JPH0745039B2 - Wastewater treatment equipment - Google Patents

Description

Description: [Object of the invention] (Field of industrial application) The present invention relates to a wastewater treatment apparatus for treating wastewater containing organic substances, and in particular, an excess biofilm on the surface of a carrier generated in association with the wastewater treatment. The present invention relates to a wastewater treatment device having improved carrier regenerating means for removing water.

(Prior Art) In the conventional wastewater treatment apparatus of this type, as shown in FIG. 3, the wastewater 1 is once guided to a regulating tank 2, where sludge 3 is settled and separated from the wastewater 1, and the upper supernatant liquid It is sent to the reaction tank 5 by the pump 4. An appropriate amount of a carrier 6 having a specific gravity of more than 1 such as sand, activated carbon, anthracite, etc. is charged into the reaction tank 5 and an air lift pipe 7 is provided upright along the longitudinal direction of the reaction tank 5. Has been done. Air is supplied to the reaction vessel 5 from an external pressurized air source 8 to an air diffuser 9 installed at the bottom of the reaction vessel, whereby air bubbles 10 generated from the air diffuser 8 cause the carrier 6 to flow. After the organic substances contained in the wastewater are removed by the aerobic microorganisms formed on the surface of the carrier, the treated water 11 is discharged from the reaction tank 5 to the river.

By the way, a biofilm is formed on the surface of the carrier 6 along with the above wastewater treatment.
12 is formed, but if this biofilm 12 is excessively formed, the treatment efficiency is significantly reduced. Therefore, the carrier 6 on which the excess biofilm 12 is deposited is collected from the inside of the gas-liquid separation cylinder 13 above the reaction tank 5 by the transportation means 14 such as a pump and sent to the regeneration mechanism 15,
The excess biofilm 12 is forcibly peeled off by stirring with a stirring device, and the peeled biofilm 12 is sent again from the wastewater line to the adjusting tank 2, while the carrier 6 from which the biofilm 12 has been peeled off is regenerated by a regeneration mechanism. It is configured to return from 15 to the inside of the reaction tank 5 through the pipe body 16 and the gas-liquid separation cylinder 13 again.

(Problems to be Solved by the Invention) However, the above-described conventional carrier regenerating means is the transportation means 14
The carrier 6 is scraped by the pump, or the carriers 6 collide with each other during the stirring process of the regeneration mechanism 15, and the carrier 6 is extremely damaged. For this reason, all the carriers 6 may be replaced or the carriers 6 may be replaced at relatively constant intervals.
It is necessary to replenish a part of In addition, the playback mechanism 15
The carrier 6 regenerated in step 1 is sent to the reaction tank 5 through the pipe body 16. At this time, the regeneration mechanism 15 and the flow path of the pipe body 16 are blocked by the carrier 6 and troubles frequently occur. There was a drawback.

The present invention has been made to improve the above problems,
Biofilm can be easily removed from the carrier without damaging the carrier,
Another object of the present invention is to provide a wastewater treatment device that appropriately discharges the wastewater containing the separated biofilm.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an air lift pipe from the upper reaction part to the upper precipitation part, and a gas-liquid extending upward from the outside of the upper part of the air lift pipe. It has a reaction tank arranged in the order of a separating cylinder, and while the carrier having a specific gravity of more than 1 is made to flow by the bubbles sent from the outside into the air lift pipe of the reaction tank, the water to be treated is treated with aerobic microorganisms on the surface of the carrier. After the treatment, the treated water is discharged to the outside of the reaction tank through the overflow groove provided outside the gas-liquid separation cylinder, and the suspension of the treatment result is precipitated in the settling section below the overflow groove to carry out the reaction. In a wastewater treatment device that discharges to the outside of the tank, a gas-liquid separation cylinder of different diameter type with an upper cross-sectional area smaller than the lower cross-sectional area is used, and an opening / closing valve for opening and closing the discharge line of the treated water is provided. Close the valve and inside the reaction tank A wastewater treatment device that raises the liquid surface to a small area above the gas-liquid separation cylinder and removes excess biofilm accumulated on the surface of the carrier by causing turbulence due to concentration and disappearance of the bubbles in this small area. Is.

