Abstract:
A wastewater disposal system passively accumulates and dumps wastewater, which may advantageously prevent ice from forming in a drain line. The system includes a dump having two compartments. The dump is pivotally mounted to oscillate between a first and a second position under the influence of the weight of wastewater accumulated in the compartments. In the first position, a first compartment is aligned with an inlet while a second compartment is tilted to discharge or dump accumulated wastewater. In the second position, the second compartment is aligned with the inlet and the first compartment tilted to discharge or dump accumulated wastewater. Such may be useful at hydrocarbon well heads, particularly in cold environments.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims benefit under 35 U.S.C. 119(e) of U.S. Provisional Patent Application Ser. No. 61/115,788, filed Nov. 18, 2008 and entitled “APPARATUS, SYSTEM AND METHOD FOR DISCHARGING WATER FROM A WELL-HOUSE,” which is incorporated herein by reference in its entirety. 
     
    
     BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates generally to discharging wastewater from well houses, and more particularly to a device for flushing ice crystals from gas or oil well house drain lines so as to prevent ice blockages during cold weather. 
         [0004]    2. Description of the Related Art 
         [0005]    Gas and oil wells typically have a well house proximal the well head for housing various mechanical and other well service equipment. Some wells produce wastewater along with the hydrocarbon stream, which wastewater needs to be separated from the production stream and then evacuated from the well house. The amount of wastewater produced varies between wells such that some wells require a substantial discharge pond. Further the evacuation of wastewater from the well house, which can be achieved using a simple drain line in warm weather, can be a serious problem during the winter in regions of the world where the temperatures drop low enough to cause the wastewater to freeze inside or at the end of the drain line sufficiently to block the exit of wastewater (plugging the drain line) causing wastewater to backup inside the well house and/or to buildup in large ice blocks adjacent the well house. While denominated as wastewater because the function of the well is to produce hydrocarbons, the wastewater may in some applications be used for some beneficial purpose or recycled. 
         [0006]    A simple continuous flow drain line typically has insufficient volume of flow to prevent freezeup since the trickle of small quantities of wastewater allows the slow moving stream to freeze completely and buildup in layers that result in a long solid plug of ice in severe weather. 
         [0007]    Various efforts have been attempted to solve the problem of ice buildup in the drain line by allowing a larger quantity of wastewater to collect (e.g., using a toilet like tank and flapper assembly) inside the well house and then release that quantity of wastewater all at once so as to use the head pressure of the reservoir to flush the lines much like a conventional flush toilet. Disadvantageously, while this method works in respect of flushing the lines once operated, there is a need for human or other deliberate intervention to operate the flapper once the reservoir fills. If the well house is left unattended (as often happens in remote northern locations) then the flapper tends to float up a little once the tank fills such that the wastewater trickles out past the flapper in much the same manner as any continuous drain. 
         [0008]    There is of course the option of using level sensor devices and electronic or electro-mechanical means to periodically operate the flapper handle as often as required, but these automated systems tend to be relatively complex, expensive to install, and require maintenance due to the often caustic nature of the wastewater that is discharged from the wastewater emitter in a typical well house. 
         [0009]    It is therefore desirable to identify a simple, reliable, inexpensive, and low maintenance means to periodically discharge wastewater from a gas or oil well house in sufficient volume to flush the drain line of ice crystals and prevent blockage. 
       BRIEF SUMMARY 
       [0010]    As described in detail herein, an apparatus collects wastewater streams, the low volume flow from which streams by itself may be insufficient to maintain the drain lines free of ice in cold weather, in a two compartment dump that gravitationally tips over about a pivot point positioned to allow tipping to occur each time the wastewater level therein shifts the dump&#39;s center of gravity off balance. Once tipped the dump&#39;s open topped design allows one dump compartment to completely empty while the second dump compartment substantially fills with wastewater until the wastewater level therein again shifts the center of gravity of the dump off balance causing the dump to tip back in the opposite direction. Advantageously, this tipping repeats, continuously alternating the dumping action between opposing dump compartments—all without human intervention. 
