JP2018176056A - Wastewater purification system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve removal efficiency of n-hexane extracted substances.SOLUTION: A wastewater purification system comprises: a plurality of treatment water tanks 210 which house adsorbent K adsorbing n-hexane extracted substances and a microorganism degrading the n-hexane extracted substances; and a control section 190 which causes wastewater containing the n-hexane extracted substances to flow through a treatment water tank 210 satisfying a predetermined adsorption condition out of the plurality of treatment water tanks 210 and, when the treatment water tank satisfies a predetermined switching condition, stops the flowing of the wastewater through the treatment water tank 210 and causes the wastewater to flow through another treatment water tank 210 satisfying the adsorption condition.SELECTED DRAWING: Figure 2

Description

  The present disclosure relates to a wastewater purification system in which microorganisms extract normal hexane extractables.

  In the past, floatation separation, pressurized floatation separation, addition of a coagulant, and adsorption by an oil adsorbent have been used as techniques for purifying a normal hexane extraction substance contained in waste water. The normal hexane extractable substance is a generic name of non-volatile substances extracted by normal hexane (n-hexane), and is, for example, oil or surfactant. Of the above techniques, floatation can not remove the emulsified oil or surfactant. In the pressure levitation separation, the moisture content of the separated matter (scum) is as high as about 98%, and the separated matter (waste) becomes large. The addition of the flocculant and the adsorption by the oil adsorbent result in a large amount of waste.

  Therefore, it is conceivable to purify the wastewater using a microorganism that degrades the normal hexane extract. However, the waste water containing the normal hexane extract contains a large amount of easily decomposable organic substances (organic substances which are relatively easily decomposed by microorganisms). For this reason, there is a problem that the decomposition of the easily degradable organic substance by the microorganism is prioritized, and the decomposition of the normal hexane-extracted substance takes a long time.

  Therefore, a technology has been developed in which a plurality of oil adsorbents are installed in a treated water tank containing microorganisms, and the waste water is circulated in the treated water tank (for example, Patent Document 1). According to the technology of Patent Document 1, a normal hexane extract substance is adsorbed to an oil adsorbent, and the adsorbed normal hexane extract substance is decomposed by a microorganism.

JP 2000-350984

  In a waste water purification system provided with an adsorbent that adsorbs normal hexane extract and a treated water tank containing a microorganism that decomposes normal hexane extract as described in Patent Document 1 above, removal of normal hexane extract is described. There is a need for the development of technology to improve efficiency.

  In view of such problems, the present disclosure aims to provide a drainage purification system capable of improving the removal efficiency of normal hexane-extracted substances.

  In order to solve the above-mentioned subject, the drainage purification system concerning one mode of this indication is an adsorption material which adsorbs a normal hexane extract, and a plurality of treated water tanks in which the microorganism which decomposes the normal hexane extract is stored. The waste water containing the normal hexane extract is circulated to the treated water tank satisfying a predetermined adsorption condition among the plurality of treated water tanks, and when the predetermined switching condition is satisfied, the waste water is circulated to the treated water tank. And a control unit that causes the drainage to flow to another treated water tank that meets the adsorption condition after stopping.

  Further, the switching condition may be that the adsorption rate of the adsorbent stored in the treated water tank in which the waste water is circulated is less than a predetermined value.

  Further, the switching condition may be that the time during which the drainage is circulated has reached a predetermined time.

  Further, the adsorption condition may be that a predetermined decomposition time has elapsed since the circulation of the drainage to the treated water tank is stopped.

  Further, a first aeration unit for supplying a gas containing at least oxygen may be provided below the adsorbent in the treatment water tank.

  In addition to the first aeration unit, a second aeration unit for supplying a larger amount of gas than the first aeration unit may be provided below the adsorbent in the treated water tank.

  The adsorbent may be made of a porous resin.

