Water treatment device

Abstract

To provide a water treatment device capable of exploitation of stable water treatment while attaining device compactification.SOLUTION: In a water treatment device 1 for removing calcium components contained in target water, a first area A1 for blending target water with a medicament for reacting with and insolubilizing calcium components contained in the target water and a second area A2 for coagulation settling a calcium insoluble matter formed in the target water are provided in a single tank 2, the second area A2 is adjacently arranged below the first area A1, and the target water including the calcium insoluble matter flows out from the first area A1 and flows into the second area A2.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water treatment apparatus for removing calcium components contained in water to be treated.

Background Art

[0002] Since the leachate in the final disposal site contains a high concentration of calcium components, scale may form on the pipes and equipment in the water treatment facilities that treat the leachate, and inconvenient situations such as pipe blockage may occur. To prevent this, a pretreatment is performed to remove the calcium components in the leachate by adding sodium carbonate, which is a calcium insolubilizing agent, to the leachate and separating it by precipitation as calcium carbonate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As conventional water treatment apparatuses, for example, as shown in Patent Document 1 and the like, there are generally known ones including a reaction tank in which a chemical that reacts with calcium components contained in water to be treated and insolubilizes them is mixed with the water to be treated, a precipitation tank in which calcium insolubles generated in the water to be treated are aggregated and precipitated, and a neutralization tank that neutralizes the water to be treated after removing the calcium insolubles.

[0005] In conventional water treatment apparatuses, since they include a plurality of tanks, the apparatus itself becomes large, and problems such as an increase in manufacturing cost and securing of an installation location may occur. Also, if the operating parameters are different for each tank, the control becomes complicated and it may be difficult to perform stable water treatment. Furthermore, the cleaning work for each tank becomes a burden, and the maintenance cost may increase.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a water treatment apparatus capable of performing stable water treatment while making the apparatus compact.

Means for Solving the Problems

[0007] The water treatment apparatus according to the present invention is characterized in that it is a water treatment apparatus for removing calcium components contained in water to be treated, a first region where a chemical that reacts with the calcium component contained in the water to be treated to insolubilize it and the water to be treated are mixed, a second region for aggregating and precipitating calcium insolubles generated in the water to be treated are provided in a single tank, the second region is disposed adjacent to and below the first region, and the water to be treated containing calcium insolubles flows out from the first region and flows into the second region.

[0008] In the water treatment apparatus according to the present invention, it is preferable that the second region has a region where the cross-sectional area becomes smaller toward the lower side.

[0009] In the water treatment apparatus according to the present invention, it is preferable to include a partition portion that partitions the first region and the second region, and an opening that communicates the first region and the second region is formed in the partition portion.

[0010] In the water treatment apparatus according to the present invention, the single tank preferably includes a rectangular portion having a rectangular cross-sectional shape, the partition portion is provided in the rectangular portion, and the opening of the partition portion is provided at a corner of the rectangle.

[0011] In the water treatment apparatus according to the present invention, a vertical wall portion extending in the vertical direction is provided in the single tank, a third region partitioned from the first region by the vertical wall portion is provided in the single tank, and the water to be treated from which calcium insolubles have been removed flows out from the second region and flows into the third region and flows out from the upper end portion of the third region, which is preferable.

[0012] In the water treatment apparatus according to the present invention, it is preferable to provide a stirring device for stirring the water to be treated in the first region.

[0013] In the water treatment apparatus according to the present invention, it is preferable to provide a discharging device for discharging the coagulated and precipitated calcium insoluble matter from the second region.

[0014] In the water treatment apparatus according to the present invention, it is preferable to provide a coagulant aid supply device for supplying a coagulant aid to the second region.

Advantages of the Invention

[0015] According to the present invention, a first region in which a chemical that reacts with a calcium component contained in the water to be treated to insolubilize it is mixed with the water to be treated, and a second region in which the calcium insoluble matter generated in the water to be treated is coagulated and precipitated are provided in a single tank. Therefore, unlike a conventional water treatment apparatus in which a mixing tank (reaction tank) and a sedimentation tank are provided separately, the apparatus itself does not become large-sized, and problems such as an increase in manufacturing cost and securing of an installation location are unlikely to occur. Since the cleaning work is also simplified, the maintenance cost can be reduced. Further, since the first region and the second region are arranged adjacent to each other in the vertical direction, the mixing reaction step of the calcium component and the chemical and the coagulation precipitation step of the calcium insoluble matter proceed continuously in the vertical direction, and the solid-liquid separation treatment can also be efficiently performed. Therefore, it is not necessary to finely set the control of operation parameters or the like in order to improve the treatment efficiency, and it is possible to simply and stably perform water treatment.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0017] (First Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings, taking as an example a form in which the water treatment apparatus according to the present invention is applied to a calcium removal apparatus for removing calcium components from leachate (an example of water to be treated) discharged from a final disposal site of waste.

