JP2019171285A - Wastewater purification device - Google Patents

Abstract

To provide a wastewater purification device that appropriately controls an amount of sludge to be returned.SOLUTION: There is provided a wastewater purification device 100, including: a reaction tank 130 that adjusts pH of waste water B in which any one or more inorganic ions of heavy metal, phosphorus, and fluorine are mixed with a coagulant; a sedimentation tank 140 that settles and separates sludge E from a suspension D produced in the reaction tank 130; a return pump 150 that returns the sludge E settled and separated in the sedimentation tank 140 to the reaction tank 130; a concentration measuring unit 160 that measures a concentration of the suspension in the reaction tank 130; and a control unit 180 that controls the return pump 150 based on a measurement result of the concentration measurement unit 160.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wastewater purification apparatus that purifies wastewater containing inorganic ions such as heavy metals, phosphorus, and fluorine.

  As a technology to purify wastewater containing inorganic ions such as heavy metals, phosphorus, fluorine, etc., a reaction tank that adjusts the pH of the wastewater, and a polymer flocculant added to the wastewater with adjusted pH to produce an agglomerated reaction solution A technique is disclosed that includes a molecular flocculant addition means, a pellet forming layer for stirring agglomeration reaction liquid to grow agglomerated pellets (sludge), and a sedimentation tank for settling and separating sludge (for example, Patent Document 1). . In the technique of Patent Document 1, an insolubilized product generator is added to the sludge separated and separated and returned to the reaction tank.

Japanese Patent Laying-Open No. 2015-66546

  In the conventional techniques such as Patent Document 1 described above, if the amount of sludge returned from the sedimentation tank is too large, the pipe connected to the reaction tank may be blocked. On the other hand, if the amount of sludge returned from the sedimentation tank is too small, there is a problem that the aggregation efficiency of inorganic ions in the reaction tank is lowered. Therefore, there is a demand for development of a technique for appropriately controlling the amount of sludge returned from the settling tank.

  In view of such a problem, an object of the present invention is to provide a wastewater purification apparatus capable of appropriately controlling the amount of sludge to be returned.

  In order to solve the above-mentioned problem, the waste water purification apparatus of the present invention is a reaction that adjusts the pH of waste water in which any one or more inorganic ions of heavy metal, phosphorus, and fluorine are mixed with a coagulant. Measure the concentration of the suspension in the tank, the sedimentation tank that settles and separates sludge from the suspension generated in the reaction tank, the return pump that returns the sludge settled and separated in the precipitation tank, and the reaction tank And a control unit that controls the return pump based on the measurement result of the concentration measurement unit.

  Moreover, the reaction tank may have a coagulation tank that mixes the waste water and the coagulation material, and a pH adjustment tank that adjusts the pH of the waste water mixed with the coagulation material.

  Moreover, the reaction tank may further have a coagulation tank that mixes the wastewater whose pH is adjusted and the coagulant.

  Further, the concentration measuring unit may measure the concentration of the suspension in the pH adjusting tank.

  The return pump may return sludge to the condensation tank.

  In addition, a sludge amount detection unit that detects the amount of sludge separated and separated in the settling tank is provided, and the control unit stops the return pump when the amount of sludge detected by the sludge amount detection unit is less than a predetermined value. May be.

  According to the present invention, it is possible to appropriately control the amount of sludge to be returned.

It is a figure explaining the waste water purification apparatus concerning this embodiment. It is a figure explaining the waste water purification apparatus of a modification.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(Drainage purification device 100)
FIG. 1 is a diagram for explaining a wastewater purification apparatus 100 according to the present embodiment. In FIG. 1, the flow of waste water A, suspensions B to D, sludge E, supernatant fluid F, and chemicals are indicated by solid arrows, and the flow of signals is indicated by broken arrows. Moreover, the sludge E in the sedimentation tank 140 is shown by hatching.

  As shown in FIG. 1, the waste water purification apparatus 100 includes a raw water tank 110, a delivery pump 120, a reaction tank 130, a sedimentation tank 140, an extraction pipe 142, a return pipe 144, a return pump 150, A pump 152, a concentration measurement unit 160, a sludge amount detection unit 170, and a control unit 180 are included.