Further, according to the present invention, at least a normally-opening on-off valve and a first normally-closing on-off valve are provided in a line which outputs from a reaction tank position corresponding to the overflow groove, and the suspension is settled at the settling section. A second normally-closed on-off valve is provided in the line that outputs from the corresponding reaction tank position, and the normally-opened on-off valve is closed when excess biofilm is removed from the carrier and when sludge is discharged.
The normally closed on-off valves are opened for a required time, and the liquid and the like flowing out from these normally closed on-off valves are discharged to the same line or different lines depending on the suspension state.

(Operation) Therefore, according to the present invention, by taking the means as described above, in the first aspect of the invention, when air is supplied from the outside to the bottom of the reaction tank, the bubbles rise through the inside of the air lift pipe. However, at this time, the water to be treated is treated by the aerobic microorganisms on the surface of the carrier while the carrier moves upward due to the bubbles. Among them, the treated water is discharged to the outside through the open / close valve, while the suspension is settled in the settling section. Then, when the biofilm is excessively formed on the carrier due to the wastewater treatment, the on-off valve is closed to raise the liquid level in the reaction tank from the large area at the lower part to the small area at the upper part of the bubble separation tube. Then, turbulence is generated on the lower side of the small area due to concentration and disappearance of air bubbles, which easily separates the biofilm from the surface of the carrier.

Next, according to claim 2, when the excessive biofilm on the surface of the carrier is removed and the sludge is discharged, when the normally open on-off valve of the output line from the reaction tank position corresponding to the overflow groove is closed, The liquid level in the tank rises from the large area in the lower part to the small area in the upper part of the bubble separation cylinder, where turbulent flow occurs due to the concentration and disappearance of the bubbles, and the biofilm separates from the carrier surface. After that, when the normally-closed on-off valve of the output line at the reaction tank position corresponding to the overflow groove and the sedimentation part is opened at different times, the suspension containing the biofilm and the suspension are normally closed separately. It can be discharged to different lines depending on the suspended state through the on-off valve.

(Example) Hereinafter, the Example of this invention is described with reference to drawings. FIG. 1 is a block diagram showing an embodiment of the present invention,
This device took in via an on-off valve 24 an adjusting tank 23 for temporarily storing the wastewater 21 coming through the pipeline 20 and settling and separating the sludge 22, and the sludge 22 settling at the bottom of the adjusting tank 23. After that, it is temporarily stored and separated into sludge 25a and supernatant 25b.
The boil is returned to the pipe 20 by the pump 26, and the sludge 25a is discharged to the outside through the opening / closing valve 27, and the pump 29.
The reaction system 30 for treating the supernatant liquid in the adjusting tank 23, that is, the waste water, which is sent from the aerobic microorganisms, and the reaction system
The discharge control means 50 controls the discharge of the treated water and the suspension obtained by the treatment of 30.

The reaction system 30 has a bottomed cylindrical reaction tank 31 having a funnel portion 31a having a wide angle in an upper direction in an intermediate portion and forming tubular portions 31b and 31c on the lower side and the upper side with the funnel portion 31a interposed therebetween. A disk-shaped air diffuser 32 is installed at the inner bottom of the reaction tank 31, and the air lift pipe 33 and the air lift pipe 33 are provided inside the reaction tank 31 from the lower tubular portion 31b to the funnel portion 31a. A gas-liquid separation cylinder 34 extending upward is provided so as to cover the outside of the upper part with a predetermined gap. The gas-liquid separating cylinder 34 has a lower portion formed into a cylindrical portion 34a having a large cross-sectional area, and an upper end portion of the cylindrical portion 34a is provided with an inverted funnel portion 34b and a cylindrical portion 34c having a small cross-sectional area. Part gas-liquid separation cylinder 34
Are configured.

The inside of the lower tubular portion 31b of the reaction tank 31 including the inside of the air lift pipe 33 constitutes the reaction portion, while the funnel portion 31
a, a precipitation part is formed from the inside of the upper tubular part 31c to the outside of the gas-liquid separation tube 34. Furthermore, sand, activated carbon,
A carrier 35 such as anthracite having a specific gravity of more than 1 is charged, for example, about 1 to 10% of the volume of the reaction section, and bubbles 37 generated from the air diffuser 32 by the air sent from the external pressurized air source 36. The carrier 35 is made to flow from the lower side to the upper side inside the air lift pipe 33 by this treatment, and the organic matter contained in the wastewater supplied from the pump 29 is treated and removed by the aerobic microorganisms on the surface of the carrier 35, and the inside of the lower portion of the upper tubular portion 31c Overflow groove 3 provided in
It is configured to release treated water 39 from 8 to the outside.

