JP2011000583A - Method and apparatus for treating waste liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating waste liquid which separate almost all foreign substances and oil in the waste liquid by being floated, and achieve continuous operation by a simple operation and achieve a compact apparatus and low equipment cost.SOLUTION: The waste liquid and a flocculant of powder or liquid are made to flow down in an introductory passage to an introductory passage lower part which is communicated with a mixing tank at an opening of a mixing tank side lower part and are made to flow in the mixing tank from the opening of the mixing tank side lower part. Further a diffuser joined to a microbubble generator disposed at an introductory passage outer wall surface lower part is made to penetrate the opening of the mixing tank side lower part and microbubbles are horizontally ejected and agitated in the mixing tank. Thereby almost all foreign substances and oil in the waste liquid are floated by being flocculated and are separated.

Description

  The present invention relates to a waste liquid treatment method and a waste liquid treatment apparatus. More specifically, the present invention relates to a method for treating emulsified waste water and a device for treating emulsified waste water, such as waste water for water screens at painting booths, compressor drains for factories, washing waste water for parts washing machines, or washing waste water for floors and cars. .

  As a water treatment method for removing suspended substances in the water to be treated, water containing micro / nano bubbles produced in a micro / nano bubble generation tank is introduced into a raw water tank storing treated water such as waste liquid from a factory, and a flocculant is further added. Disclosed is a method in which water to be treated which has been added and mixed is introduced into a pressurized levitation tank, and suspended substances in the water to be treated are separated and floated by both fine bubbles and micro-nano bubbles from the pressurized levitation tank. (For example, refer to Patent Document 1).

  In addition, as a small-sized apparatus that can perform oil-water separation processing and its method, by supplying air bubbles to the liquid to be treated stored in the treatment tank, the oil contained in the liquid to be treated floats together with the bubbles to separate the water and the oil. The liquid to be treated is pumped from the lower part of the treatment tank, air is dissolved by the air supply means, sprayed from the nozzle provided at the lower part of the treatment tank, and the liquid to be treated is returned to the treatment tank to be treated. Circulate and supply the untreated liquid to the treatment liquid circulation pipe or the lower part of the treatment tank. In the circulation pipe system, air is supplied to the liquid to be treated so that the bubbles almost rise in the treatment tank. An apparatus and a method for dissolving air by means are disclosed (for example, see Patent Document 2).

  Furthermore, a raw water tank for storing raw water that is treated water, a discharge water tank that is connected to the raw water tank so that water can be introduced, and after purifying the water that has been introduced, discharges the purified water. , Wherein an intermediate process such as a flocculant charging means, a mixing means, a floc separation tank, and a sludge storage tank is connected between the raw water tank and the discharge water tank, and the discharge water tank A water treatment apparatus and method using microbubbles in which microbubble generation means and filter medium or / and other separation means are arranged in a water tank are disclosed (for example, see Patent Document 3).

  The number of processes increases, such as the process of producing micro-nano bubble-containing water, the process of introducing and mixing micro-nano-bubble-containing water into the raw water tank, and the process of generating fine air in the pressurized flotation device. There has been a problem that it becomes high (for example, see Patent Document 1).

  In the method of injecting bubbles from the nozzle installed at the bottom of the treatment tank to the emulsified water to make the bubbles rise almost together, the contact opportunity between the bubbles and oil depends on the natural rising process of the bubbles. In other words, there is a problem that the opportunity for contact between the oil and the bubbles becomes insufficient because, for example, the small bubbles disappear due to the slow rising speed.

  In addition, there is a problem that the amount of air for dissolution must be adjusted with a valve in order to make the bubble diameter uniform and to make the bubbles rise almost uniformly in the treatment tank, and foreign matter other than oil is mixed in the waste liquid. In such a case, there is a problem that it is difficult to separate foreign matter (see, for example, Patent Document 2).

  Furthermore, the waste liquid treatment equipment is equipped with equipment for each action, such as generating microbubbles in the raw water tank into which the waste liquid has flowed, and introducing the flocculant in the next equipment, so the number of equipment is large and the equipment is large. Therefore, there is a problem that the equipment cost becomes high (for example, Patent Document 3).

