value detected by a torque meter) increases. There is a critical value of SS of about 2 to 4%.
It was found that the torque meter detection value increases rapidly when the concentration is exceeded. This SS concentration of approximately 2 to 4% is also the SS concentration that, if exceeded, tends to cause clogging of the membrane separation device, and if the operation is continued, clogging of the separation membrane will occur.

[0006] Therefore, the present invention prevents the separation membrane of the membrane separator from clogging by stopping the liquid supply to the membrane separator when the viscosity value detected by the torque meter exceeds a predetermined value. This is how it was done.

The present invention prevents clogging of a separation membrane when the membrane separation device is used for biological treatment of wastewater.

In particular, the viscosity of the raw water supplied to the membrane separation device is measured, and if the measured value exceeds a set value, the pump is stopped, the membrane operation is stopped, and cleaning is started.

In biological treatment, membrane separation equipment is used for secondary treatment systems containing a large amount of activated sludge and for advanced treatment systems consisting of flocculated sludge.
It is used in systems containing a large amount of S, and torque meters may be installed in both systems to measure it.Since clogging is particularly severe in advanced processing systems, it is preferably used in this system.

[0010] When the membrane separator is operated, the raw water becomes highly concentrated and the SS concentration increases due to fluctuations in the amount and quality of raw water, fluctuations in FLUX, etc. In the present invention, a part of the liquid in the raw water tank is extracted, the torque value is intermittently measured, and when the torque value is measured at 3% or more (
It is also possible to measure 3% or more a certain number of times. ) Stop the circulation pump and move on to cleaning. Because the amount of liquid in the raw water tank increases during cleaning and the membrane concentrate is not returned,
The concentration in the raw water tank is a predetermined value.

[0011]

Embodiment FIG. 1 is a system diagram of a water treatment apparatus incorporating a liquid supply device for a membrane separation apparatus according to an embodiment.

[0012] Raw water (not shown) obtained by adding an appropriate flocculant to the secondary treated water of biological treatment is stored in a raw water tank.

Raw water in the raw water tank 1 is supplied to a tubular membrane separation device 4 via a liquid supply pump 2 and piping 3. Permeated water is taken out of the system through piping 11, and concentrated water is returned to raw water tank 1 through piping 5. A pipe 6 is branched from the pipe 2 to introduce a portion of the supplied liquid to a torque meter 7.

The liquid whose viscosity was measured by the torque meter 7 is transferred to the pipe 8
It is returned to raw water tank 1. The detected value of the torque meter 7 is the converter 9
The signal is input to the control device 10 via the . The control device 10 outputs a control signal to the liquid supply pump 2.

FIG. 2 is a correlation diagram between the SS concentration in the raw water and the torque meter detection value, and as shown in the figure, when the SS concentration exceeds 3%, the torque meter detection value increases rapidly. In this embodiment, a value (-4V) corresponding to this sudden rise of the torque meter detection value is set as a threshold value, and when the torque meter detection value exceeds this threshold value, the liquid supply pump 2 is stopped and cleaning is started. do.

[0016] When the liquid is introduced into the torque meter 7 and measurement is started, the torque meter detection value has a characteristic that it reaches a peak value immediately after the rotation of the torque meter starts, and thereafter becomes a constant value that slightly decreases. . Therefore, the torque meter operates intermittently at regular intervals. In FIG. 2, the peak value immediately after the start of this measurement is employed as the torque meter detection value.

According to the device of this embodiment, when the SS concentration reaches a high value that is likely to cause blockage in the membrane separation device, the liquid supply pump 2 is automatically stopped, so that blockage of the membrane separation device 4 can be prevented. Prevented.

[0018] The threshold value adopted in the above embodiment is merely an example, and it goes without saying that it may be appropriately selected depending on the properties of the raw water.

[0019]

As described above, according to the liquid supply device for a membrane separator of the present invention, clogging of the separation membrane of the membrane separator can be prevented. Therefore, it becomes possible to operate the membrane separation device stably for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a water treatment device equipped with a liquid supply device for a membrane separation device according to an embodiment.

FIG. 2 is a graph showing an example of torque meter detection values.

[Explanation of symbols]

1 Raw water tank 2 Liquid supply pump 4 Membrane separation device 7 Torque meter 10 Control device

Claims (1)

[Claims] [Claim 1] A pump that supplies a liquid to a membrane separation device;
A supply of a membrane separation device comprising a torque meter that measures the viscosity of a liquid supplied to the membrane separation device, and a control device that stops the pump when the detected value of the torque meter exceeds a predetermined value. liquid equipment.