The present invention relates generally to wastewater treatment, and, more particularly, to retrievable wastewater aeration systems for use in wastewater treatment.
Maintenance of wastewater aeration systems typically requires that the associated wastewater treatment tank be drained in order to access diffusers and conduits at the bottom of the tank. Such maintenance can be very burdensome and costly. Most wastewater treatment facilities only allot small amounts of time to conduct such maintenance. Moreover, many wastewater treatment tanks were not properly designed with drains, meaning draining a wastewater treatment tank requires hiring a contractor with big pumps, and then spending hours or days hosing off the tank and shoveling solids off the floor to prepare it for entry by maintenance personnel. In many cases, time spent in the tank requires special confined-space training and/or certification with full safety equipment.
Considering these difficulties, wastewater aeration systems that may be retrieved from a wastewater treatment tank to allow maintenance outside the tank are becoming more popular and are also required by statute in a number of states when a plant is built without sufficient aeration tank redundancy. Such systems may be lifted from a tank via a winch, crane, or boom truck, sometimes in combination with a pontoon boat. Nevertheless, such liftable systems suffer from several disadvantages. They are typically formed from steel and concrete, and are therefore heavy, bulky, and expensive to manufacture. In addition, there are often a lot of support structures involved with these retrievable systems (e.g., frames, cables, and ropes), and these support structures can become entangled with rags in the wastewater. These rags can make the aeration system so heavy or bulky that it is impossible to lift. Land is also often scarce at wastewater treatment plants. Thus, there simply may not be enough room next to a wastewater treatment tank for placing the additional equipment involved in retrieving a liftable aeration system, and for maintaining the system once out of the tank.
For the foregoing reasons, there is a need for new retrievable aeration systems for use in treating wastewater.
Embodiments of the present invention address the above-identified needs by providing novel retrievable aeration systems that may be easily retrieved-from and deployed-into wastewater treatment tanks via tracks that run into and adjacent to the wastewater treatment tanks.
Aspects of the invention are directed to an apparatus for use with a wastewater treatment tank. The apparatus comprises a track, a plurality of pipe modules coupled to the track such that the plurality of pipe modules are translatable along the track, and a plurality of diffusers attached to the plurality of pipe modules. Each pipe module of the plurality of pipe modules defines a respective partially curved mating surface, a respective partially curved mating cavity, and a respective gas passage passing therethrough. The respective partially curved mating surface of a first pipe module of the plurality of pipe modules is inserted into the respective partially curved mating cavity of a second pipe module of the plurality of pipe modules, while the respective partially curved mating surface of the second pipe module of the plurality of pipe modules is inserted into the respective partially curved mating cavity of a third pipe module of the plurality of pipe modules. Each gas passage of the plurality of pipe modules is in gaseous communication with the other gas passages of the plurality of pipe modules. Each diffuser of the plurality of diffusers is in gaseous communication with the gas passages of the plurality of pipe modules.
Additional aspects of the invention are directed to a method for treating wastewater in a wastewater treatment tank. A track is installed, and a plurality of pipe modules are coupled to the track such that the plurality of pipe modules are translatable along the track. Each pipe module of the plurality of pipe modules defines a respective partially curved mating surface, a respective partially curved mating cavity, and a respective gas passage passing therethrough. A plurality of diffusers are also attached to the plurality of pipe modules. Each pipe module of the plurality of pipe modules defines a respective partially curved mating surface, a respective partially curved mating cavity, and a respective gas passage passing therethrough. The respective partially curved mating surface of a first pipe module of the plurality of pipe modules is inserted into the respective partially curved mating cavity of a second pipe module of the plurality of pipe modules, while the respective partially curved mating surface of the second pipe module of the plurality of pipe modules is inserted into the respective partially curved mating cavity of a third pipe module of the plurality of pipe modules. Each gas passage of the plurality of pipe modules is in gaseous communication with the other gas passages of the plurality of pipe modules. Each diffuser of the plurality of diffusers is in gaseous communication with the gas passages of the plurality of pipe modules.
