JP2005046787A - Flocculation and separation apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To keep a treatment speed or treatment capacity well by setting the size of a granular substance to a predetermined range even if the large granular substance flows in, in a flocculation and separation apparatus. <P>SOLUTION: This flocculation and separation apparatus is equipped with a treatment tank 1 for flocculating a suspended substance or the like in raw water and subjecting the flocculated substance or the like to solid-liquid separation to obtain treated water, a flocculant supply means for supplying an inorganic flocculant 3 and a polymer flocculant 5 to the treatment tank 1, an additive supply means 8 for supplying an additive 7 to the treatment tank 1, a concentration measuring instrument 31 for measuring the concentration of the mixture in the treatment tank 1, a first cyclone 13 for recovering the granular substance from a sediment and a second cyclone 36 for excluding the granular substance from the mixture. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to the field of water treatment, and more particularly, to a flocculation / separation apparatus for aggregating suspended components in raw water around an insoluble particulate material to form a floc, and allowing the floc to settle together with the particulate material to obtain treated water. Is.

  Conventional agglomeration separators include a series of interconnected chambers that define an agglomeration space, a settling space, a sludge recovery tank and a sludge / sand separator. The agglomeration space includes a mixing chamber, where flocculant and fine sand are added to the untreated liquid, destabilizing the colloid contained in the untreated liquid. Furthermore, the agglomeration space contains an intermediate agglomeration chamber, where destabilized colloids agglomerate around the fine sand particles. In the mixing chamber, a pipe for supplying an untreated liquid, a pipe for supplying a flocculant, and a pipe for supplying fine sand from a separator are connected. Each mixing chamber contains a stirrer.

  The settling space contains a chamber with a separating plate device. In the upper part of this chamber is provided a liquid take-out means which is coupled with a pipe for removing the clarified liquid. In addition, sludge removal means for removing sludge collected on the underside of the separator plate device is provided for transporting the sludge to the sludge recovery tank. The sludge collecting means and the separator are connected by a pipe having a pump means, and sludge containing fine sand is sent from the sludge collecting means to the separator. The separator is actually composed of a hydrocyclone, and sludge is discharged from one outlet without containing fine sand into one pipe, and the regenerated fine sand is collected in the mixing chamber by the other pipe (for example, patent Reference 1).

Japanese Patent No. 2634230 (page 3, lines 17-29, FIG. 1)

The conventional aggregating / separating apparatus has an advantage that the colloid is agglomerated around the fine sand to form a floc, and the sedimentation speed and processing capacity are increased by the weight of the fine sand. However, when the fine sand is collected in the mixing chamber by the liquid cyclone, large sand heavier than the original fine sand may be mixed into the fine sand. In addition, even when the untreated liquid is, for example, a combined sewer, large sand may flow into the mixing chamber together with rainwater. Therefore, in the conventional aggregating and separating apparatus, the following problems occur when large sand heavier than fine sand flows.
(A) Large sand not only serves as a core for agglomerating flocs, but also may destroy flocs, which lowers the processing speed.
(B) Large sand accumulates in the interior while circulating with fine sand, reducing processing capacity.
(C) It becomes necessary to increase the discharge pressure of the pump means in order to circulate large sand, which increases the operating cost.
(D) Large sand tends to block the pipe, not only lowering the processing capacity but also increasing the amount of maintenance work.
(E) Even if the large sand is the same particle as the fine sand, if it increases and circulates, it becomes the same as the contents described in (b) to (d) above.

  The present invention has been made to solve the above-described problems, and its purpose is to reduce the processing speed and processing capacity by keeping the size of the granular material within a predetermined range even when a large granular material flows in. An object of the present invention is to obtain an aggregating and separating apparatus that can be maintained well.

  The aggregating / separating apparatus according to the present invention comprises a treatment tank for aggregating suspended substances in water to be treated to obtain a treated water by solid-liquid separation, an aggregating agent supplying means, an additive supplying means, a concentration measuring means, And a particulate matter recovery means and a particulate matter exclusion means.

