JPS5923843B2 - Coagulation sedimentation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coagulation-sedimentation apparatus that adds a flocculant to a turbid liquid (water) to flocculate fine particles in the turbid liquid and separates the fine particles by sedimentation.

There are two types of coagulation-sedimentation equipment: horizontal flow type and upward flow type.

A cross-flow coagulation-sedimentation device has better separation efficiency than an up-flow type, but requires a larger installation area.

Further, although an upflow type coagulation-sedimentation apparatus requires a small installation area, it has poor separation efficiency.

For this reason, a coagulation-sedimentation device that combines a horizontal flow method and an upward flow method has been proposed and put into practical use.

FIG. 1 is a plan view showing a conventional coagulation sedimentation apparatus that combines a horizontal flow system and an upward flow system, and FIG. 2 is a cross-sectional front view thereof.

In the figure, 1 is the apparatus main body, 2 is a coagulation stirring tank, 3 is a turbid water inflow pipe, 4 is a flocculant injection pipe, 5 is a stirring blade provided in the coagulation stirring tank 2, 6 is a drive device for the stirring blade 5, Reference numeral 7 denotes a floc growth tank, in which a lower part a is formed at the bottom and a lower part b is formed at the upper part, and a partition wall 8 forms the floc growth tank 7 itself.
is provided in an inclined manner, and the volume of the floc group □ long tank 7 increases toward the exit Ib side.

Reference numeral 9 denotes a sedimentation separation tank, and 10 denotes a plurality of rectifying plates provided in the sedimentation separation tank 9. Each rectifying plate 10 is installed vertically and spaced apart from each other.

Further, each rectifying plate 10 is provided with a large number of holes.

11 is an overflow weir formed in the apparatus body 1 at the upper part of the outlet side of the sedimentation separation tank 9; 12 is a treated liquid reservoir for collecting purified water overflowing from the overflow weir 11; 13 is a treated water outflow pipe; and 14 is a sedimentation tank. A rake is installed at the bottom of the separation tank 9, 15 is a sludge concentration tank formed at the bottom of the floc growth tank 7, and 16 is a sludge discharge pipe.

In this coagulation-sedimentation device, a mixture of turbid water and a flocculant is supplied to a flocculation stirring tank 2 through a turbid water inlet pipe 3, and this mixture is stirred by stirring blades 5, and flocs are formed by the flocculation reaction of the flocculant. The flocs are generated and grown in the floc growth tank 7.

Some of the flocs that flowed into the sedimentation separation tank 9 from the floc growth tank 7 settle and accumulate in the sludge thickening tank 15, and other flocs pass through the rectifier plate 10 and are deposited in the overflow weir 11.
It gradually settles while flowing in the direction of , and is deposited at the bottom of the sedimentation separation tank 9.

The sludge accumulated at the bottom of the sedimentation separation tank 9 is scraped into the sludge concentration tank 15 by the rake 14, and the sludge collected in the sludge concentration tank 15 is transferred to the sludge discharge pipe 1.
6 and is discharged from the device.

On the other hand, the purified water overflows from the overflow weir 11 into the treated liquid reservoir 12 and then flows out of the apparatus from the treated water outflow pipe 13.

By the way, in the above-mentioned coagulation sedimentation device, the flow is rectified into a horizontal flow by passing through the holes of the rectifier plate 10 installed in the sedimentation separation tank 9, and the horizontal flow velocity is made uniform to increase the separation efficiency of sludge containing flocs. That's what I do.

However, since the rake 14 is installed at the bottom of the sedimentation separation tank 9, the lower end of each current plate 10 is connected to the rake 14.
Since there is no resistance due to the current plate 10 in this gap, the flow rate of water becomes faster than the flow rate passing through the current plate 10.

That is, the horizontal flow velocity within the sedimentation separation tank 9 becomes non-uniform,
Sludge separation efficiency decreases.

In addition, since the velocity of the flow passing through the gap between the lower end of each rectifying plate 10 and the rake 14 is high, the flocs in the sludge accumulated at the bottom of the sedimentation separation tank 9 are rolled up, and the flocs exceed the overflow weir 11. As a result, highly clear treated water cannot be obtained.

The purpose of the present invention is to solve the problems of the prior art described above,
Coagulation can improve separation efficiency by making the horizontal flow velocity in the sedimentation separation tank uniform, and can obtain highly clear treated water without causing the flocs in the sludge accumulated at the bottom of the sedimentation separation tank to be rolled up. is to provide precipitation equipment.