  Therefore, the object of the present invention is to be able to treat waste liquid containing foreign matter and oil, so that almost all foreign matter and oil can be lifted to separate the foreign matter, oil and water, and the operation is simple and compact. It is an object to provide a wastewater treatment method and apparatus that are low in equipment cost and capable of continuous operation of waste liquid treatment. Here, the foreign substance means a substance other than oil contained in the waste liquid.

  In the present invention, “waste liquid” means a waste solution (Kojien 6th edition), and includes waste water and treated water. The “mixing tank” means a tank in which the waste liquid, the flocculant, and the microbubbles are brought into contact, and the “introduction path” means a flow path for introducing the supplied liquid or liquid and powder into the mixing tank. The “diffuser” means a frustoconical pipe having a cross-sectional area that increases from the inlet side toward the outlet side.

  In order to solve the above problems, the invention of the waste liquid treatment method according to claim 1 is directed to the waste liquid 7, the flocculant 8 and the microbubbles in the mixing tank 2 from the same opening 15 disposed at the lower side of the mixing tank 2. 14 is caused to flow in the horizontal direction in the vicinity of the bottom surface, and immediately after the waste liquid 7, the flocculant 8 and the microbubbles 14 flow into the mixing tank 2, the waste liquid 7, the flocculant 8 and the microbubbles 14 are stirred and mixed. And a process including the steps.

  The invention of the waste liquid treatment method according to claim 2 is the invention of claim 1, wherein the waste liquid 7, the flocculant 8 and the microbubbles 14 are placed in the mixing tank 2 from the same opening 15 disposed at the lower side of the mixing tank 2. The step of flowing in the horizontal direction in the vicinity of the bottom surface causes the waste liquid 7 and the powder or liquid flocculant 8 to flow down in the introduction path 3 to the lower part of the introduction path 3 communicating with the mixing tank 2 at the lower opening on the side face of the mixing tank. And a step of horizontally flowing into the mixing tank 2 from the lower opening 15 on the side surface of the mixing tank 2 and generating a water flow that promotes the flow of the waste liquid 7 and the powder or liquid coagulant 8 in the introduction path 3. And a diffuser 11 in which the microbubble generator 10 is disposed at the lower part of the outer wall surface of the introduction path 3 and connected to the microbubble generator 10 in the introduction path 3 to penetrate the lower opening 15 on the side surface of the mixing tank 2. By my A step of discharging in the horizontal direction in the Robaburu 14 wherein the mixing tank 2, characterized by comprising the step of including.

  The invention of the waste liquid treatment method according to claim 3 is the invention of claim 1 or 2, wherein the step of stirring and mixing immediately after the waste liquid 7, the flocculant 8 and the microbubbles 14 flow into the mixing tank 2 is the mixing tank. 2 is a step of stirring by the stirrer 20 in the mixing tank 2 in which the corner portion between the bottom surface and the side surface of the surface 2 is the inclined surface 21.

  According to a fourth aspect of the present invention, there is provided a waste liquid treatment method according to any one of the first to third aspects, wherein the waste liquid 7 and the flocculant 8 are introduced into the mixing tank 2 from the same opening 15 disposed at the lower side of the side face of the mixing tank 2. And the step of allowing the microbubbles 14 to flow in the horizontal direction near the bottom surface, and immediately after the waste liquid 7, the flocculant 8 and the microbubbles 14 flow into the mixing tank 2, the waste liquid 7, the flocculant 8 and the microbubbles 14 are removed. Separating in the solid-liquid separation step, the step of stirring and mixing, the step of sending out the floc and liquid formed and floated in the mixing tank 2, the solid-liquid separation step of separating the sent floc and liquid into solid and liquid, and the solid-liquid separation step It is characterized by comprising the steps of: filtering the filtered liquid with a filter 35; and circulating the liquid filtered with the filter 35 as treated water.

  The invention of the waste liquid treatment apparatus according to claim 5 is configured such that the waste liquid 7, the flocculant 8 and the microbubbles 14 flow in the horizontal direction in the vicinity of the bottom surface into the mixing tank 2 from the same opening 15 disposed in the lower side of the mixing tank 2. And means for stirring and mixing the waste liquid 7, the flocculant 8 and the microbubbles 14 immediately after the waste liquid 7, the flocculant 8 and the microbubbles 14 flow into the mixing tank 2. It is characterized by.