         [0011]    As described in detail herein, a system includes the above apparatus mounted as high as practical inside the well house in order take maximum advantage of the head pressure available from the wastewater dumped into the chamber—thereby increasing the flushing pressure available to clear ice crystals from the drain line through which the wastewater is released from the well shack to the outside, for example into a discharge wastewater collection/retention/evaporation pond. The double-sloped design of the bottom of the tub chamber further facilitates flushing by tending to induce a swirling action in the wastewater as it exits the apparatus into the drain lines of the well house. 
         [0012]    A wastewater disposal apparatus, for use in a well house accumulating wastewater from a hydrocarbon well head wastewater emitter and then using said wastewater to flush drain lines and prevent ice blockage, may be summarized as comprising: an inlet fluidly coupled to said wastewater emitter; a dump having two compartments alternately accumulating wastewater in a cycle from said inlet, the dump further having a pivot point, the first of said compartments accumulating wastewater until the dump&#39;s center of gravity shifts causing the dump to be off balance and tip in a first direction about said pivot point thereby dumping said accumulated wastewater, whereupon the second of said compartments accumulates wastewater until the dump&#39;s center of gravity shifts causing the dump to be off balance and tip in a second direction about said pivot point thereby dumping said accumulated wastewater and permitting said dump compartments to repeat said cycle; a chamber pivotally coupled to said dump, for collecting said dumped accumulated wastewater; and an outlet fluidly coupling said chamber to a drain line, for disposing of said wastewater outside said well house. 
         [0013]    It is to be understood that the inlet, dump, chamber, and outlet need not be mechanically coupled to one another so long as they are operationally coupled—and means for permitting the dump to pivot are provided according to the resulting alternate embodiment of the apparatus. 
         [0014]    An apparatus may be summarized as comprising: an inlet for receiving a trickle of wastewater from a hydrocarbon well house wastewater emitter; a tub chamber, fluidly coupled to said inlet, for directing wastewater to a drain; a double-sided dump subassembly pivotally coupled at an offset point to the interior of said tub chamber, said dump subassembly having a first and second side compartment, for collecting said wastewater alternately in said first and second side compartments, said dump subassembly pivoting about a pivot point each time said first side compartment substantially fills with wastewater whereupon wastewater dumps from said first side compartment into said tub chamber, further whereupon wastewater is collected in said second side compartment until said second side compartment substantially fills with wastewater whereupon wastewater dumps from said second side compartment into said chamber; and an outlet fluidly coupled to said tub chamber for evacuating dumped wastewater to a drain. 
         [0015]    A wastewater disposal system, for use with a well house accumulating wastewater discharged from a hydrocarbon well head wastewater emitter and then using said wastewater to flush drain lines and prevent ice blockage, may be summarized as comprising: discharge reception means, for transferring a trickle of dripping wastewater from a hydrocarbon well house wastewater emitter to a wastewater accumulation and flushing apparatus; a wastewater accumulation and flushing apparatus operationally coupled to said discharge reception means, the apparatus having an outlet through which to rapidly flush said accumulated wastewater; and a drain line fluidly coupled to said outlet, for disposing of said wastewater from said well house. 
         [0016]    A method for disposing of a trickle of wastewater from a hydrocarbon well house, may be summarized as comprising: receiving dripping wastewater from a hydrocarbon well-head wastewater-emitter; accumulating said dripping wastewater to form a body of wastewater sufficient in volume to flush drain lines and prevent ice blockage, said accumulation to take place in a pivoting double-sided dump at a location where the formation of said body of wastewater shifts the balance of said pivoting dump; and permitting said shift of balance to cause the dumping of a first side of said double-sided dump simultaneously initiating the accumulation of said dripping wastewater in a second side of said double-sided dump so as to initiate a cycle alternately dumping each said body of wastewater. 
