CA1247760A - Method and apparatus for aerating and mixing waste water - Google Patents
Method and apparatus for aerating and mixing waste waterInfo
- Publication number
- CA1247760A CA1247760A CA000466000A CA466000A CA1247760A CA 1247760 A CA1247760 A CA 1247760A CA 000466000 A CA000466000 A CA 000466000A CA 466000 A CA466000 A CA 466000A CA 1247760 A CA1247760 A CA 1247760A
- Authority
- CA
- Canada
- Prior art keywords
- pipe
- air
- waste water
- aerator
- basin
- 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
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Landscapes
- Aeration Devices For Treatment Of Activated Polluted Sludge (AREA)
Abstract
A B S T R A C T
A plurality of aerators are arranged in a preselected pattern on the floor of a basin (10) or lagoon (110) containing waste water. Compressed air is supplied to the aerators by aeration pipes (26) anchored by hanger brackets (32) to the floor (16) of the basin (10). Each aerator has a porous diffuser plate (82) through which the air is passed and released into the waste water in the form of ultra fine air bubbles less than 60 microns in diameter. The air bubbles are generated in an intense manner with a high rate of air flow to increase the mixing action and liquid circulation pattern, and to create turbulent boils at the surface which provide surface aeration from atmospheric air.
A plurality of aerators are arranged in a preselected pattern on the floor of a basin (10) or lagoon (110) containing waste water. Compressed air is supplied to the aerators by aeration pipes (26) anchored by hanger brackets (32) to the floor (16) of the basin (10). Each aerator has a porous diffuser plate (82) through which the air is passed and released into the waste water in the form of ultra fine air bubbles less than 60 microns in diameter. The air bubbles are generated in an intense manner with a high rate of air flow to increase the mixing action and liquid circulation pattern, and to create turbulent boils at the surface which provide surface aeration from atmospheric air.
Description
~4~ tiO
METHOD & APPARAT~lS FOR AERATING AND MIXI NG WASTE WATER
.
This invention relates generally to the treatment of waste water and deals more particularly with improvements in the application of ultra fine air bubbles to municipal and industrial waste water.
s Various types of aeration and mixing devices have been used to treat municipal and industrial waste water, including mechanical devices which function as surface aerators. Surface aerators are active only at the surface of the waste water and do not effectively treat remote areas of the lagoon or basin. Due to the localized nature of surface aeration and inability to mix to the bottom in deep tanks or basins, there is a lack of uniform distribution of eneryy throughout the waste water and a corresponding lack of thorough mixing of the air with the liquid. surface aerators are also generally low in efficiency and high in energy consumption, and they are characterized by frequent mechanical problems. In addition, surface aeration systems are laclcing in flexibility and are difficult ancl expensive to maintain in good oL~eratiny condition.
Aeration systems known as draft tube systems utilize a series of aeration tubes which extend vertically in the waste water basin. The tubes act as draft tubes, and air is applied internally to create air lift pumpage and aeration of pumped liquid. The draft tube systems dispense the air fairly widely throughout the basin but ~ `
~;~47'~;0 are plagued by high energy requirements. Furthermore, the draft tube system does not stand up well when subjected to prolonged use in the field.
Fine bubble technology is used in a third type of aeration system. In the fine bubble system, small air bubbles are generated and applied to the waste water. The fine bubbles have been generated by mechanical devices such as eductors which draw gas into the liquid by liquid pumpage. Rapidly rotating turbines and pumps have also been used to break up a stream of compressed air into fine air bubbles at the air release point of the system.
~nother type of fine bubble aeration device that has been used to great advantage is an aeration unit having a 1 to 1 1/2 inch thick porous diffuser plate of ceramic or sintered metal through which compressed air is forced.
The aerator is sub-merged at or near the bottom of the waste water treatment basin, and the compressed air that passes through the small pores of the diffuser plate is released in the form of fine air bubbles which rise through the waste water to provide aeration. The diffuser plate aerator is generally more efficient in oxygen transfer than the other types of aerators that have bsen used, and it dispsnses the air bubbles more thoroughly throughout the waste water. The eEfective aeration that is achieved by the fins bubble systsm is due primarily to the relatively large areas of surface contact between the smalL air bubbles and the liquid.
Conventional fine bubble aeration systems are designed to maximize residence time of the compressed air bubbles in the liquid in order to maximize the oxygen transfer.
The surface area of the diffuser media is normally maximized and liquid pumpage is minimiæed. The goal of the system is to widely dispense the air bubbles across the basin, cause the bubbles to rise slowly through the waste water, and minimize directional flow by minimiziny the intensity of the air flow. For example, ~4'7 ~
conventional systems operate at an air flow rate of 0-4 cfm per square foot of diffuser media. Most common rates are 1 to 1.5 CFM per square foot.
Even though the approach taken by conventional systems maximizes the oxygen transfer of the air that is pumped through the diffuser media, there are no significant surface aeration effects since the slow rise rate of the bubble does not create appreciable turbulence at the surface. The non-directional effect resulting fr~l the wide dispension and low rate of air flow lead to mixing problems and inefficiencies, particularly in low F/M systems where the F/M ratio is less than about .2 XBOD/~MLSS. In high rate activated sludge systems having a higher F/M ratio, existing fine bubble systems function in an efficient and satisfactory manner for the most part. However, in low rate activated sludge systems or in aerated lagoon systems where the F/M ratio is extremely low, the oxygen demand can be satisfied at low ene~gy levels which do not result in enough mixing to achieve proper interaction between the food and microorganisms. Therefore, in order to provide sufficient mixing to sustain the process, energy must be added beyond that required for aeration, and the energy requirements are increased accordingly. Net energy requirements for the system are substantially greater than the theoretical energy to dissolve oxygen.
Conventional fine bubble systems for activated sludge applications are also characterized by high initial costs and high operating costs. The aerators are arranged closely together and a large number of aerators is required to adequately treat a large basin. Lengthy rigid pipe air lines are necessary to hold the aerators, along with a large number of connecting devices for joining the aerators (diffusers) to the air lines. The diffuser units can bec~ne clogged so severely from build up of deposits that application of chemicals such as ~Z47'~
hydrochloric acid is required to clear them. The aerator devices which are submeryed at the bottom of the basin are inaccessible and difficult to service. The porous diffuser media are often ceramic or sintered metal plates S which have rough texture surfaces that offer little resistance to biological growth tending to clog their pores. The diffuser plates are nonmally thick enough (1 to 1 1/2 inchs) that the pores present tortuous paths which are easily clogged by debris in the air supply, again blocking the diffuser and reducing the effectiveness of the aeration.
Fine bubble systems have not been applied to aerated lagoons. To employ the fine bubble system requires rigid air piping, strict elevation control of lagoon bottom, elevation control of air line, and strict elevation control for diffuser units. Costs to provide these features have been prohibitive because of the very large areas in lagoons. Air flow rates for fine bubble air systems are so low per unit that massive piping systems would be required.