  In addition, a pump for introducing drainage through an inlet provided above the treatment water tank or above the treatment water tank, and one end thereof is connected to a discharge opening formed below the introduction hole in the treatment water tank The waste water distribution part comprised including piping whose other end is located below the upper end of the treated water tank may be provided, and the control part may control the waste water distribution part.

  Moreover, you may provide the methane fermentation tank which accommodates a methane fermentation microbe and into which the waste_water | drain discharged | emitted from the said processing water tank is introduce | transduced.

  The wastewater purification system of the present disclosure can improve the removal efficiency of normal hexane extracted substances.

It is a figure explaining a drainage purification system. It is a figure explaining an oil purification device. It is a flowchart explaining the flow of purification processing by a control part. Fig.4 (a) is a figure explaining the water quality of an Example and a comparative example. FIG.4 (b) is a figure explaining the generation amount of the methane gas of an Example and a comparative example.

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

(Drainage purification system 100)
FIG. 1 is a diagram for explaining a drainage purification system 100. As shown in FIG. In FIG. 1, the flow of liquid is indicated by a solid arrow and the flow of gas is indicated by a broken arrow. As shown in FIG. 1, the drainage purification system 100 is configured to include an oil purification device 110 and a methane fermentation tank 120.

  Waste water (water to be treated) containing at least a normal hexane extraction substance and an organic substance is introduced into the oil purification device 110. The oil purifier 110 decomposes the normal hexane extract in the waste water to produce post-treatment water (waste water from which the normal hexane extract has been removed). The treated water produced by the oil purifier 110 is introduced into the methane fermenter 120.

  The methane fermenter 120 is, for example, a device of UASB (Upflow Anaerobic Sludge Blanket) type. The methane fermentation tank 120 contains methane fermentation bacteria, and decomposes the organic matter contained in the water after treatment to generate methane and purified water (water after treatment from which the organic matter is removed). Methane produced by the methane fermentation tank 120 is delivered to a fuel utilization facility at a later stage, and the purified water is discharged as it is or is discharged after a finishing process.

(Oil purification device 110)
Subsequently, the oil purification device 110 for producing post-treatment water will be described in detail. FIG. 2 is a diagram for explaining the oil purification device 110. As shown in FIG. As shown in FIG. 2, the oil purification device 110 includes a plurality of (here, three) processing units 150 (shown as 150A to 150C in FIG. 2), a drainage circulation unit 160, a first aeration unit 170, and a first 2 includes an aeration unit 180 and a control unit 190.

  The processing unit 150 is configured to include a processing water tank 210 and an air diffusion pipe 220. The treatment water tank 210 is a container that contains at least drainage, an adsorbent K, and microorganisms. In the processing water tank 210, a flat-plate shaped screen 212 extending in a direction (for example, a horizontal direction) intersecting the vertical direction is provided. The outer edge of the screen 212 is connected to the inner surface of the processing water tank 210. That is, the processing water tank 210 is divided by the screen 212 into the upper area 210a and the lower area 210b located below the upper area 210a. The screen 212 has a plurality of holes formed therein. The holes formed in the screen 212 are smaller than the adsorbent K.

  The adsorbent K is disposed in the upper region 210a (above the screen 212 in the treatment water tank 210). That is, the screen 212 regulates the movement of the adsorbent K to the lower region 210b. The adsorbent K is a cube formed of a porous resin, and adsorbs a normal hexane extraction substance. The porous resin is, for example, a polyurethane ether foam. By forming the adsorbent K with a porous resin, it is possible to efficiently adsorb the normal hexane extract substance.

  The microorganisms accommodated in the processing water tank 210 are aerobic microorganisms which decompose | disassemble a normal-hexane extraction material.

  The aeration tube 220 is disposed in the lower region 210 b (below the screen 212 in the treatment water tank 210). The aeration tube 220 is comprised of a tube in which a plurality of holes are formed. A first aeration unit 170 and a second aeration unit 180, which will be described later, are connected to the aeration tube 220.

  The drainage distribution unit 160 distributes drainage in the treatment water tank 210. In the present embodiment, the drainage circulation unit 160 includes a supply pipe 162, a pump 164, valves 166a to 166c, and an extraction pipe 168.