  Since the present invention includes the particulate matter removing means, even if the treated water contains large particulate matter, it is possible to exclude the large particulate matter from the treated water based on the measurement result of the concentration measuring means. The particle size distribution of the particulate material can be managed. Therefore, since the formed floc is not broken by the large granular material, the sedimentation speed of the floc, that is, the processing speed can be maintained satisfactorily. Moreover, since a large granular substance does not accumulate | store inside, processing capacity can be maintained favorable. Furthermore, there is no need to increase the pressure of the circulation line, and the circulation line is not blocked, so that an increase in maintenance work amount and operating cost can be suppressed.

Embodiment 1 FIG.
FIG. 1 shows a flocculation / separation apparatus according to Embodiment 1 for explaining the present invention. In FIG. 1, this coagulation / separation apparatus includes a treatment tank 1 for treating raw water (treated water) from, for example, combined sewer overflow water (CSO). A pipe 2 for introducing the raw water, a pipe 4 for introducing the inorganic flocculant 3, and a pipe 6 for introducing the polymer flocculant 5 are connected to the treatment tank 1. Further, a pipe 9 for introducing the additive 7 from the additive supply means 8 provided with the additive 7 is connected to the processing tank 1. The upper part of the last flow side of the treatment tank 1 leads to a water treatment facility (not shown) via a pipe 10, and the lower part leads to a first cyclone (particulate matter recovery means) 13 via a pipe 11 and a circulation pump 12. Communicates. The lower part of the first cyclone 13 communicates with the treatment tank 1 via a pipe 14 and the upper part communicates with a sludge treatment facility (not shown) via a pipe 15. In addition, it is necessary to arrange | position the injection | pouring position of the inorganic flocculant 3 and the polymer flocculent 5 so that the inorganic flocculant 3 can be inject | poured ahead of the polymer flocculent 5. FIG.

  The processing tank 1 is divided into, for example, a rapid stirring chamber 21, an injection stirring chamber 22, a floc forming chamber 23, and a solid-liquid separation chamber 24 sequentially from the upstream side. The pipe 2 for introducing the raw water and the pipe 4 from the inorganic flocculant 3 communicate with the rapid stirring chamber 21, and the rapid stirring chamber 21 is provided with a stirring device 25. The pipe 6 from the polymer flocculant 5 and the pipe 9 from the additive supply means 8 lead to the injection stirring chamber 22, and the injection stirring chamber 22 is also provided with a stirring device 26. The floc forming chamber 23 is also provided with a stirring device 27. The injection point of the polymer flocculant 5 may be any of the injection stirring chamber 22, the inlet of the floc forming chamber 23, or the lower part of the stirring device 27 of the floc forming chamber 23, and dispensed as necessary. do it.

  Usually, raw water contains a COD component, a phosphorus component, etc. with sand and suspended solids. The inorganic flocculant 3 is for facilitating the flocculation of the suspended substance, and may be iron chloride, sulfuric acid band, PAC or the like. The polymer flocculant 5 is used to further increase the suspended substance, and for example, an anionic system can be used. The additive 7 serves as a nucleus that flocculates the suspended substance and gives weight to the floc to increase its sedimentation speed. In the first embodiment, fine sand is used. The additive 7 is sometimes called a sedimentation accelerator, but insoluble particulate materials such as zirconium oxide and garnet can be used instead of fine sand.

  In addition, the mixture used for explaining the flocculation / separation apparatus according to the present invention refers to a mixture of raw water, the inorganic flocculating material 3, the polymer flocculating material 5, and the additive 7. In addition, the particulate material used for explaining the flocculation / separation apparatus according to the present invention may refer only to the additive 7, but often refers to the sum of the additive 7 and the sand contained in the raw water. . Or in this Embodiment 1, since a mixture is extracted from the rapid stirring chamber 21, only the sand contained in raw | natural water may be pointed out. Therefore, the amount of particulate matter contained in the mixture will increase or decrease depending on whether sand is contained in the raw water.