Fine bubble aeration systems traditionally require considerable maintenance, Lagoons are not usually contructed in parallel to allow units to be removed from service for maintenance. Also, lagoons are so large that dewatering for maintenance is not practical. Since fine bubble systems are fixed in place and cannot be serviced or removed from the lagoon wit~ut dewatering, fine bubble aeration has not been a viable treatment option even though substantial energy savings would be possible. The fsar of operating and maintaining fixed in place fine bubble systems has effectively prevented their application to lagoons.
The present invention provides an improved method and apparatus for treating waste water using fine bubble technology. In accordance with the invention, a series of 1~477fiV
improved aeration devices is arranged in a prede-termined pattern on the bottom of a basin or lagoon.
It is an important object of the invention to provde a method and apparatus for effectively aerating and mixing waste water in a manner to minimize the energy consumption. The needs of the biological process are adequately met while achieving substantial energy savings which become even more significant in view of expected increases in energy costs in the future.
Another object of the invention is to provide a method and apparatus of the character described which minimizes damage to biological colonies or floc in the waste water treatment basin.
According to one aspect of the invention there is provided apparatus for aerating waste water in a basin, said apparatus comprising: a main supply pipe for receiving air under pressure; a plurality of branch pipes each communicating with said main supply pipe to receive air therefrom, each branch pipe extending generally along the bottom of the basin and each branch pipe being a plastic pipe subject to longitudinal expansion and contraction in response to temperature changes in the waste water;
a plurality of aerators for each branch pipe, each aerator being adapted to release a plurality of fine air bubbles when air is supplied to the aerator and each aerato:r beinc~ provided with ballast to hold the aerator down on the bottom of the basin; a flexible conduit connecting each aerator with the corresponding branch line to provide communication between the branch lines and the corresponding aerators, thereby applying air to the aerators for release of air bubbles therefrom to effect aeration of the waste water, wherein each flexible conduit has a length at least i~4~'7~0 as great as the distance between the corresponding branch pipe and the surface of the waste water to permit each aerator to be raised to the surface of the waste water whil.e the corresponding branch pipe remains on the bottom of the basin and connected to the flexible conduit; a flexible line for each aerator connected there-with at one end and having an opposite end disposed at the surface of the waste water; a float for each line connected with said opposite end thereof, said floats floating on the surface of the waste water to maintain said lines accessible from the surface for lifting of the aerators to the surface of the waste water; and at least one hold down bracket for each branch pipe provided with ballast to hold the bracket down on the bottom of the basin, said bracket having means for holding down the branch pipe while permitting the branch pipe to longitudinally expand and contract, whereby said brackets accommodate thermally induced expansion and contraction of the branch pipes and said flexible conduits allow the aerators to remain stationary as the branch pipes expand and contract.
Other and further objects of the invention, toge-ther with the features of novelty appurtenant thereto, will appear in the course of the following description~
Figure L is a top pl.an v.iew showi.ng the waste water aeration and mixing system oE the present inventlon installed in a concrete basin in a typical activated sludge application;
Figure 2 is a sectional view taken generally along line
METHOD & APPARAT~lS FOR AERATING AND MIXI NG WASTE WATER
.
This invention relates generally to the treatment of waste water and deals more particularly with improvements in the application of ultra fine air bubbles to municipal and industrial waste water.
s Various types of aeration and mixing devices have been used to treat municipal and industrial waste water, including mechanical devices which function as surface aerators. Surface aerators are active only at the surface of the waste water and do not effectively treat remote areas of the lagoon or basin. Due to the localized nature of surface aeration and inability to mix to the bottom in deep tanks or basins, there is a lack of uniform distribution of eneryy throughout the waste water and a corresponding lack of thorough mixing of the air with the liquid. surface aerators are also generally low in efficiency and high in energy consumption, and they are characterized by frequent mechanical problems. In addition, surface aeration systems are laclcing in flexibility and are difficult ancl expensive to maintain in good oL~eratiny condition.
Aeration systems known as draft tube systems utilize a series of aeration tubes which extend vertically in the waste water basin. The tubes act as draft tubes, and air is applied internally to create air lift pumpage and aeration of pumped liquid. The draft tube systems dispense the air fairly widely throughout the basin but ~ `
~;~47'~;0 are plagued by high energy requirements. Furthermore, the draft tube system does not stand up well when subjected to prolonged use in the field.
Fine bubble technology is used in a third type of aeration system. In the fine bubble system, small air bubbles are generated and applied to the waste water. The fine bubbles have been generated by mechanical devices such as eductors which draw gas into the liquid by liquid pumpage. Rapidly rotating turbines and pumps have also been used to break up a stream of compressed air into fine air bubbles at the air release point of the system.
~nother type of fine bubble aeration device that has been used to great advantage is an aeration unit having a 1 to 1 1/2 inch thick porous diffuser plate of ceramic or sintered metal through which compressed air is forced.
The aerator is sub-merged at or near the bottom of the waste water treatment basin, and the compressed air that passes through the small pores of the diffuser plate is released in the form of fine air bubbles which rise through the waste water to provide aeration. The diffuser plate aerator is generally more efficient in oxygen transfer than the other types of aerators that have bsen used, and it dispsnses the air bubbles more thoroughly throughout the waste water. The eEfective aeration that is achieved by the fins bubble systsm is due primarily to the relatively large areas of surface contact between the smalL air bubbles and the liquid.
Conventional fine bubble aeration systems are designed to maximize residence time of the compressed air bubbles in the liquid in order to maximize the oxygen transfer.
The surface area of the diffuser media is normally maximized and liquid pumpage is minimiæed. The goal of the system is to widely dispense the air bubbles across the basin, cause the bubbles to rise slowly through the waste water, and minimize directional flow by minimiziny the intensity of the air flow. For example, ~4'7 ~
conventional systems operate at an air flow rate of 0-4 cfm per square foot of diffuser media. Most common rates are 1 to 1.5 CFM per square foot.
Even though the approach taken by conventional systems maximizes the oxygen transfer of the air that is pumped through the diffuser media, there are no significant surface aeration effects since the slow rise rate of the bubble does not create appreciable turbulence at the surface. The non-directional effect resulting fr~l the wide dispension and low rate of air flow lead to mixing problems and inefficiencies, particularly in low F/M systems where the F/M ratio is less than about .2 XBOD/~MLSS. In high rate activated sludge systems having a higher F/M ratio, existing fine bubble systems function in an efficient and satisfactory manner for the most part. However, in low rate activated sludge systems or in aerated lagoon systems where the F/M ratio is extremely low, the oxygen demand can be satisfied at low ene~gy levels which do not result in enough mixing to achieve proper interaction between the food and microorganisms. Therefore, in order to provide sufficient mixing to sustain the process, energy must be added beyond that required for aeration, and the energy requirements are increased accordingly. Net energy requirements for the system are substantially greater than the theoretical energy to dissolve oxygen.