  The supply pipe 162 is a pipe whose one end is connected to a drainage supply source and whose other end is branched into a plurality. At the other end of the supply pipe 162, an inlet port 162a is formed. The inlet 162 a is provided above the processing water tank 210 and is disposed to face the processing water tank 210.

  The pump 164 is provided in the supply pipe 162 and is drive-controlled by a control unit 190 described later. The drainage is introduced into the treatment water tank 210 by driving the pump 164.

  The valves 166 a to 166 c are respectively provided at branched points in the supply pipe 162. The valves 166 a to 166 c are configured by on-off valves, and are controlled to be opened and closed by the control unit 190.

  The extraction pipe 168 is a pipe whose one end is connected to the discharge port 210 c formed in the bottom surface of the processing water tank 210 and whose other end is located below the upper end of the processing water tank 210. The extraction pipe 168 has a bent portion 168 a bent in the horizontal direction from the vertical direction. Connected to the extraction pipe 168 is an air extraction pipe 168b extending vertically upward from the bent portion 168a. The upper end of the air removal pipe 168 b is open to the atmosphere.

  Therefore, the waste water introduced by the pump 164 passes through the adsorbent K, the screen 212, and reaches the discharge port 210c. That is, the drainage flows in a downward flow (a flow from the top to the bottom) in the treatment water tank 210. Then, the waste water comes in contact with the adsorbent K in the process of passing through the adsorbent K. As a result, the normal hexane-extracted substance in the waste water is adsorbed onto the adsorbent K. As described above, by making the flow of the drainage (or post-treatment water) into the downward flow, the ones of the normal hexane extracted substances that are more likely to rise float out of the treatment water tank 210 as compared with the case of the upward flow. It is possible to avoid the situation that

  In addition, when drainage is continuously introduced into the processing water tank 210 through the inlet port 162a, the water level of the drainage water in the processing water tank 210 is maintained at a height substantially equal to that of the bent portion 168a in the extraction pipe 168. After the treatment, the water is discharged through the discharge pipe 168. As described above, the configuration in which the extraction pipe 168 is connected to the discharge port 210c automatically discharges the same amount of post-treatment water as the drainage introduced into the treatment water tank 210 while maintaining the water level of the treatment water tank 210 ( Can overflow).

  In addition, the retention time of the drainage in the process water tank 210 by the drainage distribution part 160 is less than 1 hour (about 20 minutes), for example.

  The first aeration unit 170 is configured to include a first aeration tube 172 and a blower 174. The first aeration tube 172 is a pipe whose one end is open to the atmosphere and the other end is branched into a plurality. The other ends of the first aeration trachea 172 are respectively connected to the aeration trachea 220 accommodated in the processing water tank 210.

  The blower 174 is provided to the first aeration tube 172, and is drive-controlled by the control unit 190. By driving the blower 174, air (gas containing oxygen) is supplied to the lower region 210b through the air diffusion tube 220.

  The second aeration unit 180 includes a second aeration tube 182, a blower 184, and valves 186a to 186c. The second aeration tube 182 is a pipe whose one end is open to the atmosphere and the other end is branched into a plurality. The other ends of the second aeration trachea 182 are respectively connected to the aeration trachea 220 accommodated in the processing water tank 210.

  The blower 184 is provided in the second aeration tube 182, and is drive-controlled by the control unit 190. By driving the blower 184, air (gas) is supplied to the lower region 210b through the air diffusion pipe 220. The control unit 190 controls the blower 184 so that a larger amount of air than the air supplied by the first aeration unit 170 is supplied to the processing water tank 210.

  The valves 186 a to 186 c are respectively provided at branched locations in the second aeration tube 182. The valves 186 a to 186 c are configured by on-off valves, and are controlled to be opened and closed by the control unit 190.

