JP4208121B2 - Oil and fat-containing wastewater treatment method and treatment equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a treatment method and a treatment apparatus for wastewater containing fats and oils, for example, kitchen wastewater discharged from a kitchen such as a restaurant.
[0002]
[Prior art]
Wastewater containing fats and oils, especially wastewater containing a large amount of fats and oils such as kitchen wastewater, may cause water pollution in rivers and clogging of drainage pipes. It is disposed of by. Conventionally, in order to separate and remove oil and fat from kitchen wastewater, grease traps that collect oil and fat have been generally used. With grease traps, the kitchen wastewater is retained in the trap tank, so that the fats and oils float to the upper layer of the wastewater, and the fats and oils contained in the liquid due to the high temperature of the kitchen wastewater are lowered by heat dissipation. , Solidify. As a result, the oil and fat content of the kitchen wastewater is collected as scum in the upper drainage portion (or surface) in the trap tank, while the drainage middle layer portion where the oil and fat content is separated to some extent is discharged. In such a grease wrap, the oil and fat content is only collected (stored) as scum, so that there is a problem that a bad odor is generated due to the oxidation and decay. In addition, the oil and fat collected as scum had to be periodically pumped and removed, and the removed oil and fat had to be properly treated as industrial waste.
[0003]
Thus, in recent years, various processing apparatuses have been developed that decompose scum (oil / fat) trapped in the grease wrap with a biopharmaceutical (for example, see Patent Documents 1 to 4).
[0004]
In this type of general treatment equipment, aeration is performed while supplying (or in the presence of) a biopharmaceutical (including enzyme bacteria, bacteria, etc.) to the kitchen wastewater retained in the trap tank. Is intended to decompose oil and fat (see, for example, Patent Documents 1 and 2). Aeration has the effect of increasing the amount of dissolved oxygen in the waste water to promote decomposition by aerobic bacteria, and stirring the waste water in the trap tank to promote emulsification and decomposition of fats and oils.
[0005]
In place of or in addition to aeration, it has also been proposed to stir the drainage with a submersible pump (see, for example, Patent Documents 3 and 4). By such a forced stirring operation, the scum is pulverized and the emulsification and decomposition of the oil and fat are promoted. In order to efficiently pulverize and emulsify the scum floating on the upper drain of the trap tank, it is common to arrange the suction port of the submersible pump in the vicinity of the drain liquid level of the trap tank.
[0006]
[Patent Document 1]
JP-A-9-314167
[Patent Document 2]
JP 2000-325938 A
[Patent Document 3]
JP 2000-33388 A
[Patent Document 4]
JP 2002-219488 A
[0007]
[Problems to be solved by the invention]
In a conventional processing apparatus that performs aeration, aeration is performed by supplying air from outside the apparatus to the wastewater in the trap tank. Usually, the trap tank is covered with a lid for the purpose of preventing the spread of malodors. However, the pressure in the trap tank is external pressure (usually atmospheric pressure) as much as air is supplied in such a processing device. As a result, the trap tank odor leaks to the outside.
[0008]
Moreover, in the conventional processing apparatus using a submersible pump, since the suction port is limited and fixed, only the waste water existing in the vicinity thereof can be sucked, and stagnation is easily formed in the upper drainage portion of the trap tank. Therefore, in such a processing apparatus, there is a problem that scum accumulates in the stagnation and cannot be sucked into the submersible pump and remains without being processed.
[0009]
In general, kitchen wastewater is hardly discharged depending on the time of day, or is discharged in a large amount at a time, and the amount of wastewater to be treated varies greatly. When the amount of treatment is excessive, the rate of increase in fat and oil trapped in the trap tank may be significantly larger than the rate of fat and oil decomposition by the biopharmaceutical.
[0010]
In such a case, in a conventional processing apparatus that performs aeration, a thick solidified film of oil and fat is formed on the liquid surface of the trap tank, and this serves as a barrier to supply sufficient oxygen and kill bacteria such as bacteria. There is a difficulty that it ends up.
[0011]
On the other hand, in the conventional treatment apparatus using a submersible pump, the formation of a solidified film is prevented by forcibly stirring and circulating the wastewater, but the upper part of the drainage of the trap tank does not catch up with the decomposition of fats and oils by the biologics. A large amount of scum is inevitable. Since this large amount of scum is sucked from the suction port near the drainage liquid level to the submersible pump through the pipe, there is a problem that the pump efficiency is deteriorated or the scum is clogged in the suction port or the pipe.
[0012]
The present invention has been made to solve the above conventional problems, and an object of the present invention is to provide a more efficient and clean treatment method and a treatment apparatus therefor for treating wastewater containing oil and fat. There is to do.
