CA1331569C - Solid-liquid separator - Google Patents
Solid-liquid separatorInfo
- Publication number
- CA1331569C CA1331569C CA000614060A CA614060A CA1331569C CA 1331569 C CA1331569 C CA 1331569C CA 000614060 A CA000614060 A CA 000614060A CA 614060 A CA614060 A CA 614060A CA 1331569 C CA1331569 C CA 1331569C
- Authority
- CA
- Canada
- Prior art keywords
- filter medium
- solid
- waste water
- tank
- liquid separator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
- B01D24/02—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration
- B01D24/20—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof with the filter bed stationary during the filtration the filtering material being provided in an open container
- B01D24/26—Upward filtration
- B01D24/263—Upward filtration the filtering material being supported by pervious surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D24/00—Filters comprising loose filtering material, i.e. filtering material without any binder between the individual particles or fibres thereof
- B01D24/46—Regenerating the filtering material in the filter
- B01D24/4605—Regenerating the filtering material in the filter by scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer
- B01D24/4621—Regenerating the filtering material in the filter by scrapers, brushes, nozzles or the like placed on the cake-side of the stationary filtering material and only contacting the external layer by nozzles acting on the cake side of the filter material, or by fluids acting in co-current direction with the feed stream
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D36/00—Filter circuits or combinations of filters with other separating devices
- B01D36/04—Combinations of filters with settling tanks
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Filtration Of Liquid (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A solid-liquid separator for subjecting waste water to preliminary sedimentation in a sedimentation zone to separate solid matter from the waste water and then passing the waste water upward through a filter medium layer to remove SS (suspended solids) from the waste water.
A solid-liquid separator for subjecting waste water to preliminary sedimentation in a sedimentation zone to separate solid matter from the waste water and then passing the waste water upward through a filter medium layer to remove SS (suspended solids) from the waste water.
Description
~ 1~ ~
SOLID-LIQUID SEPARATOR
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a solid-liquid separator for a ;~
primary treatment of waste water containing solid matter.
Prior art methods of removing solid matter from waste water will be discussed hereinbelow in conjunction with the drawings.
SUMMARY OF THE INVENTION
This invention contemplates overcoming the above-10 mentioned problems involved in the prior art.
It is an object of this invention to provide a solid~
liquid separator for a primary treatment of waste water which has a high SS removal performance and has little possibility of clogging.
In accordance with one aspect of the invention there is provided a solid-liquid separator for a pretreatment of waste water of the upward flow type in which the waste water is introduced into a tank packed with a filter medium via an upper portion of the tank and is discharged from the tank via a lower portion of the tank, wherein a sedimentation zone comprising a space portion for sedimentation separation is provided on the lower side of a filter medium layer in the tank, and means for discharging the sedimented solid matter is provided in the sedimentation zone, and wherein said filter medium has a small cylindrical shape with a surface provided with numerous whisker-shaped protrusions. -', 1331~69 BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a flow sheet showing a sedimentation method according to the prior art;
Fig. 2 is a flow sheet showing the sand filtration method according to the prior art;
Fig. 3 is a flow sheet showing one embodiment of this invention; and Fig. 4 is an illustration of a small cylindrical filter medium.
~he conventional methods of removing solid matter contained in waste water, mostly, adopt the sedimentation method, shown in Fig. 1, as seen in sewage treatment plants.
In the figure, waste water containing solid matter is introduced into a sedimentation tank 100 via an upper portion of the tank, and is permitted to dwell in the tank for a predetermined time, while solid-liquid separation takes place.
The supernatant in the sedimentation tank 100 is discharged to the exterior as treated water.
Though the sedimentation method is an excellent and reasonable treating method, a large installation area is required for carrying out the method because it is impossible to obtain a high value of water surface area load. In addition, the SS (suspended solids) removal rates attainable by the sedimentation method have been about 30 to 60%. With the recent demand for a more efficient and compacter plant for sewage treatment, there has arisen a request for development of a solid-liquid separator with a higher performance. One ~ : .
SOLID-LIQUID SEPARATOR
BACKGROUND OF THE INVENTION
Field of the Invention This invention relates to a solid-liquid separator for a ;~
primary treatment of waste water containing solid matter.