  The invention of the waste liquid treatment apparatus according to claim 6 is the invention of claim 5, wherein the waste liquid 7, the flocculant 8 and the microbubbles 14 are placed in the mixing tank 2 from the same opening 15 disposed at the lower side of the mixing tank 2. Means for flowing in the horizontal direction in the vicinity of the bottom surface causes the waste liquid 7 and the powder or liquid flocculant 8 to flow down in the introduction path 3 to the lower part of the introduction path 3 communicating with the mixing tank 2 at the lower opening on the side face of the mixing tank. , A means for horizontally flowing into the mixing tank 2 from the lower opening 15 on the side surface of the mixing tank 2 and a water flow for promoting the flow of the waste liquid 7 and the powder or liquid coagulant 8 in the introduction path 3 is generated. The microbubble generator 10 is disposed at the lower part of the outer wall surface of the introduction path 3 and is connected to the microbubble generator 10 in the introduction path 3 so as to penetrate the lower opening 15 on the side surface of the mixing tank 2. By diffuser 11 Characterized by comprising the microbubbles 14 means and means for discharging horizontally within said mixing tank 2.

  The invention of the waste liquid treatment apparatus according to claim 7 is the invention of claim 5 or 6, wherein the means for stirring and mixing immediately after the waste liquid 7, the flocculant 8 and the microbubbles 14 flow into the mixing tank 2 is the mixing tank. 2 is a means for stirring by the stirrer 20 in the mixing tank 2 with the corner portion between the bottom surface and the side surface of the surface 2 as an inclined surface 21.

  According to an eighth aspect of the present invention, there is provided a waste liquid treatment apparatus according to any one of the fifth to seventh aspects, wherein the waste liquid 7 and the flocculant 8 are introduced into the mixing tank 2 from the same opening 15 disposed at the lower side of the side face of the mixing tank 2. And means for causing the microbubbles 14 to flow in the horizontal direction near the bottom, and immediately after the waste liquid 7, the flocculant 8 and the microbubbles 14 flow into the mixing tank 2, the waste liquid 7, the flocculant 8 and the microbubbles 14 are removed. A means for stirring and mixing; a means for sending out the flocs and liquids formed and floated in the mixing tank 2; a solid-liquid separation means for separating the sent flocks and liquids into solid and liquid; and separation by the solid-liquid separation means And a means for circulating the filtered liquid with a filter and a means for circulating the liquid filtered with the filter as treated water.

  According to the first aspect of the present invention, since the oil and foreign matters floating in the waste liquid 7, the flocculant 8 and the microbubbles 14 are allowed to flow into the mixing tank 2 with almost no contact, the previous step of the mixing process is unnecessary. As a result, the number of processes is reduced, and the effect of downsizing equipment and reducing equipment costs is achieved.

  Since the coagulant 8 having an effect for separating oil and foreign matter and water and the microbubble 14 having an effect for separating the oil and water are used at the same time, the amount of the coagulant 8 used can be reduced and the coagulant can be aggregated. Separation effect between the foreign substance and water of the agent 8 and the oil / water separation action and the oil / water separation action of the microbubbles 14 improve the separation effect, so that most of the oil and foreign substances in the waste liquid 7 are flocked and floated to be separated from the water. There is an effect that can be.

  The waste liquid 7, the flocculant 8 and the microbubbles 14 that have flowed into the mixing tank 2 are allowed to flow in the horizontal direction near the bottom from the same opening 15 at the bottom of the side face of the mixing tank 2, and are stirred and mixed immediately after the inflow. It is possible to increase the chance of contact of the oil and foreign matter with the flocculant 8 and the microbubbles 14, so that almost all the oil and foreign matter in the waste liquid 7 is flocked and floated without being settled.

  The invention of claim 2 has the same effect as that of claim 1. Further, since the powder flocculant 8 flows down together with the water flow flowing down the introduction path 3, the powder flocculant 8 also communicates with the waste liquid 7 and the microbubbles 14 at the lower part of the introduction path 3 in the same opening 15 of the mixing tank 2. From the above, there is an effect that it can flow into the mixing tank 2. Here, the water that becomes the water stream means waste liquid 7, waste liquid 7 and treated water, waste liquid 7 and fresh water, treated water or fresh water, and fresh water means water that does not contain contaminants, for example, tap water. .

