JP3895064B2 - Aggregation floc storage and collection device, aggregation filtration device, and aggregation floc capture and recovery method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a coagulation filtration apparatus suitable for adding a flocculant to secondary treated water and removing suspended matters in the secondary treated water, and a method for capturing and recovering the aggregated floc.
[0002]
[Prior art]
Conventionally, when a flocculant is added to secondary treated water to remove suspended matter in the secondary treated water (hereinafter referred to as SS) and phosphorus components contained in the secondary treated water, solid-liquid separation is usually performed by the coagulation precipitation method. Is done.
This coagulation sedimentation apparatus is a combination of a coagulation tank having a two-chamber structure consisting of a rapid stirring chamber and a slow stirring chamber, and an aggregation precipitation tank. First, raw water and a coagulant are mixed in the rapid stirring chamber of the coagulation tank, Next, flocs are grown in the slow stirring chamber of the coagulation tank, and the coagulation flocs are gravity settled in the coagulation sedimentation tank.
[0003]
Therefore, in addition to requiring a separate processing tank, solid-liquid processing is performed by precipitating and separating the floc that has been agglomerated in the aggregation precipitation tank over time. Must be included.
[0004]
In this regard, in the case of the agglomerated biological filtration device described in Japanese Patent No. 2635866, raw water to which a flocculant is added is introduced from the lower part of the filtration tank based on the filtration tank filled with the filter medium. A treatment water discharge device is installed at the upper part of the bed, and water is passed upward from the lower part, and aeration is performed by aeration air. Satisfies the demand for
[0005]
[Problems to be solved by the invention]
However, in the case of the above-described biological filtration apparatus, in order to collect the flocs captured in the filter layer, after aeration with backwash air supplied from the lower part of the filtration tank, backwash water is also supplied from the lower part. Thus, the backwash sludge drainage is discharged from the upper part of the filter layer.
[0006]
Therefore, it is necessary to inject backwash water every time backwashing is performed, and the discharged backwash sludge treated water is diluted and increased, and the sludge concentration storage tank of the post-treatment tank is increased. Detrimental effects of increasing the capacity, increasing the load on the post-treatment tank, or reducing the wastewater treatment efficiency by returning the desorbed liquid to the previous process more than necessary for reprocessing. There is.
[0007]
In addition, since flocs trapped in the filter layer are biologically processed by aeration with air for aeration, flocs that have been flocked and flowed into the filter tank are dispersed by aeration from the aeration device, leading to flock destruction. It also becomes.
[0008]
Therefore, in the present invention, although it is a single tank, it is possible to efficiently capture the flocs without causing formation of flocs and destruction of the formed flocs, and the captured flocs can be efficiently collected. In addition, the present invention has invented a coagulation filtration device that does not require backwashing water by providing a tank structure that can be recovered and allowing only air backwashing during backwashing.
[0009]
[Means for Solving the Problems]
Specifically, in claim 1, a mixed liquid containing flocculant as an upward flow from a latent flow port at a lower end portion of the flocculant layer while allowing flocification to proceed while downflowing raw water to which the flocculant is added, and a mixed liquid The filter tank is provided in a donut shape on the outer periphery of the agglomerated layer, and the floc is captured and stored in the lower part of the filter tank, and this is stored in the sludge cake layer. And a first partition net to be formed, and a second partition net for capturing and storing flocks at a position above the first partition net and forming it into a sludge cake layer, A filter layer chamber is provided above the second partition net, and a third partition net is provided at the lower part of the filter layer chamber, and a filter medium is filled on the third partition net. Sea urchin to configure.
[0016]
In addition, in terms of the method, in claim 2, the flocculant is added to the raw water and stirred to advance the floc, while the mixed liquid containing the flocs floc is flowed downward in the flocculant tank, Next, the mixed liquid containing the coagulation floc is caused to flow into the filtration tank so as to be pushed out from the lower end portion of the coagulation tank, and then the mixed liquid containing the aggregation floc is passed through the filtration tank as an upward flow. The method of coagulation filtration, wherein the liquid mixture containing the coagulation flocs is caused to flow upward from the first partition net, through the second partition net, and through the third partition net, In this case, the aggregated floc is precipitated and captured at the upper part of the first and second partition nets, and the captured aggregated floc is placed on the upper part of the first and second partition nets. There thereby formed into the sludge cake layer, then filtered mixture containing flocs by the sludge cake layer.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the coagulation filtration tank S according to the present invention will be described based on a longitudinal sectional view of FIG. 1 showing a state embedded in the ground and a plan view of FIG.