         [0017]    A wastewater disposal system may be summarized as comprising: an inlet configured to fluidly couple to a source of wastewater; a dump pivotally coupled to oscillate back and forth about a pivot axis between a first position and a second position, the dump having two compartments that are open at a respective top of the compartments, the compartments each having a respective interior to accumulate wastewater therein, a shape of the interiors such that a respective centroid of the interiors is each laterally offset from the pivot axis, and where in the first position the first one of the compartment is in a substantially upright position with the open top of the first one of the compartments aligned with the inlet to accumulate wastewater from the inlet into the interior of the first one of the compartments and the second one of the compartments is in a tilted position with at least a portion of the open top of the second one of the compartments spaced at or below the pivot axis to dump at least some wastewater accumulated in the second one of the compartments and in the second position the first one of the compartments is in a tilted position with at least a portion of the open top of the first one of the compartments spaced at or below the pivot axis to dump at least some wastewater accumulated in the first one of the compartments and the second one of the compartments is in a substantially upright position with the open top of the second one of the compartments aligned with the inlet to accumulate wastewater from the inlet into the interior of the second one of the compartments, and where the dump is passively driven by the accumulation of wastewater in and the dumping of wastewater from the first and the second ones of the compartments; a chamber positioned with respect to the dump to collect the accumulated wastewater dumped from each of the first and the second compartments; and an outlet configured to fluidly couple the chamber to a drain line. The wastewater disposal system may further comprise a discharge reception coupled to transfer a trickle of dripping wastewater from a hydrocarbon well house wastewater emitter to the inlet; and the drain line positioned to carry the collected wastewater from a well house. The shape of the interior of the second one of the compartments of the dump is the same as the shape of the interior of the first one of the compartments. The shape of the interiors of the first and the second ones of the compartments are each pyramidal, with an apex at a bottom and a base at the top of the first and the second ones of the compartments. The centroid of the interior of the second one of the compartments is spaced equally from the pivot axis as the centroid of the interior of the first one of the compartments. The wastewater disposal system may further comprise a cover selectively positionable to open and close the chamber. The inlet may be an integral part of the cover. The chamber may include at least one down sloping floor. The outlet may be an integral part of the chamber and the down sloping floor communicates with the outlet. 
         [0018]    A wastewater disposal system to dispose of wastewater from a hydrocarbon well head may be summarized as including a chamber having an interior, a top, a bottom, and an outlet at least proximate the bottom of the chamber, the outlet configured to fluidly couple the interior of the chamber to a drain line; a dump having an interior, a top that is open and a bottom, the dump received in the interior of the chamber and pivotally coupled to oscillate back and forth in the interior of the chamber about a horizontal pivot axis when in use, a shape of the interior of the dump having a centroid that is radially offset from the pivot axis toward the top of the dump; and an inlet positioned relatively above the top of the dump and configured to fluidly couple a source of wastewater from an exterior of the chamber to the interior of the dump, where in a first position the dump is substantially upright in the interior of the chamber with the top of the dump aligned with the inlet to accumulate wastewater from the inlet in the interior of the dump with the top of the dump spaced relatively above the pivot axis, and in a second position the dump is substantially tilted in the interior of the chamber with at least a portion of the top of the dump spaced relatively at or below the pivot axis to dump at least some wastewater accumulated in the interior of the dump into the interior of the chamber, the dump passively pivoted by the accumulation of wastewater in and the dumping of wastewater from the interior of the dump. 
         [0019]    The wastewater disposal system may further include a discharge reception coupled to transfer a trickle of dripping wastewater from a hydrocarbon well house wastewater emitter to the inlet; and the drain line positioned to carry the collected wastewater from a well house. The interior of the dump may have a parabolic shaped cross-section, the apex of the parabolic shaped cross-section being a bottom of the dump. 