  Although the details will be described later, the configuration provided with the second aeration unit 180 allows the organic matter and the microorganisms adsorbed to the adsorbent K to be desorbed from the adsorbent K. Thereby, the adsorption rate of the adsorbent K can be improved.

  The control unit 190 is configured of a semiconductor integrated circuit including a CPU (central processing unit). The control unit 190 reads a program, parameters, and the like for operating the CPU itself from the ROM, and controls the entire oil purification device 110 in cooperation with the RAM as a work area and other electronic circuits. In the present embodiment, the control unit 190 controls the pump 164, the valves 166a to 166c, the blowers 174 and 184, and the valves 186a to 186c.

  FIG. 3 is a flowchart for explaining the flow of the purification processing by the control unit 190. In an initial state, the control unit 190 stops driving the pump 164 and the blowers 174 and 184, and closes the valves 166a to 166c and the valves 186a to 186c. In addition, when the user inputs a stop instruction, the control unit 190 stops the process performed at that time.

(Processing unit determination processing S110)
The control unit 190 determines one processing unit 150, for example, the processing unit 150A, among the plurality of processing units 150. Then, the control unit 190 drives the pump 164 to open the valve 166a corresponding to the processing water tank 210 of the processing unit 150A. Then, the drainage is introduced into the processing water tank 210 of the processing unit 150A, and the drainage flows in the processing water tank 210. Thereby, in the treatment water tank 210 of the treatment unit 150A, an adsorption process is performed in which the normal hexane extracted substance in the waste water is adsorbed to the adsorbent K.

  Further, the control unit 190 drives the blower 174. Thereby, the waste water in the process water tank 210 is stirred, and the contact probability of a normal-hexane extraction substance and the adsorption material K can be improved. Therefore, it becomes possible to improve the adsorption efficiency of the normal hexane extracted substance by the adsorbent K.

(Switching condition determination processing S120)
The control unit 190 determines whether or not a predetermined switching condition is satisfied with respect to the processing water tank 210 of the processing unit 150 in which the drainage is being circulated. As a result, when the control unit 190 determines that the switching condition is satisfied, the control unit 190 shifts the processing to the suction condition determination processing S130. On the other hand, when determining that the switching condition is not satisfied, the control unit 190 repeats the switching condition determination process S120. Thus, the adsorption process is maintained in one processing unit 150 (processing unit 150A) until the switching condition is satisfied.

  Here, the switching condition is the time during which the drainage is being circulated (hereinafter referred to as "circulation time"), that is, the elapsed time from the start of the circulation of the drainage to the treatment water tank 210 has reached a predetermined time. It is. The predetermined time is a time when the concentration of the normal hexane-extracted substance in the water after treatment reaches a predetermined allowable value, and is derived in advance by experiment. Further, the allowable value is a predetermined value less than the upper limit value of the normal hexane-extracted substance capable of maintaining the activity of the methane fermentation bacteria of the methane fermentation tank 120 at a predetermined value or more.

  As the flow time becomes longer, the pores of the adsorbent K are filled with the normal hexane extract substance or the like, and the adsorption rate of the adsorbent K decreases. Therefore, as the flow time becomes longer, the concentration of the normal hexane extract in the post-treatment water increases. Therefore, by setting that the flow time has reached the predetermined time as the switching condition, the concentration of the normal hexane-extracted substance in the post-treatment water can be suppressed to the allowable value or less. In addition, let the adsorption rate of the adsorption material K when it reaches predetermined time be a 1st predetermined value.

(Suction condition determination processing S130)
If it is determined that the processing water tank 210 of the processing unit 150 which distributes the drainage satisfies the predetermined switching condition, the control unit 190 determines that the processing water tank satisfies the predetermined adsorption condition except for the processing unit 150 which currently distributes the drainage. It is determined whether there is a processing unit 150 having 210. As a result, when the control unit 190 determines that there is the processing unit 150 having the processing water tank 210 that satisfies the suction condition, the processing moves to the switching processing S140. On the other hand, when the control unit 190 determines that there is no processing unit 150 having the processing water tank 210 satisfying the suction condition, the processing returns to the switching condition determination processing S120. Thus, the adsorption processing is maintained in one processing unit 150 (processing unit 150A) until one of the processing water tanks 210 reaches the adsorption condition.