[0013]
[Means for Solving the Problems]
According to one aspect of the present invention, wastewater containing fats and oils (fat containing fats and oils) is supplied into the treatment tank, and the wastewater in the treatment tank flows into the inner tank located inside the treatment tank by overflow. The waste water in the inner tank is pumped up by the submersible pump located inside the inner tank, and at least a part of the drainage pumped up by the submersible pump is flowed down toward the waste water in the treatment tank, and the waste water in the treatment tank is taken out. A method for treating oil and fat-containing wastewater is provided.
[0014]
According to another aspect of the present invention, a treatment tank for storing and retaining wastewater, and a position in the treatment tank, a side portion is partitioned by a wall, and wastewater in the treatment tank flows in due to overflow. The inner tank is open at the top, the submersible pump that is located inside the inner tank and pumps up the wastewater in the inner tank, and a part of the wastewater pumped up by the submersible pump is connected to the submersible pump in the treatment tank. An oil / fat-containing wastewater treatment device including a pipe configured to flow down toward the wastewater is also provided, and the treatment method of the present invention can be performed using this treatment device.
[0015]
According to the method and apparatus for treating fat-containing wastewater of the present invention, since the fat-containing wastewater is passed through the submersible pump, the scum is efficiently crushed by the action of the impeller in the pump. At the same time, the fat and oil and water are sufficiently mixed with stirring, and preferably in an emulsified state. Thereby, there exists an advantage that decomposition | disassembly of the fats and oils by cleaning agents, such as a biopharmaceutical, is accelerated | stimulated. Moreover, formation of a thick solidified film is prevented by the forced stirring action by the submersible pump. Thereby, even when a biopharmaceutical is used as a cleaning agent, killing of bacteria such as bacteria is effectively reduced.
[0016]
In addition, according to the present invention, the inner tank (pump tank) is provided inside the processing tank, and the upper layer of the waste water staying in the processing tank is allowed to flow into the inner tank, so the oil and fat content is compared. Only the upper layer containing a large amount can be passed through the submersible pump. Thereby, grinding | pulverization of scum and stirring mixing of fats and oils and a water | moisture content can be implemented efficiently.
[0017]
Further, in the present invention, since the upper drainage portion of the treatment tank is overflowed to the inner tank, the upper layer portion is wider than the conventional case where the suction port is fixed near the drainage liquid surface and sucked into the submersible pump through the pipe. It can drop into the inner layer from the liquid surface area. According to such a characteristic, there exists an advantage that it is hard to form a stagnation in a processing tank. In addition, even if the amount of processing is excessive and a large amount of scum is temporarily formed in the drainage upper layer of the treatment tank, the scum is not sucked through the pipe to the submersible pump, and the sucked scum is Since it can be immediately crushed by the impeller, there is almost no problem that the pump efficiency is deteriorated or the piping is clogged.
[0018]
In addition, since aeration is not performed in the present invention, the cause of odor leaking from the processing tank to the outside of the apparatus is eliminated, and odor leakage can be effectively prevented. In the present invention, when the waste water pumped up by the submersible pump flows down to the waste water in the treatment tank, the waste water sufficiently comes into contact with the air in the treatment tank, so that the dissolved oxygen in the waste water increases and the biopharmaceutical is used. Even in this case, aerobic bacterial degradation can be promoted.
[0019]
In addition, since the existing grease trap and the trap tank of the processing apparatus can be applied to the processing tank used for carrying out the present invention, the processing apparatus of the present invention can be introduced without increasing the space, and the introduction cost can be reduced. There is also an advantage that it can be reduced.
[0020]
In one aspect of the present invention, the pumping of the waste water by the submersible pump can be performed under such a condition that the flow rate of the waste water flowing into the inner tank is equal to or less than the flow rate of the waste water flowing out from the inner tank. If the flow rate of the wastewater flowing into the inner tank is larger than the flow rate of the wastewater returned from the inner tank to the treatment tank by the submersible pump, the wastewater present in the inner tank will gradually increase even though the submersible pump is operating. Therefore, it is not preferable.
[0021]
Preferably, the pumping of the wastewater by the submersible pump is performed under the condition that the flow rate of the wastewater flowing into the inner tank is smaller than the flow rate of the drainage flowing out from the inner tank. According to such a process, the amount of drainage existing in the inner tank gradually decreases and the drainage liquid level gradually decreases due to the operation (operation) of the submersible pump. Since the scum floats on the drainage liquid level in the inner tank, it is ensured that all the scum that has fallen into the inner tank passes through the submersible pump by lowering the drainage liquid level of the inner tank in this way. In this case, finally, all drainage flowing into the inner tank is immediately sucked out by the submersible pump.