The agglomeration filtration tank S is composed of a cylindrical agglomeration tank A vertically supported at the center of the tank, and a flat donut-like filtration tank B on the outer periphery thereof.
[0020]
Reference numeral 1 denotes a main body wall of the coagulation filtration tank S, which uses a ready-made concrete product molded into a cylindrical shape, but it can be formed into a bottomed rectangular tube shape or made of FRP. Reference numeral 2 denotes a bottom wall of the coagulation filtration tank S, which has a hopper shape with a downward slope toward the center of the tank, and a discharge pump 4 is installed in a recess 3 that is recessed at the center position.
[0021]
An inflow pipe 5 for secondary treated water, which is raw water, is provided with a flocculant injection pipe 6 in the middle of the pipe, and a pipe joint 7 at the end of the advection pipe 5 is connected to the upper end of the coagulation tank A. I'm facing the club.
8 is a flocculant tank, 9 is an air supply pipe attached to the upper edge of the flocculant tank A, and the air diffuser 10 formed at the lower end of the flocculant tank A is submerged in the liquid of the surface layer portion of the flocculant tank A. .
[0022]
The agglomeration tank A is formed of a hollow tube made of FRP or vinyl chloride, and its lower end opening 11 faces a position directly above the recess 3 in the central part of the aggregation filtration tank S. Reference numeral 12 denotes a process water submergence port including a coagulation flock that penetrates from the lower end edge of the coagulation tank A to the filtration tank B.
[0023]
13 and 14 are partition nets that perform the function of capturing and storing the coagulation floc X that is coagulated in the coagulation tank A and flows upward from the latent flow port 12, and has a mesh of about # 20 to 30. Is supported in a stretched manner at a vertical position at a lower position of the filtration tank B corresponding to the lower outer position. The partition nets 13 and 14 and the partition net for filter medium sedimentation described later are composed of a rectangular inner frame 21 at the inner position and a polygon outer frame 22 at the outer position shown in the plan view of FIG. It is stretched and attached to the upper part of the formed base F.
Reference numeral 15 denotes a backwashing device, which is piped in a rectangular shape at a lower position of the gantry F that supports the partition nets 13 and 14.
[0024]
Reference numeral 16 denotes a partition net for preventing sedimentation of the filter medium, which is formed in a filter tank B corresponding to a height position on the upper side from the middle part of the aggregation tank A, and is filled with the filter medium Z on the upper side of the partition net 16. ing.
As the filter medium Z, in this embodiment, a plastic hollow container having a capacity of about several tens of cc and a specific gravity slightly larger than the specific gravity of water 1 is adopted.
Reference numeral 20 denotes a backwashing device in which a rectangular pipe is provided at a lower position of the gantry F that supports the partition net 16 for preventing the filter medium sedimentation.
[0025]
Reference numeral 17 denotes a tubular water collecting device, which is piped in a polygonal shape in the water of the supernatant liquid that has flowed out to the surface layer portion of the filter medium Z, and the overflow port 18 of the supernatant liquid faces upward in four directions of the water collecting device 17. It is open. Reference numeral 19 denotes a drainage pipe for the supernatant liquid flowing into the water collecting device 17 from the overflow port 18.
[0026]
Accordingly, in the filtration tank B partitioned as described above, the bottom chamber B1 is provided between the bottom wall 3 and the lowermost partition net 13 and the first stage partition net 13 and the second upper partition net 13 are provided. The first flock storage chamber B2 is between the partition net 14 and the second flock storage chamber B3 is between the second stage partition net 14 and the filter net sediment prevention partition net 16 at the upper part thereof. In the upper part, a filter bed chamber B4 filled with a filter medium Z on the partition net 16 is formed, and a supernatant discharge chamber B5 is formed in the upper part of the filter bed chamber B4.
[0027]
Next, the process steps of the aggregation filtration in the present invention will be described.
(Aggregation treatment)
First, secondary treated water to which the flocculant is added from the flocculant tank 8 flows into the flocculation tank A in the middle of the inflow pipe 5 of the raw water.