  The raw water tank 110 stores waste water (raw water) A discharged from a factory or the like. The waste water A contains one or more inorganic ions of heavy metal, phosphorus, and fluorine. The delivery pump 120 delivers the waste water A stored in the raw water tank 110 to the reaction tank 130 (condensation tank 220).

  The reaction tank 130 includes a tank body 210, partition plates 212a and 212b, stirrers 214a to 214c, a coagulant supply unit 222, a regulator supply unit 232, and a coagulant supply unit 242.

  The tank body 210 has an internal space divided into three spaces by partition plates 212a and 212b. The three spaces are juxtaposed in the horizontal direction. Of the three spaces, the space located on the left side in FIG. 1 functions as the coagulation tank 220, the space located on the right side in FIG. 1 functions as the coagulation tank 240, and the space between the coagulation tank 220 and the coagulation tank 240. Functions as the pH adjusting tank 230.

  The stirrer 214a is provided in the condensation tank 220. The stirrer 214b is provided in the pH adjustment tank 230. The stirrer 214c is provided in the aggregation tank 240.

  The coagulant supply unit 222 includes a tank 224 and an infusion pump 226. The tank 224 stores a coagulation material (medicine). The injection pump 226 supplies the condensing material stored in the tank 224 to the condensing tank 220. The setting material is an iron-based setting material or an aluminum-based setting material. The condensing material condenses (aggregates) inorganic ions contained in the waste water A. Therefore, when the coagulant is supplied to the coagulation tank 220 by the coagulant supply unit 222, the waste water A and the coagulant are mixed by the stirrer 214a. Thus, in the condensation tank 220, a suspension B in which inorganic ions in the waste water A are condensed is generated. The suspension B overflows (overflows) into the pH adjustment tank 230.

  The regulator supply unit 232 includes a tank 234 and an infusion pump 236. The tank 234 stores a pH adjuster (medicine). The infusion pump 236 supplies the pH adjusting agent stored in the tank 234 to the pH adjusting tank 230. The pH adjuster is an alkali compound or an acid compound. The pH adjuster is, for example, an aqueous solution of slaked lime. The pH adjuster adjusts (for example, neutralizes) the pH of the suspension B. Therefore, when the pH adjusting agent is supplied to the pH adjusting tank 230 by the adjusting agent supply unit 232, the suspension B and the pH adjusting agent are mixed by the stirrer 214b. Thus, the pH of the suspension B is adjusted in the pH adjustment tank 230, and the suspension C is generated. The suspension C overflows into the coagulation tank 240.

  The flocculant supply unit 242 includes a tank 244 and an infusion pump 246. The tank 244 stores a flocculant (medicine). The injection pump 246 supplies the coagulant stored in the tank 244 to the coagulation tank 240. The flocculant is a polymer flocculant. The flocculant aggregates inorganic ions contained in the suspension C. Therefore, when the coagulant is supplied to the coagulation tank 240 by the coagulant supply unit 242, the suspension C and the coagulant are mixed by the stirrer 214c. In this way, the suspension D in which the inorganic ions in the suspension C are aggregated is generated in the aggregation tank 240. The suspension D flows into the settling tank 140.

  The sedimentation tank 140 sediments and separates sludge E (inorganic ions aggregated) from the suspension D. The supernatant liquid F (liquid obtained by separating the sludge E from the suspension D) obtained by the sedimentation separation of the sludge E by the settling tank 140 is discharged into sewage or a river.

  An extraction pipe 142 is connected to the sedimentation tank 140. The return pipe 144 connects the extraction pipe 142 and the condensation tank 220. A return pump 150 is provided in the return pipe 144. The return pump 150 is driven by the delivery pump 120, and when the interface height detected by the sludge amount detection unit 170 described later is equal to or higher than a predetermined lower limit height, the sludge E that has been separated by settling in the settling tank 140 is used. Is returned to the condensation tank 220. A drawing pump 152 is provided on the downstream side of the connection portion of the extraction pipe 142 with the return pipe 144. Therefore, among the sludge E settled and separated by the settling tank 140, the sludge E other than the portion returned by the return pump 150 is sent to the waste disposal facility in the subsequent stage through the extraction pipe 142 and the extraction pump 152, and is disposed at a predetermined amount. Processing is performed.