[0022]
In the above aspect, the submersible pump is configured to be switchable between an operation state (ON) in which pumping is performed and a stop state (OFF) in which pumping is not performed, depending on the amount of drainage in the inner tank. preferable. For example, the on / off of the submersible pump can be controlled in this way by using a float switch or a liquid level sensor.
[0023]
According to such a configuration, when the amount of drainage in the inner tank (for example, the drainage liquid level) falls below the first predetermined amount (first level), the pump is turned off and pumping is stopped, and the inflow of drainage into the inner tank When the amount of drainage gradually increases and eventually reaches a second predetermined amount (second level) that is greater than the first predetermined amount, the pump can be turned on and pumping can be performed again. As a result, air can be prevented from being mixed into the pump chamber, and the electric power required for the operation of the submersible pump can be minimized.
[0024]
However, the present invention is not limited to this, and any suitable submersible pump can be used. For example, a submersible pump whose operation is controlled by a timer or the like may be used.
[0025]
Note that “drainage flowing into the inner tank” means not only drainage flowing into the inner tank due to overflow beyond the wall of the inner tank, but also other paths (for example, part of drainage pumped by a submersible pump described later). Means all drainage that can flow into the inner tub by return, holes and gaps, etc. that may be present in the inner tub wall. In addition, “drainage flowing out from the inner tank” means not only drainage in the inner tank pumped by the submersible pump, but also other paths (for example, holes and gaps that may exist in the wall of the inner tank) in some cases. It means all drainage that can flow out.
[0026]
The flow rate of the waste water flowing into the inner tank due to the overflow is roughly the opening area of the wall located below the liquid level (WL) of the processing tank on the virtual plane obtained by extending the wall surface of the inner tank in the vertical direction, and the inner side. It can be predicted by the product of the flow rate of the drainage that is about to flow into the tank.
[0027]
In addition, the flow rate of drainage pumped from the inner tank by the submersible pump depends on the capacity of the submersible pump used, the head to be pumped, and scum (and residue) and piping that can be passed to the submersible pump (including ejectors described later). It can be predicted considering the pressure loss.
[0028]
In one aspect of the present invention, the inner tank wall is provided with a notch from the upper end downward. In the present invention, it is not necessary to make the entire circumference of the upper end of the wall of the inner tank lower than the drainage liquid level (WL) in the treatment tank, and a part of the upper end of the inner tank (for example, at least the lower end part of the notch) If it is lower than (WL), the wastewater flows into the inner tank from that portion by overflow. The shape of the notch is not particularly limited and may be arbitrarily selected, and may be, for example, a triangle, a rectangle, and a semicircle.
[0029]
In such an aspect, the flow rate of the wastewater flowing into the inner tank due to overflow depends on the area of the notch (more specifically, the opening area below the drainage liquid level (WL)). Therefore, by appropriately designing the area of the notch, the flow rate of the wastewater flowing into the inner tank can be predicted and adjusted.
[0030]
In particular, the inner tank is preferably configured to change the height of the notch by moving the lower end portion of the notch up and down. When the height of the notch is changed, the opening area of the notch can be changed. Therefore, by adjusting the notch height at the site of wastewater treatment, it becomes possible to appropriately adjust the flow rate of wastewater flowing into the inner tank due to overflow.
[0031]
In one aspect of the present invention, the piping is configured to return a part of the drainage pumped up by the submersible pump to the inner tank so that the flow rate can be adjusted. According to such a configuration, by returning a part of the drainage pumped up by the submersible pump to the inner tank, the drainage in the inner tank can be agitated with the force of the returned drainage, and floated on the upper drainage layer in the inner tank. Any scum that may be present can be passed through a submersible pump to promote scum crushing and oil emulsification. Moreover, the flow volume of the waste_water | drain which flows into an inner tank can also be adjusted by adjusting the flow volume of the waste_water | drain returning to an inner tank.
[0032]
In one embodiment of the present invention, a cleaning agent such as a biopharmaceutical used to break down fats and oils is supplied into the inner tank. Thereby, the biopharmaceutical can be sufficiently brought into contact with and mixed with the scum collected in the inner tank, and the decomposition efficiency of the oil and fat can be improved. In addition, the deodorizing effect can be improved by supplying the deodorant into the inner tank. The cleaning agent and / or deodorant can be automatically supplied to the inner tank by a predetermined amount at a predetermined time using, for example, a timer and a pump. As the cleaning agent and / or deodorant, an appropriate agent known in the art can be used.