[0018] 〔Configuration of Water Treatment Apparatus〕 As shown in FIGS. 1 and 2, the water treatment apparatus 1 according to the present embodiment includes a main body portion 2 (an example of a single tank), a stirring device 3, and a discharge device 4. The water treatment apparatus 1 also includes a leachate supply device 5, a chemical solution supply device 6, a hydroxide supply device 7, a flocculant supply device 8, a flocculation aid supply device 9, and a control device (not shown).

[0019] The main body portion 2 has a straight body portion 20 with a rectangular cross-sectional shape and an inclined portion 21 having an inverted quadrangular pyramid shape whose cross-sectional area becomes smaller toward the lower side. A first region A1 where a chemical solution that reacts with the calcium component contained in the leachate to insolubilize it and the leachate are mixed is formed inside the straight body portion 20. Further, a second region A2 for aggregating and precipitating the calcium insolubles generated in the leachate is formed inside the inclined portion 21 and has a region whose cross-sectional area becomes smaller toward the lower side. The second region A2 is disposed adjacent to the lower side of the first region A1.

[0020] A vertical wall portion 22 extending in the vertical direction is provided inside the main body portion 2, and a third region A3 partitioned from the first region A1 is formed by the vertical wall portion 22. As shown in FIG. 2, the vertical wall portion 22 is provided at one of the four corners of the straight body portion 20. Further, an overflow portion 23 is provided at the upper end portion of the main body portion 2, and the downstream end of the third region A3 is connected to the overflow portion 23.

[0021] The leachate supplied to the first region A1 is mixed with a chemical solution to form calcium-insoluble compounds. The leachate containing the calcium-insoluble compounds flows out of the first region A1 and into the second region A2, where the calcium-insoluble compounds aggregate and precipitate. The leachate from which the calcium-insoluble compounds have been removed in the second region A2 flows from the second region A2 through a gap provided below the vertical wall portion 22 and into the third region A3, and then overflows and flows out from an overflow portion 23 provided at the upper end portion of the third region A3.

[0022] The stirring device 3 includes a stirring blade 30, a motor driving unit 31, etc. The stirring blade 30 is disposed within the first region A1, and its stirring speed and stirring timing are adjusted by a control device.

[0023] The discharging device 4 is provided at the lower end portion of the inclined portion 21 and includes a suction pipe 40, a withdrawal pump 41, etc., and discharges the aggregated and precipitated calcium-insoluble compounds from the second region A2. By operating the withdrawal pump 41, the solid portion (calcium-insoluble compounds) separated from the liquid in the second region A2 is sucked from the suction pipe 40 and discharged as sludge to an external sludge storage tank (not shown), etc. The timing of driving the withdrawal pump 41 and its suction force are adjusted by a control device.

[0024] The leachate supply device 5 includes a storage tank for storing leachate, a liquid feeding pump, etc., and the liquid feeding pump is provided in a pipe connecting the leachate storage tank and the straight barrel portion 20 of the main body portion 2. The control device adjusts the supply amount of the leachate supplied to the main body portion 2 by controlling the liquid feeding pump.

[0025] The chemical solution supply device 6 includes a storage tank for storing the chemical solution, a liquid feeding pump, etc., and the liquid feeding pump is provided in a pipe connecting the chemical solution storage tank and the straight barrel portion 20 of the main body portion 2. The control device adjusts the supply amount of the chemical solution supplied to the main body portion 2 by controlling the liquid feeding pump. Examples of the chemical solution include, but are not limited to, an aqueous sodium carbonate solution.

[0026] The hydroxide supply device 7 includes a storage tank for storing hydroxide and a liquid feed pump or the like. The liquid feed pump is provided in a pipe connecting the hydroxide storage tank and the straight body portion 20 of the main body portion 2. By controlling the liquid feed pump, the control device adjusts the supply amount of the hydroxide supplied to the main body portion 2. Examples of the hydroxide include, but are not limited to, an aqueous sodium hydroxide solution.

[0027] The flocculant supply device 8 includes a storage tank for storing the flocculant and a liquid feed pump or the like. The liquid feed pump is provided in a pipe connecting the flocculant storage tank and the straight body portion 20 of the main body portion 2. By controlling the liquid feed pump, the control device adjusts the supply amount of the flocculant supplied to the main body portion 2. Examples of the flocculant include, but are not limited to, ferric chloride, ferric polysulfate, and bando sulfate.