Then, the secondary treatment water and the flocculant that flowed in are bubbled by the jet from the air diffuser 10, so that the mixed liquid is uniformly stirred, and the flocculant treatment for the mixed liquid is promoted. In the process of gradually flowing down the agglomeration tank A as a downward flow, the flocculation proceeds by gradually taking in the SS in the secondary treated water and the phosphorus component in the treated water.
[0028]
The mixed liquid containing the coagulation floc X thus coagulated passes through the latent flow port 12 of the lower end opening 11 of the coagulation tank A, flows into the bottom chamber B1 of the filtration tank B, and turns to an upward flow. Ascend the filtration tank B.
[0029]
Then, the floating and sedimentation state of various large and small aggregated floc X contained in the mixed liquid rising in the filtration tank B will be described based on the enlarged schematic diagram of FIG.
[0030]
(First stage filtration)
First, when the aggregated floc X passes through the partition net 13 in the lowermost stage (first stage), that is, when the aggregated floc X passes through the mesh of the partition net 13, it adheres to the mesh of the partition net 13. The sludge is caught by being entangled as a seed, and a part of the sludge passes through the partition net 13 and gently rises in the first flock chamber B2.
Along with this floating, a part of the fine floc X is re-aggregated and formed into a floc lump having a settled particle diameter so that it gradually settles and settles on top of the first stage partition net 13. The layered sludge cake layer Y1 is formed on the partition net 13 after being stored.
[0031]
Further, the flocs floc X that floats one after another from the bottom chamber B1 passes through the mesh of the partition net 13, and the sludge cake layer Y1 deposited thereon takes in the flocs floc X that is going to dive through and float. It is captured by coalescence.
In other words, the sludge cake layer Y1 having the partition net 13 as a core is attached while performing a filtering function as a filter of the aggregated floc X that is about to float and pass.
Further, a part of the fine floc X passes without being captured by the sludge cake layer Y1 or is separated and floats or floats in the first floc storage chamber B2 in the same manner as described above. Is settled by reaggregating into a floc lump having a settled particle diameter and deposited on the sludge cake layer Y1.
[0032]
(Second stage filtration)
Next, a part of the fine floc X that floats up in the first floc storage chamber B2 uses the sludge adhering to the mesh of the partition net 14 as a seed when it passes through the mesh of the partition net 14 of the second stage. It is caught by being entangled, and a part thereof passes through the partition net 14 and gently rises in the second flock chamber B3.
Along with this floating, a part of the fine floc X is re-aggregated and formed into a floc lump having a precipitated particle size, and settles, and settles and is stored on the upper part of the partition net 14 in the second stage. Eventually, a layered sludge cake layer Y2 is formed on the partition net 14.
[0033]
Further, the aggregated floc X that floats in the first floc storage chamber B2 passes through the mesh of the partition net 14, and the sludge cake layer Y deposited thereon takes in the aggregated floc X that is about to sink through and float up. Is captured and integrated. In other words, the sludge cake layer Y2 floats and functions as a filter of the aggregated floc X that is about to pass through, and is subjected to filtration treatment and coalescence.
Further, a part of the fine floc X passes without being captured by the sludge cake layer Y2 or is separated and floats in the second floc storage chamber B3 as described above, or floats and settles. It settles by being re-agglomerated into a floc lump having a particle size, and is deposited on the sludge cake layer Y2.
[0034]
(Third stage filtration)
A part of the fine floc X that has floated to the second floc storage chamber B3 passes through the mesh of the partition net 16 for preventing the filter medium sedimentation, and is trapped between the filter medium Z filled in the filter layer B4 and inside the filter medium Z and filtered. Provided for processing.
The tertiary treated water thus filtered flows out into the supernatant chamber B5 of the supernatant of the surface layer portion, and flows into the water collecting device 17 from the overflow port 18 to be drained.
[0035]
As the agglomeration filtration process as described above is repeated, the thickness of the sludge cake layers Y1 and Y2 stored in the upper part of the first stage partition net 13 and the second stage partition net 14 is further increased. The filter effect is gradually reduced by the aggregated floc X trapped between the filter media sediment prevention partition net 16 and the filter medium Z, and the trapping efficiency and storage efficiency of the aggregated floc X are gradually decreased.