Conventional fine bubble systems for activated sludge applications are also characterized by high initial costs and high operating costs. The aerators are arranged closely together and a large number of aerators is required to adequately treat a large basin. Lengthy rigid pipe air lines are necessary to hold the aerators, along with a large number of connecting devices for joining the aerators (diffusers) to the air lines. The diffuser units can bec~ne clogged so severely from build up of deposits that application of chemicals such as ~Z47'~
hydrochloric acid is required to clear them. The aerator devices which are submeryed at the bottom of the basin are inaccessible and difficult to service. The porous diffuser media are often ceramic or sintered metal plates S which have rough texture surfaces that offer little resistance to biological growth tending to clog their pores. The diffuser plates are nonmally thick enough (1 to 1 1/2 inchs) that the pores present tortuous paths which are easily clogged by debris in the air supply, again blocking the diffuser and reducing the effectiveness of the aeration.
Fine bubble systems have not been applied to aerated lagoons. To employ the fine bubble system requires rigid air piping, strict elevation control of lagoon bottom, elevation control of air line, and strict elevation control for diffuser units. Costs to provide these features have been prohibitive because of the very large areas in lagoons. Air flow rates for fine bubble air systems are so low per unit that massive piping systems would be required.
Fine bubble aeration systems traditionally require considerable maintenance, Lagoons are not usually contructed in parallel to allow units to be removed from service for maintenance. Also, lagoons are so large that dewatering for maintenance is not practical. Since fine bubble systems are fixed in place and cannot be serviced or removed from the lagoon wit~ut dewatering, fine bubble aeration has not been a viable treatment option even though substantial energy savings would be possible. The fsar of operating and maintaining fixed in place fine bubble systems has effectively prevented their application to lagoons.
The present invention provides an improved method and apparatus for treating waste water using fine bubble technology. In accordance with the invention, a series of 1~477fiV
improved aeration devices is arranged in a prede-termined pattern on the bottom of a basin or lagoon.
It is an important object of the invention to provde a method and apparatus for effectively aerating and mixing waste water in a manner to minimize the energy consumption. The needs of the biological process are adequately met while achieving substantial energy savings which become even more significant in view of expected increases in energy costs in the future.
Another object of the invention is to provide a method and apparatus of the character described which minimizes damage to biological colonies or floc in the waste water treatment basin.
According to one aspect of the invention there is provided apparatus for aerating waste water in a basin, said apparatus comprising: a main supply pipe for receiving air under pressure; a plurality of branch pipes each communicating with said main supply pipe to receive air therefrom, each branch pipe extending generally along the bottom of the basin and each branch pipe being a plastic pipe subject to longitudinal expansion and contraction in response to temperature changes in the waste water;
a plurality of aerators for each branch pipe, each aerator being adapted to release a plurality of fine air bubbles when air is supplied to the aerator and each aerato:r beinc~ provided with ballast to hold the aerator down on the bottom of the basin; a flexible conduit connecting each aerator with the corresponding branch line to provide communication between the branch lines and the corresponding aerators, thereby applying air to the aerators for release of air bubbles therefrom to effect aeration of the waste water, wherein each flexible conduit has a length at least i~4~'7~0 as great as the distance between the corresponding branch pipe and the surface of the waste water to permit each aerator to be raised to the surface of the waste water whil.e the corresponding branch pipe remains on the bottom of the basin and connected to the flexible conduit; a flexible line for each aerator connected there-with at one end and having an opposite end disposed at the surface of the waste water; a float for each line connected with said opposite end thereof, said floats floating on the surface of the waste water to maintain said lines accessible from the surface for lifting of the aerators to the surface of the waste water; and at least one hold down bracket for each branch pipe provided with ballast to hold the bracket down on the bottom of the basin, said bracket having means for holding down the branch pipe while permitting the branch pipe to longitudinally expand and contract, whereby said brackets accommodate thermally induced expansion and contraction of the branch pipes and said flexible conduits allow the aerators to remain stationary as the branch pipes expand and contract.
Other and further objects of the invention, toge-ther with the features of novelty appurtenant thereto, will appear in the course of the following description~
Figure L is a top pl.an v.iew showi.ng the waste water aeration and mixing system oE the present inventlon installed in a concrete basin in a typical activated sludge application;
Figure 2 is a sectional view taken generally along line
2-2 of Figure 1 in the direction of the arrows;
Figure 3 is a fragmentary sectional view on an enlarged J ~` ~
1~47';~V
sca]e taken generally alony line 3-3 of Figure 1 in the direction of the arrows and showing one of the anchor brackets included in the system;
Figure 4 is top plan view of the anchor bracket shown in Figure 3, with the broken lines illustrating the bracket ~4~7'7~(~
released from the aeration pipe;
Fig. 5 is a top plan view on an enlarged scale showing one of the aeration units included in the system;
Fiy. 6 is a sectional view taken generally along line 6-6 of Fig. 5 in the direction of the arrows;
Fig. 7 is a top plan view showing the aeration system installed in an earth basin in a typical lagoon application; and Fig. 8 is a sectional view taken generally along line 8-8 of Fiy. 7 in the direction of the arrows.
Referring to Figs. 1 and 2, the present invention provides a method and apparatus for aerating and mixing waste water contained in a sunken concrete basin generally designated by numeral 10. The basin 10 has concrete end walls 12, side walls 14, and a floor 16. The basin 10 may be used in an activated sludge system having a relatively high F/M ratio (greater than about 0.05 #BOD/#MLSS).
Numeral L designates the liquid level of the waste water in the basin. The basin is open to the atmosphere at the top.
In accordance with the present invention, compressed air is filtered by central filtration equipment (not shown) and delivered to a main header pipe l8 having an erld cap 20 on one end. The main suppLy pipe 1~ extends along the top of one of the end walls 12 of the concrete basin. Branching away from the main pipe 18 at spaced apart locations are a plurality of carbon steel branch pipes 22 which are generally vertical pipes extending down into the basin 10 from the main pipe 18. Each of the branch pipes 22 is equipped with a throttling valve 24 for controlling the flow into the branch pipe. The lower end of each pipe 22 is located adjacent the floor 16 of the 1~4~7'~t~0 basin and is elbowed to extend horizontall~. Each branch pipe 22 connects at its lower end Wit}l a plastic aeration pipe 26. Steel to plastlc adaptor connection 28 connect pipes 22 and 26. The lateral aeration pipes 26 extend 5 horizontally along the floor 16 and are spaced apart and parallel to one another, as best shown in Fig. 1. The pipes 26 extend the length of the basin 10 and are provided with end caps 30.
