AEROBIC WASTEWATER TREATMENT SYSTEM

Abstract

A wastewater treatment system consisting of a single tank extended aeration activated sludge process with a continuously operating clarifier skimming device which is capable of producing a clear odorless effluent which meets applicable state discharge standards.

Claims

1. A self-contained wastewater treatment system with a continuously operating clarifier skimming device, comprises: (a) a vessel having a bottom, side walls and a lid defining a hollow interior for containing wastewater, said vessel being adapted for installation underground; (b) an influent line positioned at a first upper portion of said vessel for transferring a wastewater stream to said vessel; c) an effluent line positioned at a second upper portion of said vessel generally opposite said influent line for discharging treated wastewater from said vessel; (d) a baffle disposed within said interior, generally between said influent line and said effluent line and extending transversely toward opposing side walls of said vessel, said baffle extending upwardly toward said lid and above an operating water surface elevation within said vessel, wherein said baffle includes a bottom edge separated by a predetermined distance from said bottom of said vessel to define a flow opening, and wherein said baffle defines an upstream aeration chamber and a downstream clarifier chamber within said vessel; (e) said side walls including a downstream end wall, said downstream end wall having a lower inclined wall which intersects said bottom of said vessel adjacent said flow opening; (f) aeration means for producing aeration within said aeration chamber, positioned to produce a generally circular flow path within said aeration chamber, said circular flow path having a flow path component adjacent said flow opening with a flow direction generally away from said clarifier chamber; (g) solids removal means operatively disposed between said aeration chamber and said clarifier chamber for drawing solids in said wastewater within said clarifier chamber and transferring said solids into said aeration chamber; (h) means for producing a selected volume of air at a continuous flow rate in fluid communication with said aeration means and a skimmer; and (I) laundering means adjacent to and in fluid communication with an effluent line preventing solids from exiting through said effluent line said laundering means adjacent and in fluid communication with the effluent line for preventing solids from exiting through the effluent line, wherein an effluent outlet assembly comprises an effluent outlet assembly including a down turned 90 degree elbow conduit having a first and second end, wherein said first end defining a horizontal conduit portion sealably attached to a vessel wall positioned with a top portion extending above a water line and a bottom portion extending below said water line, and said second end defining a vertical conduit portion having a distal end disposed below said water line including at least one opening therein sized for controlling the exit velocity of said water preventing solids from exiting through the effluent line.

2. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 1 wherein said means for producing a selected volume of air at a continuous flow rate in fluid communication with said aeration means and a skimmer comprises a restriction means comprising a simple flat disc having at least one aperture of a selected size there through allowing a selected small amount of air from the compressor to flow through the flow restricting device continually without requiring a valve.

3. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 1, wherein said solids removal means is a skimmer comprising a generally U-shaped tube having a suction portion extending into said clarifier chamber and a discharge portion extending into said aeration chamber, and further including a solids removal air line in fluid communication with said discharge portion wherein air is passed into said discharge portion to create a suction within said suction portion sufficient to collect solids located in said clarifier chamber and transfer said solids to said aeration chamber.

4. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 1 self-contained wastewater treatment system with a continuously operating clarifier skimming device, wherein said baffle includes side edges forming a continuous seal with said opposing side walls.

5. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 1, wherein said aeration means comprises an air diffuser formed into a horizontal conduit having a plurality of air exit holes formed therein.

6. The self-contained wastewater treatment system with a continuously operating clarifier skimming device according to claim 1, further comprising a float switch within said vessel for activating an alarm during a predetermined high water level within said vessel.

7. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 1, wherein said second end defining a vertical conduit portion having a distal end disposed below said water line includes a plurality of drilled holes forming openings sized for controlling the exit velocity of said water preventing solids from exiting through the effluent line.

8. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 2 wherein the volume of air flowing through said air flow restricting device to said skimmer assembly is from about 0.5% to 5.0% of the total volume of air produced by the compressor.

9. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 2 wherein the volume of air flowing through said air flow restricting device to said skimmer assembly is from about 0.5% to 2.0% of the total volume of air produced by the compressor.

10. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 2 wherein the volume of air flowing through said air flow restricting device to said skimmer assembly is about 1% of the total volume of air produced by the compressor.

11. A self-contained wastewater treatment system with a continuously operating clarifier skimming device, consisting of: (a) a vessel having a bottom, side walls and a lid defining a hollow interior for containing wastewater, said vessel being adapted for installation underground; (b) an influent line positioned at a first upper portion of said vessel for transferring a wastewater stream to said vessel; c) an effluent line positioned at a second upper portion of said vessel generally opposite said influent line for discharging treated wastewater from said vessel; (d) a baffle disposed within said interior, generally between said influent line and said effluent line and extending transversely toward opposing side walls of said vessel, said baffle extending upwardly toward said lid and above an operating water surface elevation within said vessel, wherein said baffle includes a bottom edge separated by a predetermined distance from said bottom of said vessel to define a flow opening, and wherein said baffle defines an upstream aeration chamber and a downstream clarifier chamber within said vessel; (e) said side walls including a downstream end wall, said downstream end wall having a lower inclined wall which intersects said bottom of said vessel adjacent said flow opening; (f) aeration means for producing aeration within said aeration chamber, positioned to produce a generally circular flow path within said aeration chamber, said circular flow path having a flow path component adjacent said flow opening with a flow direction generally away from said clarifier chamber; (g) solids removal means operatively disposed between said aeration chamber and said clarifier chamber for drawing solids in said wastewater within said clarifier chamber and transferring said solids into said aeration chamber; (h) restrictive means for producing a selected volume of air at a continuous flow rate in fluid communication with said aeration means and a skimmer comprising a disc having at least one aperture of a selected size there through allowing a selected amount of air from the compressor to flow through the flow restricting device continually without requiring a valve; and (I) laundering means adjacent to and in fluid communication with an effluent line preventing solids from exiting through said effluent line said laundering means adjacent and in fluid communication with the effluent line for preventing solids from exiting through the effluent line, wherein an effluent outlet assembly comprises an effluent outlet assembly including a down turned 90 degree elbow conduit having a first and second end, wherein said first end defining a horizontal conduit portion sealably attached to a vessel wall positioned with a top portion extending above a water line and a bottom portion extending below said water line, and said second end defining a vertical conduit portion having a distal end disposed below said water line including at least one opening therein sized for controlling the exit velocity of said water preventing solids from exiting through the effluent line.

12. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11, wherein said solids removal means is a skimmer comprising a generally U-shaped tube having a suction portion extending into said clarifier chamber and a discharge portion extending into said aeration chamber, and further including a solids removal air line in fluid communication with said discharge portion wherein air is passed into said discharge portion to create a suction within said suction portion sufficient to collect solids located in said clarifier chamber and transfer said solids to said aeration chamber.

13. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11 self-contained wastewater treatment system with a continuously operating clarifier skimming device, wherein said baffle includes side edges forming a continuous seal with said opposing side walls.

14. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11, wherein said aeration means comprises an air diffuser formed into a horizontal conduit having a plurality of air exit holes formed therein.

15. The self-contained wastewater treatment system with a continuously operating clarifier skimming device according to claim 11, further comprising a float switch within said vessel for activating an alarm during a predetermined high water level within said vessel.

16. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11, wherein said second end defining a vertical conduit portion having a distal end disposed below said water line includes a plurality of drilled holes forming openings sized for controlling the exit velocity of said water preventing solids from exiting through the effluent line.

17. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11 wherein the volume of air flowing through said air flow restricting device to said skimmer assembly is from about 0.5% to 5.0% of the total volume of air produced by the compressor.

18. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11 wherein the volume of air flowing through said air flow restricting device to said skimmer assembly is from about 0.5% to 2.0% of the total volume of air produced by the compressor.