  When the flow rate of the waste liquid 7 or the flocculant 8 decreases in the flow of the waste liquid 7 or the flocculant 8, the waste liquid 7 or the flocculant 8 is added to the introduction path 3 by adding the treated water or fresh water to flow down. There is an effect that the lower part can be reached.

  The microbubble generator 10 is disposed outside the mixing tank 2, connected to the microbubble generator 10, and the microbubble 14 is horizontally placed in the mixing tank 2 by the diffuser 11 that penetrates the lower opening 15 on the side wall of the mixing tank. By discharging in the direction, the flocculant 8 and the microbubbles 14 do not coexist in the introduction path 3 in spite of being discharged together with the flocculant 8 from the same opening 15. There is an effect that the phenomenon that 8 does not flow down does not occur. Note that the spread angle of the diffuser 11 is increased to such an extent that the angle of the spread range of the microbubbles 14 generated from the microbubble generator 10 is not hindered.

  In addition, since the microbubbles 14 and the water containing the microbubbles 14 are discharged in the mixing tank 2 in the horizontal direction from the diffuser 11 existing at the center position of the opening 15, the outer periphery of the diffuser 11 and the inner periphery of the opening 15. This has the effect of promoting the inflow of the waste liquid 7 and the flocculant 8 into the mixing tank 2 from the gap with the part.

  The invention of claim 3 has the same effect as the invention of claim 1 or 2. Further, the water flow including the waste liquid 7, the flocculant 8, and the microbubbles 14 that flowed in horizontally from the vicinity of the bottom of the side surface of the mixing tank 2 rises against the slope 21 at the lower corner of the side wall of the mixing tank 2 according to the flow generated by the stirrer 20. The effect of increasing the contact opportunity between the oil or foreign matter and the flocculant 8 or the microbubbles 14 over the entire mixing tank 2 can be achieved.

  The invention of claim 4 has the same effect as any of the inventions of claims 1 to 3. Furthermore, waste water treatment can be continuously performed in which the supplied waste liquid is separated into sludge 36, which is the discharge, and reusable treated water for the microbubble generator 10 and for generating the flow-promoting water flow in the introduction path 3. There is an effect.

  The invention of claim 5 has the same effect as the invention of claim 1.

  The invention of claim 6 has the same effect as the invention of claim 2.

  The invention of claim 7 has the same effect as the invention of claim 3.

  The invention of claim 8 has the same effect as the invention of claim 4.

It is a schematic diagram of a waste liquid processing apparatus. It is the schematic diagram which looked at the introduction path and the mixing tank outer surface from the A direction of the schematic diagram of the waste liquid processing apparatus of FIG. It is the schematic diagram which looked at the opening part in a mixing tank and the discharge part of a diffuser from the B direction of the schematic diagram of the waste-liquid processing apparatus of FIG.

  Hereinafter, embodiments and functions of the present invention will be described.

  This will be described with reference to FIGS. The waste liquid treatment apparatus 1 includes a raw water tank 4, an introduction path 3, a mixing tank 2, a coagulant quantitative supply device 6, a microbubble generator 10, a solid-liquid separator 31, a separation liquid tank 32, and the like.

  Waste water 7 is accommodated in the raw water tank 4, and the waste liquid 7 is supplied to the introduction path 3 through the waste liquid supply pipe 22 at a flow rate adjusted by a flow rate adjusting valve (not shown) by a supply pump 5.

  A coagulant 8 suitable for the type of waste liquid is accommodated in a hopper (not shown) of the coagulant quantitative supply device 6, and the coagulant 8 can quantitatively supply powder when the coagulant 8 is powder, for example. A fixed amount set by a screw feeder (not shown) is supplied to the introduction path 3 through the flocculant supply pipe 23. When the flocculant 8 is a liquid, a constant amount set by, for example, a supply pump (not shown) capable of supplying the liquid in a constant amount is supplied to the introduction path 3 through the flocculant supply pipe 23.