Prior art methods of removing solid matter from waste water will be discussed hereinbelow in conjunction with the drawings.
SUMMARY OF THE INVENTION
This invention contemplates overcoming the above-10 mentioned problems involved in the prior art.
It is an object of this invention to provide a solid~
liquid separator for a primary treatment of waste water which has a high SS removal performance and has little possibility of clogging.
In accordance with one aspect of the invention there is provided a solid-liquid separator for a pretreatment of waste water of the upward flow type in which the waste water is introduced into a tank packed with a filter medium via an upper portion of the tank and is discharged from the tank via a lower portion of the tank, wherein a sedimentation zone comprising a space portion for sedimentation separation is provided on the lower side of a filter medium layer in the tank, and means for discharging the sedimented solid matter is provided in the sedimentation zone, and wherein said filter medium has a small cylindrical shape with a surface provided with numerous whisker-shaped protrusions. -', 1331~69 BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a flow sheet showing a sedimentation method according to the prior art;
Fig. 2 is a flow sheet showing the sand filtration method according to the prior art;
Fig. 3 is a flow sheet showing one embodiment of this invention; and Fig. 4 is an illustration of a small cylindrical filter medium.
~he conventional methods of removing solid matter contained in waste water, mostly, adopt the sedimentation method, shown in Fig. 1, as seen in sewage treatment plants.
In the figure, waste water containing solid matter is introduced into a sedimentation tank 100 via an upper portion of the tank, and is permitted to dwell in the tank for a predetermined time, while solid-liquid separation takes place.
The supernatant in the sedimentation tank 100 is discharged to the exterior as treated water.
Though the sedimentation method is an excellent and reasonable treating method, a large installation area is required for carrying out the method because it is impossible to obtain a high value of water surface area load. In addition, the SS (suspended solids) removal rates attainable by the sedimentation method have been about 30 to 60%. With the recent demand for a more efficient and compacter plant for sewage treatment, there has arisen a request for development of a solid-liquid separator with a higher performance. One ~ : .
3 ~
~? ~
example of such means for solid-liquid separation is a sand ~ -filtration method, as shown in Fig. 2.
In the figure, sand 102 is packed in a filtration tank 101 as a filter medium. Raw water, or waste water to be treated, is introduced into the filtration tank 101 via an upper portion of the tank, and is passed downward between the grains of the sand 102, while the SS (suspended solids) are caught by the sand 102. The water thus treated is discharged to the exterior via a lower portion of the filtration tank 10 101. ' The conventional sand filtration method displays excellent performance with a high SS removal rate and a high filtration rate, when applied to low-concentration waste water such as waste water to be just subjected to a secondary treatment. If the conventional sand filtration method is applied to a primary treatment of waste water, however, the surfaces of the sand 102 will be clogged in a short time, making it impossible to achieve filtration. As a method for overcoming the problem, there has been an attempt to use a 20 granular filter medium having a large grain diameter. In that ~;
case, however, the low void ratio in the filter medium layer ~-leads to a higher linear velocity of waste water flowing ~ -through the voids in the filter medium layer, resulting in a lower SS removal rate. Thus, the attempt has not produced a 25 satisfactory effect.
One embodiment of this invention will now be described below while referring to the drawings.
''";~
- 3 - ~
1~ , :~ . ~ ~ ,.. :-: .::. . . -133~569 Referring to Fig. 3, there is shown an upward flow type solid-liquid separator, in which a sedimentation zone 4 comprising a space portion is provided on the lower side of a filter medium layer 3. In the sedimentation zone 4, a sludge discharge pipe 6 is provided as means for discharging solid matter. A
filter medium 3a to be packed in the filter medium layer 3 is preferably a small cylindrical filter medium, formed or molded from a plastic or the like, as shown in Fig. 4, which has a void ratio of at least 70%, has a surface corrugated or provided with whisker-shaped protrusions, and has a specific gravity of not more than lØ Also shown in Fig. 3 are an inlet pipe 1 provided at a lower portion, an outlet pipe 5 provided at an upper portion, and a filter medium presser 7.
As shown in Fig. 3, in operation of the upper flow type solid-liquid separator 2, waste water containing solid matter, as raw water, is introduced through the inlet pipe 1 into the sedimentation separation zone 4 provided on the lower side of the filter medium layer 3.