  Next, features of the aggregating apparatus in Embodiment 1 of the present invention will be described. The floc forming chamber 23 of the processing tank 1 is provided with a concentration measuring device (concentration measuring means) 31 for measuring the proportion of the particulate matter in the mixture. An ultrasonic densitometer, an infrared densitometer, or the like can be used for this type of density measuring device 31. In FIG. 1, the concentration measuring device 31 is shown as a circulation type using pipes 32 and 33, but can instead be a throwing type. A second cyclone (particulate matter exclusion means) 36 is connected to the rapid stirring chamber 21 of the treatment tank 1 via a pipe 34 and a drawing pump 35. On the downstream side of the drawing pump 35, the pipe 34 is connected to a sand basin or the like via a valve (not shown) and a branch path 34a. The second cyclone 36 can be arranged so that the mixture naturally flows down from the treatment tank 1. The upper part of the second cyclone 36 is passed through the injection stirring chamber 22 of the processing tank 1 via a pipe 37, and the lower part is passed through a sand basin etc. via a pipe 38. Each electrical device described above is electrically connected to a controller (control means) 39 so that automatic control is possible.

  Here, the magnitude | size of the additive 7 supplied from the additive supply means 8 is 100-400 micrometers. In addition, the first cyclone 13 causes particulate matter having a size of 100 μm or more to flow out to the pipe 14 to the treatment tank 1, and deposits containing particulate matter having a size of 100 μm or less, that is, sludge to a sludge treatment facility or the like. The pipe 15 is discharged. Further, the second cyclone 36 discharges a particulate material having a size of 400 μm or more to a pipe 38 to a sedimentation basin or the like, and a mixture containing the particulate material having a size of 400 μm or less to a pipe 37 to the treatment tank 1. I try to let it flow. In the controller 39, reference values for instructing the additive supply means 8, the extraction pump 35, and the like are set.

  In the flocculation / separation apparatus having such a configuration, the inorganic flocculant 3 flows into the raw water flowing into the rapid stirring chamber 21 of the treatment tank 1, and the inorganic flocculant 3 is rapidly and uniformly introduced into the raw water by the action of the stirring apparatus 25. Spread. Next, the raw water containing the inorganic flocculant 3 flows from the rapid stirring chamber 21 into the injection stirring chamber 22, and the polymer flocculant 5 and the additive 7 flow into the raw water in the injection stirring chamber 22. The flocculant 5 and the additive 7 are uniformly diffused in the raw water by the action of the stirring device 26 to become a mixture. Further, the mixture flows from the injection stirring chamber 22 into the floc forming chamber 23, and the flocs are largely aggregated around the particulate matter with the action of the stirring device 27. The mixture containing floc flows into the solid-liquid separation chamber 24 from the floc forming chamber 23, and flocs are precipitated together with the particulate matter to form a precipitate, and treated water is generated above the precipitate. This treated water flows out into the pipe 10 toward the water treatment device or the like.

  On the other hand, the precipitate generated in the solid-liquid separation chamber 24 flows into the first cyclone 13 through the pipe 11 and the circulation pump 12. The first cyclone 13 separates particulate matter having a size of 100 μm or more from the precipitate and discharges it to the pipe 14 to the treatment tank 1, and discharges the remaining sludge to the pipe 15 to the sludge treatment facility or the like. . Thus, the particulate matter becomes a nucleus for forming flocs while circulating through the treatment tank 1, pipe 11, circulation pump 12, first cyclone 13, and pipe 14, and increases the sedimentation speed of flocs to increase the processing capacity. Keep good.