  The introduction path 3 is provided obliquely so as to circumscribe the side surface of the mixing tank 2, the upper part has an opening, and the lower part has an opening 15 communicating with the mixing tank 2. The microbubble generator 10 is circumscribed on the opposite side of the opening 15 at the lower part of the mixing tank 2 at the lower part of the introduction path 3, and a diffuser 11 connected to the microbubble generator 10 in the introduction path is provided. The position of the opening of the diffuser 11 extends through the opening 15 to the inside of the mixing tank 3. The protruding length of the diffuser 11 into the mixing tank 2 is 0.5 cm to 5 cm, preferably 1 cm to 2 cm, from the side surface 16 of the mixing tank 2.

  The method for supplying the flocculant 8 to the introduction path 3 in the case of the waste liquid 7 and the powder is shown in FIG. 2 in the vicinity of the upper opening of the introduction path 3 obliquely provided from the waste liquid supply pipe 22. Since the mixing tank 2 and the introduction path 3 communicate with each other, the liquid is supplied to the inclined portion surface above the introduction path liquid level 26 which is substantially the same height as the mixing tank liquid level 25, and the inner wall lower surface of the introduction path 3 is directed downward. Let it flow down. When the flocculant 8 that is powder is supplied from the flocculant supply pipe 23 to the inclined surface of the introduction path 3 or the liquid surface 26 of the introduction path with the waste liquid flowing down to the inclined surface, the flocculant 8 is introduced together with the waste liquid 7. It flows down toward the lower part of the road 3.

  Here, when the flow rate of the waste liquid 7 and the flocculant 8 toward the lower portion of the introduction path 3 is slow, the treated water flowing out from the water flow generation pipe 24 is caused to flow down to the upper opening of the introduction path 3. The flow of the waste liquid 7 and the flocculant 8 is promoted. Here, the flow rate of the treated water can be adjusted by the flow rate adjusting valve 34, and the treated water may be fresh water.

  A water supply pipe 12 and an air supply pipe 13 are connected to the microbubble generator 10, and the microbubble generator 10 receives treated water from the water supply pipe 12 and air from the air supply pipe 13. , The microbubbles 14 are generated, and the microbubbles 14 are discharged into the mixing tank 2 through the diffuser 11. Further, by adjusting the flow rate of the treated water and adjusting the air flow rate, the size of the bubble diameter of the microbubbles 14 generated from the microbubble generator 10 and the amount of the generated microbubbles 14 can be adjusted.

  Since the diffuser 11 connected to the microbubble generator 10 has a structure that does not allow the microbubbles 14 to leak into the introduction path 3, the microbubbles 14 can prevent the powder flocculant 8 from descending in the introduction path 3. Does not occur.

  When the water containing the microbubbles 14 is discharged from the diffuser 11 into the liquid in the mixing tank 2, the mixing tank 2 of the waste liquid 7 and the flocculant 8 from the gap between the opening 15 communicating with the introduction path 3 and the outer surface of the diffuser 11. Inflow is promoted.

  Here, the length of protrusion of the diffuser 11 into the mixing tank 2 is 0.5 cm to 5 cm, preferably 1 cm to 2 cm, from the side surface 16 of the mixing tank 2. And it is effective in promoting the inflow of the flocculant 8 into the mixing tank 2.

  The mixing tank 2 is provided with a stirrer 20, provided with an opening 15 communicating with the introduction path 3 at a lower portion of the side face 16 in contact with the introduction path 3, and a side face 17 on the opposite side of the side face 16 has a weir 18 structure. The corner portion between the bottom surface of the tank 2 and the side surface such as the side surface 17 is composed of a slope 21, for example, a slope 21 of 45 °.

  The waste liquid 7, the coagulant 8 and the microbubbles 14 that have flowed in or discharged from the opening 15 have a slow rising speed in the liquid, particularly because the microbubbles 14 have a fine bubble diameter, and may disappear during the rising in the stationary liquid state. Is expensive. In addition, some types of flocs produced by the flocculant 8 settle.

  Therefore, the microbubble 14, the waste liquid 7 in which oil and foreign matter are suspended, and the flocculant 8 are stirred at the same time, thereby increasing the chance of contact between the microbubble 14, oil and foreign matter, and the flocculant 8. The flocs generated by the oil and the flocculant 8 and the microbubbles 14 or the foreign matter and the flocculant 8 and the microbubbles 14 are promoted to incline, for example, 45 ° at the bottom and side corners of the mixing tank 2. By changing the water flow from the horizontal flow to the upward flow by the inclined surface 21 having the flocs, it is possible to prevent the floc from sinking to the bottom surface of the mixing tank 2 and to float all the flocs.