Of the solids contained in the raw water introduced, those having a relatively higher specific gravity are separated through sedimentation in the sedimentation zone 4. The raw water retaining the solids having a lower specific gravity is then passed upward through the filter medium layer 3, while the second solid-liquid separation takes place. The water thus treated is .~ ~
~ - 4 -::
;t~
discharged via the discharge pipe 5 provided at an upper portion of the separator 2. The filter medium 3a packed in the filter medium layer 3 has an extremely high void ratio; therefore, the solid matter is not only caught ``
at the sur~aces at a lower portion of the filter medium layer 3 but is caught in a three-dimensional manner throughout the filter medium layer 3. Accordingly, thè
solid-liquid separator 2 has an enhanced SS retention capacity and a low possibility of clogging, so that it is possible to continue the treating operation for a long time.
With the sedimentation separation zone 4 particularly provided on the lower side of the filter medium layer 3, the solids having a higher specific ;
gravity are removed in the zone, and the solids load on the filter medium layer 3 is alleviated accordingly.
The results of experiments show that about one-third of the total amount of SS removed by the solid-liquid separator are removed in the sedimentation zone 4. The solids separated through sedimentation in the sedimentation zone 4 are discharged, either intermit-tently or continuously, to the exterior of the system ;~
via the sludge discharge pipe 6. The capacity of the sedimentation separation zone 4 is set to the range of about 20% to 50~ of a tank effective capacity.
It is the first condition of the filter medium 3aused as a filler is that a void rate is large, i.e. more .
than 70%, preferably more than 90~. More useful effects can be provided by a miniature cylindrical-type filter medium with innumerable fine voids in the filter medium layer. Use of the filter medium with large void rate results in reduction of linear velocity of waste water flowing through the voids in the filter mediums 3a. In this case, it is possible to improve the SS catching capacity rapidly since SS can be caught in three-dimension. In addition, SS removal rate can be elevated since the fine voids in the miniature cylinder function as sedimentation separation cores, respectively.
Moreover, further effects can be obtained by ; molding the surface of the miniature cylinder in wave-shape or by planting innumerable whisker-shaped protrusions thereon.
After the amount of the solids caught in the filter medium 3a reaches more than a fixed amount, SS is leaked into waste water. The filter medium 3a has to be washed immediately therebefore. In washing, air is fed from an air pipe provided under the filter medium layer 3 which is agitated and thereby the caught solids are kept in -~
suspension state. For effective agitation by air, it is desirable that the specific gravity of the filter medium 3a used is about 1.0, preferably 0.9 to 1Ø With such a filter medium, air scrubbing brings the filter medium layer 3 into a fluidized state, whereby separation of .
.
133~569 the solids fxom the filter medium 3a and suspension of - the separated solids are achievable effectively. After the air scrubbing, the waste water is drained from the tank via a discharge port provided at a lower portion of the tank, whereby most of the solids caught are removed, resulting in an initial condition.
Table 1 shows the results of a test of solid-liquid separation according to this invention. A good SS ~ ;
removal rate of 71.3 to 86.7% was achieved at a filtration rate of 60 to 70 m3/m2-d, corresponding to about 2 times the treating rate of the conventional sedimentation method. Also, the SS retention was at least 5 kg-SS/m2, the value being at least 5 times the value attained in the conventional sand filtration ~-system (about 1.0 kg-SS/m2).
Table 1 Test Results (feed water = raw sewage) -;-_ I Size of Filtration f eed treated Rretova f _ medium water water _ Test 1 21~ x 21L 60 m3/m2.d 300 mg/Q 40 mg/Q 86.7%
lTest 2 ,l 70 ~ 174 ~ 50 ~ 71.3%
! .
SS retention = at least 5 kg-SS/m2 ~ 25 As has been described above, the solid-liquid ¦ separator according to this invention is designed for l`~
introducing waste water into a sedimentation zone provided on the lower side of a filter medium layer to ~ - 7 -:~
~` ' ' .
..