In the discharge control means 50, the first level sensor is provided at the precipitation portion.
51, a second level sensor 52 is arranged on the upper side thereof, a pipe 53 is connected from the upper cylindrical portion 31c of the reaction tank 31 to the pipe 20, and the outside of the reaction tank 31 corresponding to the overflow groove 38. Parallel to the position via the normally open on-off valve 54 and the normally-closed on-off valve 55, respectively connected to the treated water discharge line 56 and the pipe line 20, and further outside the reaction tank 31 corresponding to the precipitation part, that is, the funnel part. 31a is connected to the conduit 20 or the concentration tank 28 as shown by the dotted line in the drawing through a normally-closed on-off valve 57. The level sensors 51, 52 and the open / close valves 54, 55, 57 are connected to a control unit 58. The control unit 58 has a function of controlling the opening / closing valves 54,5, 57, etc. for a predetermined time while receiving the outputs of the level sensors 51, 52 according to the normal operation, the removal of the biofilm from the carrier, and the like.

Next, the operation of the apparatus configured as described above will be described separately with reference to FIG. 2 in the normal operation step, the biofilm removal step, the sludge removal step, the restoration step, and the like.

(1) Normal operation step This step is a step of removing organic matter in the wastewater 21, and is a step of growing the biofilm 40 on the surface of the carrier 3. First, the supernatant liquid, which is waste water, is sent from the adjusting tank 23 to the reaction tank 31 by the pump 29. At this time, an external pressurized air source is used.
Air bubbles from 36 through the air diffuser 32 to the inside lower part of the air lift pipe 33
Raise 37. Then, the bubbles 37 cause the carrier 35
The organic substances in the wastewater are treated and removed by the aerobic microorganisms on the surface of the carrier while flowing inside the air lift pipe 33, and at the same time, the biofilm 40 grows on the surface of the carrier 35 during this treatment. At this time, since the on-off valve 54 is opened by the command from the control unit 58, the treated water 39 obtained by the above-mentioned treatment is the overflow groove 38.
Is discharged from the treated water discharge line 56 through the on-off valve 54. Therefore, during this normal operation, the liquid surface of the reaction tank 31 is an overflow surface regulated by the overflow groove 38 located in the large area tubular portion 34a of the different-diameter type gas-liquid separation tube 34.

On the other hand, during this normal operation, the air lift pipe is installed inside the reaction tank 31.
33 Bubbles 37 move upwards inside 33
35 also rises. Then, the bubbles 37 disappear in the large area tubular portion 34a of the gas-liquid separation tube 34. As a result, the carrier 35 goes over the upper end of the air lift pipe 33 and descends to the outside of the air lift pipe. Thus, in the reaction tank 31, sufficient agitation and oxygen supply are performed, aerobic microorganisms that feed on the organic matter in the waste water grow, and the biofilm formed by these aerobic microorganisms on the carrier surface.
Grows gradually. In the settling section, the biofilm 40 containing the suspension rising from the reaction section, the suspended solids such as suspended microorganisms 4
1 separates and floats, and the supernatant liquid from the overflow groove 38 is treated water 3
Emitted as 0.

(2) Biofilm removal step This step is a step of periodically peeling off the biofilm 40 excessively grown on the surface of the carrier 35, and the control section 58 sets a predetermined date and time, for example, every day at 23:00 as shown in step S1. It is determined whether or not the time has reached 00, and when it reaches 23:00, the on-off valve 54 is closed (step S2). Since the pump 29 is operating even when the on-off valve 54 is closed, the liquid level in the reaction tank 31 rises, and when the liquid level reaches the level sensor 52, a timer (not shown) in the control unit 58. Is activated (steps S3, S4). The liquid level gradually rises until this timer is activated and a predetermined time t1 elapses. At this time, the liquid in the reaction tank 31 is sent to the adjustment tank 23 through the conduit 53.