Even additional aspects of the invention are directed to a wastewater treatment system. The wastewater treatment system comprises a wastewater treatment tank, a track, a plurality of pipe modules coupled to the track such that the plurality of pipe modules are translatable along the track, and a plurality of diffusers attached to the plurality of pipe modules. A portion of the track occupies the wastewater treatment tank. Each pipe module of the plurality of pipe modules defines a respective partially curved mating surface, a respective partially curved mating cavity, and a respective gas passage passing therethrough. The respective partially curved mating surface of a first pipe module of the plurality of pipe modules is inserted into the respective partially curved mating cavity of a second pipe module of the plurality of pipe modules, while the respective partially curved mating surface of the second pipe module of the plurality of pipe modules is inserted into the respective partially curved mating cavity of a third pipe module of the plurality of pipe modules. Each gas passage of the plurality of pipe modules is in gaseous communication with the other gas passages of the plurality of pipe modules. Each diffuser of the plurality of diffusers is in gaseous communication with the gas passages of the plurality of pipe modules.
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
The present invention will be described with reference to illustrative embodiments. For this reason, numerous modifications can be made to these embodiments and the results will still come within the scope of the invention. No limitations with respect to the specific embodiments described herein are intended or should be inferred.
As used in the present description and the appended claims, the term “attached” means joined, connected, or bound to another object with or without intervening elements. The terms “above,” “lateral to,” “vertically,” and “parallel to” are referenced to a retrievable aeration system as the retrievable aeration system is oriented in
The retrievable aeration system 100 depends on a plurality of pipe modules 105 that are coupled to a track 110 such that the plurality of pipe modules 105 are translatable along the track 110 (i.e., the pipe modules 105 are translatably coupled to the track 110). As will be detailed below, these pipe modules 105 utilize a novel “ball and socket” means of interconnection that allows a train of pipe modules 105 to bend as it progresses along the track 110. The track 110 runs along a bottom 1010 of the wastewater treatment tank 1000, ascends vertically up a sidewall 1015 of the wastewater treatment tank 1000, and then runs above the ledge 1005 on a moveable table 1020, which supports the track 110 above the ledge 1005. A winch 1025 at an end of the moveable table 1020 aids with retrieval. A plurality of tube diffusers 115 are attached to about half of the pipe modules 105. These tube diffusers 115 are disposed just above the bottom 1010 of the wastewater treatment tank 1000 when the retrievable aeration system 100 is in its deployed state, as shown in
Additional details of the retrievable aeration system 100 and the wastewater treatment tank 1000 are shown in
Further details of the pipe modules 105 and the tube diffusers 115 are shown in
A split flange 175 (i.e., a flange formed of two halves) acts to capture the partially curved mating surface 155 of one pipe module 105 in the partially curved mating cavity 160 of an adjacent pipe module 105. A perspective view of one-half of the split flange 175 is shown in
Each pipe module 105 further comprises a respective plate 195 attached to the bottom of its body 150. Each plate supports two shafts 200 and two rollers 135. Plate bolts 205 pass through the plates 195 to attach the plates 195 and into internally threaded receiving holes in the bodies 150.
The bodies 150 of the pipe modules 105 describe grooves 207 in their top and bottom surfaces (
Attachment of the tube diffusers 115 to the sides of the pipe modules 105 is via threaded receiving holes 215 in the bodies 150 of the pipe modules 105 that are intended to support the tube diffusers 115, in combination with corresponding threaded nipples 220 at a respective end of each one of the tube diffusers 115. The tube diffusers 115 are otherwise conventional and will be familiar to one having ordinary skill in the relevant arts. Aspects of tube diffusers are also described in, as just one example, U.S. Pat. No. 9,440,200 to Frankel et al., entitled “Tube Diffuser,” which is hereby incorporated by reference herein.