. .~
11 331~6~
preliminarily separate solid matter from the waste water through sedimentation and thereafter passing the waste water upward through the filter medium layer to remove the SS from the waste water. Therefore, the solid-liquid separator of this invention has a high SS-removing ability as well as a high value of water surface area load, and is capable of a highly efficient treatment of waste water with low possibility of clogging.
~? ~
example of such means for solid-liquid separation is a sand ~ -filtration method, as shown in Fig. 2.
In the figure, sand 102 is packed in a filtration tank 101 as a filter medium. Raw water, or waste water to be treated, is introduced into the filtration tank 101 via an upper portion of the tank, and is passed downward between the grains of the sand 102, while the SS (suspended solids) are caught by the sand 102. The water thus treated is discharged to the exterior via a lower portion of the filtration tank 10 101. ' The conventional sand filtration method displays excellent performance with a high SS removal rate and a high filtration rate, when applied to low-concentration waste water such as waste water to be just subjected to a secondary treatment. If the conventional sand filtration method is applied to a primary treatment of waste water, however, the surfaces of the sand 102 will be clogged in a short time, making it impossible to achieve filtration. As a method for overcoming the problem, there has been an attempt to use a 20 granular filter medium having a large grain diameter. In that ~;
case, however, the low void ratio in the filter medium layer ~-leads to a higher linear velocity of waste water flowing ~ -through the voids in the filter medium layer, resulting in a lower SS removal rate. Thus, the attempt has not produced a 25 satisfactory effect.
One embodiment of this invention will now be described below while referring to the drawings.
''";~
- 3 - ~
1~ , :~ . ~ ~ ,.. :-: .::. . . -133~569 Referring to Fig. 3, there is shown an upward flow type solid-liquid separator, in which a sedimentation zone 4 comprising a space portion is provided on the lower side of a filter medium layer 3. In the sedimentation zone 4, a sludge discharge pipe 6 is provided as means for discharging solid matter. A
filter medium 3a to be packed in the filter medium layer 3 is preferably a small cylindrical filter medium, formed or molded from a plastic or the like, as shown in Fig. 4, which has a void ratio of at least 70%, has a surface corrugated or provided with whisker-shaped protrusions, and has a specific gravity of not more than lØ Also shown in Fig. 3 are an inlet pipe 1 provided at a lower portion, an outlet pipe 5 provided at an upper portion, and a filter medium presser 7.
As shown in Fig. 3, in operation of the upper flow type solid-liquid separator 2, waste water containing solid matter, as raw water, is introduced through the inlet pipe 1 into the sedimentation separation zone 4 provided on the lower side of the filter medium layer 3.
Of the solids contained in the raw water introduced, those having a relatively higher specific gravity are separated through sedimentation in the sedimentation zone 4. The raw water retaining the solids having a lower specific gravity is then passed upward through the filter medium layer 3, while the second solid-liquid separation takes place. The water thus treated is .~ ~
~ - 4 -::
;t~
discharged via the discharge pipe 5 provided at an upper portion of the separator 2. The filter medium 3a packed in the filter medium layer 3 has an extremely high void ratio; therefore, the solid matter is not only caught ``
at the sur~aces at a lower portion of the filter medium layer 3 but is caught in a three-dimensional manner throughout the filter medium layer 3. Accordingly, thè
solid-liquid separator 2 has an enhanced SS retention capacity and a low possibility of clogging, so that it is possible to continue the treating operation for a long time.
With the sedimentation separation zone 4 particularly provided on the lower side of the filter medium layer 3, the solids having a higher specific ;
gravity are removed in the zone, and the solids load on the filter medium layer 3 is alleviated accordingly.
The results of experiments show that about one-third of the total amount of SS removed by the solid-liquid separator are removed in the sedimentation zone 4. The solids separated through sedimentation in the sedimentation zone 4 are discharged, either intermit-tently or continuously, to the exterior of the system ;~
via the sludge discharge pipe 6. The capacity of the sedimentation separation zone 4 is set to the range of about 20% to 50~ of a tank effective capacity.