[0033]
In a preferred embodiment of the present invention, an ejector (also referred to as an ejector) is inserted into the pipe at a position higher than the liquid level of the waste water in the treatment tank. According to such a configuration, at least a part of the waste water pumped up by the submersible pump is supplied to the ejector, and the waste water obtained by mixing with the air in the ejector is discharged from the ejector toward the waste water in the treatment tank. Can flow down. Thus, by passing the wastewater through the ejector, the dissolved oxygen in the wastewater increases, and even when a biopharmaceutical is used, aerobic bacterial degradation can be promoted. Further, since the ejector does not need to suck the air in the processing apparatus and supply the air from the outside of the apparatus, the air can be circulated in the apparatus, and a bad odor does not leak outside.
[0034]
The ejector preferably generates ultrasonic waves when the wastewater passes through the inside thereof, whereby the oil and fat components that can be contained in the wastewater can be ultrasonically decomposed. In addition, it is preferable that the ejector is configured so that it can be disassembled, so that even if scum or solids that could not be crushed are clogged in the ejector, only the piping part into which the ejector is inserted is removed, and the ejector is disassembled. Can be cleaned. However, the present invention is not limited to this, and an ejector having any appropriate structure may be used as long as it has a function of sucking and discharging a liquid.
[0035]
As mentioned above, according to this invention, the processing method and processing apparatus of the waste water containing fats and oils more efficient and clean compared with the past are provided.
[0036]
In the present invention, “wastewater containing fats and oils” (referred to herein as “fat containing fats and oils” or simply “wastewater”) means animal and / or vegetable fats and oils, etc. An aqueous fluid containing a fat or oil that is liquid or solid at room temperature. The waste water containing fats and oils can contain any liquid and solid matter in addition to the fats and oils and water. The wastewater containing oil and fat is not necessarily limited to this, but is typically kitchen wastewater and may contain so-called raw garbage such as vegetable waste.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, four embodiments of the present invention will be described with reference to the drawings.
[0038]
(Embodiment 1)
As shown to Fig.1 (a)-(c), in the processing apparatus 30 of this embodiment, the inflow pipe | tube 3 and the inflow pipe 3 and the opposing both sides of the processing tank 1 for accommodating and retaining oil-containing wastewater The discharge pipe 5 is connected to each other. The inflow pipe 3 is provided at a position higher than the discharge pipe 5 in order to prevent the backflow of drainage. Since the waste water in the treatment tank 1 is discharged through the discharge pipe 5 due to overflow, the waste water level of the treatment tank 1 (WL: indicated by a solid line in FIGS. 1B and 1C) is roughly It is equal to the lower end position of the discharge pipe 5. The upper part of the processing tank 1 is closed with an upper lid 7 so that it can be opened and closed.
[0039]
The internal space of the processing tank 1 is upstream (that is, in FIG. 1B) by the partition plates 9a and 9b. left Side) in order from the first tank, the second tank, and the third tank. Drainage located in the first tank, the second tank, and the third tank is separated by the partition plates 9a and 9b in the middle to upper layer parts, but in the lower layer part, the partition plates 9a and 9b and the bottom surface of the treatment tank 1 are separated. It communicates with the gap between them.
[0040]
In the first tank, a basket 11 is arranged so as to receive the fat and oil-containing wastewater supplied from the inflow pipe 3 to the treatment tank 1. A plurality of holes (not shown) are provided in the basket 11 in a mesh shape, for example.
[0041]
In the second tank, an inner tank (pump tank) 13 is installed inside the processing tank 1. The side of the inner tank 13 is partitioned by a wall 13a, and the upper part is open. A cutout 13b is provided in the wall 13a of the inner tank 13 from the upper end downward. In the present embodiment, the prismatic inner tank 13 having a square cross section is provided with a trapezoidal notch 13b whose lower bottom is shorter than the upper bottom. In the present embodiment, one notch 13 b is provided on each of the walls 13 a located on the upstream side and the downstream side of the inner tank 13. However, the present invention is not limited to this, and the inner tub 13 may have any suitable shape, for example, a prismatic shape, a columnar shape, a truncated cone shape, or the like, and the notch 13b also has any suitable shape. For example, it may be a rectangle, an inverted triangle, a semicircle, or the like. The number of notches 13b may be one, but it is preferable to provide at least two notches with respect to the central axis of the inner tank 13.
[0042]
The upper end of the wall 13a of the inner tank 13 only needs to be higher than the drainage liquid level (WL) of the processing tank 1, and is, for example, at a position of approximately +50 to +100 mm (WL reference). The lower end of the notch 13b provided downward from the upper end of the wall 13a is at a position lower than the drainage liquid level (WL), for example, approximately -20 to -60 mm, preferably -30 to -40 mm (WL reference). is there. Of the opening area of the cutout 13b, the area of the drainage liquid level (WL) or less is the sum of the two cutouts. For example, when the nominal drainage capacity of the treatment tank 1 is 200 liters, it is about 800 to 1400 mm. ² , Preferably about 1000 to 1200 mm ² It can be. By appropriately setting the total area of the notches below the drainage liquid level (WL), the flow rate of drainage flowing into the inner tank 13 due to overflow can be adjusted.
