JP2012179579A - Flocculation reaction device and flocculation reaction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flocculation reaction device capable of suppressing a driving force required for driving an agitator from increasing, and capable of easily forming a coarse flocculated floc.SOLUTION: The flocculation reaction device includes a flocculation tank 10 in which a rapid agitation zone 16 and a slow agitation zone 17 are formed, a supply passage 13 for sludge 2 which communicates with the rapid agitation zone 16, a discharge passage 14 for the sludge 2 which communicates with the slow agitation zone 17, a first agitator 11 to rapidly agitate the sludge 2 of the rapid agitation zone 16, and a second agitator 12 to rapidly agitate the sludge 2 of the slow agitation zone 17, and also includes a flocculant adding means 15 for adding the flocculant 3 to each of the rapid agitation zone 16 and the slow agitation zone 17.

Description

  The present invention relates to an agglomeration reaction apparatus and an agglomeration reaction method in which a flocculant is added to a processing stock solution such as sludge for aggregation.

  Conventionally, as this type of agglomeration reaction apparatus, for example, as shown in FIG. 3, a coagulation tank 71, a supply port 72 for processing stock solution 70 such as sludge, a discharge port 73 for processing stock solution 70, and a pair of upper and lower stirring devices 74 and 75. The stirring devices 74 and 75 are constituted by motors 74a and 75a, rotating shafts 74b and 75b, and stirring blades 74c and 75c, respectively. The supply port 72 is provided with an injection port 76 for the polymer flocculant 79.

  The stirring blades 74c and 75c of the stirring devices 74 and 75 are rotated by motors 74a and 75a, respectively. At this time, the rotational speed of the stirring blade 75c of the lower stirring device 75 is higher than the rotational speed of the stirring blade 74c of the upper stirring device 74. Also, the lower stirring device 74 performs rapid stirring while the lower stirring device 75 performs slow stirring.

  The processing stock solution 70 is supplied from the supply port 72 into the aggregation tank 71 and the polymer flocculant 79 is added from the injection port 76. In the upper half region 77 in the coagulation tank 71, the processing stock solution 70 and the polymer flocculant 79 are rapidly stirred by the upper stirring device 74, so that the polymer flocculant 79 is quickly mixed with the processing stock solution 70. Distributed.

  Further, in the lower half region 78 in the coagulation tank 71, the processing stock solution 70 and the polymer coagulant 79 are gently stirred by the lower stirring device 75, so that formation of coagulation flocs is mainly promoted.

The flocculator having the above-described configuration is described in, for example, Patent Document 1 below.
Further, in Patent Document 2 below, an aggregation region is formed in the lower part of the reaction tank and a concentration region is formed in the upper part, a rotatable impeller is provided in the aggregation region, a cylindrical screen is provided in the aggregation region, A coagulation reaction tank is described in which a sludge input system is connected to the lower part of the region, and a flocculant supply system is connected to the sludge input system.

Japanese Patent No. 4223528 Japanese Patent No. 3835988

  In general, the polymer flocculant has a high viscosity, and the viscosity of the processing stock solution to which the polymer flocculant is added also increases. In the conventional type shown in FIG. 3, since all of the polymer flocculant 79 necessary for call neutralization and floc formation is added from the injection port 76, a large amount of polymer flocculant 79 is added. Flows into the upper half region 77 in the agglomeration tank 71, and when the polymer aggregating agent 79 is to be uniformly dispersed in the processing stock solution 70 in order to neutralize the call, the agitating blade of the upper agitating device 74 is used. There is a problem that the rotational speed of 74c needs to be significantly increased, and the driving force required to drive the upper stirring device 74 increases.

  Further, by increasing the stirring strength of the upper stirring device 74, the polymer flocculant 79 is uniformly dispersed and the neutralization of the call is promoted. On the other hand, in the upper half region 77, the flocs flocs are fine. It will become. Once the flocs flocs are refined, they have a characteristic that they hardly become coarse even if they are slowly stirred in the lower half region 78 thereafter. For this reason, there is a problem that formation of coarse aggregated flocs in the lower half region 78 is prevented.

  In order to avoid the above-mentioned problem and form a coarse aggregate floc, the injection rate of the polymer flocculant 79 is increased and the aggregate floc that can withstand strong stirring by the upper stirring device 74 is used. Therefore, an excessive amount of the polymer flocculant 79 is required.

Moreover, the thing described in the said patent document 2 also has the same problem.
The present invention provides an agglomeration reaction apparatus and an agglutination reaction method capable of suppressing an increase in driving force required to drive a stirring device and capable of easily forming a coarse agglomeration floc. Objective.