[0028] The flocculation aid supply device 9 includes a storage tank for storing the flocculation aid and a liquid feed pump or the like. The liquid feed pump is provided in a pipe connecting the flocculation aid storage tank and the main body portion 2. By controlling the liquid feed pump, the control device adjusts the supply amount of the flocculation aid supplied to the main body portion 2. Examples of the flocculation aid include, but are not limited to, a polymer flocculant. Further, the flocculation aid supply device 9 in the present embodiment is configured to supply the flocculation aid to the second region A2, but is not necessarily limited to such a configuration.

[0029] The control device is a device that controls the operations of each part of the water treatment device 1 based on the measured values of the instruments provided in each part of the water treatment device 1, and a known arithmetic device can be used. The control device may have a storage device for storing various data, an input device used by the user, an output device for presenting information to the user, and the like. The control device can communicate with at least the above-described stirring device 3, discharge device 4, leachate supply device 5, chemical solution supply device 6, hydroxide supply device 7, flocculant supply device 8, and flocculation aid supply device 9, and controls the operation and stop of these devices.

[0030] In the water treatment apparatus 1, the leachate flows from above into the first region A1 in the straight cylindrical portion 20 of the main body portion 2 by the leachate supply device 5. At this time, the chemical solution supplied by the chemical solution supply device 6 to the first region A1 and the hydroxide supplied by the hydroxide supply device 7 to the first region A1 are mixed. When the chemical solution is an aqueous sodium carbonate solution and the hydroxide is an aqueous sodium hydroxide solution, calcium ions Ca 2+ in the leachate and sodium carbonate Na2CO3 cause the reaction represented by the following formula (1), and calcium carbonate CaCO3 (an example of a calcium-insoluble substance) precipitates. The aqueous sodium hydroxide solution serves to adjust the leachate to be basic so that the reaction of formula (1) proceeds easily. Ca 2+ +Na2CO3→CaCO3↓+2Na + (1)

[0031] For the leachate in which calcium carbonate has precipitated due to the reaction of formula (1), a flocculant is supplied and mixed by the flocculant supply device 8 in the first region A1, and the aggregation of the calcium carbonate precipitate proceeds. Further, a flocculation aid such as a polymer flocculant may be added by the flocculation aid supply device 9 in the upper region of the second region A2 (or the lower region of the first region A1).

[0032] In the second region A2, the calcium carbonate precipitate generated in the leachate is subjected to coagulation sedimentation. The leachate containing the aggregated calcium carbonate precipitate is subjected to solid-liquid separation in the second region A2, and the precipitated solid portion of calcium carbonate is discharged as sludge. On the other hand, the liquid portion after the solid portion is removed flows from the second region A2 into the third region A3 and overflows from the overflow portion 23 at the upper end portion of the third region A3 and is sent to a subsequent process (not shown).

[0033] Regarding the size of the water treatment device 1, it is desirable that the hydraulic retention time (HRT) be designed to be in the range of 30 minutes or more and 120 minutes or less. For example, it is desirable that the HRT be designed to be approximately 60 minutes. According to this range, the solid-liquid separation effect of calcium carbonate generated by the reaction and the effect of making the device more compact are further improved. That is, if the HRT is less than 30 minutes, it may be difficult to separate the solid and liquid of calcium carbonate generated by the reaction, and if the HRT exceeds 120 minutes, the effect of making the device more compact may be diminished.

[0034] (Second Embodiment) Hereinafter, regarding the second embodiment of the water treatment device 1 according to the present invention, in the same manner as in the above-described first embodiment, a form applied to a calcium removal device that removes calcium components from leachate discharged from a final disposal site of waste will be described with reference to the drawings by taking it as an example. However, the configuration different from the above-described first embodiment will be mainly described, and the same reference numerals will be given to the common configurations and the description thereof will be omitted.

[0035] 〔Configuration of Water Treatment Device〕 As shown in FIGS. 3 and 4, the water treatment device 1 according to the present embodiment includes a partition portion 24 that partitions a first region A1 and a second region A2, and an opening 25 that communicates the first region A1 and the second region A2 is formed in the partition portion 24.

[0036] In the present embodiment, both the straight body portion 20 and the inclined portion 21 of the main body portion 2 have a rectangular cross-sectional shape. Note that in the present embodiment, the cross-sectional shapes of the straight body portion 20 and the inclined portion 21 of the main body portion 2 are rectangular, but the present invention is not limited to this configuration, and other shapes such as a cylindrical shape may be used. The partition portion 24 is provided at the lower end position of the straight body portion 20, and as shown in FIG. 4, openings 25 are formed at the four corners of the partition portion 24. Note that the number of installations, installation positions, and shapes of the openings 25 are not limited to the configuration of the present embodiment.