10 Each lateral aeration pipe 26 is held down adjacent the floor 16 by a plurality of anchor brackets 32. The brackets 32 are spaced apart along the length of each pipe 26 at 8-12 feet intervals. The spacing between adiacent pairs of pipes 26 is preferably in the range of 4-12 15 feet. The brackets 32 are identical to one another.
Referring now to Figs. 3 and 4 in particular, each anchor bracket 32 includes a conventional concrete block 34 having a central transverse web 36 separating the hollow 20 interior of the block into spaced apart openings 38.
A stainless steel pipe hanger 40 includes a pair of vertical bracket arms 42 which are connected at their lower ends by a horizontal bight portion 44 of the hanger. The bracket arms 42 are spaced apart a distance 25 greater than the diameter of the lateral aeration pipe 26. Arms 42 extend upwardly through the openings 38 in the concrete block on oppos ite sides of web 36. The bight portion 44 underlies web 36 and angles between the lower ends of the bracket arms 42. The openings 38 in the 30 concrete block are f illed with concrete 46 which acts as ballast. The bracket arms 42 are embedded in the concrete 46 to secure the pipe hanger in place.
The upper ends of bracket arms 42 are provided with 35 opposed hooks 48 which curve in opposite directions.
Each hook 48 opens downwardly and is large enough to closely receive the aeration pipe 26, as shown in Fig.
Figure 3 is a fragmentary sectional view on an enlarged J ~` ~
1~47';~V
sca]e taken generally alony line 3-3 of Figure 1 in the direction of the arrows and showing one of the anchor brackets included in the system;
Figure 4 is top plan view of the anchor bracket shown in Figure 3, with the broken lines illustrating the bracket ~4~7'7~(~
released from the aeration pipe;
Fig. 5 is a top plan view on an enlarged scale showing one of the aeration units included in the system;
Fiy. 6 is a sectional view taken generally along line 6-6 of Fig. 5 in the direction of the arrows;
Fig. 7 is a top plan view showing the aeration system installed in an earth basin in a typical lagoon application; and Fig. 8 is a sectional view taken generally along line 8-8 of Fiy. 7 in the direction of the arrows.
Referring to Figs. 1 and 2, the present invention provides a method and apparatus for aerating and mixing waste water contained in a sunken concrete basin generally designated by numeral 10. The basin 10 has concrete end walls 12, side walls 14, and a floor 16. The basin 10 may be used in an activated sludge system having a relatively high F/M ratio (greater than about 0.05 #BOD/#MLSS).
Numeral L designates the liquid level of the waste water in the basin. The basin is open to the atmosphere at the top.
In accordance with the present invention, compressed air is filtered by central filtration equipment (not shown) and delivered to a main header pipe l8 having an erld cap 20 on one end. The main suppLy pipe 1~ extends along the top of one of the end walls 12 of the concrete basin. Branching away from the main pipe 18 at spaced apart locations are a plurality of carbon steel branch pipes 22 which are generally vertical pipes extending down into the basin 10 from the main pipe 18. Each of the branch pipes 22 is equipped with a throttling valve 24 for controlling the flow into the branch pipe. The lower end of each pipe 22 is located adjacent the floor 16 of the 1~4~7'~t~0 basin and is elbowed to extend horizontall~. Each branch pipe 22 connects at its lower end Wit}l a plastic aeration pipe 26. Steel to plastlc adaptor connection 28 connect pipes 22 and 26. The lateral aeration pipes 26 extend 5 horizontally along the floor 16 and are spaced apart and parallel to one another, as best shown in Fig. 1. The pipes 26 extend the length of the basin 10 and are provided with end caps 30.
10 Each lateral aeration pipe 26 is held down adjacent the floor 16 by a plurality of anchor brackets 32. The brackets 32 are spaced apart along the length of each pipe 26 at 8-12 feet intervals. The spacing between adiacent pairs of pipes 26 is preferably in the range of 4-12 15 feet. The brackets 32 are identical to one another.
Referring now to Figs. 3 and 4 in particular, each anchor bracket 32 includes a conventional concrete block 34 having a central transverse web 36 separating the hollow 20 interior of the block into spaced apart openings 38.
A stainless steel pipe hanger 40 includes a pair of vertical bracket arms 42 which are connected at their lower ends by a horizontal bight portion 44 of the hanger. The bracket arms 42 are spaced apart a distance 25 greater than the diameter of the lateral aeration pipe 26. Arms 42 extend upwardly through the openings 38 in the concrete block on oppos ite sides of web 36. The bight portion 44 underlies web 36 and angles between the lower ends of the bracket arms 42. The openings 38 in the 30 concrete block are f illed with concrete 46 which acts as ballast. The bracket arms 42 are embedded in the concrete 46 to secure the pipe hanger in place.
The upper ends of bracket arms 42 are provided with 35 opposed hooks 48 which curve in opposite directions.
Each hook 48 opens downwardly and is large enough to closely receive the aeration pipe 26, as shown in Fig.
3. Each hook has an out turned free end 49 which is 7'7~V
spaced above block 34 a distance greater than lthe diameter of pipe 26.
Each bracket 32 is applied to the proper aeration pipe 26 5 by initially positioning the block 34 as shown in broken lines in Fig. 4. In this position, the long axis of the block is parallel with the axis of the aeration pipe 26, and the aeration pipe extends between the upper portions of the bracket arms 42. Block 34 is either 10 rotated through ~0 to the solid line position shown in Fig. 4, as indicated by the directional arrow. The free ends 49 of hooks 48 c lear the top of the pipe 26, and the opposing hooks 48 are aligned directly above the aeration pipe. When the pipe is thereaEter raised, it 15 fits closely in both of the hooks 48 and is firmly gripped therein and prevented from floating upwardly away from the floor 16 of the basin. The concrete ballast 46 and block 34 together have enough weight (approximately 85 lbs.) to anchor bracket 32 down on the floor 16 of the 20 basin. The brackets 32 acc~mmodate thermal expansion and contraction of the aeration pipes 26 without affecting the location or operation of the aeration units 50 supplied by the pipes.
25 Each of the lateral aeration pipes 26 supplies compressed air to a plurality of aeration units 50 which are identical to one another. A flexible hose 52 directs the air to each aeration unit 50 from the correspondiny pipe 26. One end of each hose 52 connects with the 30 aeration unit, and the opposite end oE the hose has a T connection with the aeration pipe 26. The aeration units supplied by each pipe 26 are spaced apart at intervals of 4-12 feet.
35 Each hose 52 has a length at least as great as the distance between the pipe 26 and the surface of the waste water. Consequently, each hose is long enough to permit the associated aeration unit 50 to be raised to the ~ 24t7~tio surface of the waste water for servicing while the aeration system remains in operation. This feature permits the systeln to remain on line while servicing of the individual aeration units is carried out.