  The floated flock overflows from the weir 18 of the mixing tank 2 together with the liquid floating the floc, and is guided to the solid-liquid separator 31. Here, the supply to the solid-liquid separator 31 may be carried out by receiving the overflow in a tank and transferring it by a pump, or may be carried out by a natural flow without using a pump.

  The solid-liquid separator 31 is disposed downstream of the mixing tank 2 and upstream of the separation liquid tank 32. In the solid-liquid separator 31, the sludge 36 separated as a solid is discharged, and the remaining liquid is sent to the separation liquid tank 32.

  The separation liquid tank 32 is provided with a filter 35, and the remaining liquid is filtered by the filter 35 to become treated water. A treated water pump 33 is disposed downstream of the separation liquid tank 32, and the treated water pump 33 is connected to a water supply pipe 12 for generating microbubbles, a water flow generating pipe 24, and a drainage pipe. Yes. Then, the treated water is drained by the treated water pump 33, supplied for generating a water flow in the introduction path 3, or supplied for the microbubble generator 10 to circulate the treated water and recycle it. Can be used.

  The waste liquid treatment apparatus 1 can be continuously operated by the above steps or the configuration of each part.

  Next, although an Example is given and this invention is demonstrated, this invention is not limited by an Example.

  As the microbubble generator 10, a brand name Awataro (manufactured by Nitta Muhr), which is a gas-liquid shearing type microbubble generator, was used.

Compressor drain and compressor oil emulsion are used as the liquid to be processed, inorganic powder flocculant is used as the flocculant 8, the processing volume of the liquid to be processed is 3 l / min, the liquid pressure for generating microbubbles is 2 kg / cm ² , and the rotational speed of the agitator is 20 revolutions. Table 1 shows the processing effects when the processing time is 150 rpm and the processing time is 15 minutes. Here, the amount of the flocculant 8 is% by weight with respect to the liquid to be treated, and the treatment time refers to the volume in the mixing tank 2 supplied to the water to be treated, the liquid for generating microbubbles and the introduction path supplied per unit time. The average residence time is divided by the sum of the water flow generating liquids, and SS means the detected amount of suspended substances in JIS K 0102 14 which is a test item of the pollution load analysis. Means the detected amount of the hexane extract of JIS K 0102 24.2.

  According to Table 1, in the case of a compressor drain, the separation and removal rate of oil is 99.3%, the separation and removal rate of suspended substances is 93.7%, and in the case of a compressor oil emulsion, the separation and removal rate of oil is 98. The separation and removal rate of suspended substances was 98.3%. Here, the separation and removal rate means the ratio of the reduced content to the content before processing. Thus, it can be seen that both the oil and suspended solids are largely separated and removed.

DESCRIPTION OF SYMBOLS 1 Waste liquid processing apparatus 2 Mixing tank 3 Introducing path 4 Raw water tank 5 Supply pump 6 Coagulant fixed amount supply machine 7 Waste liquid 8 Coagulant 10 Micro bubble generator 11 Diffuser 12 Water supply pipe 13 Air supply pipe 14 Micro bubble 15 Opening 16 Side surface 17 Side 18 Weir 20 Stirrer 21 Slope 22 Waste liquid supply pipe 23 Coagulant supply pipe 24 Pipe for water flow generation 25 Mixing tank liquid level 26 Introduction path liquid level 31 Solid-liquid separator 32 Separation liquid tank 33 Treated water pump 34 Flow rate adjustment valve 35 Filter 36 Sludge

JP 2009-34683 A JP 2004-16885 A JP 2009-72747 A

Claims (8)

