JP4353584B2 - Sand-added coagulating sedimentation equipment - Google Patents

Description

【００２７】
〔従来装置〕
従来装置のラインミキサー前で無機凝集剤として塩化第二鉄を３ｍｇ／ｌ注入し、凝集槽に高分子凝集剤としてアニオン系有機高分子凝集剤を１ｍｇ／ｌと砂を添加し、凝集槽滞留時間を５ｍｉｎと４ｍｉｎとして処理した結果を表１に示す。
【００２８】
〔本発明装置〕
図１に示したように、１箇所にて、シリカ成分を有する無機高分子凝集剤として鉄シリカ凝集剤１５ｍｇ／ｌを添加し、凝集槽滞留時間を４ｍｉｎとして処理した結果を表１に示す。
【００２９】
【表１】

【００３０】
表１に示すように、特定の高分子凝集剤を添加することにより、一種の凝集剤の添加でありながら、同等程度の処理水の濁度を得るのに、凝集槽での滞留時間を約２０％短縮することができた。また、１箇所からの添加のみでよいため、凝集剤添加系を大幅に簡素化できた。
【００３１】
【発明の効果】
以上説明したように、本発明の砂添加凝集沈澱装置によれば、シリカ成分を有する特定の高分子凝集剤を用いることにより、凝集剤添加系を大幅に簡素化でき、それによって装置全体の大幅な簡素化をはかることができる。装置の簡素化により、メンテナンスの容易化をはかることもできる。
【００３２】
また、シリカ成分を有する特定の高分子凝集剤の砂との良好な親和性により、優れた凝集性能を発揮でき、所望の凝集フロックを効率よく生成することができるとともに、凝集槽での滞留時間の短縮も達成できる。その結果、装置の処理性能、処理能力の向上をはかることができる。
【図面の簡単な説明】
【図１】本発明の一実施態様に係る凝集沈澱装置の全体構成図である。
【図２】従来の凝集沈澱装置の概略構成図である。
【符号の説明】
１ 砂添加凝集沈澱装置
２ 凝集槽
３ 沈澱槽
４ 原水供給ライン
５ 原水
６ 混和部
７ 高分子凝集剤
８ 砂
９ モータ
１０ 攪拌機
１１ せき
１２ 沈澱物
１３ 処理水
１４ 傾斜板
１５ 汚泥
１６ 引き抜き分離ライン
１７ サイクロン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sand-added coagulating sedimentation apparatus that separates suspended substances in raw water into sludge and treated water by coagulating sedimentation using sand and a coagulant, and in particular, by using a specific coagulant, coagulation performance. The present invention relates to a sand-added coagulating sedimentation apparatus that improves the overall system and simplifies the entire system.
[0002]
[Prior art]
An apparatus for separating and removing substances suspended in raw water (hereinafter sometimes referred to as SS [Suspended Solid]) by precipitation is known. As a conventional coagulating sedimentation apparatus for removing SS in raw water, an apparatus that simply adds a coagulant to raw water to precipitate the aggregate, pulls the aggregate as sludge, and derives treated water from the top is well known.
[0003]
In such a general coagulation precipitation apparatus, it takes a long time to precipitate the coagulum, and a very large sedimentation tank is required. Therefore, the coagulation precipitation can be performed more efficiently. A device has been proposed.
[0004]
For example, in French Patent No. 1411792, in a flocculation tank, a granular material (typically sand) having a particle size of about 10 to 200 μm is added to raw water together with a flocculating agent, and the inside of the flocculation tank is agitated. Is agglomerated as a relatively large floc containing particulate matter having a large specific gravity and a floc in the water to be treated introduced from the coagulating tank is precipitated in the precipitation tank to separate it from the treated water. . The sediment floc extracted from the sedimentation tank is separated into sludge and particulates by a cyclone as a separator, and the separated particulates are returned to the agglomeration tank and recycled.
[0005]
The processing steps in such a coagulating sedimentation apparatus can be expressed as shown in FIG. 2, for example. In the process shown in FIG. 2, the inorganic flocculant 102 is added to the raw water 101 supplied in the mixing tank 103, the polymer flocculant 104 is added to the raw water, and the sand 105 to be circulated is further added. Thus, aggregated flocs are formed in the floc forming tank 106. The water to be treated (raw water) containing the aggregated floc is introduced into the sedimentation tank 107 where the aggregated floc is precipitated and separated from the treated water 108. The sediment is extracted by the sludge extraction pump 109 and sent to the cyclone 111 through the extraction line 110. In the cyclone 111, the sludge 112 and the sand 105 are separated by centrifugal separation, and the separated sand 105 is returned to the flock formation tank 106 for circulation. In FIG. 2, the mixing tank 103 and the flock forming tank 106 are shown as separate tanks, but they can also be used as a single tank (aggregation tank). The agent is line-injected using a line mixer or the like and mixed into raw water, and a polymer flocculant and sand are added in a coagulation tank.
[0006]
Apart from the structure of such a granular material addition type coagulation sedimentation apparatus, as a general water treatment coagulant, a silicic acid solution using water glass or the like was incorporated with iron ions to suppress the progress of gelation. Inorganic polymer flocculants are known (for example, JP-A-1-284314).
[0007]
An example in which this type of inorganic polymer flocculant is applied to the above-mentioned granular material addition type coagulating precipitation apparatus has not yet been found.
[0008]
[Problems to be solved by the invention]
In the agglomeration precipitation apparatus of the above-mentioned granular material addition type, it is necessary to provide a special mixing tank for mixing the inorganic flocculant or a line mixer, etc. The system up to (tank) is complicated.
[0009]
The present inventor has paid attention to such problems related to the complication of the system and, as a result of earnestly examining the possibility of applying the above-mentioned inorganic polymer flocculant to the particulate addition type coagulation precipitation apparatus, In the case where sand is used as an object, the present inventors have found that an inorganic polymer flocculant or a specific flocculant similar thereto can contribute to the improvement of the aggregation performance and the simplification of the system, thereby completing the present invention.
[0010]
That is, the object of the present invention is to simplify the entire flocculant addition system by using a specific flocculant, particularly in a sand-added flocculent precipitation apparatus, thereby simplifying the entire apparatus and improving the flocculant performance. The goal is to improve performance.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a sand-added coagulating sedimentation apparatus according to the present invention comprises a coagulating tank for coagulating suspended substances in raw water by adding a coagulant and silica sand, and an untreated water introduced from the coagulating tank. A sedimentation tank that precipitates agglomerates and separates them into treated water and sediments, withdraws the sediments from the sedimentation tank, separates the extracted sediments into sludge and sand, and returns the separated sand to the agglomeration tank A sand-added coagulating sedimentation apparatus equipped with a separation line is characterized in that only one kind of inorganic polymer coagulant having an iron component together with a silica component is used as the coagulant.