Referring now to Figs. 5 and 6 in particular, the body of each aeration unit 50 is formed by a thin shell 54. A
flat flange on the periphery of shell 54 provides a stable base 56 which rests on the floor 16 of the basin. Inside of the base 56, shell 54 is shaped to provide a continuous upstanding wall 58 which surrounds a generally horizontal deck 60. The deck 60 is elevated above base 56 but is lower than a horizontal ledge 62 formed on top of the wall 58.
The area located below deck 60 and within the wall 58 defines a ballast compartment 64. The ballast compartment 64 is filled with concrete 66 which serves as ballast to hold the aerator unit down on the floor of the basin. The concrete 66 fills the interior of wall 58 and has a flat bottom surface which is coplanar with the base 56.
The area above deck 60 and within the wall 58 provides an air chamber 68 which receives the compressed air supplied through the flexible hose 52. The end of hose 52 is clamped to a plastic inlet fitting 70 by a hose clamp 72. The fitting 70 extends through wall 58, and its end is threaded at 74 to receive a retainer nut 76 which secures the inlet fitting to the body of the aerator unit. Fitting 70 may be equipped with a balancing valve 78 which can be adjus~.ed to control the flow of air into the air chamber 68. Fitting 70 may also have a check valve 80 which permits the flow of air into air chamber 68 but prevents back flow out oE air chamber. The check valve 80 prevents the entry of water and debris into the piping when the aeration device is inactive for extended periods.
lZ~t7'760 The top of the air chamber 6~ is covered by a flexible plastic difiEuser plate 82 which rests on top of ledge 62 at its periphery. Stainless steel anchor bolts 84 which are embedded in the concrete ballast 66 project upwardly 5 through the periphery of the ;liffuser plate 82. The periphery of the diffuser plate is held down on ledge 62 by stainless steel straps 86 which also receive the anchor bolts 84. Stainless steel nuts 88 are threaded onto bolts 84 and are tightened down against the straps 86 in order 10 to secure the diffuser plate 82 in place, Plate 82 is generally parallel to the deck 60.
The diffuser plate 82 is a -porous plate having a porosity or void ratio of at least 40%. The diffuser plate has a lS large number of small pores which are less than 60 microns in diameter and which are about 35 microns in diameter on average. The thickness of plate 82 is less than one half inch in order to reduce the length of the path that is taken by air passing through its pores. At 20 the same time, the plate is thin enough to readily flex due to abrupt changes in the air pressure. The flexibility of the plate permits it to flex when the air supply is interrupted and then resumed, and the periodic flexing of the E~late dislodges any biological growth that 25 would otherwise tend to build up~ The use oE a thin plate also reduces the pressure losses during operation, An eyebolt 90 is embedded in the concrete ballast 66 of each aeration unit, The eye bolt projects Erom one end of 30 the aerator body, and a flexible rope 92 is tied to each eye bolt. Each rope 92 has a length yreater than the depth of the waste water so that it can extend to the surface with the aerator on the floor 16 of the basin. A
floating rope 94 (Fiy. 2) is tied to the top end of each 35 rope 92 and floats on top of the waste wa ter~ The aerator units 50 can be raised to the surface for servicing simply by pulling the corresponding ropes 92.
Each rope 92 is formed from a substance that does not 1~4'~'7tj0 deteriorate when exposed to the waste water.
In operation of the aeration system, compressed air is supplied to the main header pipe 18 and is directed through the branch pipes 22 to the lateral aeration pipes 26. The throttling valve 24 permit the flow rates to the various aeration pipes 26 to be controlled as desired. Normally, each pipe 26 will receive the same amount of air, although special distribution patterns are possible.
The air in the aeration pipes 26 passes through the flexible hoses 52 to the aeration units 50. The balancing valves 78 can be adjusted to supply each aeration unit 50 with the desired amount of air. By properly adjusting the balancing valves 78, the system can be controlled in a manner to compensate for variations in the elevation of the basin floor and to preven-t starving of the aeration units that are far downstream in a system having long aeration pipes. Normally, the same amount of air is supplied to each aeration unit, although other distribution patterns are possible.
The compressed air that is supplied to each aeration unit 50 enters the air chamber 68. The pores in the diffuser plate 82 provide the only means of egress of air from the air chamber, and the air passes through the diffuser plate and is released thereErom in a series of ultra fine air bubbles. E~ch bubble has a di~neter Less than 60 microns and 35 [nicrons is the normal bubble size. The air bubbles rise through the waste water to provide the desired aeration and mixing action. Due to the small size of the ultra fine air bubbles, there are larye areas of surface contact between the air and liquid, and the transfer of oxygen to the waste water is thus effectively carried out. Since the aerator units 50 are at discrete locations, the bubbles are released from a plurality of discrete locations distributed uniformly on ~247'7~0 -l4-the floor of the basin~
The fine bubbles are generated from the aerator units 50 in a highly intense manner. The flow rate of air through each diffuser plate 82 is between 5 and 50 cfm per square foot of surface area presented on the diffuser plate, depending upon the particular application of the system. The highly intense manner in which the fine air bubbles are genera-t~ provides agitation and mixing of the liquid, resulting in a high liquid velocity. The liquid is thus mixed in a thorough manner and solids are maintained in suspension without the need to provide added energy for the purpose of mixing of the waste water.
The rapid rise rate of the air bubbles and the high liquid velocity creates a large turbulent boil of liquid at the surface of the waste water above each aerator unit. ~he turbulant boil results in substantial surface aeration from atmospheric air above the basin and draws atmospheric air into the waste water. The intense application of fine air bubbles at a relatively small number of locations produces a net oxygen transfer and mixing rate that is superior to conventional fine bubble systems when pumped air, dif~usion, and surface aeration are all taken into account.
The individual aeration units 50 are spaced apart from one another to a greater extent than in conventionaL fine bubble systems. ~y releasing air at high rate~ ~rom a relativeLy smaLl number o~ discrete locations that are widely spaced, improved liquid circulation patterns are achieved. The turbulent circulation patterns of the air bubbles that are released frc~ adjacent aerators impinging against and overlap and interact with one another to provide improved mixing and aeration. At the same time, high pumpage rates of the aerator units distribute air and energy uniformly throughout the basin 10.
1~4~;t~(3 The method and apparatus of the present invention is equally well suited for use in relatively low F/~ systems such as the typical lagoon application shown in Figs. 7 and 8. Numeral 110 generally designates a lagoon having sloping ends 112, sloping sides 114, and a generally horizontal bottom 116.