  Here, the adsorption condition is that the adsorption rate of the adsorbent K is equal to or higher than a second predetermined value which exceeds the first predetermined value. That is, the treated water tank 210 that satisfies the suction condition does not satisfy the switching condition. In other words, the processing water tank 210 satisfying the switching condition does not satisfy the suction condition. Accordingly, the switching condition is not satisfied at the same time as the suction condition is satisfied, and the suction condition is not satisfied at the same time as the switching condition.

(Switching process S140)
The control unit 190 determines one processing unit 150, for example, the processing unit 150B, among the processing units 150 having the processing water tank 210 satisfying the suction condition. Then, the control unit 190 opens the valve 166b corresponding to the processing water tank 210 of the processing unit 150B. Then, the drainage is introduced into the processing water tank 210 of the processing unit 150B, and the drainage flows in the processing water tank 210. Thereby, in the treatment water tank 210 of the treatment unit 150B, an adsorption process is performed in which the normal hexane extracted substance in the waste water is adsorbed to the adsorbent K. Thus, the adsorption processing is maintained in one processing unit 150 (processing unit 150B) until one of the processing water tanks 210 satisfies the adsorption condition.

  As described above, the control unit 190 can continuously remove the normal hexane extraction substance from the waste water by switching the circulation destination of the waste water to the treatment unit 150 having the treated water tank 210 satisfying the adsorption condition.

  In addition, the control unit 190 closes the valve 166a corresponding to the treated water tank 210 (the treated water tank 210 currently circulating drain) which satisfies the switching condition, and introduces drainage into the treated water tank 210 of the processing unit 150A. Execute stop processing to stop. Then, although the treatment water tank 210 of the treatment unit 150A is filled with the drainage, the circulation of the drainage is stopped.

  As described above, the treated water tank 210 contains a microorganism that decomposes the normal hexane extract. In addition, the waste water contains microorganisms that decompose normal hexane extract substances. Therefore, the treatment tank 210 is filled with drainage and left undisturbed, whereby decomposition (decomposition processing) of the normal hexane extracted substance adsorbed to the adsorbent K is performed by the microorganism. The blower 174 is driven even while the disassembling process is being performed. Thereby, the microorganisms in the processing water tank 210 can be activated, and the decomposition of the normal hexane extract can be promoted.

  And, as the execution time of the decomposition process elapses, the decomposition of the normal hexane extract by the microorganism proceeds. Therefore, for example, the processing water tank 210 of the processing unit 150 for which the predetermined decomposition time has elapsed after the stop processing is performed (after the suction processing ends) will satisfy the suction condition. Here, the decomposition time is the time until the adsorption rate of the adsorbent K reduced to the first predetermined value returns to the second predetermined value or more due to the decomposition of the normal hexane-extracted substance by the microorganism.

  Further, the control unit 190 opens the valve 186a corresponding to the processing unit 150 whose decomposition time has elapsed, for example, the processing water tank 210 of the processing unit 150A, and executes an aeration process of starting the driving of the blower 184. Then, after a predetermined time has elapsed since the start of driving of the blower 184, the control unit 190 closes the valve 186a to stop the blower 184.

  By executing the aeration process, a large amount of gas can be supplied into the processing water tank 210 of the processing unit 150A, and organic substances and microorganisms adsorbed on the adsorbent K can be desorbed from the adsorbent K. Therefore, the adsorption rate of the adsorbent K can be further improved from the second predetermined value.

  In addition, when the separated organic substances and microorganisms are extracted from a drain pipe (not shown) provided in the processing water tank 210 and supplied to the processing water tank 210 where the stop processing is performed (the decomposition processing is started) Good. This can further accelerate the decomposition process. The separated organic substances and microorganisms may be discarded.