[0036]
(Sludge collection processing)
At this stage, by operating the discharge pump 4, the mixed liquid containing the coagulation flock of the coagulation filtration tank S and the stored sludge cake can be ½ to 2 times the tank capacity at an appropriate suction speed. Pull out about 3/3.
Then, the sludge in the bottom chamber B1 and the sludge in the sludge cake layers Y1 and Y2 having the partition nets 13 and 14 as the core are drawn down and returned to the flow rate adjustment tank in the previous process for reprocessing. Or it is used for the solid-liquid process of the liquid mixture containing the aggregation floc X by sending out to the sludge sediment storage tank of a post process.
[0037]
Further, in the case of the floc X captured by the filter medium Z in the filter layer chamber B4, the floc X is pumped out toward the second flock storage chamber B3 and the first flock storage chamber B2 on the lower side, and the second flock storage chamber B3. The sludge cake Y2 is pumped out toward the first floc storage chamber B2 and the bottom chamber B1, and is used for floc capture and filtration processing in the next and subsequent times.
Further, in the case of the sludge cake Y1 in the first floc storage chamber B2 and the accumulated sludge in the bottom chamber B1, the entire amount is pumped out and sent to the flow rate adjusting tank or the sludge sedimentation storage tank.
[0038]
(Back washing process)
As the collection process of the mixed liquid containing sludge as described above is repeated about several times per day, the collection efficiency gradually decreases, and it is necessary to back-wash the filtration tank B at a rate of about once a week. Arise. In that case, the backwashing air is jetted out from the backwashing devices 15 and 20 and the inside of the tank is aerated and agitated, and then the entire amount of the backwashed sewage is pumped out by the discharge pump 4, Send to sludge concentration storage tank.
[0039]
[Modification]
In the case of the above-described embodiment, the two partition nets 13 and 14 are formed at a lower position of the filtration tank B with a space therebetween in the vertical direction, but this is simply one, or three or more. It is possible to adjust the trapping efficiency of the floc floc X by adjusting the vertical distance, or to adjust the extraction efficiency of the sludge cake. Of course, it depends on the size of the mesh of the partition nets 13, 14, 16, so that the size of the mesh can be a large, medium and small mesh structure for each of the partition nets 13, 14, 16.
[0040]
Moreover, in the case of the said embodiment, although the discharge pump 4 was installed in the hollow 3, the discharge pump 4 is installed outside the tank, and the suction port of the suction hose or the suction pipe (not shown) is formed in the hollow 3. You can make it come.
[0041]
In the case of the above embodiment, the supernatant water collecting device 17 is piped to the spring chamber B5 with a polygonal tube, but it is used as a water collecting tank or at the outer peripheral position of the spring chamber B5. A catchment can also be provided on the inner periphery of the main body wall 1.
[0042]
In the case of the above-described embodiment, the flocculant supply pipe 6 is provided in the middle of the raw water inflow pipe 5, but the lower end supply port of the supply pipe 6 is connected to the upper end opening of the flocculant tank A and the pipe joint. 7 can also be faced directly.
[0043]
【The invention's effect】
The present invention is configured as described above, and among them, in claim 1, in the flocculation filtration apparatus in which the treated water is allowed to flow in an upward flow into a filtration tank provided with a filter layer filled with a filter medium, A partition net that captures and stores agglomerated flocs is provided at the lower position of the filtration tank, and a floc storage chamber is provided on the upper side of the flocs that floats to form a settled particle size and settles. However, the fine flocs that pass through the partition net and float to the floc storage chamber are re-agglomerated and settled to form a floc lump. The sludge cake can be stored in layers.
In addition, the fine flocs that have escaped from the partition net and floated up are finally captured by the filter layer in the upper layer of the filtration tank and used for the filtration process, so the number of backwashes to prevent the filter layer from clogging is reduced. Significantly reduce operating costs.
[0044]
Further, in claim 2, since the mixed liquid containing the sludge cake stored with the partition net as a core and the floc captured in the filter layer is pumped down by the discharge pump, the useful liquid is used. In addition to the properties, the liquid mixture containing sludge cake trapped in the partition net and stored in layers, that is, the liquid mixture containing a large amount of coagulated floc is returned to the flow control tank for reprocessing. Or sent to a sludge concentration storage tank and subjected to solid-liquid separation by gravity sedimentation or the like, thereby significantly improving solid-liquid separation efficiency.