The aeration system for lagoon llQ is for the most part the same as the system for the concrete basin 10, and the same reference numerals are used in Figs. 7 and 8 for components that are identical to those used in the basin shown in Figs. 1 and 2. The aeration system of the present invention is installed in the lagoon 110 in essentially the same manner as in the concrete basin 10 shown in Figs. 1 and 2. However, the lateral aeration pipes 126 extend across the width of the lagoon 110 and are spaced apart more widely than in the activated sludged application. Also, the steel branch pipes 122 which connect with the main header pipe 118 incline in a manner to conform generally with the incline of the side walls 114. The aerator units 150 used in the lagoon application are identical to the aerators 50 described previously, although the lagoon aerators 150 are normally spaced apart from one another at 20-50 foot intervals due to the low F/M ratio and low oxygen uptake rate of the waste water in the lagoon.
The aeration system operates in the lagoon application in the same manner as in the activated sludge appLicatiorl.
The thorough mixing and air distribution throughout the lagoon makes the process efficient in the dispensed growth biological system as well as in the activated sludge application, The method and apparatus of the present application is flexible enough to accommodate variations in the system loading, season of the year, and type of aerobic process desired. At the same time, the capital cost of the equipment is relatively low since only a relatively few 1~47~7~0 aerator units are required. The maintenance requirements are also reduced due to the ease with which the aerators can be serviced while the system remains in operation.
Due to its improved efficiency, the energy costs of operatin~ the system are also reduced. It is a~ain pointed out that the system can be installed in both new and existing bioloyical reactors.
When the aeration units are used in an earthen basin or lagoon, they protect the underlying surface against erosion. This anti-erosion effect is unnecessary in concrete basins such as the basin 10. If additional protection against erosion is desired in an earthen basin, a flat plastic plate (not shown) can be bolted to the lS flange or base 56 of each aeration unit. This plate extends beyond the base 56 to the extent desired, and it shields the underlying surface against erosion.
Fr~n the foregoiny, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth toyether with other advantayes which are obvious and which are inherent to the structure.
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations.
This is contemplated by and is within the scope of the claims.
Since many possible embodi~nents may be made of the invention without departiny from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limitiny sense.
spaced above block 34 a distance greater than lthe diameter of pipe 26.
Each bracket 32 is applied to the proper aeration pipe 26 5 by initially positioning the block 34 as shown in broken lines in Fig. 4. In this position, the long axis of the block is parallel with the axis of the aeration pipe 26, and the aeration pipe extends between the upper portions of the bracket arms 42. Block 34 is either 10 rotated through ~0 to the solid line position shown in Fig. 4, as indicated by the directional arrow. The free ends 49 of hooks 48 c lear the top of the pipe 26, and the opposing hooks 48 are aligned directly above the aeration pipe. When the pipe is thereaEter raised, it 15 fits closely in both of the hooks 48 and is firmly gripped therein and prevented from floating upwardly away from the floor 16 of the basin. The concrete ballast 46 and block 34 together have enough weight (approximately 85 lbs.) to anchor bracket 32 down on the floor 16 of the 20 basin. The brackets 32 acc~mmodate thermal expansion and contraction of the aeration pipes 26 without affecting the location or operation of the aeration units 50 supplied by the pipes.
25 Each of the lateral aeration pipes 26 supplies compressed air to a plurality of aeration units 50 which are identical to one another. A flexible hose 52 directs the air to each aeration unit 50 from the correspondiny pipe 26. One end of each hose 52 connects with the 30 aeration unit, and the opposite end oE the hose has a T connection with the aeration pipe 26. The aeration units supplied by each pipe 26 are spaced apart at intervals of 4-12 feet.
35 Each hose 52 has a length at least as great as the distance between the pipe 26 and the surface of the waste water. Consequently, each hose is long enough to permit the associated aeration unit 50 to be raised to the ~ 24t7~tio surface of the waste water for servicing while the aeration system remains in operation. This feature permits the systeln to remain on line while servicing of the individual aeration units is carried out.
Referring now to Figs. 5 and 6 in particular, the body of each aeration unit 50 is formed by a thin shell 54. A
flat flange on the periphery of shell 54 provides a stable base 56 which rests on the floor 16 of the basin. Inside of the base 56, shell 54 is shaped to provide a continuous upstanding wall 58 which surrounds a generally horizontal deck 60. The deck 60 is elevated above base 56 but is lower than a horizontal ledge 62 formed on top of the wall 58.
The area located below deck 60 and within the wall 58 defines a ballast compartment 64. The ballast compartment 64 is filled with concrete 66 which serves as ballast to hold the aerator unit down on the floor of the basin. The concrete 66 fills the interior of wall 58 and has a flat bottom surface which is coplanar with the base 56.
The area above deck 60 and within the wall 58 provides an air chamber 68 which receives the compressed air supplied through the flexible hose 52. The end of hose 52 is clamped to a plastic inlet fitting 70 by a hose clamp 72. The fitting 70 extends through wall 58, and its end is threaded at 74 to receive a retainer nut 76 which secures the inlet fitting to the body of the aerator unit. Fitting 70 may be equipped with a balancing valve 78 which can be adjus~.ed to control the flow of air into the air chamber 68. Fitting 70 may also have a check valve 80 which permits the flow of air into air chamber 68 but prevents back flow out oE air chamber. The check valve 80 prevents the entry of water and debris into the piping when the aeration device is inactive for extended periods.
lZ~t7'760 The top of the air chamber 6~ is covered by a flexible plastic difiEuser plate 82 which rests on top of ledge 62 at its periphery. Stainless steel anchor bolts 84 which are embedded in the concrete ballast 66 project upwardly 5 through the periphery of the ;liffuser plate 82. The periphery of the diffuser plate is held down on ledge 62 by stainless steel straps 86 which also receive the anchor bolts 84. Stainless steel nuts 88 are threaded onto bolts 84 and are tightened down against the straps 86 in order 10 to secure the diffuser plate 82 in place, Plate 82 is generally parallel to the deck 60.
The diffuser plate 82 is a -porous plate having a porosity or void ratio of at least 40%. The diffuser plate has a lS large number of small pores which are less than 60 microns in diameter and which are about 35 microns in diameter on average. The thickness of plate 82 is less than one half inch in order to reduce the length of the path that is taken by air passing through its pores. At 20 the same time, the plate is thin enough to readily flex due to abrupt changes in the air pressure. The flexibility of the plate permits it to flex when the air supply is interrupted and then resumed, and the periodic flexing of the E~late dislodges any biological growth that 25 would otherwise tend to build up~ The use oE a thin plate also reduces the pressure losses during operation, An eyebolt 90 is embedded in the concrete ballast 66 of each aeration unit, The eye bolt projects Erom one end of 30 the aerator body, and a flexible rope 92 is tied to each eye bolt. Each rope 92 has a length yreater than the depth of the waste water so that it can extend to the surface with the aerator on the floor 16 of the basin. A
floating rope 94 (Fiy. 2) is tied to the top end of each 35 rope 92 and floats on top of the waste wa ter~ The aerator units 50 can be raised to the surface for servicing simply by pulling the corresponding ropes 92.