  As described above, the drainage purification system 100 according to the present embodiment switches the distribution destination of drainage from the treatment water tank 210 having a reduced adsorption rate to the treatment water tank 210 having a regenerated adsorption rate. That is, the adsorption processing and the decomposition processing are performed in different time zones in one processing water tank 210. Further, the adsorption processing and the decomposition processing are performed in parallel by using a plurality of treated water tanks 210. Therefore, even if the decomposition of the normal hexane extract by the microorganism is slower than the adsorption of the normal hexane extract by the adsorbent K, the removal efficiency of the normal hexane extract is improved while suppressing the outflow of the normal hexane extract. It can be done.

(Modification)
In the above embodiment, the case where the passage time reaches the predetermined time is described as an example of the switching condition. However, it is measured that the adsorption rate of the adsorbent K contained in the treated water tank 210, which is circulating the waste water, is less than the first predetermined value (predetermined value), and the switching is made to become less than the first predetermined value. It may be a condition.

  For example, when the normal hexane extraction material is a surfactant, a bubble sensor is installed at a predetermined position above the water surface of the processing water tank 210. Then, when the bubble sensor detects a bubble, the control unit 190 determines that the adsorption rate of the adsorbent K is less than the first predetermined value. Here, the predetermined position is a position corresponding to the height of the bubble when the adsorption rate of the adsorbent K becomes the first predetermined value, and is derived in advance by experiment.

(Example)
The water quality of the post-treatment water (Example) treated with waste water using the oil purification device 110 equipped with one treatment unit 150 (Example) and the waste water (Comparative Example) not subjected to any treatment was compared. In the example, the effective volume of the treatment water tank 210 was 1.5 L, and the drainage was allowed to flow for a residence time of 20 minutes.

  FIG. 4 is a diagram for explaining an experimental result. Fig.4 (a) is a figure explaining the water quality of an Example and a comparative example. FIG.4 (b) is a figure explaining the generation amount of the methane gas of an Example and a comparative example. In FIG. 4A, the example is shown in white and the comparative example is shown in black.

  As a result, as shown in FIG. 4A, the concentration of CODCr, which is an index of the total amount of organic substances, was 4070 mg / L in the comparative example and 1890 mg / L in the example (removal rate 54%). The concentration of the suspended substance (SS: Suspended Substance) was 2360 mg / L in the comparative example, and 247 mg / L in the example (90% removal rate). The concentration of the normal hexane extract was 1385 mg / L for the comparative example and 129 mg / L for the example (removal rate: 91%).

  From the above results, it was found that the removal rate of suspended solids and the removal rate of normal hexane extract were higher than the removal rate of CODCr. Thereby, it was confirmed that the oil purifier 110 can selectively remove suspended solids and normal hexane extracted substances.

  Moreover, the methane fermentation process was performed using the methane fermenter 120 of a UASB system. The comparative example was introduced from 1st to 21st to perform methane fermentation treatment, and the example was introduced from 22d (t1) onward.

  As a result, as shown in FIG. 4 (b), it was found that the amount of generated methane gas was significantly increased in the example from the comparative example. As shown in FIG. 4 (a), in the example, the amount of suspended matter which is a source of generation of methane gas is smaller than that of the comparative example, but the amount of generation of methane gas is larger than that of the comparative example. This is considered to be because, in the example, the activity of the methane fermentation bacteria is increased in the methane fermentation tank 120 because the normal hexane extract that inhibits the activity of the methane fermentation bacteria is removed. From the above results, it was confirmed that methane can be efficiently produced by introducing post-treatment water from which the normal hexane extract has been removed by the oil purification device 110 into the methane fermentation tank 120.

  Although the embodiments have been described above with reference to the accompanying drawings, it goes without saying that the present disclosure is not limited to the above embodiments. It is apparent that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that they are naturally within the technical scope of the present disclosure. Be done.