[0045]
Further, in claim 3, since the plurality of partition nets are provided at the lower position of the filtration tank and spaced apart from each other in the vertical direction, the collection efficiency and the storage efficiency of the aggregated flocs having the plurality of partition nets as a core are increased. Further improve the storage of sludge cake.
[0046]
According to a fourth aspect of the present invention, the raw water to which the flocculant is added is stirred by bubbling and descended in a downward flow, whereby the flocculant tank that promotes the formation of the floc flocs is Provided with a filtration tank of a mixed liquid containing agglomerated floc that rises as a flow, provided with a partition net for preventing filter material settling at the upper position of the filter tank, and forming a filter layer filled with the filter medium on the partition net; A partition net that captures the aggregated flocs is provided in multiple stages at the lower position of the filtration tank, a backwash device is provided at the lower position of the partition net and the partition nut for preventing sedimentation of the filter medium, and the mixed liquid containing the sludge cake is discharged by a discharge pump. It is a coagulation filtration device that pumps up.
Further, in claim 5, a coagulation tank having a bottom opening is provided at the center of the tank, an upward flow filtration tank is provided at an outer position of the coagulation tank, and the filtration tank is partitioned by a partition net with a vertical interval. The filtration tank is divided into a chamber from the bottom of the tank to a bottom chamber, a plurality of floc storage chambers, a filter layer chamber, and a supernatant discharge chamber, so that the tank structure of the tertiary treatment is remarkably reduced in size and size. Can bring various effects.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a coagulation filtration tank according to the present invention.
FIG. 2 is a plan view of a coagulation filtration tank.
FIG. 3 shows flocs trapped by two partition nets partitioned at the lower part of the filtration tank, sludge cake stored in layers on the nets, and floc storage through the net in an upward flow. It is a schematic diagram which shows the condition where the fine floc which floats up a chamber or floats is re-aggregated into the floc lump of a sedimentation particle size, and settles.
[Explanation of symbols]
S Coagulation filtration tank A Coagulation tank B Filtration tank B1 Bottom chamber B2 First flock storage chamber B3 Second frock storage chamber B4 Filtration chamber B5 Spring chamber F Base 1 Main body wall 2 Bottom wall 3 Depression 4 Discharge pump 5 Inflow pipe 6 Injection Pipe 7 Pipe joint 8 Coagulant tank 9 Air supply pipe 10 Air diffuser 11 Lower end opening 12 Submerged outlets 13, 14, 16 Partition nets 15, 20 Backwashing equipment 17 Water collecting device 18 Overflow port 19 Drain pipe 21 Inner frame 22 Outer frame 23 Connecting frame

Claims (2)

An agglomerated layer that advances flocking while lowering the raw water to which the aggregating agent is added;
In a flocculation filtration apparatus provided with a filtration tank that raises the mixed liquid containing the flocculation floc as an upward flow from the latent flow port at the lower end of the flocculation layer,
The filtration tank is provided in a donut shape on the outer periphery of the aggregated layer,
A first partition net that captures and stores the floc and forms it into a sludge cake layer is provided at the lower portion of the filtration tank, and the floc is captured and stored at a position above the first partition net. And providing a second partition net for forming this into a sludge cake layer,
Furthermore, a filter layer chamber is provided above the second partition net,
In addition, a third partition net is provided at the bottom of the filter bed chamber,
A coagulation filtration device characterized in that a filter medium is filled on the third partition net. While adding flocculant to raw water and stirring,
The mixed liquid containing the coagulation floc is made to flow downward in the coagulation tank,
Next, the mixed liquid containing the aggregation floc is caused to flow into the filtration tank so as to be extruded from the lower end of the aggregation tank,
Next, a coagulation filtration method in which the liquid mixture containing the coagulation floc is passed through the filtration tank as an upward flow,
The mixed liquid containing agglomerated flocs flows upward from the first partition net, through the second partition net, through the third partition net,
At that time, the aggregated floc is precipitated and captured at the upper part of the first and second partition nets, and each of the sludge cake layers is collected at the upper part of the first and second partition nets. Formed into
Then, the coagulation filtration method characterized by filtering the liquid mixture containing the coagulation floc by each sludge cake layer.

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