Each rope 92 is formed from a substance that does not 1~4'~'7tj0 deteriorate when exposed to the waste water.
In operation of the aeration system, compressed air is supplied to the main header pipe 18 and is directed through the branch pipes 22 to the lateral aeration pipes 26. The throttling valve 24 permit the flow rates to the various aeration pipes 26 to be controlled as desired. Normally, each pipe 26 will receive the same amount of air, although special distribution patterns are possible.
The air in the aeration pipes 26 passes through the flexible hoses 52 to the aeration units 50. The balancing valves 78 can be adjusted to supply each aeration unit 50 with the desired amount of air. By properly adjusting the balancing valves 78, the system can be controlled in a manner to compensate for variations in the elevation of the basin floor and to preven-t starving of the aeration units that are far downstream in a system having long aeration pipes. Normally, the same amount of air is supplied to each aeration unit, although other distribution patterns are possible.
The compressed air that is supplied to each aeration unit 50 enters the air chamber 68. The pores in the diffuser plate 82 provide the only means of egress of air from the air chamber, and the air passes through the diffuser plate and is released thereErom in a series of ultra fine air bubbles. E~ch bubble has a di~neter Less than 60 microns and 35 [nicrons is the normal bubble size. The air bubbles rise through the waste water to provide the desired aeration and mixing action. Due to the small size of the ultra fine air bubbles, there are larye areas of surface contact between the air and liquid, and the transfer of oxygen to the waste water is thus effectively carried out. Since the aerator units 50 are at discrete locations, the bubbles are released from a plurality of discrete locations distributed uniformly on ~247'7~0 -l4-the floor of the basin~
The fine bubbles are generated from the aerator units 50 in a highly intense manner. The flow rate of air through each diffuser plate 82 is between 5 and 50 cfm per square foot of surface area presented on the diffuser plate, depending upon the particular application of the system. The highly intense manner in which the fine air bubbles are genera-t~ provides agitation and mixing of the liquid, resulting in a high liquid velocity. The liquid is thus mixed in a thorough manner and solids are maintained in suspension without the need to provide added energy for the purpose of mixing of the waste water.
The rapid rise rate of the air bubbles and the high liquid velocity creates a large turbulent boil of liquid at the surface of the waste water above each aerator unit. ~he turbulant boil results in substantial surface aeration from atmospheric air above the basin and draws atmospheric air into the waste water. The intense application of fine air bubbles at a relatively small number of locations produces a net oxygen transfer and mixing rate that is superior to conventional fine bubble systems when pumped air, dif~usion, and surface aeration are all taken into account.
The individual aeration units 50 are spaced apart from one another to a greater extent than in conventionaL fine bubble systems. ~y releasing air at high rate~ ~rom a relativeLy smaLl number o~ discrete locations that are widely spaced, improved liquid circulation patterns are achieved. The turbulent circulation patterns of the air bubbles that are released frc~ adjacent aerators impinging against and overlap and interact with one another to provide improved mixing and aeration. At the same time, high pumpage rates of the aerator units distribute air and energy uniformly throughout the basin 10.
1~4~;t~(3 The method and apparatus of the present invention is equally well suited for use in relatively low F/~ systems such as the typical lagoon application shown in Figs. 7 and 8. Numeral 110 generally designates a lagoon having sloping ends 112, sloping sides 114, and a generally horizontal bottom 116.
The aeration system for lagoon llQ is for the most part the same as the system for the concrete basin 10, and the same reference numerals are used in Figs. 7 and 8 for components that are identical to those used in the basin shown in Figs. 1 and 2. The aeration system of the present invention is installed in the lagoon 110 in essentially the same manner as in the concrete basin 10 shown in Figs. 1 and 2. However, the lateral aeration pipes 126 extend across the width of the lagoon 110 and are spaced apart more widely than in the activated sludged application. Also, the steel branch pipes 122 which connect with the main header pipe 118 incline in a manner to conform generally with the incline of the side walls 114. The aerator units 150 used in the lagoon application are identical to the aerators 50 described previously, although the lagoon aerators 150 are normally spaced apart from one another at 20-50 foot intervals due to the low F/M ratio and low oxygen uptake rate of the waste water in the lagoon.
The aeration system operates in the lagoon application in the same manner as in the activated sludge appLicatiorl.
The thorough mixing and air distribution throughout the lagoon makes the process efficient in the dispensed growth biological system as well as in the activated sludge application, The method and apparatus of the present application is flexible enough to accommodate variations in the system loading, season of the year, and type of aerobic process desired. At the same time, the capital cost of the equipment is relatively low since only a relatively few 1~47~7~0 aerator units are required. The maintenance requirements are also reduced due to the ease with which the aerators can be serviced while the system remains in operation.
Due to its improved efficiency, the energy costs of operatin~ the system are also reduced. It is a~ain pointed out that the system can be installed in both new and existing bioloyical reactors.
When the aeration units are used in an earthen basin or lagoon, they protect the underlying surface against erosion. This anti-erosion effect is unnecessary in concrete basins such as the basin 10. If additional protection against erosion is desired in an earthen basin, a flat plastic plate (not shown) can be bolted to the lS flange or base 56 of each aeration unit. This plate extends beyond the base 56 to the extent desired, and it shields the underlying surface against erosion.
Fr~n the foregoiny, it will be seen that this invention is one well adapted to attain all the ends and objects hereinabove set forth toyether with other advantayes which are obvious and which are inherent to the structure.
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations.
This is contemplated by and is within the scope of the claims.
Since many possible embodi~nents may be made of the invention without departiny from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limitiny sense.
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. Apparatus for aerating waste water in a basin, said apparatus comprising:
a main supply pipe for receiving air under pressure;
a plurality of branch pipes each communicating with said main supply pipe to receive air therefrom, each branch pipe extending generally along the bottom of the basin and each branch pipe being a plastic pipe subject to longitudinal expansion and con-traction in response to temperature changes in the waste water;
a plurality of aerators for each branch pipe, each aerator being adapted to release a plurality of fine air bubbles when air is supplied to the aerator and each aerator being provided with ballast to hold the aerator down on the bottom of the basin;
a flexible conduit connecting each aerator with the corres-ponding branch line to provide communication between the branch lines and the corresponding aerators, thereby applying air to the aerators for release of air bubbles therefrom to effect aeration of the waste water, wherein each flexible conduit has a length at least as great as the distance between the corresponding branch pipe and the surface of the waste water to permit each aerator to be raised to the surface of the waste water while the corresponding branch pipe remains on the bottom of the basin and connected to the flexible conduit;
a flexible line for each aerator connected therewith at one end and having an opposite end disposed at the surface of the waste water;
a float for each line connected with said opposite end thereof, said floats floating on the surface of the waste water to maintain said lines accessible from the surface for lifting of the aerators to the surface of the waste water; and at least one hold down bracket for each branch pipe provided with ballast to hold the bracket down on the bottom of the basin, said bracket having means for holding down the branch pipe while permitting the branch pipe to longitudinally expand and contract, whereby said brackets accommodate thermally induced expansion and contraction of the branch pipes and said flexible conduits allow the aerators to remain stationary as the branch pipes expand and contract.