  During this time, the concentration measuring device 31 introduces the mixture from the treatment tank 1 and measures the proportion of the particulate matter in the mixture. The controller 39 compares the measured value from the concentration measuring device 31 with a preset reference value. When the measured value becomes smaller than the reference value, the controller 39 instructs the additive supply means 8 to supply the additive 7 into the processing tank 1 until the measured value matches the reference value. On the other hand, when rainwater or the like merges and the measurement value of the concentration measuring device 31 rises, the controller 39 commands the extraction pump 35 to withdraw the mixture from the rapid stirring chamber 21 and supply it to the second cyclone 36. Turn to the sand pond.

  That is, first, the controller 39 controls the mixture to go to the second cyclone 36. As a result, the second cyclone 36 discharges the particulate matter having a size of 400 μm or more to the pipe 38 to the sedimentation basin and the like, and the mixture containing the particulate matter having a size of 400 μm or less flows out to the pipe 37 to the treatment tank 1. Let On the other hand, if the measured value does not decrease to the reference value even after the predetermined time has elapsed, the controller 39 controls the mixture to go to a sand basin or the like via the branch path 34a. When the measured value falls to the reference value, the controller 39 stops the operation of the drawing pump 35.

  The amount of additive 7 circulating in the apparatus was 150 kg, and the apparatus was operated for 4 hours at the first time. During this period, the concentrations at 1 hour, 2 hours, and 3 hours increased to 10000 mg / L, 12,500 mg / L, and 13000 mg / L, respectively. At that time, the proportions of the granular material having a size of 400 μm or more were 0%, 10%, and 20%, respectively. When the concentration reached 13000 mg / L, the extraction pump 35 and the second cyclone 36 were operated for 5 minutes. As a result, the concentration dropped to 11000 mg / L after 10 minutes, and the proportion of the particulate material having a size of 400 μm or more at this time was 15%. And the density | concentration after a total of 4 hours was set to 11500 mg / L, and the ratio of the granular material of a magnitude | size of 400 micrometers or more at this time was 20%.

  The second operation was started under the same conditions as when the first operation was stopped. Concentrations at 1 hour and 2 hours increased to 12000 mg / L and 13000 mg / L, respectively. At that time, the proportions of the granular material having a size of 400 μm or more were 30% and 36%, respectively. When the concentration reached 13000 mg / L, the extraction pump 35 and the first cyclone 36 were operated for 5 minutes. As a result, the concentration became 14000 mg / L after 5 minutes, and the ratio of the granular material having a size of 400 μm or more at this time was 25%. At the same time, the drawing pump 35 and the second cyclone 36 were further operated, and after 5 minutes, the concentration dropped to 11500 mg / L. At this time, the ratio of the particulate matter having a size of 400 μm or more was 20%. The concentrations in the third and fourth hours were 11000 mg / L and 11500 mg / L, respectively, and the proportions of granular materials having a size of 400 μm or more were 23% and 20%, respectively.

  As described above, the coagulation / separation apparatus according to Embodiment 1 was able to operate satisfactorily with the result that the suspended solid removal rate was 80% or more when it was operated in the range of 5000 to 14000 mg / L. In contrast, in the conventional aggregating and separating apparatus, when the concentration is about 10000 mg / L, the particulate matter having a size of 400 μm or less is 100% (the particulate matter having a size of 400 μm or more is 0%). The removal rate is 85%, and when the granular material with a size of 400 μm or less is 80% (the granular material with a size of 400 μm or more is 20%), the removal rate becomes 82%, and the granular material with a size of 400 μm or more. The removal rate decreased with increasing material.

  As described above, in the coagulation / separation apparatus according to the first embodiment, the first cyclone 13 maintains the size of the particulate matter in the mixture in the treatment tank 1 to 100 μm or more, and the raw water containing the large particulate matter. Is discharged into the processing tank 1, the large particulate matter is excluded by the second cyclone 36 or directly to the outside through the branch 34 a, so that the size of the particulate matter in the mixture is 100 to 100 It can be automatically maintained within a range of 400 μm, that is, the size (particle size) of the particulate material in the mixture can be automatically managed.