  For example, in the said embodiment, the waste water purification system 100 mentioned and demonstrated the structure provided with the three treated water tanks 210 to the example. However, the drainage purification system 100 may be provided with at least two or more treatment water tanks 210.

  Moreover, in the said embodiment, the case where the adsorption material K was comprised with porous resin was mentioned as the example, and was demonstrated. However, the adsorbent K is not limited in its material as long as it can adsorb a normal hexane-extracted substance.

  Moreover, in the said embodiment, the case where the adsorption material K was cube shape was mentioned as the example, and was demonstrated. However, the adsorbent K is not limited in shape as long as it can adsorb a normal hexane-extracted substance. For example, the adsorbent K may be in the form of a sheet.

  Moreover, in the said embodiment, the structure which the 1st aeration part 170 supplies air was mentioned as the example, and was demonstrated. However, the first aeration unit 170 may supply a gas containing at least oxygen. Moreover, the 1st aeration part 170 is not an essential structure.

  Moreover, in the said embodiment, the structure which the 2nd aeration part 180 supplies air was mentioned as the example, and was demonstrated. However, the second aeration unit 180 may supply at least a gas. Moreover, the 2nd aeration part 180 is not an essential structure.

  Moreover, in the said embodiment, the waste water purification system 100 mentioned and demonstrated the structure provided with the methane fermentation tank 120 to an example. However, the methane fermenter 120 is not an essential component.

  Moreover, in the said embodiment, the structure which determines indirectly that the adsorption rate of the adsorption material K became less than 1st predetermined value was mentioned as the example, and was demonstrated. However, it may be directly determined that the adsorption rate of the adsorbent K has become less than the first predetermined value as a switching condition.

  The present disclosure can be applied to a wastewater purification system that causes normal hexane extract substances to be decomposed by microorganisms.

K Adsorbent 100 Drainage Purification System 160 Drainage Distribution Unit 162a Inlet 164 Pump 168 Extraction Pipe (Piping)
170 first aeration unit 180 second aeration unit 190 control unit 210 treated water tank 210 c discharge port

Claims (9)

An adsorbent which adsorbs normal hexane extract substances, and a plurality of treated water tanks in which microorganisms which decompose the normal hexane extract substances are accommodated;
The drainage water containing the normal hexane extract is circulated to the treatment water tank satisfying a predetermined adsorption condition among the plurality of treatment water tanks, and the circulation of the drainage water to the water tank is stopped when the predetermined switching condition is satisfied. And a control unit that causes the drainage to flow to another treated water tank that satisfies the adsorption condition.
Wastewater purification system equipped with   The drainage purification system according to claim 1, wherein the switching condition is that an adsorption rate of the adsorbent contained in the treated water tank in which the drainage is circulated is less than a predetermined value.   The drainage purification system according to claim 1, wherein the switching condition is that a time during which the drainage is circulated has reached a predetermined time.   The drainage purification system according to any one of claims 1 to 3, wherein the adsorption condition is that a predetermined decomposition time has elapsed since the circulation of the drainage to the treatment water tank is stopped.   The waste water purification system according to any one of claims 1 to 4, further comprising a first aeration unit which supplies a gas containing at least oxygen below the adsorbent in the treatment water tank.   The waste water purification system according to claim 5, further comprising a second aeration unit which supplies a larger amount of gas than the first aeration unit in addition to the first aeration unit below the adsorbent in the treated water tank.   The drainage purification system according to any one of claims 1 to 6, wherein the adsorbent is made of a porous resin. A pump for introducing drainage through an inlet provided at an upper portion of the processing water tank or above the processing water tank;
Piping whose one end is connected to a discharge port formed below the inlet in the processing water tank and whose other end is located below the upper end of the processing water tank;
And a drainage distribution unit comprising
The drainage control system according to any one of claims 1 to 7, wherein the control unit controls the drainage circulation unit.   The waste water purification system according to any one of claims 1 to 8, further comprising a methane fermentation tank containing methane fermentation bacteria and into which waste water discharged from the treatment water tank is introduced.

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