a main supply pipe for receiving air under pressure;
a plurality of branch pipes each communicating with said main supply pipe to receive air therefrom, each branch pipe extending generally along the bottom of the basin and each branch pipe being a plastic pipe subject to longitudinal expansion and con-traction in response to temperature changes in the waste water;
a plurality of aerators for each branch pipe, each aerator being adapted to release a plurality of fine air bubbles when air is supplied to the aerator and each aerator being provided with ballast to hold the aerator down on the bottom of the basin;
a flexible conduit connecting each aerator with the corres-ponding branch line to provide communication between the branch lines and the corresponding aerators, thereby applying air to the aerators for release of air bubbles therefrom to effect aeration of the waste water, wherein each flexible conduit has a length at least as great as the distance between the corresponding branch pipe and the surface of the waste water to permit each aerator to be raised to the surface of the waste water while the corresponding branch pipe remains on the bottom of the basin and connected to the flexible conduit;
a flexible line for each aerator connected therewith at one end and having an opposite end disposed at the surface of the waste water;
a float for each line connected with said opposite end thereof, said floats floating on the surface of the waste water to maintain said lines accessible from the surface for lifting of the aerators to the surface of the waste water; and at least one hold down bracket for each branch pipe provided with ballast to hold the bracket down on the bottom of the basin, said bracket having means for holding down the branch pipe while permitting the branch pipe to longitudinally expand and contract, whereby said brackets accommodate thermally induced expansion and contraction of the branch pipes and said flexible conduits allow the aerators to remain stationary as the branch pipes expand and contract.
2. Apparatus as set forth in claim 1, including valve means associated with each branch pipe for controlling the flow of air thereto from the main supply pipe.
3. Apparatus as set forth in claim 2, including valve means associated with each aerator for controlling the flow of air thereto from the corresponding branch pipe.
4. Apparatus as set forth in claim 1, wherein each of said aerators includes:
an aerator body;
weighted ballast on said aerator body providing same with sufficient weight to remain on the bottom of the basin;
means providing an enclosed air chamber on said aerator body communicating with the corresponding flexible conduit to receive air therefrom; and a porous medium overlying said air chamber on the aerator body, said porous medium having a plurality of small pores pro-viding the sole egress from said air chamber, whereby air is discharged from said air chamber through said pores to release a plurality of fine air bubbles into the basin for aeration of the waste water therein.
an aerator body;
weighted ballast on said aerator body providing same with sufficient weight to remain on the bottom of the basin;
means providing an enclosed air chamber on said aerator body communicating with the corresponding flexible conduit to receive air therefrom; and a porous medium overlying said air chamber on the aerator body, said porous medium having a plurality of small pores pro-viding the sole egress from said air chamber, whereby air is discharged from said air chamber through said pores to release a plurality of fine air bubbles into the basin for aeration of the waste water therein.
5. Apparatus as set forth in claim 4, wherein said ballast comprises concrete and said aerator body serves as a mold for receiving the concrete.
6. Apparatus as set forth in claim 1, wherein said bracket comprises:
a weighted ballast block having a pair of bracket arms extending generally upwardly therefrom and spaced apart from one another a distance at least as great as the diameter of the branch pipe to permit the pipe to extend between the bracket arms; and a pair of opposing hooks on the respective bracket arms for receiving the pipe, said hooks opening downwardly and extending in opposite directions and each having a free end spaced above the block a distance at least as great as the diameter of the pipe, whereby the bracket can be applied to the pipe by positioning said block adjacent the pipe with the pipe extending between said bracket arms, thereafter rotating the block to position said hooks above the pipe with the free ends of each hook clearing the pipe and the hooks aligned with the pipe axis, and finally inserting the pipe into the hooks.
a weighted ballast block having a pair of bracket arms extending generally upwardly therefrom and spaced apart from one another a distance at least as great as the diameter of the branch pipe to permit the pipe to extend between the bracket arms; and a pair of opposing hooks on the respective bracket arms for receiving the pipe, said hooks opening downwardly and extending in opposite directions and each having a free end spaced above the block a distance at least as great as the diameter of the pipe, whereby the bracket can be applied to the pipe by positioning said block adjacent the pipe with the pipe extending between said bracket arms, thereafter rotating the block to position said hooks above the pipe with the free ends of each hook clearing the pipe and the hooks aligned with the pipe axis, and finally inserting the pipe into the hooks.
7. Apparatus as set forth in claim 6, wherein:
said ballast block is a concrete block having an open interior and a web portion dividing said interior into a pair of openings;
said bracket arms extend upwardly through the respective openings in said block on opposite sides of said web portion;
said bracket arms are interconnected by a bight portion of the bracket extending beneath said web portion of the block;
and said openings in the block are substantially filled with ballast material in which portions of the bracket arms are embedded.
said ballast block is a concrete block having an open interior and a web portion dividing said interior into a pair of openings;
said bracket arms extend upwardly through the respective openings in said block on opposite sides of said web portion;
said bracket arms are interconnected by a bight portion of the bracket extending beneath said web portion of the block;
and said openings in the block are substantially filled with ballast material in which portions of the bracket arms are embedded.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000466000A CA1247760A (en) | 1984-10-22 | 1984-10-22 | Method and apparatus for aerating and mixing waste water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000466000A CA1247760A (en) | 1984-10-22 | 1984-10-22 | Method and apparatus for aerating and mixing waste water |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1247760A true CA1247760A (en) | 1988-12-28 |
Family
ID=4128963
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000466000A Expired CA1247760A (en) | 1984-10-22 | 1984-10-22 | Method and apparatus for aerating and mixing waste water |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1247760A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109704449A (en) * | 2019-02-26 | 2019-05-03 | 江苏方洋水务有限公司 | A kind of efficient ozone water treatment system and the preparation of continous way ozone and method for treating water |
| CN111533304A (en) * | 2020-04-10 | 2020-08-14 | 西安建筑科技大学 | Aeration unit and device for simultaneously removing turbid scale of surface water |
-
1984
- 1984-10-22 CA CA000466000A patent/CA1247760A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN109704449A (en) * | 2019-02-26 | 2019-05-03 | 江苏方洋水务有限公司 | A kind of efficient ozone water treatment system and the preparation of continous way ozone and method for treating water |
| CN111533304A (en) * | 2020-04-10 | 2020-08-14 | 西安建筑科技大学 | Aeration unit and device for simultaneously removing turbid scale of surface water |
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