[0043]
In the present embodiment, the inner tank 13 is fixed to the bottom surface of the processing tank 1. However, the present invention is not limited to this, and the inner tank 13 does not have to be fixed to the bottom surface of the processing tank 1. In this case, the inner tank 13 does not float on the wall 13 a of the inner tank 13 so as not to be lifted by buoyancy. May have a small hole near the bottom.
[0044]
Inside the inner tank 13, a submersible pump 15 that pumps the waste water in the inner tank 13 is installed. The submersible pump 15 is connected to an external power source (not shown). The capacity of the submersible pump 15 can be appropriately selected by those skilled in the art by taking into consideration the flow rate of the drainage to be pumped from the inner tank 13, the head, the pressure loss, and the like.
[0045]
A pipe 17 is connected to the discharge side of the submersible pump 15. The pipe 17 extends upward from the inner tank 13 and branches left and right at a position higher than the drainage liquid level (WL) of the treatment tank 1 ( 1 (a) and 1 (c)), each branched pipe is open facing the drainage of the treatment tank 1 around the inner tank 13. The upper end of the wall 13 a of the inner tank 13 is higher than the drainage liquid level (WL) of the processing tank 1 in the vicinity of the discharge port of the pipe 17.
[0046]
An ejector 19 is inserted into each of the branched pipes 17. The ejector 19 may have any suitable structure, but may have, for example, a structure including an inner tube 19a and an outer tube 19b that houses the inner tube 19a, as shown in FIG. The inner tube 19a is fixed to the outer tube 19b by an elastic member such as rubber, for example, in the vicinity of the upstream end portion thereof. An opening 19c is provided above the outer tube 19b so that air around the ejector 19 can be sucked through the opening 19c. It is preferable that the ejector 19 is configured to be disassembled.
[0047]
The pipe 17 does not necessarily have to be branched, but when the ejector 19 is inserted into the pipe 17 as in the present embodiment, even if one of the ejectors 19 is clogged, the other ejector 19 functions. There is an advantage that it can be secured.
[0048]
Moreover, the processing apparatus 30 of this embodiment is provided with two tanks (not shown) each containing a cleaning liquid and a deodorant outside the processing tank 1, and is pumped through the hose extending from each of these tanks to the inner tank. It is preferable that the cleaning agent and the deodorizing agent can be supplied into the inside 13. The pump for feeding can be automatically controlled using a timer or the like.
[0049]
Next, the processing method of the fat and oil containing waste water of this embodiment using such a processing apparatus 30 is demonstrated.
[0050]
First, the fat and oil containing waste water to be processed is supplied from the inflow pipe 3 to the processing tank 1 and passed through the basket 11 in the first tank. At this time, solids that can be contained in the wastewater are captured by the basket 11. The drainage that has passed through the basket 11 moves to the second tank through a gap between the partition plate 9a and the bottom surface of the processing tank 1.
[0051]
In the second tank, since the fat and oil contained in the wastewater has a specific gravity smaller than that of water, the fat and oil floats in the upper layer of the wastewater while the wastewater stays and is trapped between the partition plates 9a and 9b. The trapped fats and oils form a scum that floats on the drainage liquid surface. On the other hand, residues and the like that can be contained in the wastewater settle at the bottom of the treatment tank 1.
[0052]
The drainage of the second tank passes through the notch 13b of the inner tank 13 and flows into the inner tank 13 due to overflow. Therefore, the scum floating on the drainage liquid surface can be efficiently dropped into the inner tank 13. Further, the waste water flowing into the inner tank 13 due to the overflow can stir and mix the waste water in the inner tank 13, and the scum that has already been dropped into the inner tank 13 can be crushed. A cleaning agent such as a biopharmaceutical and a deodorizing agent are automatically supplied to the inner tank 13 as necessary.
[0053]
Drainage stored in the inner tank 13 is sucked into the submersible pump 15 and pumped up. Inside the submersible pump 15, the scum sucked together with the waste water is pulverized by the impeller, and the oil and fat and water are sufficiently stirred and mixed, preferably in an emulsified state. Thereby, decomposition | disassembly of the fats and oils by a cleaning agent is accelerated | stimulated.