In order to achieve this object, the present invention provides a flocculation stirring tank for stirring a turbid liquid and a flocculant, and a flocculation tank having an inlet downward and an outlet upward, and for growing flocs from the stirred liquid of the flocculation stirring tank. A growth tank, a sedimentation separation tank in which a plurality of rectifying plates are installed vertically and spaced apart from each other, a sludge concentration tank in which the flocs grown in the floc growth tank are deposited, and flocs that have settled in the sedimentation separation tank are A means for transferring sludge to a sludge thickening tank, and a means installed at the upper part of the exit side of the sedimentation separation tank,
In a coagulation-sedimentation apparatus comprising an overflow weir for overflowing purified liquid from a sedimentation separation tank into a treated liquid reservoir, among the rectifying plates of the sedimentation separation tank, the one adjacent to the floc growth tank is connected to the floc growth tank. A vertical baffle plate section extending to a position below the outlet of the tank, and an inclined baffle plate section connected to the lower end of the vertical baffle plate section and inclined in the same direction as the inclined partition wall forming the floc growth tank. It is characterized by having been configured.

Hereinafter, the present invention will be explained with reference to detailed drawings.

FIG. 3 is a plan view showing the coagulation sedimentation apparatus according to the present invention;
The figure is a sectional front view of FIG. 3.

In the figures, the same reference numerals as in FIGS. 1 and 2 represent the same or equivalent items.

In the coagulation sedimentation apparatus according to the present invention, among the current plates 10 installed in the sedimentation separation tank 9, the current plate 100 adjacent to the floc growth tank 7 extends to a position below the outlet lower b of the floc growth tank 7. a vertical rectifier plate part 100a, and an inclined rectifier plate part 100b connected to the lower end of the vertical rectifier plate part 100a and inclined in the same direction as the inclined partition wall 8 of the floc growth tank 7.
It is made up of.

Further, the lower end of the inclined current plate portion 100b of the current plate 100 extends to a position where the movement of the rake 14 is not obstructed.

Incidentally, the inclination angle θ of the inclined current plate portion 100b of the current plate 100 is preferably as large as possible, but in consideration of the accumulation of flocs, it is preferable that the angle θ be the same as that of the inclined partition wall 8 of the floc growth tank 7 (about 30 degrees).

However, in the coagulation-sedimentation apparatus according to the present invention, the water flow excluding the lower part of the sedimentation separation tank 9 is rectified into a horizontal flow by passing through the vertical baffle plate portion 100a of the baffle plate 100 and the joint holes in the rear baffle plate 10. The horizontal flow velocity is made uniform, and the water flow below the sedimentation separation tank 9 passes through the holes in the inclined rectifying plate portion 100b of the rectifying plate 100, and is subjected to resistance in the same way as the vertical rectifying plate portion 100a, and is rectified into a horizontal flow. At the same time, the horizontal flow velocity becomes equal to the horizontal flow velocity.

Therefore, the horizontal flow velocity in the sedimentation separation tank 9 becomes uniform, so
Separation efficiency of sludge containing flocs is increased.

In addition, by equalizing the horizontal flow velocity, the sedimentation separation tank 9
Since the flocs in the sludge deposited at the bottom do not roll up, highly clear treated water can be obtained.

As explained above, according to the coagulation and sedimentation apparatus according to the present invention, it is possible to equalize the horizontal flow velocity in the sedimentation separation tank and improve the sludge separation efficiency, and furthermore, the flocs in the sludge deposited at the bottom of the sedimentation separation tank can be rolled up. Treated water with a high degree of clarity can be obtained since the water rise phenomenon does not occur.

[Brief explanation of drawings]

Fig. 1 is a plan view showing a conventional coagulation sedimentation device, Fig. 2 is a sectional front view of Fig. 1, Fig. 3 is a plan view showing a coagulation sedimentation device according to the present invention, and Fig. 4 is a cross section of Fig. 3. It is a front view. 1... Device main body, 2... Coagulation stirring tank,
7...floc growth tank? a, 7b...
- Inlet and outlet of floc growth tank, 8... Slanted partition wall, 9... Sedimentation separation tank, 10...
Current plate, 11... Overflow weir, 12...
Processing liquid reservoir, 14... Rake, 15...
Sludge concentration tank, 100... Rectifier plate, 100a
...Vertical rectifier plate section, 100b... Inclined rectifier plate section.

Claims (1)

[Claims] 1. A flocculation stirring tank that stirs the turbid liquid and flocculant, a floc growth tank that has an inlet facing downward and an outlet upward, and that grows flocs from the stirring liquid of the flocculation stirring tank, and a plurality of rectifying plates. Sedimentation separation tanks installed vertically and spaced apart from each other, a sludge concentration tank for depositing flocs grown in the floc growth tank, and means for transferring the sludge settled in the sedimentation separation tank to the sludge concentration tank. , a flocculating sedimentation apparatus comprising an overflow weir which is installed at the upper part of the exit side of the sedimentation separation tank and causes the clarified liquid of the sedimentation separation tank to overflow into the treated liquid reservoir; A rectifying plate adjacent to the growth tank includes a vertical rectifying plate portion extending to a position below the outlet of the floc growth tank, and an inclined partition wall connected to the lower end of the vertical rectifying plate portion and forming a floc growth tank. 1. A coagulation-sedimentation device characterized by comprising: an inclined rectifying plate section inclined in the same direction;