JPS61171508A - Apparatus for flocculating suspension - Google Patents

Abstract

PURPOSE:To enhance stirring efficiency, by a method wherein a slow speed stirring tank is partitioned by a plurality of partition walls permitting the free passage of a suspension provided at constant intervals in a water flowing direction and the partitioned chambers are packed with a hollow medium while air jet pipes are provided to the bottom surface of the stirring tank so as to be directed to said chambers. CONSTITUTION:A flocculation tank 3 being a slow speed stirring tank is partitioned by porous plate shaped partition walls 4 to provide a large number of stirring chambers 3a, 3b... in a water flowing direction and the stirring chambers are fully packed with hollow medii 5. The suspention, to which a flocculant was added in a high speed stirring tank 1, is guided to the flocculation tank 3 and slowly stirred by vortex streams while passed through the stirring chambers 3a, 3b... to flocculate the suspended substance in the suspension while formed flocs are separated from water in a sedimentation basin 8 to be discharged. When the flocs clog the hollow medii or accumulated to the bottom part of the tank, a blower 7 is driven to inject air in the stirring chambers through air jet pipes 6 and the flocs brought to a suspended state is sent to the sedimentation basin 8 to be discharged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to a suspension flocculation device for water treatment.

[Prior art and its problems]

For example, in a water treatment plant for waterworks, as a coagulation method to separate turbidity in suspension, which is raw water taken from rivers, lakes, etc., raw water taken from rivers, lakes, etc. is first put into a rapid stirring tank. A flocculant such as sulfuric acid is added to the suspension in a rapid stirring tank, and after forced rapid stirring, the suspension is sent to the next slow stirring tank 9, where the suspension is slowly stirred. do,
A method has been used in which the suspended solids contained in the suspension are turned into flocs.

FIG. 3 is a plan view showing an example of the conventional agglomeration device described above, and FIG. 4 is a sectional view taken along the line A--A in FIG. 1. In the drawing, 9 is a rapid stirring tank having a stirrer 11, and 10 is a flocculation tank as a slow stirring tank.

The flocculation tank 10 is partitioned in the water flow direction by a partition wall 12 consisting of a plurality of porous plates provided at regular intervals, and is provided with a plurality of stirring chambers 13. A mechanical floracurator 14 consisting of wings is provided.

The suspension led to the rapid stirring tank 9 is added with a flocculant in the rapid stirring tank 9 and rapidly stirred by the stirrer 11, and then led to the stirring chamber 13 of the flocculating tank 10, where it is mixed with a flocculator. During the slow mechanical stirring by 14, the suspended solids contained in the suspension are flocculated.

However, since the above-described conventional device requires a mechanical drive mechanism, there is a problem in that the flocculator 14 may fail and require maintenance and inspection.

FIG. 5 is a plan view showing another example of the conventional agglomerating device, and FIG. 6 is a vertical cross-sectional view showing still another example.

In the apparatus shown in FIG.
However, the stirring chamber 13 is divided into a plurality of partition walls 15 installed alternately at regular intervals on both the left and right ends, and in the apparatus shown in FIG. A plurality of partition walls 16 installed alternately at regular intervals
1/i: Formed by partitioning.

The suspension flows through the coagulation tank 10 in a zigzag manner through the partition walls 15 or 16, and a part of the energy of the flowing water is converted into stirring energy and is slowly stirred.

However, the conventional apparatus described above requires a long stirring tank due to low stirring efficiency, and has problems such as low adaptability to changes in the amount and quality of water in the suspension to be treated.

[Purpose of the invention]

Therefore, an object of the present invention is to be able to efficiently aggregate suspended solids contained in a suspension in a short period of time, without mechanical failure, and without requiring maintenance or inspection. , an object of the present invention is to provide a suspension flocculation device.
1 [Summary of the Invention] This invention provides a rapid stirring tank having a stirrer for rapidly stirring a suspension while adding a flocculant, and a suspension rapidly stirred in the rapid stirring tank. A suspension flocculating device comprising a slow stirring tank for slowly stirring the suspension to flocculate the suspended solids contained in the suspension, the slow stirring tank being fixed in the direction of water flow. A plurality of stirring chambers are provided in the slow stirring tank by partitioning with a plurality of partition walls at intervals through which the suspension can freely pass, and each of the plurality of stirring chambers is filled with a large number of hollow media. , and characterized in that an air jet pipe is provided on the bottom surface of the slow stirring tank for jetting air toward a large number of hollow media filled in the stirring chamber along its length. It is.

[Structure of the invention]

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a vertical longitudinal sectional view showing one embodiment of the apparatus of the present invention. Raw water, which is a suspension taken from a river or the like, is supplied to the rapid stirring tank 1. In the rapid stirring tank 1, a predetermined amount of flocculant such as sulfuric acid bandate is added to the raw water, and after being sufficiently stirred and mixed by the vertical shaft stirrer 2 with blades, the mixture is transferred to the slow stirring tank 1 and collection tank 3. to go into. Note that the bladed vertical shaft stirrer 2 may be replaced with a pump type stirrer or the like.