19. The self-contained wastewater treatment system with a continuously operating clarifier skimming device of claim 11 wherein the volume of air flowing through said air flow restricting device to said skimmer assembly is about 1% of the total volume of air produced by the compressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] A better understanding of the present invention will be had upon reference to the following description in conjunction with the accompanying drawings in which like numerals refer to like parts throughout the views wherein:

[0034] FIG. 1 is a top view of a preferred embodiment of the present invention;

[0035] FIG. 2 is a side view of a laundering means attaching to the effluent line;

[0036] FIG. 3 is an end view of the laundering means of FIG. 2;

[0037] FIG. 4 is a side elevation sectional view of the present invention shown in position buried beneath the surface of the ground;

[0038] FIG. 5 is a detailed sectional view of the skimmer assembly;

[0039] FIG. 6 is perspective view including a cut-away section showing the flow path of the system and the baffle and air diffuser within the aeration chamber; and

[0040] FIG. 7 shows an exploded view of a section of the conduit extending from the air compressor to the skimmer and the air flow restriction device comprising a washer having an aperture therein for insertion in the conduit; and

[0041] FIG. 8 shows an assembled view of the section of the conduit extending from the air compressor to the skimmer and the air flow restriction device of FIG. 7, wherein the washer having an aperture therein is inserted into the conduit.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms a, an, and the may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms comprises, comprising, including, and having, are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0043] When an element or layer is referred to as being on, engaged to, connected to, or coupled to another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being directly on, directly engaged to, directly connected to, or directly coupled to another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., between versus directly between, adjacent versus directly adjacent, etc.). As used herein, the term and/or includes any and all combinations of one or more of the associated listed items.

[0044] Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as first, second, and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0045] Spatially relative terms, such as inner, outer, beneath, below, lower, above, upper, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the Figures. For example, if the device in the Figures is turned over, elements described as below or beneath other elements or features would then be oriented above the other elements or features. Thus, the example term below can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0046] As used herein, the term about can be reasonably appreciated by a person skilled in the art to denote somewhat above or somewhat below the stated numerical value, to within a range of 10%.

[0047] The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout.

[0048] The apparatus of the present invention, designated by numeral 10 in the drawings, includes a vessel 11 having a bottom 12 which is preferably rectangular and four upstanding vertical side walls 13-16 which are connected edge-to-edge. A lid 17 forms a sealed closure over the vessel 11 to define an interior 18 which can contain a fluid volume therein. Access hatch 19 allows periodic inspection of the unit for purposes of repair and/or maintenance and vent 33 extends above the surface of the ground.

[0049] The interior 18 of the vessel 11 comprises a pair of separate chambers including an aeration chamber 21 and a clarifier chamber 22. The aeration chamber 21 and clarifier chamber 22 are defined and separated by an upstanding vertical and transversely extending baffle 23 which is preferably connected at its upper edge 24 to lid 17. The bottom 25 of the baffle 23 is positioned near the bottom 12 of the vessel 11, but does not touch the bottom 12. Baffle 23 preferably forms a continuous seal and connection with side walls 14 and 15 so that fluid can only flow from one end of vessel 11 to the other under baffle 23 and more particularly under the bottom edge 25 thereof.

[0050] Downstream of baffle 23 is an inclined wall 26 which is connected to the bottom 12 of vessel 11 and also to side wall 16. An opening 28 defines a flow zone from aeration chamber 21 and into clarifier 22. Flow opening 28 thus is the relatively small area defined by bottom 25 of baffle 23, and by side walls 14 and 15 and by the bottom 27 of inclined wall 26.

[0051] By positioning the bottom inclined wall 26 adjacent the bottom 25 of baffle 23, a small flow zone is produced. Also, the inclined wall 26 is inclined sufficiently so that solid material cannot collect upon it. A suitable inclination for wall 26 would be at least fifty-three degrees (53 degrees) from horizontal. Thus, any solid matter which might flow through flow opening 28 and into clarifier 22 will settle upon inclined wall 26 and slide downwardly until it reaches the bottom 27 of inclined wall 26. This places any solid material which might enter clarifier 22 back adjacent flow opening 28 so that turbulence is created in aeration chamber 21 by diffuser assembly 38 can carry away suspended solid material form the mixed liquor back into aeration chamber 21. Arrows 45 illustrate a circular or rolling flow pattern within aeration chamber 21 which creates a flow path component at opening 28 away from clarifier 22. Notice that inclined wall 26 extends fully across vessel 11 between side walls 14 and 15 and from side wall 16 forwardly to bottom edge 27. Thus, any solid material over the entire horizontal cross-section of clarifier 22 will be channeled back to flow opening 28.