  With the configuration including the return pump 150, the sludge E can be reused as a coagulant, a pH adjuster, and a flocculant. Therefore, the coagulant supplied by the coagulant supply unit 222, the pH adjuster supplied by the adjuster supply unit 232, and the coagulant supplied by the coagulant supply unit 242 can be reduced. Thereby, it becomes possible to reduce the quantity of the sludge E sent to a waste disposal facility of a back | latter stage. That is, volume reduction of the sludge E can be achieved.

  The concentration measurement unit 160 measures the concentration of the suspension (aggregate) in the suspension C of the pH adjustment tank 230. The concentration measuring unit 160 is configured by, for example, an SS densitometer (turbidimeter) or an MLSS densitometer.

  The sludge amount detection unit 170 includes an interface sensor (level sensor) or a turbidimeter. The sludge amount detection unit 170 detects the height from the bottom surface of the settling tank 140 to the interface between the sludge E and the supernatant liquid F that has been separated by settling. The sludge amount detection unit 170 is operated only while the delivery pump 120 is driven.

  The control unit 180 is composed of a semiconductor integrated circuit including a CPU (central processing unit), reads programs and parameters for operating the CPU itself from the ROM, and cooperates with a RAM as a work area and other electronic circuits. The wastewater purification apparatus 100 is managed and controlled.

  The control unit 180 is connected to the management server 20 via the communication network 10 such as the Internet or a dedicated line. The control unit 180 transmits the acquired information to the management server 20 via the communication network 10. The control unit 180 includes, for example, information indicating the driving status of the delivery pump 120 and the return pump 150, information indicating the driving status of the injection pumps 226, 236, and 246, information indicating the driving status of the agitators 214a to 214c, and the concentration measuring unit 160. The information indicating the measurement result and the information indicating the detection result of the sludge amount detection unit 170 are transmitted to the management server 20.

  Therefore, the management server 20 can continuously acquire information from the control unit 180. Then, the management server 20 confirms or analyzes the acquired information. Thereby, the management server 20 can grasp the state of the waste water purification apparatus 100 and can grasp whether or not maintenance is required for the waste water purification apparatus 100.

  In the present embodiment, the control unit 180 controls the return pump 150 based on the measurement result of the concentration measurement unit 160 and the detection result of the sludge amount detection unit 170.

  Specifically, the control unit 180 controls the return pump 150 so that the measurement result of the concentration measurement unit 160 falls within a predetermined appropriate range.

  If the amount of sludge E returned from the sedimentation tank 140 is too large, the pipe connected to the reaction tank 130 may be blocked. On the other hand, if the amount of sludge E returned from the sedimentation tank 140 is too small, in the reaction tank 130 (condensation tank 220, pH adjustment tank 230, coagulation tank 240), as a coagulant, pH adjuster, and coagulant. The functioning sludge E is reduced. If it does so, the aggregation efficiency of the inorganic ion in the reaction tank 130 will fall.

  Therefore, the return amount of sludge E at which the agglomeration efficiency of inorganic ions becomes a predetermined allowable value is set to the lower limit value of the appropriate range, and the maximum return amount of sludge E that can prevent the blockage of the piping is set to the upper limit value of the appropriate range Is done. Here, an allowable value is determined based on the discharge | release reference value of the inorganic ion contained in the supernatant liquid F, for example.

  Thus, the control part 180 can control appropriately the quantity of the sludge E to return by the structure which controls the return pump 150 so that the measurement result of the density | concentration measurement part 160 may become an appropriate range. Thereby, blockage of the pipe connected to the reaction tank 130 can be prevented, and the aggregation efficiency of inorganic ions in the reaction tank 130 can be maintained.

  When the amount of sludge E is small in the sedimentation tank 140, the sludge E is hardly returned even if the return pump 150 is driven. That is, the aggregation efficiency of inorganic ions in the reaction tank 130 is not improved. Therefore, the control unit 180 stops the return pump 150 when the delivery pump 120 is driven and the height of the interface detected by the sludge amount detection unit 170 is less than a predetermined lower limit height. Thereby, the situation where the return pump 150 is driven unnecessarily can be avoided.

  As described above, the waste water purification apparatus 100 of the present embodiment can appropriately control the amount of sludge E returned to the reaction tank 130. Therefore, it is possible to prevent the piping connected to the reaction tank 130 from being blocked and to maintain the aggregation efficiency of inorganic ions in the reaction tank 130.