In order to achieve the above object, the agglomeration reaction apparatus in the first invention has a rapid stirring region and a slow stirring region formed in the aggregation tank,
The supply route of the processing stock solution communicates with the rapid stirring area,
The discharge route of the processing stock solution communicates with the slow stirring area,
A first stirring device that rapidly stirs the processing stock solution in the rapid stirring region and a second stirring device that stirs the processing stock solution in the slow stirring region slowly;
Flocculant addition means for adding the flocculant to each of the rapid stirring region and the slow stirring region is provided.

  According to this, the processing stock solution is supplied from the supply path to the rapid stirring area in the coagulation tank, flows from the rapid stirring area to the slow stirring area, and is discharged from the slow stirring area to the discharge path. At this time, the flocculant addition means adds the flocculant to each of the rapid stirring region and the slow stirring region, and in the rapid stirring region, the processing stock solution and the flocculant are rapidly stirred by the first stirring device. In the stirring region, the processing stock solution and the flocculant are gently stirred by the second stirring device.

  In the rapid stirring region, the processing stock solution and the flocculant are rapidly stirred, so that the flocculant is mixed and uniformly dispersed in the processing stock solution, and call neutralization is performed. In the rapid stirring region, fine aggregate flocs that have been neutralized by charging are formed. In the slow stirring region, the flocculant added separately from the rapid stirring region is slowly stirred with the processing stock solution. Therefore, coarse aggregated flocs are easily formed by the crosslinking action of the coagulant added to the slow stirring region. As a result, a coarse floc can be formed without increasing the injection rate of the flocculant, and there is no need to add an excessive amount of flocculant.

  In addition, it is possible to add the flocculant necessary for call neutralization and the flocculant necessary for the formation of the floc floc separately to the rapid stirring region and the slow stirring region separately. Therefore, the increase in driving force required to drive the first stirrer is suppressed as compared with the case where the entire amount of flocculant necessary for call neutralization and formation of flocculent flocs is added to the rapid stirring region. be able to. Thereby, the total driving force required to drive the first and second stirring devices can be reduced.

  In the agglomeration reaction apparatus according to the second aspect of the invention, the aggregating agent adding means distributes the aggregating agent into the first addition amount necessary for the call neutralization action and the second addition amount necessary for the crosslinking action, The addition amount of the flocculant is added to the rapid stirring region, and the second addition amount of the flocculant is added to the slow stirring region.

  According to this, the driving force required to drive the first stirrer is higher than when the total amount of the flocculant obtained by adding the first addition amount and the second addition amount is added to the rapid stirring region. The increase can be suppressed.

The agglomeration reaction apparatus according to the third aspect of the present invention is provided with a partition member that partitions the rapid agitation region and the slow agitation region in the aggregation tank,
The partition member is provided with a communication portion that communicates with the rapid stirring region and the slow stirring region.

  According to this, the processing stock solution is supplied from the supply path to the rapid stirring area in the coagulation tank, flows from the rapid stirring area to the slow stirring area through the communicating portion, and is discharged from the slow stirring area to the discharge path. The stirring flow rate in the rapid stirring region is higher than the stirring flow rate in the slow stirring region, but the rapid stirring region and the slow stirring region are separated by a partition member. It can suppress that the stirring flow rate influences each other and fluctuates.

In the agglomeration reaction method in the fourth invention, the processing stock solution is supplied to the rapid agitation region in the agglomeration tank, flows from the rapid agitation region to the slow agitation region in the agglomeration tank, and discharged from the slow agitation region,
Add the amount of flocculant necessary for the neutralization action to the rapid stirring area, and rapidly stir the processing stock solution and flocculant in the rapid stirring area, and slowly stir the amount of flocculant necessary for the crosslinking action. It is added to the region to slowly stir the processing stock solution and the flocculant in the slow stirring region.

  As described above, according to the present invention, it is possible to suppress an increase in driving force required to drive the stirring device, and it is easy to make coarse flocculation flocs without adding an excessive amount of flocculating agent. Can be formed.

It is a figure which shows the structure of the aggregation reaction apparatus in the 1st Embodiment of this invention. It is a figure which shows the structure of the aggregation reaction apparatus in the 2nd Embodiment of this invention. It is a figure which shows the structure of the conventional agglutination reaction apparatus.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
First, a first embodiment will be described with reference to FIG.
Reference numeral 1 denotes an agglomeration reaction apparatus, which is a pretreatment stage for dewatering sludge 2 (an example of a treatment stock solution) generated in sewage or wastewater treatment, and adds the polymer flocculant 3 to the sludge 2 for aggregation. The flocculation reaction apparatus 1 includes a flocculation tank 10, first and second stirring devices 11, 12, a sludge 2 supply path 13, a sludge 2 discharge path 14, and a flocculant addition means 15. .