It is the first condition of the filter medium 3aused as a filler is that a void rate is large, i.e. more .
than 70%, preferably more than 90~. More useful effects can be provided by a miniature cylindrical-type filter medium with innumerable fine voids in the filter medium layer. Use of the filter medium with large void rate results in reduction of linear velocity of waste water flowing through the voids in the filter mediums 3a. In this case, it is possible to improve the SS catching capacity rapidly since SS can be caught in three-dimension. In addition, SS removal rate can be elevated since the fine voids in the miniature cylinder function as sedimentation separation cores, respectively.
Moreover, further effects can be obtained by ; molding the surface of the miniature cylinder in wave-shape or by planting innumerable whisker-shaped protrusions thereon.
After the amount of the solids caught in the filter medium 3a reaches more than a fixed amount, SS is leaked into waste water. The filter medium 3a has to be washed immediately therebefore. In washing, air is fed from an air pipe provided under the filter medium layer 3 which is agitated and thereby the caught solids are kept in -~
suspension state. For effective agitation by air, it is desirable that the specific gravity of the filter medium 3a used is about 1.0, preferably 0.9 to 1Ø With such a filter medium, air scrubbing brings the filter medium layer 3 into a fluidized state, whereby separation of .
.
133~569 the solids fxom the filter medium 3a and suspension of - the separated solids are achievable effectively. After the air scrubbing, the waste water is drained from the tank via a discharge port provided at a lower portion of the tank, whereby most of the solids caught are removed, resulting in an initial condition.
Table 1 shows the results of a test of solid-liquid separation according to this invention. A good SS ~ ;
removal rate of 71.3 to 86.7% was achieved at a filtration rate of 60 to 70 m3/m2-d, corresponding to about 2 times the treating rate of the conventional sedimentation method. Also, the SS retention was at least 5 kg-SS/m2, the value being at least 5 times the value attained in the conventional sand filtration ~-system (about 1.0 kg-SS/m2).
Table 1 Test Results (feed water = raw sewage) -;-_ I Size of Filtration f eed treated Rretova f _ medium water water _ Test 1 21~ x 21L 60 m3/m2.d 300 mg/Q 40 mg/Q 86.7%
lTest 2 ,l 70 ~ 174 ~ 50 ~ 71.3%
! .
SS retention = at least 5 kg-SS/m2 ~ 25 As has been described above, the solid-liquid ¦ separator according to this invention is designed for l`~
introducing waste water into a sedimentation zone provided on the lower side of a filter medium layer to ~ - 7 -:~
~` ' ' .
..
. .~
11 331~6~
preliminarily separate solid matter from the waste water through sedimentation and thereafter passing the waste water upward through the filter medium layer to remove the SS from the waste water. Therefore, the solid-liquid separator of this invention has a high SS-removing ability as well as a high value of water surface area load, and is capable of a highly efficient treatment of waste water with low possibility of clogging.
Claims (5)
1. A solid-liquid separator for a pretreatment of waste water of the upward flow type in which the waste water is introduced into a tank packed with a filter medium via an upper portion of the tank and is discharged from the tank via a lower portion of the tank, wherein a sedimentation zone comprising a space portion for sedimentation separation is provided on the lower side of a filter medium layer in the tank, and means for discharging the sedimented solid matter is provided in the sedimentation zone, and wherein said filter medium has a small cylindrical shape with a surface provided with numerous whisker-shaped protrusions.
2. A solid-liquid separator as set forth in claim 1, wherein the void ratio of said filter medium is 90-95%.
3. A solid-liquid separator as set forth in claim 1, wherein the specific gravity of said filter medium is 0.92-0.95.
4. A solid-liquid separator as set forth in claim 1, wherein a slant plate is provided in the sedimentation zone on the lower side of the filter medium layer.
5. A solid-layer separator as set forth in claim 1, wherein said filter medium size is 21 ? x 21 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000614060A CA1331569C (en) | 1989-09-28 | 1989-09-28 | Solid-liquid separator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000614060A CA1331569C (en) | 1989-09-28 | 1989-09-28 | Solid-liquid separator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1331569C true CA1331569C (en) | 1994-08-23 |
Family
ID=4140758
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000614060A Expired - Fee Related CA1331569C (en) | 1989-09-28 | 1989-09-28 | Solid-liquid separator |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1331569C (en) |
-
1989
- 1989-09-28 CA CA000614060A patent/CA1331569C/en not_active Expired - Fee Related
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKLA | Lapsed |