  Further, as described above, the concentration measuring unit 160 measures the concentration of the suspension in the pH adjusting tank 230. The pH adjustment tank 230 is a tank in which the returned sludge E is substantially uniformly dispersed. Therefore, by measuring the concentration of the suspension in the pH adjustment tank 230, the concentration of the suspension in the reaction tank 130 can be accurately measured.

(Modification)
FIG. 2 is a diagram for explaining a modified waste water purification apparatus 300. In FIG. 2, the flow of waste water A, suspensions B to D, sludge E, supernatant fluid F, and chemicals are indicated by solid arrows, and the flow of signals is indicated by broken arrows. In FIG. 2, broken lines indicating the flow of signals between the control unit 380 and the valves 390 and 392 are not shown for the sake of simplicity. Moreover, the sludge E in the sedimentation tank 140 is shown by hatching.

  As shown in FIG. 2, the waste water purification apparatus 300 includes a raw water tank 110, a delivery pump 120, a reaction tank 130, a sedimentation tank 140, an extraction pipe 142, a return pipe 144, a return pump 350, a concentration It includes a measurement unit 160, a sludge amount detection unit 170, a control unit 380, and valves 390 and 392. In addition, about the component substantially equivalent to the waste water purification apparatus 100 mentioned above, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  The return pump 350 is provided between the sedimentation tank 140 in the extraction pipe 142 and the connection location of the return pipe 144. In the modification, the return pump 350 is operated when the delivery pump 120 is operated and the height of the interface detected by the sludge amount detection unit 170 is equal to or higher than a predetermined lower limit height.

  The valves 390 and 392 are open / close valves. The valve 390 is provided on the downstream side of the connection portion of the extraction pipe 142 with the return pipe 144. The valve 392 is provided in the return pipe 144.

  The control unit 380 controls opening and closing of the valves 390 and 392 based on the measurement result of the concentration measurement unit 160 and the detection result of the sludge amount detection unit 170. The valves 390 and 392 are controlled to be opened and closed exclusively.

  More specifically, the control unit 380 closes the valve 390 and opens the valve 392 when the measurement result of the concentration measurement unit 160 is less than the appropriate range and within the appropriate range. To do. In addition, when the measurement result of the concentration measurement unit 160 exceeds the appropriate range, the control unit 380 closes the valve 392 and stops the return pump 350.

  As described above, the control unit 380 controls the operation of the return pump 350 and the opening / closing control of the valve 392 so that the measurement result of the concentration measuring unit 160 falls within the appropriate range, so that the amount of sludge E to be returned is appropriate. Can be controlled. Thereby, blockage of the pipe connected to the reaction tank 130 can be prevented, and the aggregation efficiency of inorganic ions in the reaction tank 130 can be maintained.

  Further, the return pump 350 according to the modified example has a function of returning the sludge E to the coagulation tank 220 and a function of discarding the sludge E to the outside. Therefore, the waste water purification apparatus 300 can be made compact. Moreover, the initial cost and maintenance cost of the waste water purification apparatus 300 can be reduced.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  For example, in the above embodiment and the modification, the configuration in which the condensation tank 220, the pH adjustment tank 230, and the aggregation tank 240 are integrally formed has been described as an example. However, the condensation tank 220, the pH adjustment tank 230, and the coagulation tank 240 may be configured separately.

  Moreover, in the said embodiment and modification, the reaction tank 130 has the coagulation tank 220, the coagulation material supply part 222, the pH adjustment tank 230, the adjustment agent supply part 232, the coagulation tank 240, and the coagulant supply part 242. Was described as an example. However, the coagulation tank 240 and the coagulant supply unit 242 are not essential components.

  Moreover, in the said embodiment and modification, the reaction tank 130 mentioned and demonstrated the structure which has the tank main body 210 and the partition plates 212a and 212b as an example. However, the reaction vessel 130 may not have the partition plates 212a and 212b. In this case, in the tank body 210, the drainage A and the coagulant are first mixed, and then the pH of the suspension B in which the coagulant is mixed is adjusted. Thereafter, the suspension C whose pH has been adjusted and the flocculant are mixed.