  Therefore, in the flocculation / separation apparatus according to the first embodiment, the floc is not destroyed by the particulate matter contained in the raw water that has flowed in, the floc can be formed well, and the processing speed is good. Can be maintained. Further, even if the particulate matter circulates, it does not accumulate inside and does not reduce the processing capacity. Furthermore, it is not necessary to increase the discharge pressure of the circulation pump 12, and an increase in operating cost can be suppressed. Further, since the particulate material does not block the circulation lines such as the pipes 11 and 14, it is possible to maintain a good processing capacity and suppress an increase in maintenance work amount. And since a mixture is extracted from the rapid stirring chamber 21, the large granular material immediately after flowing into the processing tank 1 will be extracted, and the influence by a large granular material can be suppressed to the minimum.

Embodiment 2. FIG.
FIG. 2 shows an aggregating / separating apparatus according to Embodiment 2 for explaining the present invention. The same parts as those in FIG. The concentration measuring device 31 in the first embodiment is a circulation type that draws the mixture from the bottom of the processing tank 1, but the concentration measuring device 41 in the second embodiment is provided above the processing tank 1 as a sensor type. . That is, the sensor unit 41 a of the concentration measuring device 41 is provided at a predetermined position in the processing tank 1, and the lead wire reaching the sensor unit 41 a is protected by the pipe 42. At this time, if the sensor unit 41a is provided at the same position as the intake port 32a of the pipe 32 of the first embodiment, a measurement value equivalent to that of the first embodiment can be obtained. Needless to say, the concentration measuring device 41 may be a circulation type or a throwing type as in the first embodiment instead of the sensor type.

  In addition, in Embodiment 1 described above, the mixture is extracted from the bottom wall of the rapid stirring chamber 21 of the processing tank 1, but in Embodiment 2, it is extracted from the bottom wall of the flock forming tank 23. That is, the second cyclone 45 is connected to the flock formation chamber 23 via the pipe 43 and the extraction pump 44. Further, between the drawing pump 44 and the second cyclone 45, the pipe 43 is connected to a sand basin or the like via a valve (not shown) and a branch passage 43a. The upper part of the second cyclone 45 is connected to the pouring / stirring chamber 22 of the treatment tank 1 via a pipe 46, and the lower part is connected to a sand basin etc. via a pipe 47. Each electric device is connected to the controller 48 to enable automatic control.

  Furthermore, the concentration measuring device 41, the second cyclone 45, and the controller 48 in the second embodiment are the same as the concentration measuring device 31, the second cyclone 36, and the controller 39 in the first embodiment. Therefore, the coagulation / separation apparatus according to the second embodiment can eliminate the large particulate matter immediately before flowing into the solid-liquid separation chamber 24, so the size of the particulate matter returning from the first cyclone 13 to the treatment tank 1 is large. Is limited to 400 μm or less, and the processing capability can be improved.

Embodiment 3 FIG.
FIG. 3 shows an aggregating / separating apparatus according to Embodiment 3 for explaining the present invention. Since the aggregating and separating apparatus in the third embodiment is a modification of the second embodiment, the same parts as those in FIG. In the second embodiment, the processing tank 1 is composed of four chambers. However, in the third embodiment, the rapid stirring chamber 21 existing in the second embodiment is omitted, and the processing tank 51 is replaced with the injection stirring chamber 22 and the floc. It is composed of three chambers, a forming chamber 23 and a solid-liquid separation chamber 24. Further, the pipe 4 from the inorganic flocculant 3 communicates with the pipe 52 for introducing the raw water. Therefore, the coagulation / separation apparatus according to the third embodiment has the same effects as those of the second embodiment, and further reduces the installation space by omitting the rapid stirring chamber 21 that was necessary in the second embodiment. In addition, since the stirrer 25 that is necessary in the second embodiment is not necessary, the equipment cost and the operation cost can be reduced.