[0054]
Such pumping by the submersible pump 15 is preferably performed under the condition that the flow rate of the wastewater flowing into the inner tank 13 is smaller than the flow rate of the drainage flowing out from the inner tank 13, and as a result, the drainage liquid level of the inner tank 13. Gradually decreases. The scum dropped into the inner tank 13 is difficult to be sucked into the submersible pump 15 when the amount of drainage in the inner tank 13 is large, and may float on the upper drainage layer of the inner tank 13. As a result of the reduction, all of the scum dropped into the inner tank 13 can be surely passed through the submersible pump 15. If the submersible pump 15 is continuously operated under such conditions, finally, all drainage flowing into the inner tank 13 is immediately sucked into the submersible pump 15. The submersible pump 15 can be operated even if air is mixed in the pump chamber, but the operation is stopped when the drainage of the inner tank 13 becomes small by a timer or the like, and the amount is increased to a certain amount. Then, the driving may be resumed.
[0055]
The drainage pumped up by the submersible pump 15 flows down to the treatment tank 1 through the pipe 17 and the ejector 19. Since the discharge port of the pipe 17 is higher than the drainage liquid level (WL) of the treatment tank 1, the wastewater flowing down from the pipe 17 hits the drainage liquid level of the treatment tank 1 and floats on the liquid level. The resulting scum can be crushed by the impact force.
[0056]
Moreover, since air is mixed in waste water by passing the ejector 19 inserted in the piping 17, the dissolved oxygen amount of waste water increases and aerobic bacteria decomposition | disassembly is accelerated | stimulated. Since the air mixed with the waste water exists around the ejector 19, the air circulates inside the treatment tank 1 closed by the upper lid 7, and the air of the treatment device 30 does not leak outside. In addition, since the ejector 19 emits ultrasonic waves when drainage passes through the inside thereof, the emulsification of oil and fat can be further promoted and ultrasonic decomposition can be performed.
[0057]
Although the ejector 19 may be clogged with scum or the like, even if one of the ejectors 19 is clogged, the other ejector 19 can be discharged from the pipe 17 to the treatment tank 1 through drainage. Further, the ejector 19 that is clogged can be disassembled and cleaned by stopping the operation of the submersible pump 15 and removing the ejector 19 from the pipe 17.
[0058]
According to the present embodiment, as shown in FIG. 1A, the waste water that has flowed down from the pipe 17 to the treatment tank 1 flows between the inner tank 13 and the treatment tank 1 to the upstream side and the downstream side. 13 around the wall 13 a and overflows from the notch 13 b of the inner tank 13 and flows into the inner tank 13. Thus, by forming the flow of waste water, waste water in the vicinity of the third tank can be drawn into the inner tank 13, and untreated waste water (that is, waste water that is not passed through the submersible pump 15) is discharged into the second tank. Can be effectively prevented from moving to the third tank.
[0059]
The waste water that has been treated in the second tank as described above and from which the fats and oils have been removed moves to the third tank through the gap between the partition plate 9b and the bottom surface of the treatment tank 1, and passes through the discharge pipe 5. It is discharged to the outside of the processing device 30 by overflow.
[0060]
As described above, wastewater containing oil and fat is treated. According to the processing apparatus and the processing method of the present embodiment, the scum (oil / fat content) trapped in the processing tank can be dropped into the inner tank and pulverized reliably to promote the emulsification / decomposition of the oil / fat content.
[0061]
In the present embodiment, the notch 13b is provided in the wall 13a of the inner tank 13, and the ejector 19 is inserted into the pipe 17. However, it is noted that these are not essential for the implementation of the present invention. I want. For example, even if the inner tank 13 is not provided with the notch 13b and the entire upper end of the wall 13a of the inner tank 13 is located below the drainage liquid level (WL) of the processing tank 1, the wastewater of the processing tank 1 is discharged. It can flow into the inner tank 13 by overflow. Further, for example, the ejector 19 may be omitted, and the waste water pumped up by the submersible pump 15 may be allowed to flow down to the treatment tank 1 through the pipe 17 as it is.
[0062]
(Embodiment 2)
In the present embodiment, the first embodiment is modified so that the operation of the submersible pump is controlled in accordance with the amount of drainage in the inner tank, more specifically, the liquid level position. Hereinafter, the same reference numerals are used for the same members as in the first embodiment, and the processing apparatus and the processing method of the present embodiment are the same as those in the first embodiment unless otherwise described (the same applies to the following embodiments). is there).
[0063]
As shown in FIG. 3, the processing apparatus of the present embodiment is configured to perform ON / OFF switching of the submersible pump 15 using a float switch (not shown) including a float 41. With this float switch, the submersible pump 15 is turned off when the level of the drainage liquid in the inner tank 13 falls below the first level, for example, approximately +100 to +130 mm from the bottom surface of the inner tank 13, and is below the first level. It is controlled so as to be turned on when the second level is higher than a position of, for example, about −320 to −360 mm (WL reference). Any appropriate switch can be used as such a float switch.