[0012]
The inorganic polymer flocculant, for example, can be used after the water glass-based component.
[0013]
In the sand added flocculator apparatus according to the present invention as described above, polymeric flocculants having a silica component, so also have excellent affinity for silica sand having a silica component, a polymer having the silica component If the flocculant is added in place of the conventional addition of both the inorganic flocculant and the organic polymer flocculant, extremely excellent flocculant properties can be exhibited while being a kind of polymer flocculant. In particular, due to the good coagulation performance of the polymer flocculant having a silica component, the residence time in the coagulation tank can be shortened, and the processing capacity of the entire system can be improved.
[0014]
In addition, since it is only necessary to add one specific polymer flocculant, the line mixer used for the conventional apparatus when both the inorganic flocculant and the organic polymer flocculant are used, and for addition mixing Special mixing tanks can be abolished, and the above-mentioned specific polymer flocculant only needs to be added at one place. In particular, the flocculant addition system is greatly simplified, and the entire apparatus is greatly reduced. Simplification is possible. Maintenance is also facilitated by simplifying the entire system.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a sand-added coagulating sedimentation apparatus 1 according to an embodiment of the present invention. The coagulation precipitation apparatus 1 includes a coagulation tank 2 and a precipitation tank 3 disposed adjacent thereto. The raw water 5 is supplied to the coagulation tank 2 via the raw water supply line 4. In this embodiment, the silica component is mixed in the inlet part of the coagulation tank 2 or the mixing part 6 substantially integrated with the coagulation tank 2. Is added to the raw water.
[0016]
In the agglomeration tank 2, sand 8 is added as a granular material for forming a relatively large and heavy agglomeration floc. The raw water to which the polymer flocculant 7 having the silica component and the sand 8 are added is stirred in the coagulation tank 2 by a stirrer 10 driven by a motor 9, and the suspended matter in the raw water is The flocs are aggregated as a floc containing the polymer flocculant 7 and sand 8.
[0017]
As the polymer flocculant 7 having a silica component, for example, water glass (inorganic polymer) is used as a base component, a silica component is contained in a predetermined ratio, and an iron component is included together with the silica component. That is, it is prepared as an inorganic polymer flocculant substantially free of organic components. Further, a polymer flocculant prepared from a silicic acid solution containing iron ions and other metal ions in addition to them as described in JP-A-1-284314 can also be used.
[0018]
However, in the present invention, not only those disclosed in the above-mentioned JP-A-1-284314, but basically any inorganic polymer flocculant having an iron component together with a silica component, which contains a silica component. By this, good affinity with the sand 8 containing the silica component is obtained, and by having a polymer form structure, the sand 8 is entangled to form a relatively large floc and exhibits excellent cohesive performance. Is done.
[0019]
That is, in the agglomeration in the agglomeration tank 2, the polymer flocculant 7 containing the silica component causes the suspended substance to agglomerate, and at that time, the polymer flocculant 7 is entangled to grow into a larger floc and has a specific gravity. The large sand 8 is contained, and as a whole, it grows into a relatively large and high-specific gravity floc. In this growth process, a good affinity between the polymer flocculant 7 containing the silica component and the sand 8 acts, so that the flocs are generated very efficiently and the agglomeration performance is improved.
[0020]
The addition amount of such a polymer flocculant may be appropriately determined from the range of about 1 to 30 mg / l in consideration of the state of raw water and the processing speed.
[0021]
In the present embodiment, the water to be treated containing the grown flocculated floc is introduced into the sedimentation tank 3 through the underwater baffle 11. An overflow basin may be used instead of the underwater basin 11. In the settling tank 3, the flocs flocs in the introduced water are precipitated downward, and the precipitate 12 is separated from the treated water 13 above. A plurality of inclined plates 14 are juxtaposed in the upper part of the settling tank 3 to prevent the floc (precipitate) from flowing out together with the treated water 13.
[0022]
At the bottom of the sedimentation tank 3, the slurry-like sediment 12 is drawn from the sedimentation tank 3, and the separated sediment 12 is separated into sludge 15 and sand 8, and the separated sand 8 is directly returned to the coagulation tank 2. A drawing separation line 16 is connected. The sand 8 separated by the separator such as the cyclone 17 is returned again to the agglomeration tank 2 and circulated for use.
[0023]
In the sand-added coagulating sedimentation apparatus 1 configured as described above, the coagulation performance to floc in the coagulation tank 2 is achieved due to the good affinity between the polymer coagulant 7 and the sand 8 both containing the silica component. And effectively produces the desired agglomerated floc. As a result of the efficient generation of the desired flocculent flocs, an efficient sedimentation operation can be obtained even in the next precipitation step, and the precipitate and treated water are efficiently separated, improving the performance and capacity of the entire apparatus. .
[0024]
Further, as the flocculant, only one kind of the specific polymer flocculant 7 needs to be added, and the polymer flocculant 7 has only to be added at one place. Is greatly simplified, and as a result, the entire system, that is, the entire apparatus is also greatly simplified. Therefore, maintenance is greatly facilitated.
[0025]
In order to confirm the effect of the present invention, an experiment was conducted under the following conditions using the apparatus according to the present invention shown in FIG. 1 and the conventional apparatus shown in FIG.
[0026]