Embodiment 4 FIG.
FIG. 4 shows an aggregating / separating apparatus according to Embodiment 4 for explaining the present invention. Since the coagulation / separation apparatus in the fourth embodiment is a modification of the first embodiment, the same parts as those in FIG. In the first embodiment described above, the processing tank 1 is constituted by one, but in this fourth embodiment, the processing tank 1 of the first embodiment is divided into the first processing tank 53 and the second processing tank 54, The first processing tank 53 is composed of three chambers: a rapid stirring chamber 21, an injection stirring chamber 22 and a floc forming chamber 23, and the solid-liquid separation chamber 24 is included in the second processing tank 54. The first processing tank 53 and the second processing tank 54 are connected by a pipe 55. The aggregating and separating apparatus according to the fourth embodiment has the same effects as those of the first embodiment, and the degree of freedom in the arrangement of the second treatment tank 54 is improved, so that the installation space can be effectively used.

  As described above, the aggregation processing apparatus according to the present invention has been described in the first to fourth embodiments. However, those skilled in the art have described the first to fourth embodiments as examples, and depart from the scope of the claims. It will be appreciated that many other examples are possible without doing so. For example, the concentration measuring devices 31 and 41 can be of a type other than the ultrasonic densitometer and the infrared densitometer, and the first cyclone 13 and the second cyclone 36 and 45 are separated by other types. Means can be used. Moreover, although it comprised so that the whole could be controlled automatically by the controllers 39 and 48, it can comprise so that one part may be operated manually. Furthermore, the reference values of 100 μm and 400 μm are substantive and approximate numerical values, and the reference values and concentration reference values of the granular substances set in the controllers 39 and 48 are matched to the quality and quantity of raw water and treated water. Needless to say, it can be changed.

  In addition, it goes without saying that the pipes 2 and 52 for introducing the raw water into the treatment tanks 1, 51 and 53 may be flow paths made of concrete or the like. 1 to 4, the pipe 9 from the additive supply means 8 and the pipe 14 from the first cyclone 13 are merged, but needless to say, it is not necessary to merge. In this case, the injection position of the pipe 14 from the first cyclone 13 is preferably positioned in the vicinity of the injection position of the pipe 6 from the polymer flocculant 5, but it is positioned in the flock formation chamber 23 as necessary. In this case, the same effect can be obtained. The drawing pumps 35 and 44 are illustrated apart from the processing tanks 1, 51 and 53, but can be installed on their bottom walls. Further, in order to facilitate the drawing of the mixture by the drawing pumps 35 and 44, a scraping machine, a screw conveyor, etc. are provided in the processing tanks 1, 51 and 53, or the bottom walls of the processing tanks 1, 51 and 53 are inclined. It is also desirable to let them.

  As an example of use of the present invention, in addition to the above-mentioned treatment of combined waterworks overflow (CSO), overall purification of rivers, lakes, seas, etc., more specifically, advanced treatment of sewage secondary treated water, rainfall There is treatment of spilled water. The present invention can also be used for backwash wastewater treatment such as an aerobic filter bed, replacement of the first sedimentation basin, and measures against initial polluted water during rainfall.

1 is a schematic block diagram showing a coagulation / separation device in Embodiment 1 of the present invention. FIG. It is a schematic block block diagram which shows the coagulation-separation apparatus in Embodiment 2 of this invention. It is a schematic block block diagram which shows the coagulation / separation apparatus in Embodiment 3 of this invention. It is a schematic block block diagram which shows the coagulation / separation apparatus in Embodiment 4 of this invention.

Explanation of symbols

1, 51, 53 Treatment tank 3 Inorganic flocculant supply means 5 Polymer flocculant supply means 8 Additive supply means 13 First cyclone (particulate matter recovery means)
31, 41 Concentration measuring device (concentration measuring means)
36, 45 Second cyclone (particulate matter exclusion means)

Claims (1)

  A treatment tank that agglomerates suspended substances in the water to be treated and separates into solid and liquid to obtain treated water, a flocculant supply means, an additive supply means, a concentration measurement means, a particulate matter recovery means, and a particulate matter An aggregating / separating device comprising an exclusion means.

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