- The aggregation tank 3 is partitioned by a perforated plate-type partition wall 4, and is provided with a large number of stirring chambers 3a, 3b, . . . in the water flow direction. Each of the stirring chambers 3a, 3b, . . . is almost completely filled with a plastic hollow medium 5 having the shape shown in a perspective view in FIG. The hollow medium 5 may have any shape as long as it has water permeability as shown in FIG. 2 and generates a vortex in the suspension passing through it. Any material having a specific gravity of 1 or more may be used, such as , plastic, etc. The size and the number of fillers are appropriately determined depending on the water quality of the treatment liquid, the amount of treatment, etc.

The suspension to which the flocculant has been added and mixed in the rapid stirring tank 1 is led to the flocculating tank 3, which is a slow stirring tank, and is moved from upstream to downstream within the flocculating tank 3 depending on the height difference. 3
It flows through a, 3b...

At this time, the suspension is mixed in the stirring chambers 3a + 3b...
It comes into contact with the hollow medium 5 filled inside and becomes turbulent,
A vortex is created. Due to this vortex, a part of the flowing water energy of the suspension is converted into stirring energy, and the desired slow stirring is performed throughout the entire area of the coagulation tank 3. As a result of such slow stirring, the suspended solids contained in the suspension become flocs, are separated from the water in the sedimentation tank 8, and are discharged through the discharge port 8a.

An air jet pipe 6 made of ceramic, hard vinyl chloride, iron, or the like is provided on the bottom of the coagulation tank 3 along its length. The air jet pipe 6 has a large number of air jet ports provided on its upper surface, and one end thereof is connected to the blower 7 by a hose 6a.

Normally, the SS concentration in raw water at water treatment plants, etc. is 20 to 50.
mf/l, but during heavy rain or typhoons, it suddenly increases to 1.
It may increase to about 00 to 2000 mg/l. In addition to increasing the SS concentration in raw water, if the flocculation device is operated for a long time, the hollow medium 5 may become clogged with flocs.
The flocs are deposited at the bottom of the flocculation tank 3, and the floc formation efficiency of suspended solids in the flocculation tank 3 is deteriorated.

Therefore, in this invention, when the above-mentioned problem occurs, the blower 7 is driven and the large number of stirring chambers 6a, 6b, etc. filled in the flocculation tank 3 are Air is ejected towards the hollow medium 5. As a result, the flocs clogged in the hollow medium 5 and the flocs deposited at the bottom of the flocculation tank 3 are separated from the hollow medium 5 and the bottom of the flocculation tank 3 and become suspended, and are affected by the energy of the flowing water flowing through the flocculation tank 3. is led to the sedimentation tank 8, and the discharge port 8a of the sedimentation tank 8
is discharged through the The air is ejected from the air ejection tube 6 described above continuously or intermittently as appropriate depending on the clogging and accumulation state of the flocs.

〔Effect of the invention〕

Next, the effects of this invention will be described.

(1) A large number of hollow media filled in the stirring chamber
(Due to the generated eddy current, part of the flowing water energy of the suspension is converted into stirring energy, so the stirring efficiency is improved compared to the conventional method, and the device can be made smaller.

(2) By changing the filling meter, size, etc. of the hollow medium, arbitrary stirring intensity and stirring time can be selected.

(3) Since no mechanical force is used for stirring in the coagulation tank, no breakdowns occur and almost no maintenance or inspection is required.

(4) If the hollow medium is clogged with flocs and the flocs are deposited at the bottom of the coagulation tank 3, they can be easily removed and the device can always be operated in the best condition. can.

(5) In addition to purifying water supplies, it can be widely used for purifying sewage and industrial wastewater.

(6) It is extremely economical, as it can be used without modifying conventional equipment and maintenance costs are low.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view showing an embodiment of the device of the present invention, FIG. 2 is a perspective view showing an example of a hollow medium used in the present invention, and FIG. 3 is a plan view showing an example of a conventional device. 4 is a sectional view taken along the line A-A in FIG. 3, FIG. 5 is a plan view showing another example of the conventional device, and FIG. 6 is a vertical cross-section showing still another example of the conventional device. It is a diagram. In the drawings, 1... Rapid stirring tank 2... Stirrer 3... Coagulation tank 3a, 3b... Stirring chamber 4... Partition wall
5...Hollow medium 6...Air jet pipe 7.
...Plower 8...Sedimentation basin.

Claims (1)

[Claims] For rapidly stirring a suspension with the addition of a flocculant,
a rapid stirring tank having a stirrer; and a slow stirring tank for slowly stirring the suspension rapidly stirred in the rapid stirring tank to flocculate suspended matter contained in the suspension. In the suspension flocculating device, the slow stirring tank is partitioned by a plurality of partition walls spaced apart from each other in the water flow direction through which the suspension can freely pass, so that a plurality of A stirring chamber is provided, each of the plurality of stirring chambers is filled with a large number of hollow media, and a large number of hollow media are filled in the stirring chamber over the length direction of the bottom surface of the slow stirring tank. A suspension agglomeration device characterized by being provided with an air ejection pipe for ejecting air toward.