[0052] Aeration chamber 21 contains a diffuser assembly 38 which is positioned generally under inlet 29 and at the bottom of vessel 11 adjacent side wall 13. Diffuser assembly 38 preferably includes one or more aspirations fluidically connected to an air line 42 extending upwardly and fluidically connected to air line 74 which extends through the lid 17 or side wall 13 and out of vessel 11. Air is pumped continuously through air line 74 and 42 by a single outlet compressor/blower 80 located at ground level above the vessel 11. The diffuser includes a plurality of side openings or apertures 43 spaced apart along the sides of the diffuser. It is important that side openings 43 be placed on the sides of the diffuser 38 as opposed to the top or bottom, so that air bubbles may exit laterally from the diffuser 38. Prior art diffuser assemblies suffered from frequent clogging of the openings by solids either falling into the openings on the tops of the conduit or closing such openings on the bottoms of the conduit by accumulation of solids at the bottom of the vessel 11. The diffuser minimizes the likelihood that settleable solids will clog the openings 43, thus ensuring greater aeration efficiency. Also, the diffuser assembly 38 resting on the bottom 12 of the vessel 11, prevents it from walking away from the side wall 13 during operation. This is a significant advantage over prior art diffusers, because undesirable movement of the diffuser causes an interruption and/or nonuniformity of the necessary continuous flow path 45 within the aeration chamber 21. In one preferred embodiment, approximately 99 percent of the air from the compressor exits through the diffuser 38 and about one percent of the air exits through conduit 74 which is reduced in diameter to about inch diameter line and shown as conduit 75 in which an air flow restricting device 36 is inserted prior to the skimmer assembly 34. The amount of air flowing through the restricting device is preferably from 0.5 to 5.0%, more preferably from 0.5 to 2.0% and more preferably about 1%.

[0053] Wastewater enters the aeration chamber 21 through inlet pipe 29 and clarified supernatant liquid exits the clarifier 22 through a launder 31 to outlet pipe 30. As shown in more detail in FIGS. 2 and 3, he wastewater treatment system may further comprise laundering means adjacent the effluent line for preventing solids from exiting through the effluent line. In a preferred embodiment, the laundering means includes an effluent outlet assembly comprising a down turned 90 degree elbow conduit having a first and second end, wherein the first end 60 defines a horizontal conduit portion sealably attached to the vessel wall positioned with a top portion above the water line and bottom portion below the water line. The second end 62 defines a vertical conduit portion having a distal end disposed below the water line. At least one hole, a plurality of apertures or holes, or more preferably a pair of holes are formed or drilled in a tube, pipe or other conduit whereby the volume of fluid is determined by the size of the holes. Preferably the hole size is utilized to control water exit velocity resulting in a laundering means 66 and 67 for preventing solids from exiting through the effluent line. The down turned conduits having openings therein provide sufficient surface area for efficient discharge and replaces the weir type device in the prior art devices while allowing more control of the velocity of the fluid for better clarifier results.

[0054] Notably, the effluent line 30 is at the same height, which is approximately equal to the height of liquid within vessel 11 under normal operating conditions. Much of the solids that might exist in clarifier 22 are laundered away from the effluent line 30. It should be understood that the launder 31, as specifically disclosed herein, may be effected in a multitude of ways not employing pipes. For example, any structural arrangement which establishes a single quiescent zone prior to passing of the liquid over a weir would be functionally equivalent.

[0055] A skimmer assembly 34, or solids removal means, is shown for the purposes of transferring solids from the clarifier 22 back into the aeration chamber 21. Conveniently, the skimmer 34 acts as an air lift pump and may be powered by the same air compressor/blower 80 that operates the diffuser assembly 38, as will be explained in further detail below.