Then, as the liquid level in the reaction tank 31 rises, the liquid level moves from the large-area tubular portion 34a of the gas-liquid separation tube 34 to the small-area tubular portion 34c through the reverse funnel portion 34b. As a result, the bubbles 37 rising from the lower side inside the air lift pipe 33 are generated in the small area tubular portion 34c.
Repeatedly disappearing bubbles 37 while concentrating with the reverse funnel 34b
And violent turbulence is generated underneath. As a result, the biofilm 40 on the surface of the carrier 35 is subjected to a large shearing force due to the concentration and turbulence of the bubbles 38, and the biofilm 40 is easily separated from the carrier 35. The separated biofilm 40 is deposited with the suspension 40 in the lower part of the precipitation part, while the regenerated carrier 35 is automatically collected in the reaction part. At the settling point, the suspension 41 increases and the turbidity of the supernatant increases (suspends).

(3) Sludge discharge step This step is a step of discharging the upper layer suspension and the lower layer suspension 41 of the precipitation portion generated in the above step (2) as waste liquid.
Specifically, as shown in step S5, the timer is set to the predetermined time t1.
When a predetermined time t1 has elapsed, the open / close valve 55 is first opened while the open / close valve 54 is closed by a command from the control unit 58, and a timer is started (step
S6). Here, when the opening / closing valve 55 is opened, the upper layer suspension of the precipitation portion is sent to the adjusting tank 23 through the opening / closing valve 55. Then, due to the discharge of the suspension, the liquid surface descends to the overflow groove 38, that is, from the small area tubular portion 34c of the gas-liquid separation tube 34 to the large area tubular portion 34a, so that the turbulent flow is eliminated and the organism The peeling action of the film 40 stops. Thereafter, when the timer elapses a predetermined time t2 as in step S7, the opening / closing valve 55 is closed and the opening / closing valve 57 is opened (step S8). Then, the lower suspension of the precipitation part
41 is sent to the adjustment tank 23 or the concentration tank 28 through the opening / closing valve 57. Usually, this suspension 41 has sludge in a concentrated state,
It is desirable to send it to the concentration tank 28. In this way suspension 41
When is discharged, the liquid level in the reaction tank 31 is further lowered, but at this time, the control unit 58 monitors the output of the level sensor 51.

(4) Returning Step Here, the control unit 58 determines that the liquid level of the reaction tank 31 has reached a predetermined level from the output of the level sensor 51 (step S
9), the opening / closing valve 57 is closed and at the same time the opening / closing valve 54 is opened (step S10). At this time, since the pump 29 is operating, when the liquid level of the reaction tank 31 gradually rises and reaches the overflow groove 38, the above-mentioned normal operation process is started. Therefore, this step is a step of clarifying the upper layer of the precipitation part.

Therefore, according to the configuration of the above embodiment, the lower side is the large area tubular portion 34a, the upper side is the small area tubular portion 34c, the carrier 3
5 When removing the excess biofilm on the surface, by moving the liquid surface of the reaction tank 31 from the large-area tubular portion 34a to the small-area tubular portion 34c, the bubbles 37 from the air diffuser 32 have a small-area tubular shape. The defoaming operation is repeated while concentrating at the portion 34c, and turbulent flow is generated on the lower side thereof, and the biofilm 40 can be easily separated from the surface of the carrier 35 by the concentration, defoaming, turbulent flow, etc. of the bubbles 37. Moreover, since the gas-liquid separation cylinder 34 is simply a different diameter type,
The biofilm 40 can be peeled off in a very simple and inexpensive structure. Further, since the carrier 35 from which the biofilm 40 has been peeled off is directly recovered in the reaction section,
The carrier 35 can be regenerated in a completely original size without the trouble that the carrier 35 is broken and damaged by the transportation means 14 and the regenerating mechanism 15 and the pipeline is blocked by the carrier 35 unlike the conventional case.

Furthermore, after raising the liquid level in the reaction tank 31, each on-off valve 55, 5
Since 7 is discharged to the outside while opening in a predetermined order, the upper layer suspension and the lower layer suspension of the precipitation part can be separately discharged, and if they are separately sent to the adjusting tank 23 and the concentration tank 28, It contributes to the improvement of the efficiency of wastewater treatment, and normal operation can be resumed in the clear liquid state when returning.