         [0020]    The wastewater disposal system wherein the chamber is open at the top may further include a cover selectively positionable to open and close the top of the chamber. The inlet may be an integral part of the cover. The dump may be pivotally coupled to the cover. The dump may be pivotally coupled to the chamber. The chamber may include at least one floor that slopes relatively downward with respect to the top of the chamber. The downward sloping floor may slope toward the outlet of the chamber. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0021]    In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements in the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not drawn to scale, and some of these elements are arbitrarily enlarged and positioned to improve drawing legibility. Further, the particular shapes of the elements as drawn, are not intended to convey any information regarding the actual shape of the particular elements, and have been solely selected for ease of recognition in the drawings. 
           [0022]      FIG. 1  is a perspective view of a wastewater disposal system according to one embodiment of an apparatus according to one illustrated embodiment showing a tub chamber with a lid engaged and closed. 
           [0023]      FIG. 2  is a cross-sectional view of the apparatus of  FIG. 1 , showing a double dump subassembly internal to the tub chamber. 
           [0024]      FIG. 3  is a cross-sectional view of the wastewater disposal system installed in a gas well house, attached to a wastewater emitter assembly, and draining wastewater into a discharge pond, according to one illustrated embodiment. 
           [0025]      FIG. 4  is a perspective view of a wastewater disposal system according to another illustrated embodiment, showing the dump sub-assembly inside the tub chamber. 
           [0026]      FIG. 5  is an isometric view of a wastewater disposal system according to yet another illustrated embodiment, showing a chamber having an outlet proximate a bottom thereof and a cover having an inlet proximate a top thereof. 
           [0027]      FIG. 6  is an exploded view of the wastewater disposal system of  FIG. 5 , showing a dump pivotally coupled within an interior of the chamber. 
           [0028]      FIG. 7  is a cross-sectional view of the wastewater disposal system of  FIG. 5 , showing a parabolic cross-section of the dump and sloped floor of the chamber. 
           [0029]      FIG. 8  is a right side elevational view of the wastewater disposal system of  FIG. 5 , showing the floor of the chamber sloping downward from a rear toward a front of the chamber. 
       
    
    
     DETAILED DESCRIPTION 
       [0030]    In the following description, certain specific details are set forth in order to provide a thorough understanding of various disclosed embodiments. However, one skilled in the relevant art will recognize that embodiments may be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures associated with dump assemblies have not been shown or described in detail to avoid unnecessarily obscuring descriptions of the embodiments. 
         [0031]    Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is as “including, but not limited to.” 
         [0032]    Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” in various places throughout this specification are not necessarily all referring to the same embodiment. Further more, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. 
         [0033]    As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise. 
         [0034]    The headings and Abstract of the Disclosure provided herein are for convenience only and do not interpret the scope or meaning of the embodiments. 
         [0035]    Referring to  FIG. 1  there is illustrated one embodiment of a wastewater collection apparatus denoted generally as  100 , wherein tub chamber  110  has a recessed upper edge  115  into which top  120  slidingly engages to form the upper boundary of the space within tub chamber  110 . The top  120  is selectively removable. Positioned proximal the center (lengthwise) and middle (widthwise) of top  120  there is an inlet  130  being any suitable structure to allow connection to a discharge line (not shown in  FIG. 1 ) from a typical hydrocarbon well house wastewater emitter or source (not shown). Inlet  130  includes an opening the purpose of which is to guide a stream of wastewater into the space within tub chamber  110 . Similarly positioned proximal the center and middle of the bottom of tub chamber  110  there is provided outlet  140  being any suitable structure to allow connection to a typical drain line (not shown in  FIG. 1 ) through which wastewater is evacuated from a well house. On an exterior face of tub chamber  110  there are provided any suitable mounting structure, for example mounting brackets  150 , to permit apparatus  100  to be securely fastened (typically to the interior wall of a well house) so as to support the weight of the apparatus and wastewater that it collects or accumulates between dumping cycles. 