  A rapid stirring region 16 is formed in the lower part of the coagulation tank 10, and a slow stirring region 17 is formed in the upper part. In addition, a partition plate 18 (an example of a partition member) that partitions the rapid stirring region 16 and the slow stirring region 17 is provided in the aggregation tank 10. A communication hole 19 (an example of a communication part) is formed at the center of the partition plate 18, and the rapid stirring region 16 and the slow stirring region 17 communicate with each other through the communication hole 19.

  The first stirring device 11 rapidly stirs the sludge 2 in the rapid stirring region 16, and includes a plurality of upper and lower stirring blades 11a that are rotatable in the rapid stirring region 16, and a rotating shaft 11b that supports the stirring blades 11a. And a driving device 11c such as a motor for rotating the rotating shaft 11b.

  The second stirring device 12 is for stirring the sludge 2 in the slow stirring region 17 at a slow speed, and a plurality of upper and lower stirring blades 12a that are rotatable in the slow stirring region 17 and a rotation that supports the stirring blades 12a. It has a shaft 12b and a driving device 12c such as a motor that rotationally drives the rotating shaft 12b.

  The supply path 13 includes a pipe line that supplies the sludge 2 to the coagulation tank 10 and communicates with the lower part of the rapid stirring region 16. The supply path 13 is provided with a supply pump 21 that supplies the sludge 2. The discharge path 14 is composed of a conduit for discharging the sludge 2 from the coagulation tank 10 and communicates with the upper part of the slow stirring region 17.

  The flocculant addition means 15 distributes the polymer flocculant 3 into a first addition amount A1 necessary for the call neutralization action and a second addition amount A2 necessary for the crosslinking action, and the first addition amount A1. The polymer flocculant 3 is added to the rapid stirring region 16 from the downstream end of the supply path 13, and the polymer flocculant 3 of the second addition amount A2 is added to the slow stirring region 17. The first addition amount A1 is a predetermined amount set based on the properties of the sludge 2, and the second addition amount A2 is a predetermined amount set based on the dewatering status in the post-treatment process.

  The flocculant addition means 15 includes a tank 15a for storing the polymer flocculant 3, a main addition path 15b connected to the tank 15a, and first and second branch addition paths 15c and 15d branched from the main addition path 15b. The first and second flow rate adjusting valves 15e and 15f (an example of the flow rate adjusting means) provided in the first and second branch addition paths 15c and 15d, and the addition pump provided in the main addition path 15b 15g. The first branch addition path 15 c is connected to the downstream end of the supply path 13, and the second branch addition path 15 d is connected to the slow stirring region 17.

Hereinafter, the aggregation reaction method using the aggregation reaction apparatus 1 will be described.
The supply pump 21 is driven to supply the sludge 2 from the supply path 13 to the flocculation tank 10, and the addition pump 15g is driven to open the first and second flow rate adjustment valves 15e and 15f by a predetermined opening, The drive devices 11 c and 12 c are driven to rotate the stirring blade 11 a of the first stirring device 11 at a high speed, and the stirring blade 12 a of the second stirring device 12 is made to be more than the stirring blade 11 a of the first stirring device 11. Rotate at low speed.

  Thereby, the sludge 2 is supplied from the supply path 13 to the rapid stirring region 16 in the coagulation tank 10, flows through the communication hole 19 from the rapid stirring region 16 to the slow stirring region 17, and is discharged from the slow stirring region 17. It is discharged to the path 14.

  At this time, the polymer flocculant 3 in the tank 15a of the flocculant addition means 15 is pumped by the addition pump 15g and branches from the main addition path 15b to the first and second branch addition paths 15c and 15d. The first addition amount A1 of the polymer flocculant 3 is added to the sludge 2 flowing through the downstream end of the supply path 13 and supplied to the rapid stirring region 16 together with the sludge 2, and the second addition amount A2 The polymer flocculant 3 is added to the slow stirring region 17.

  In the rapid stirring region 16, the sludge 2 and the polymer flocculant 3 having the first addition amount A1 are rapidly stirred by the stirring blade 11a rotating at a high rotational speed, and then in the slow stirring region 17 The sludge 2 and the polymer flocculant 3 having the second addition amount A2 are slowly stirred by the stirring blade 12a rotating at a low rotation speed.

  Since the sludge 2 and the polymer flocculant 3 are rapidly stirred in the rapid stirring region 16, the polymer flocculant 3 is mixed with the sludge 2 and uniformly dispersed, and the call neutralization is performed. In the rapid agitation region 16, fine aggregation flocs that have been neutralized by charging are formed. In the slow agitation region 17, the polymer flocculant 3 added separately from the rapid agitation region 16 is added to the sludge 2. Therefore, coarse aggregated flocs are easily formed by the crosslinking action of the polymer flocculant 3 added to the slow stirring region 17. Thereby, a coarse aggregate floc can be formed without increasing the injection rate of the polymer flocculant 3, and it is not necessary to add an excessive amount of the polymer flocculant 3.