With respect to the transport of pressurized air, each pipe module 105 defines a respective gas passage 225 passing therethrough, which, in turn, merges with the two respective receiving holes 215 of each pipe module 105 (
Configured in the manner shown in
It should again be emphasized that the above-described embodiments of the invention are intended to be illustrative only. Other embodiments can use different types and arrangements of elements for implementing the described functionality. These other embodiments would also fall within the scope of the invention.
For example, while the retrievable aeration system 100 shown in the figures above is formed of interconnected pipe modules 105 for its entire length, in alternative embodiments, some portion of those pipe modules 105 may be replaced by a flexible pipe.
In the first alternative retrievable aeration system 1400, the flexible pipe 1405 is supported by a series of spaced-apart pipe support assemblies 1420 placed along its length.
In other alternative embodiments falling within the scope of the invention, different forms of track may be utilized.
Lastly, in even other alternative embodiments of the invention, a retrievable aeration system may use diffusers different from those utilized above.
Disc diffusers (also called “fine bubble diffusers”) are commonly available, and their construction and function will already be familiar to one having ordinary skill in the art. They are also described in, for example, U.S. Pat. No. 9,498,756 to Frankel et al., entitled “Assembly for Wastewater Treatment,” which is hereby incorporated by reference herein.
The pipe modules 105, 1605, 1805 set forth above may be formed of any suitable material, including, as just one example, plastic. In one or more embodiments, the plastic pipe modules 105, 1605, 1805 may be formed by injection molding. Injection molding will be familiar to one having ordinary skill in the relevant manufacturing arts. It is also described in, for example, D. V. Rosato et al., “Injection Molding Handbook,” Springer Science and Business Media, 2012, which is hereby incorporated by reference herein. The tracks 110, 1610 may be formed of, for example, metal (e.g., stainless steel).
The above described embodiments, and more generally, embodiments in accordance with aspects of the invention have several advantages. As just indicated, many components may be formed of economical materials, like plastic. At the same time, although retrievable from a wastewater treatment tank and serviceable outside the tank, the retrievable aeration systems do not require three-dimensional tubular or cable frames, and do not require cranes, boom trucks, or boats for maintenance. Instead, a light-duty winch may be utilized. The retrievable aerations systems are also modular, meaning that they may be mass produced, stored and shipped in boxes, and there is little or no need for any custom metal or plastic fabrication.
At the same time, retrievable aeration systems in accordance with aspects of the invention may accommodate many different types of diffusers, and can be maintained on narrow concrete walkways (i.e., ledges) between wastewater treatment tanks. If necessary, for example, the trains of pipe modules may be made to make several 90-degree turns to accommodate the layout of the wastewater treatment facility, even passing over obstructions such as guardrails and the like.
After maintenance, retrievable aeration systems in accordance with aspects of the invention can be re-installed into a wastewater-filled wastewater treatment tank, and, because they are translated along a fixed track, will return to the same position in the wastewater treatment tank, unlike liftable grids which typically require a lot of clearance when being dropped back into place in a filled wastewater treatment tank so that they do not strike or overlap the next grid. Locking mechanisms may be added to the retrievable aeration systems to lock the systems in a particular place on their track if deemed necessary. These locking mechanisms may be actuated by one or more cables accessible outside the wastewater treatment tank. Once in place, the present retrievable aeration systems with their fixed tracks will resist any horizontal loads from flow boosters and the like. Retrievable aeration systems in accordance with aspects of the invention may also be readily retrieved from and deployed into covered wastewater treatment tanks without needing to remove the cover.
All the features disclosed herein may be replaced by alternative features serving the same, equivalent, or similar purposes, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.
Any element in a claim that does not explicitly state “means for” performing a specified function or “step for” performing a specified function is not to be interpreted as a “means for” or “step for” clause as specified in AIA 35 U.S.C. § 112(f). In particular, the use of “steps of” in the claims herein is not intended to invoke the provisions of AIA 35 U.S.C. § 112(f).