  Moreover, in the said embodiment and modification, the density | concentration measurement part 160 mentioned and demonstrated the structure which measures the density | concentration of the suspension of the pH adjustment tank 230 as an example. However, the concentration measurement unit 160 is not limited to the measurement position as long as the concentration of the suspension in the reaction vessel 130 can be measured. For example, the concentration measurement unit 160 may measure the concentration of the suspension in the condensation tank 220 or the aggregation tank 240 in addition to or instead of the pH adjustment tank 230.

  Moreover, in the said embodiment and modification, the return pumps 150 and 350 demonstrated and demonstrated the structure which returns the sludge E to the condensation tank 220 as an example. However, the return pumps 150 and 350 are not limited to the return locations as long as the sludge E can be returned to the reaction tank 130. For example, the return pumps 150 and 350 may return the sludge E to the pH adjustment tank 230 or the coagulation tank 240 in addition to or instead of the condensation tank 220.

  Moreover, in the said embodiment and modification, the case where the sludge amount detection part 170 was comprised with the interface sensor was mentioned as an example, and was demonstrated. However, the configuration of the sludge amount detection unit 170 is not limited as long as it can detect the amount of sludge E settled and separated in the settling tank 140. When the sludge amount detection unit 170 detects the amount of sludge E, the control units 180 and 380 stop the return pumps 150 and 350 when the amount of sludge E detected by the sludge amount detection unit 170 is less than a predetermined value. To do.

  In addition, for example, the sludge amount detection unit 170 includes a first SS densitometer that measures the turbidity at a predetermined first location of the sedimentation tank 140 and a second turbidity that measures the turbidity at a second location above the first location. 2 SS densitometers. In this case, the control unit 180 stops the return pump 150 when the amount of sludge E measured by the first SS densitometer is less than a predetermined value. In addition, when the amount of sludge E measured by the second SS densitometer is equal to or greater than a predetermined value, the control unit 180 sends the sludge E in the sedimentation tank 140 to a subsequent disposal processing facility.

  Moreover, in the said embodiment and modification, the condensing material supply part 222, the adjustment agent supply part 232, and the coagulant | flocculant supply part 242 demonstrated as an example the structure provided with the injection pumps 226, 236, and 246. However, the tanks 224, 234, and 244 are disposed above the condensation tank 220, the pH adjustment tank 230, and the coagulation tank 240, and the drug is self-weighted from the tanks 224, 234, and 244 to the condensation tank 220, the pH adjustment tank 230, and the aggregation tank 240. However, instead of the infusion pumps 226, 236, 246, an on-off valve may be provided. In this case, the control unit 180 controls opening / closing of the on-off valve.

  INDUSTRIAL APPLICABILITY The present invention can be used for a wastewater purification device that purifies wastewater containing inorganic ions such as heavy metals, phosphorus, and fluorine.

100, 300 Wastewater purification device 130 Reaction tank 140 Precipitation tank 150, 350 Return pump 160 Concentration measuring section 170 Sludge amount detecting section 180, 380 Control section 220 Coagulation tank 230 pH adjustment tank 240 Coagulation tank

Claims (6)

A reaction vessel that adjusts the pH of the wastewater in which any one or more inorganic ions of heavy metal, phosphorus, and fluorine are mixed with the coagulant;
A settling tank for settling and separating sludge from the suspension produced in the reaction tank;
A return pump for returning the sludge settled and separated in the settling tank to the reaction tank;
A concentration measuring unit for measuring the concentration of the suspension in the reaction vessel;
Based on the measurement result of the concentration measuring unit, a control unit for controlling the return pump;
A waste water purification apparatus comprising: The reactor is
A condensing tank for mixing the drainage and the condensing material;
A pH adjusting tank for adjusting the pH of the waste water mixed with the coagulant;
The waste water purification apparatus of Claim 1 which has these.   The waste water purification apparatus according to claim 2, wherein the reaction tank further includes a coagulation tank that mixes the waste water whose pH is adjusted and the coagulant.   The waste water purification apparatus according to claim 2 or 3, wherein the concentration measuring unit measures the concentration of the suspension in the pH adjusting tank.   The waste water purification apparatus according to any one of claims 2 to 4, wherein the return pump returns the sludge to the condensation tank. A sludge amount detection unit for detecting the amount of sludge settled and separated in the settling tank;
The waste water purification apparatus according to any one of claims 1 to 5, wherein the control unit stops the return pump when the amount of the sludge detected by the sludge amount detection unit is less than a predetermined value.

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