         [0036]    According to one embodiment of apparatus  100 , most of the wastewater collection apparatus  100  is made from any suitable molded plastic, graphite or similar lightweight material that is corrosion resistant, durable, and water-proof, in a thickness sufficiently strong to carry the load of wastewater for which it is designed, but light enough in weight so as to be operationally compatible with the weight of the volume of wastewater collected or accumulated by the design. It is to be understood that the dimensions of apparatus  100  will be determined by the capacity required for the installation at which the apparatus  100  is applied. In cases where the well produces large volumes of wastewater, a higher capacity unit may be installed, however it is contemplated that an apparatus  100  capable of dumping a few gallons per cycle will be appropriate for most installations. 
         [0037]    Referring to  FIGS. 2 and 4  the interior components of apparatus  100  are illustrated showing dump  200  that comprises two compartments  205  and  210  to alternately collect or accumulate wastewater dripping into tub chamber  110  through inlet  130 . The sub-assembly dump  200  includes pivot pin  220  that is secured to the interior of tub chamber  110  by any suitable structure that permits dump  200  to pivot about a pivot axis defined by the pin  220 . According to a preferred embodiment of apparatus  100  pin  220  slidingly engages a slot (not shown) molded into the interior side walls of tub chamber  110 —so as to be easily removable for de-scaling and cleaning—but still maintain the position of dump  200  substantially aligned with the center (lengthwise) and middle (laterally) of inlet  130  and at a height above outlet  140  that permits dump  200  to tip in either direction (i.e., towards either end of tub chamber  110 ), oscillating back and forth between a first and a second position, without interference from any portion of the interior of tub chamber  110  or from the wastewater swirling through outlet  140  during each dump cycle. In the first position, the first one of the compartments  205  is in a substantially upright position with the open top of the first one of the compartments  205  aligned with the inlet  130  to accumulate wastewater from the inlet  130  into the interior of the first one of the compartments  205  and the second one of the compartments  210  is in a tilted position with at least a portion of the open top of the second one of the compartments  210  spaced at or below the pin  220  and its associated pivot axis to dump at least some wastewater accumulated in the second one of the compartments  210 . In the second position the first one of the compartments  205  is in a tilted position with at least a portion of the open top of the first one of the compartments  205  spaced at or below the pin  220  and its associated pivot axis to dump at least some wastewater accumulated in the first one of the compartments  205  and the second one of the compartments  210  is in a substantially upright position with the open top of the second one of the compartments  210  aligned with the inlet  130  to accumulate wastewater from the inlet  130  into the interior of the second one of the compartments  210 . Thus, the dump  200  is passively driven by the accumulation of wastewater in and the dumping of wastewater from the first and the second ones of the compartments  205 ,  210 . 
         [0038]    The position of pivot pin  220  is generally approximately ¼ of the distance between a bottom  225  and a top  226  of the dump  200 , however the determination of the optimal location of pin  220  is based on the dimensional and weight parameters of apparatus  100 , which parameters are in turn determined by the wastewater capacity required and the density and mass of materials used in a given installation. In the illustration of  FIG. 2  it may be seen that pin  220  is substantially aligned (lengthwise) with a centerline of inlet  130 . As illustrated in  FIG. 2 , the open top of the compartment  205  is aligned with the inlet  130  so as to permit wastewater to drip (or otherwise flow) into compartment  205  during the current cycle. As the wastewater level inside compartment  205  rises it gradually shifts the center of gravity of dump  200  away from (in this example to the right of) the center line shared by pin  220  and inlet  130 . 
         [0039]    The wastewater dripping into compartment  205  eventually reaches a level that, by shifting the balance of total mass to the opposite side, induces the tipping of dump  200  (in this example to the right) such that at least a portion of the open top of the compartment  205  is at or below the level of the pin  220 , consequently dumping of the wastewater from compartment  205  into the interior of tub chamber  110 . Since the top opening of compartment  205  is wider (in this embodiment a V-shaped profile or pyramidal shape) at top (i.e., base of pyramid)  226  than at bottom (i.e., apex of pyramid)) 225 —the volume and hence mass of wastewater at the top of compartment  205  is substantially more than at its bottom, the largest portion of which body of wastewater is thus both higher above and on the opposite side of the pin  220  and its associated pivot axis to the placement of wastewater that induced the previous dump cycle. The wastewater level at which tipping occurs is partly defined by the weight of the counter-balancing empty compartment  210 —together with that of the portion of the material (from which dump  200  is constructed) to the opposing (in this example left) side of the pivot point at which pin  220  is located, as well as the weight of that portion of the wastewater in compartment  205  that is then on the opposite (here left) side of pivot pin  220 . In order to tip based on imbalance, the weight of the accumulated wastewater (and material used in the manufacture of that part of dump  200 ) on the dumpward side of dump  200  basically needs to exceed the combined weight of the smaller body of wastewater and all of the material used in the manufacture of the portion of dump  200  on the opposite side. 