  In the waste liquid treatment method, the step of causing the waste liquid, the flocculant and the microbubble to flow in the mixing tank in the horizontal direction from the same opening disposed in the lower part of the side surface of the mixing tank, and the waste liquid, the flocculant and the microbubble. Immediately after flowing into the mixing tank, the waste liquid, the flocculant and the microbubbles are stirred and mixed.   In the waste liquid treatment method, the step of causing the waste liquid, the flocculant, and the microbubbles to flow horizontally in the vicinity of the bottom surface into the mixing tank from the same opening disposed in the lower part of the side surface of the mixing tank includes the waste liquid and the powder or liquid. A step of causing the flocculant to flow down in the introduction path to the lower part of the introduction path communicating with the mixing tank at the lower side opening of the mixing tank, and horizontally flowing into the mixing tank from the lower opening of the mixing tank side surface, and the waste liquid, And a step of generating a water flow that promotes the flow down of the powder or liquid flocculant in the introduction path, and a microbubble generator is disposed at the lower part of the outer wall surface of the introduction path and connected to the microbubble generator in the introduction path. And a step of discharging the microbubbles in the horizontal direction in the mixing tank by means of a diffuser penetrating the lower opening on the side face of the mixing tank. Waste processing method as claimed.   In the waste liquid treatment method, the step of stirring and mixing immediately after the waste liquid, the flocculant, and the microbubbles flow into the mixing tank is performed by a stirrer in the mixing tank with the corner portion between the bottom surface and the side surface of the mixing tank as an inclined surface. The waste liquid treatment method according to claim 1, wherein the waste liquid treatment method is a step of stirring.   In the waste liquid treatment method, the step of causing the waste liquid, the flocculant and the microbubbles to flow horizontally in the vicinity of the bottom surface into the mixing tank from the same opening disposed at the lower side of the mixing tank, and the waste liquid, the flocculant and the microbubbles Immediately after flowing into the mixing tank, the step of stirring and mixing the waste liquid, the flocculant and the microbubbles, the step of sending out the floc and liquid formed and floating in the mixing tank, and the sent out floc and liquid A solid-liquid separation step of separating the liquid, a step of filtering the liquid separated by the solid-liquid separation step, and a step of circulating the liquid filtered by the filter as treated water. The waste liquid treatment method according to any one of claims 1 to 3.   In the waste liquid processing apparatus, means for causing the waste liquid, the flocculant and the microbubbles to flow in the mixing tank in the horizontal direction from the same opening disposed in the lower part of the side surface of the mixing tank, and the waste liquid, the flocculant and the microbubbles A waste liquid treatment apparatus comprising: means for stirring and mixing the waste liquid, the flocculant, and the microbubbles immediately after flowing into the mixing tank.   In the waste liquid processing apparatus, the means for causing the waste liquid, the flocculant and the microbubbles to flow horizontally in the vicinity of the bottom surface into the mixing tank from the same opening disposed in the lower part of the side surface of the mixing tank is the waste liquid and the powder or liquid. Means for causing the flocculant to flow down in the introduction path to the lower part of the introduction path communicating with the mixing tank at the lower opening on the side surface of the mixing tank, and horizontally flowing into the mixing tank from the lower opening on the side surface of the mixing tank, the waste liquid, And a means for generating a water flow for promoting the flow down of the powder or liquid flocculant in the introduction path, and a microbubble generator disposed below the outer wall surface of the introduction path, and the microbubble generator in the introduction path Means for discharging microbubbles in the horizontal direction in the mixing tank by means of a diffuser that is connected and penetrates the lower opening on the side face of the mixing tank. Waste liquid treatment apparatus of claim 5, wherein.   In the waste liquid treatment apparatus, the means for stirring and mixing immediately after the waste liquid, the flocculant, and the microbubbles flow into the mixing tank is provided by the stirrer in the mixing tank with the corner portion between the bottom surface and the side surface of the mixing tank as an inclined surface. The waste liquid treatment apparatus according to claim 5, wherein the waste liquid treatment apparatus is a stirring means.   In the waste liquid processing apparatus, means for causing the waste liquid, the flocculant and the microbubbles to flow in the mixing tank in the horizontal direction from the same opening disposed in the lower part of the side surface of the mixing tank, and the waste liquid, the flocculant and the microbubbles Immediately after flowing into the mixing tank, the means for stirring and mixing the waste liquid, the flocculant and the microbubbles, the means for sending the flocs and liquids formed and floated in the mixing tank, and the sent flocs and liquids Solid-liquid separation means for separating the liquid, means for filtering the liquid separated by the solid-liquid separation means, and means for circulating the liquid filtered by the filter as treated water. The waste liquid treatment apparatus according to any one of claims 5 to 7, wherein

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