[0064]
In the treatment method of the present embodiment using the treatment apparatus as described above, the pumping by the submersible pump 15 is performed under the condition that the flow rate of the wastewater flowing into the inner tank 13 is smaller than the flow rate of the drainage flowing out from the inner tank 13. As a result, the drainage liquid level in the inner tank 13 gradually decreases, but when the liquid level falls below the first level, the submersible pump 15 is turned off by the float switch and stops pumping. While the operation is stopped, the waste water flows into the inner tank 13 and the drain liquid level of the inner tank 13 gradually rises. When the liquid level eventually reaches the second level or higher, which is higher than the first level, the submersible pump 15 is turned on by the float switch and pumping is performed again.
[0065]
According to this embodiment, the submersible pump 15 can be operated intermittently. When the drainage liquid level in the inner tank 13 is equal to or lower than the first level, the operation of the submersible pump 15 is stopped so that air can be prevented from being mixed into the pump chamber. Further, the submersible pump 15 is operated only when necessary, and when the drainage liquid level in the inner tank 13 is sufficiently low, the operation is temporarily stopped, thereby minimizing the electric power required for the operation of the pump.
[0066]
(Embodiment 3)
In the present embodiment, the first embodiment is modified so as to adjust the flow rate of the wastewater flowing into the inner tank by changing the height of the cutout of the inner tank.
[0067]
The processing apparatus of the present embodiment is configured by using another inner tank 43 as shown in FIGS. 4A to 4C instead of the inner tank 13 shown in FIGS. . A side portion of the inner tank 43 is partitioned by a wall 43a, and a cutout 43b is provided downward from the upper end of the wall 43a. Furthermore, a movable weir 43c is provided in a portion located on the lower side of the notch 43b of the wall 43a. The movable weir 43c is formed by, for example, bonding two plates with an adhesive 43d (see FIG. 4C) so that the wall 43a provided with the notch 43b is sandwiched from the inside and the outside, and the bonded plate is , And configured to move up and down along the lower and both sides of the notch 43a.
[0068]
If such an inner tank 43 is used, the lower end portion of the notch moves up and down by moving the movable weir 43c up and down, so that the height H of the notch 43b can be changed.
[0069]
According to the present embodiment, the height H of the notch 43b and the opening area thereof (more specifically, the opening area below the drainage liquid surface (WL)) can be changed at the site of processing. Therefore, the flow rate of the waste water flowing into the inner tank 43 due to the overflow can be adjusted appropriately according to the individual case at the processing site so that the flow rate of the waste water flowing out from the inner tank 43 is preferably smaller. .
[0070]
(Embodiment 4)
In the present embodiment, the first embodiment is modified so that a part of the drainage pumped up by the submersible pump is returned to the inner tank.
[0071]
As shown in FIG. 5, the processing apparatus of this embodiment is configured to include a branching pipe 45 and a valve 47 in the middle of the pipe 17. The flow rate of the drainage flowing through the pipe 45 can be adjusted by the opening degree of the valve 47. The pipe 45 may be fixed to the submersible pump 15 and / or the pipe 17 with an appropriate support member (not shown).
[0072]
If the configuration as described above is used, a part of the drainage pumped up by the submersible pump 15 can be returned to the inner tank 13 through the pipe 45.
[0073]
According to this embodiment, the waste water in the inner tank 13 can be agitated and mixed by the flow of waste water flowing down from the pipe 45 in addition to the flow of waste water flowing into the inner tank 13 due to overflow. Further, the drainage flowing down from the pipe 45 can hit the drainage liquid level of the inner tank 13 and crush the scum that may float on the liquid level by the collision force.
[0074]
Also in this embodiment, it is preferable that the flow rate of the wastewater flowing into the inner tank 13 is smaller than the flow rate of the drainage flowing out from the inner tank 13, but since the drainage is returned to the inner tank 13 through the pipe 45, Note that the flow rate of the waste water flowing into the inner tank 13 increases.
[0075]
According to the present embodiment, since the flow rate of the drainage returned to the inner tank 13 through the pipe 45 can be adjusted by the valve 47, the flow rate of the drainage flowing into the inner tank 13 by the return from the pipe 45 can also be adjusted. .
[0076]
The third and fourth embodiments can be modified so that the submersible pump 15 is intermittently operated in the same manner as the second embodiment.
[0077]
Although the four embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be easily made by those skilled in the art without departing from the concept of the present invention. It will be understood.
[0078]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the processing method of the wastewater containing fats and oils more efficient and clean compared with the past, and the processing apparatus for it are provided.