[0037] Further, the overflow portion 23 in the present embodiment is configured by a suction-type overflow pipe that opens at the water surface to be treated in the third region A3.

[0038] The leachate supplied to the first region A1 is mixed with a chemical solution to produce calcium-insoluble compounds. The leachate containing the calcium-insoluble compounds flows from the first region A1 into the second region A2 through the opening 25 of the partition 24, and the calcium-insoluble compounds aggregate and precipitate. The leachate from which the calcium-insoluble compounds have been removed in the second region A2 flows from the second region A2 into the third region A3 through the gap provided below the vertical wall portion 22 and the opening 25 of the partition 24, and overflows from the overflow portion 23 provided at the upper end portion of the third region A3.

[0039] According to this configuration, by providing a partition that separates the first region and the second region, the division between the first region and the second region becomes clear. As a result, the mixing reaction step of the calcium component and the chemical agent in the first region and the aggregation precipitation step of the calcium-insoluble compounds in the second region can be carried out more efficiently. In addition, since the calcium carbonate precipitate generated in the first region tends to accumulate at the corners of the partition, by providing openings at the four corners of the partition, the calcium carbonate precipitate can be efficiently moved to the second region.

[0040] 〔Other Embodiments〕 1. The discharge device in the water treatment apparatus of the above-described embodiment is configured to include a suction pipe and a pumping-out pump or the like, but is not limited to this configuration. For example, instead of a pumping-out pump, an electric valve or the like may be provided at the bottom of the inclined portion so that the sludge falls into the sludge storage tank.

[0041] 2. The water treatment apparatus in the above-described embodiment is configured to include a third region by a vertical wall portion, but is not necessarily limited to this configuration, and the vertical wall portion and the third region may be provided as needed. In this case, for example, a pumping-out pipe equipped with a suction pump or the like may be separately provided, and the supernatant liquid in the second region may be configured to be sent to a subsequent process thereby.

[0042] Although the present invention has been described with reference to the drawings as described above, the present invention is not limited to the configurations of the drawings and can be implemented in various modes without departing from the gist of the present invention.

Industrial Applicability

[0043] The present invention can be used, for example, in a calcium removal device for removing calcium from leachate discharged from a final disposal site of waste.

Explanation of Signs

[0044] 1: Water treatment device 2: Main body part (single tank) 20: Straight body part 21: Inclined part 22: Vertical wall part 23: Overflow part 24: Partition part 25: Opening 3: Stirring device 30: Stirring blade 31: Motor drive part 4: Discharge device 40: Suction pipe 41: Extraction pump 5: Leachate supply device 6: Chemical solution supply device 7: Hydroxide supply device 8: Coagulant supply device 9: Coagulation aid supply device A1: First region A2: Second region A3: Third region

Claims

1. A water treatment apparatus for removing calcium components contained in water to be treated, comprising: a first region where a chemical that reacts with the calcium components contained in the water to be treated to insolubilize them is mixed with the water to be treated; a second region where calcium insolubles generated in the water to be treated are coagulated and precipitated, provided in a single tank; The water treatment apparatus, wherein the second region is disposed adjacent to and below the first region, and the water to be treated containing calcium insolubles flows out of the first region and into the second region.

2. The water treatment apparatus according to claim 1, wherein the second region has a region where the cross-sectional area becomes smaller toward the lower side.

3. The water treatment apparatus according to claim 1, further comprising a partition portion that partitions the first region and the second region, and an opening that communicates the first region and the second region is formed in the partition portion.

4. The water treatment apparatus according to claim 3, wherein the single tank includes a rectangular portion having a rectangular cross-sectional shape, the partition portion is provided in the rectangular portion, and the opening of the partition portion is provided at a corner of the rectangle.

5. The water treatment apparatus according to any one of claims 1 to 4, further comprising a vertical wall portion extending in the vertical direction in the single tank, and a third region partitioned from the first region by the vertical wall portion is provided in the single tank. The water to be treated from which calcium insolubles have been removed flows out of the second region and into the third region, and flows out from the upper end portion of the third region.

6. The water treatment apparatus according to claim 1, further comprising a stirring device for stirring the water to be treated in the first region.

7. The water treatment apparatus according to claim 1, further comprising a discharge device for discharging the coagulated and precipitated calcium insolubles from the second region.

8. The water treatment apparatus according to claim 1, further comprising a flocculation aid supply device for supplying a flocculation aid to the second region.

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