[0027]
[Conventional device]
3 mg / l of ferric chloride was injected as an inorganic flocculant before the line mixer of the conventional equipment, and 1 mg / l of an anionic organic polymer flocculant and sand were added to the flocculant as a polymer flocculant, and the flocculant stayed Table 1 shows the results of processing with time of 5 min and 4 min.
[0028]
[Device of the present invention]
As shown in FIG. 1, Table 1 shows the results of processing at a location where iron silica flocculant 15 mg / l was added as an inorganic polymer flocculant having a silica component and the flocculation tank residence time was 4 min.
[0029]
[Table 1]

[0030]
As shown in Table 1, by adding a specific polymer flocculant, in order to obtain a turbidity of the same level of treated water while adding a kind of flocculant, the residence time in the flocculant tank is about It could be shortened by 20%. Moreover, since the addition from one place is sufficient, the flocculant addition system can be greatly simplified.
[0031]
【The invention's effect】
As described above, according to the sand addition agglomeration precipitation apparatus of the present invention, the use of a specific polymer flocculant having a silica component can greatly simplify the flocculant addition system, thereby greatly increasing the overall apparatus. Simplification can be achieved. Maintenance can also be facilitated by simplifying the apparatus.
[0032]
In addition, because of the good affinity of the specific polymer flocculant having a silica component with the sand, it can exhibit excellent agglomeration performance, can efficiently generate the desired agglomeration floc, and the residence time in the agglomeration tank Can also be achieved. As a result, the processing performance and processing capacity of the apparatus can be improved.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a coagulation precipitation apparatus according to an embodiment of the present invention.
FIG. 2 is a schematic configuration diagram of a conventional coagulation precipitation apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Sand addition coagulation precipitation apparatus 2 Coagulation tank 3 Precipitation tank 4 Raw water supply line 5 Raw water 6 Mixing part 7 Polymer flocculant 8 Sand 9 Motor 10 Stirrer 11 Cough 12 Precipitate 13 Treated water 14 Inclined plate 15 Sludge 16 Extraction separation line 17 Cyclone

Claims (3)

A coagulation tank for coagulating suspended solids in raw water by adding a coagulant and silica sand; a precipitation tank for precipitating aggregates in the water to be treated introduced from the coagulation tank and separating them into treated water and precipitates; A sand-added coagulating sedimentation apparatus comprising a pulling and separating line for drawing a precipitate from a tank, separating the extracted precipitate into sludge and sand and returning the separated sand to a coagulating tank, wherein the coagulant contains silica. A sand-added coagulating sedimentation apparatus characterized by using only a kind of inorganic polymer coagulant having an iron component together with the component . The sand-added coagulating sedimentation apparatus according to claim 1 , wherein the inorganic polymer coagulant contains water glass as a base component. The sand-added coagulating sedimentation apparatus according to claim 1 or 2 , wherein the inorganic polymer coagulant is added at one location.

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