[0056] Referring specifically to FIG. 5, the skimmer 34 is constructed from a generally U-shaped pipe 70 which is attached across the baffle 23, wherein the U-shaped pipe 70 includes a suction portion 71 whose terminal end is positioned immediately below the normal operating liquid level within the clarifier 22, as well as a discharge portion 72 whose terminal end is positioned above the normal operating liquid level within the aeration chamber 21. In a preferred embodiment, an air line 74 is fluidically connected on one end 73 to the discharge portion 72 of the skimmer 34 below the liquid level in the aeration chamber 21.

[0057] Skimmer air line 37 extends across aeration chamber 21 and is fluid connection at its opposite end 74 to a air restricting device 36 which is in turn in fluid connection to the diffuser air line 42 which are supplied air from a single outlet compressor/blower unit 80 in fluid communication therewith. The compressor/blower 80 is in turn fluidically connected to the diffuser and skimmer air line 74. The single outlet compressor/blower 80 provides the flow of air to the air flow restricting device 36 and then to the skimmer in order to control the vacuum created by the skimmer 34 which is operated to provide the requisite effective amount of air flow to remove floating solids from the clarifier 22 without significantly detracting from the aeration and turbulence created by the diffuser assembly 38.

[0058] Under normal operating conditions and for most of the time, air from the external compressor/blower 80 travels through the air line 74 for operation of the diffuser assembly 38 air flow restricting device 36 and then subsequently to the skimmer 34. The flow restricting device 36 comprises restriction means such as a simple flat disc, blank, or washer having at least one aperture 39 of a selected size for to allow a selected small amount of air from the compressor to flow through the flow restricting device 36 continually without requiring a valve as best illustrated in FIGS. 7 and 8. It is contemplated that a valve, section of conduit having a reduced air flow or other means can be used to restrict the air flow to a selected rate and/or volume; however, the present system does not require opening and closing or adjustment of the valve to operate continuously. The rate of air flow can be selected by simply choosing a washer having an aperture of a different size, increasing the number of apertures or increasing the pressure of the air flow from the compressor. Air bubbles exiting the end 73 of the skimmer travel upward through the discharge portion 72 of the skimmer 34, which forces liquid within the U-shaped pipe 70 to move from the clarifier 22 into the aeration chamber 21. The suction created near the surface of the clarifier 22 cause any floating solids to be sucked into the skimmer 34 and deposited back into the aeration chamber 21. By way of example, skimmer 34 is operated at a selected air flow rate. The continuous skimming operation performed continually drastically reduces the solids present in the clarifier 22, forcing those solids to be further biodegraded.

[0059] Optionally, an alarm system can be implemented to detect flooding conditions within the vessel 11 or a loss of power to the compressor/blower assembly 80. As shown in figures, a normally closed float switch 69 is affixed within the clarifier 22 just above the normal liquid level. The float switch 69 is connected to the alarm circuitry by a normally open float. When the float switch 69 rises, indicating a high water level, the normally open switch closes and activates the alarm circuitry indicating a high water condition. The alarm may be any audible and/or visual indication that a high water condition is present. The activation of alarm also occurs in the event that power is interrupted to the transformer.

[0060] Thus, the apparatus of the present invention is a paragon of simplicity, yet has been found to be highly efficient in the treatment of wastewater, and superior in terms of minimizing effluent solids in comparison to prior art systems. It is believed that the use of the laundering means 31 even without the use of the skimmer 34, provide significant advantages in treatment efficiency over the prior art. Likewise, it is believed that the use of the skimmer 34, even without the use of the laundering means 31, provides similar advantages. Therefore, the scope of the present invention should not be viewed as being limited to having each and every one of the aforementioned components. Rather, the invention affords the user to include some or all of the novel features discussed herein to achieve varying ranges of treatment efficiency depending upon resources and the need to comply with any applicable environmental and/or health regulations.

[0061] The foregoing detailed description is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modification will become obvious to those skilled in the art upon reading this disclosure and may be made upon departing from the spirit of the invention and scope of the appended claims. Accordingly, this invention is not intended to be limited by the specific exemplification presented herein above. Rather, what is intended to be covered is within the spirit and scope of the appended claims.