Although the cylindrical reaction tank 31 is used in the above embodiment, the sectional shape is not particularly limited. Also, a gas-liquid separation cylinder
The reverse funnel 34b is provided in the middle of the 34, but the large area tubular portion 3
4a and the small area tubular portion 34c may be formed alone, or the upper portion may be the small area tubular portion 34c and the reverse funnel portion 34b may be provided at the lower end thereof.
It is also possible to use only the structure. In addition, the present invention can be modified in various ways without departing from the scope of the invention.

[Effects of the Invention] As described above, according to the present invention, the following various effects are achieved.

First, in claim 1, the biofilm can be removed from the surface of the carrier with a simple structure, and further, the biofilm can be removed in the reaction tank, and the regenerated carrier can be directly recovered in the reaction section. It can be regenerated as before without damaging the carrier.

Next, according to claim 2, the biofilm and the suspended matter, which are separated from the carrier, can be appropriately discharged, and can be appropriately sorted and discharged according to the suspended state, which greatly contributes to the improvement of the efficiency of wastewater treatment. Can be made.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a wastewater treatment apparatus according to the present invention, FIG. 2 is a flow chart for explaining the overall operation of the apparatus of FIG. 1, and FIG. 3 is a block diagram of a conventional apparatus. 21 …… waste water, 23 …… adjustment tank, 28 …… concentration tank, 30 …… reaction system, 31 …… reaction tank, 32 …… air diffuser, 33 …… air lift pipe, 34 …… gas-liquid separation cylinder, 34a …… Large area tubular part, 34b ……
Reverse funnel part, 34c ... Small area tubular part, 35 ... Carrier, 37 ...
… Bubbles, 38 …… Overflow groove, 39 …… Treatment liquid, 40 …… Biofilm,
41 …… Suspended matter, 50 …… Discharge control means, 51, 52 …… Level sensor, 54, 55, 57 …… Open / close valve, 58 …… Control section.

Claims (2)

[Claims] 1. A reaction vessel having an air lift pipe and a gas-liquid separation cylinder extending from the upper outer side to the upper side of the air lift pipe from the lower side reaction section to the upper side precipitation section, and the air lift of the reaction tank from the outside. The treated water is treated with aerobic microorganisms on the surface of the carrier while flowing the carrier with a specific gravity of more than 1 by the bubbles sent to the inside of the pipe, and the treated water reacts from the overflow groove provided outside the gas-liquid separation cylinder. Released to the outside of the tank,
Further, in the wastewater treatment device for precipitating the suspension of the treatment result in the precipitation part in the lower part of the overflow groove and discharging it to the outside of the reaction tank, the gas-liquid of different diameter type in which the upper cross-sectional area is smaller than the lower cross-sectional area. A separation cylinder is used and an on-off valve for opening and closing the treated water discharge line is provided, and the on-off valve is closed to raise the liquid level inside the reaction tank to a small area above the gas-liquid separation cylinder. A wastewater treatment device, characterized in that a turbulent flow due to concentration, defoaming, etc. of the bubbles is caused in a portion to remove an excessive biofilm deposited on the surface of the carrier. 2. An air lift pipe having an air lift pipe and a gas-liquid separating cylinder extending from the upper outside of the air lift pipe to the upper side in this order from the lower side reaction part to the upper side precipitation part, and the air lift of the reaction tank from the outside. The treated water is treated with aerobic microorganisms on the surface of the carrier while flowing the carrier with a specific gravity of more than 1 by the bubbles sent to the inside of the pipe, and the treated water reacts from the overflow groove provided outside the gas-liquid separation cylinder. Released to the outside of the tank,
In addition, in the wastewater treatment device that precipitates the suspension of the treatment result in the settling section at the lower part of the overflow groove and discharges it to the outside of the reaction tank, at least in the line that outputs from the reaction tank position corresponding to the overflow groove. An opening and closing valve for opening and a first closing valve for normally closing are provided, and a second opening and closing valve for normally closing is provided in a line which outputs from the reaction tank position corresponding to the sedimentation portion where the suspension precipitates. Liquid that flows out from these normally closed on-off valves by closing the normally-opening on-off valves and removing the first and second normally-closing on-off valves for the required time when removing excess biofilm on the carrier surface and during sludge discharge And the like are discharged to the same line or different lines depending on the state of suspension.