[0079]
According to the processing method and the processing apparatus of the present invention, scum can be efficiently pulverized, and emulsification and decomposition of oil and fat can be promoted. Even when a biopharmaceutical is used, it is possible to increase the dissolved oxygen in the wastewater and promote aerobic bacterial degradation without killing bacteria such as bacteria. Furthermore, it is possible to effectively prevent odor leakage to the outside of the apparatus. In addition, there is an advantage that the existing grease trap and the trap tank of the processing apparatus can be effectively used as the processing tank according to the present invention.
[Brief description of the drawings]
FIG. 1 is a schematic view of a processing apparatus according to an embodiment of the present invention, FIG. 1 (a) is a top view, and FIG. 1 (b) is taken along line AA in FIG. 1 (a). FIG. 1C is a side view when seen along the line A′-A ′ in FIG.
FIG. 2 is a schematic sectional view of an ejector used in the embodiment shown in FIG.
FIG. 3 is a schematic side view of a processing apparatus according to another embodiment of the present invention.
4A and 4B are schematic views of an inner tank used in a processing apparatus according to another embodiment of the present invention. FIG. 4A is a side view when a movable weir is in an upper position, and FIG. FIG. 4C is a side view when the movable weir is at the lower position, and FIG. 4C is a cross-sectional view when seen along the line BB in FIG.
FIG. 5 is a schematic side view of a processing apparatus according to another embodiment of the present invention.
[Explanation of symbols]
1 treatment tank
3 Inflow pipe
5 Discharge pipe
7 Top cover
9a, 9b Partition plate
11 baskets
13 Inner tank (pump tank)
13a wall
13b cutout
15 Submersible pump
17 Piping
19 Ejector
30 processing equipment
41 Float
43 Inner tank (pump tank)
43a wall
43b Notch
43c Movable weir
43d adhesive
45 Piping
47 Valve

Claims (16)

A method for treating wastewater containing fats and oils,
Supply wastewater containing fats and oils into the treatment tank,
Let the waste water in the treatment tank flow into the inner tank located inside the treatment tank by overflow,
The water in the inner tank is pumped up by a submersible pump located inside the inner tank,
Let at least a part of the waste water pumped up by the submersible pump flow down toward the waste water in the treatment tank,
Look including to retrieve the waste water in the treatment tank, the side wall of the inner tank is not in contact with the side wall of the processing tank, processing method.   The treatment method according to claim 1, wherein the pumping of the wastewater by the submersible pump is performed under a condition that the flow rate of the wastewater flowing into the inner tank is smaller than the flow rate of the drainage flowing out from the inner tank.   The pumping up of the drainage by the submersible pump is stopped when the amount of drainage in the inner tank is equal to or less than the first predetermined amount, and is performed again when the amount is equal to or greater than the second predetermined amount greater than the first predetermined amount. Processing method.   The processing method according to claim 2 or 3, wherein a flow rate of drainage flowing into the inner tank depends on an area of a notch provided downward from an upper end of the inner tank wall.   The processing method according to claim 4, further comprising changing the height of the notch.   The processing method according to any one of claims 1 to 5, further comprising returning a part of the waste water pumped up by the submersible pump to the inner tank.   The at least part of the waste water pumped up by the submersible pump is supplied to the ejector, and the waste water obtained by mixing with the air in the ejector is discharged from the ejector and flows down toward the waste water in the treatment tank. The processing method in any one of.   The processing method according to claim 7, wherein the ejector generates ultrasonic waves when drainage passes.   The processing method according to claim 1, further comprising supplying a cleaning agent into the inner tank. An apparatus for treating wastewater containing fats and oils,
A treatment tank for containing and retaining waste water;
An inner tank located inside the treatment tank, whose side is partitioned by a wall, and whose upper part is opened so that the waste water in the treatment tank flows in due to overflow,
A submersible pump that is located inside the inner tank and pumps up the waste water in the inner tank.
A pipe connected to the submersible pump and configured to flow at least part of the drainage pumped up by the submersible pump toward the drainage in the treatment tank, and the side wall of the inner tank is in contact with the side wall of the treatment tank Not a processing device.   The processing apparatus according to claim 10, wherein the submersible pump is configured to be switchable between an operating state and a stopped state according to an amount of drainage in the inner tank.   The processing apparatus of Claim 10 or 11 with which the notch is provided in the wall of an inner tank toward the downward direction from the upper end.   The processing apparatus according to any one of claims 10 to 12, wherein the cutout has a variable height by moving a lower end portion up and down.   The processing apparatus according to any one of claims 10 to 13, wherein the pipe is configured to return part of the drainage pumped up by the submersible pump to the inner tank so that the flow rate can be adjusted.   The processing apparatus in any one of Claims 10-14 by which the ejector is inserted in piping at the position higher than the liquid level of the waste_water | drain in a processing tank.   The processing apparatus according to claim 15, wherein the ejector is configured to be disassembled.

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