  Also, the rapid stirring region 16 and the slow stirring region 17 are separated in a state where the amount of the polymer flocculant 3 required for call neutralization is separated from the amount of the polymer flocculant 3 required for formation of the floc floc. Compared with the case where the total amount (= A1 + A2) of the polymer flocculant 3 required for call neutralization and formation of the floc floc is added to the rapid stirring region 16, the first The increase in driving force required for driving the stirring device 11 can be suppressed, and the driving device 11c of the first stirring device 11 can be reduced in size and weight. Thereby, the total driving force required to drive the first and second stirring devices 11 and 12 can be reduced.

  Moreover, although the stirring flow rate in the rapid stirring region 16 is higher than the stirring flow rate in the slow stirring region 17, the rapid stirring region 16 and the slow stirring region 17 are partitioned by the partition plate 18, so It can suppress that the stirring flow rate and the stirring flow rate in the slow stirring region 17 influence each other and fluctuate. It is also possible to suppress the polymer flocculant 3 added to the slow stirring region 17 from the second branch addition path 15d from reacting with the sludge 2 in the rapid stirring region 16.

  In the first embodiment, the flow rate control valves 15e and 15f are provided in the branch addition paths 15c and 15d, and the flow rate of the polymer flocculant 3 flowing through the branch addition paths 15c and 15d is the first and second addition amounts A1. , A2 are adjusted by the flow rate adjusting valves 15e, 15f, but as a second embodiment, as shown in FIG. 2, instead of the flow rate adjusting valves 15e, 15f, addition pumps 15h, 15i And the addition pumps 15h and 15i may adjust the flow rate of the polymer flocculant 3 flowing through the branch addition paths 15c and 15d to the first and second addition amounts A1 and A2.

  In each of the above embodiments, the first branch addition path 15 c is connected to the downstream end of the supply path 13. However, the first branch addition path 15 c may be directly connected to the rapid stirring region 16 of the coagulation tank 10. .

  In each of the above embodiments, the driving device 12c (motor) of the second stirring device 12 is used that rotates at a lower speed than the driving device 11c (motor) of the first stirring device 11. The same thing as the drive device 11c may be used as the drive device 12c, the rotational speed of the drive device 12c may be decelerated with a reduction device, and the stirring blade 12a may be rotated at low speed.

  Moreover, you may rotate the 2nd stirring blade 12a via a deceleration means, rotating the 1st stirring blade 11a using the 1st drive device 11c.

1 Coagulation reactor 2 Sludge (treatment stock solution)
DESCRIPTION OF SYMBOLS 3 Coagulant | flocculant 10 Coagulation tank 11 1st stirring apparatus 12 2nd stirring apparatus 13 Supply path 14 Discharge path 15 Coagulant addition means 16 Rapid stirring area 17 Slow stirring area 18 Partition plate (partition member)
19 Communication hole (communication part)
A1 First addition amount A2 Second addition amount

Claims (4)

A rapid stirring region and a slow stirring region are formed in the coagulation tank,
The supply route of the processing stock solution communicates with the rapid stirring area,
The discharge route of the processing stock solution communicates with the slow stirring area,
A first stirring device that rapidly stirs the processing stock solution in the rapid stirring region and a second stirring device that stirs the processing stock solution in the slow stirring region slowly;
An agglomeration reaction apparatus comprising a flocculant addition means for adding a flocculant to each of a rapid stirring region and a slow stirring region. The flocculant addition means distributes the flocculant into the first addition amount necessary for the call neutralization action and the second addition amount necessary for the crosslinking action, and the first addition amount of the flocculant is in the rapid stirring region. The agglomeration reaction apparatus according to claim 1, wherein a second addition amount of the flocculant is added to the slow stirring region. In the coagulation tank, a partition member for separating the rapid stirring region and the slow stirring region is provided,
The aggregation reaction apparatus according to claim 1 or 2, wherein the partition member is provided with a communication portion that communicates with the rapid stirring region and the slow stirring region. While supplying the processing stock solution to the rapid stirring area in the coagulation tank, flowing from the rapid stirring area to the slow stirring area in the coagulating tank, while discharging from the slow stirring area,
Add the amount of flocculant necessary for the neutralization action to the rapid stirring area, and rapidly stir the processing stock solution and flocculant in the rapid stirring area, and slowly stir the amount of flocculant necessary for the crosslinking action. A coagulation reaction method characterized by adding to the region and slowly stirring the processing stock solution and the flocculant in the slow stirring region.

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