         [0040]    The principle of operation of dump  200  may be understood by considering a first class lever in which the pin  220  is the fulcrum and the body of dump  200  operates as the lever. The point where one applies force is called the effort and the effect of applying such force is called the load. With the offset position of pin  220 , as an empty dump  200  tips to either side—the majority of the empty body (and hence its mass—in this example=the load) is positioned on that side to which dump  200  was tipped. Once so tipped, an empty dump  200  will tend to remain in that position resting on the bottom of tub chamber  110  (so to tip this load back—force is applied to the opposite side). And, the smaller portion of the mass of the empty body of dump  200  will then be positioned on the opposite side of pin  220  and its associated pivot axis with (as may be seen in  FIG. 2 ) the open top to compartment  205  (i.e., the effort since it is here where the incrementally increasing force of the weight of wastewater dripping into compartment  205  is applied) facing upward and exposed to inlet  130 . Advantageously, the offset positioning of pin  220  and the wide opening to compartments  205  and  210  ensures that only the compartment away from the tipped side is exposed to inlet  130  (i.e., alternating aligning the open top of each compartment with the inlet  130 ), such that when wastewater enters apparatus  100 , only one compartment at a time is positioned to collect wastewater. In the present example shown in  FIG. 2  as wastewater accumulates in compartment  205  the combined mass to the right side of pin  220  and the pivot axis increases as the wastewater level rises. Eventually the weight of the wastewater (generally heavier per unit volume than the materials from which dump  200  is constructed) in compartment  205  exceeds the weight of the empty compartment  210  even when combined with both—the extra material (typically plastic) between pin  220  and vertex  226 —and the wastewater located inside compartment  205 , but to the left of pin  220 . Once the combined mass to the right of pin  220  exceeds that to the left of pin  220 , the center of gravity of dump  200  having shifted across the point of balance, dump  200  tips to the right and the wastewater accumulated in compartment  205  spills into tub chamber  110  from which it may drain via outlet  140 . 
         [0041]    It will be understood by a person of skill in the art of mechanical designs that the density and weight of the (typically molded plastic) material used to construct dump  200  should be such that it is light enough to permit the weight of the volume of wastewater collected in compartment  205  to be enough to shift the combined center of gravity sufficiently to initiate the dumping action without human or other intervention. If the material from which dump  200  is constructed is so heavy that the combined (i.e., of the dump plus one compartment full of wastewater) center of gravity remains either on or (in this example) to the left of the centerline between  130  and  220 , then dump  200  will not tip without assistance. 
         [0042]    If pin  220  is positioned too low (i.e., too close to bottom  225 ), then it will tend to dump prematurely thereby inefficiently not taking advantage of the capacity of compartment  205  and likely not collecting sufficient wastewater to generate the flushing action used to clear the drain line of ice. And, if pin  220  is positioned too high (i.e., too close to top  226 ) then dump  200  will not tip without help. Preferably, the position of pin  220  along the line between base  225  and vertex  226  is such that compartment  205  (or alternately compartment  210 ) is substantially full of wastewater at the time of dumping—to take best advantage of the flushing effect. In an embodiment where the distance between bottom  225  and top  226  was 12 inches a pin position of approx 3 inches between pin  220  and bottom  225  provided an apparatus  100  that functioned well and reliably. 
         [0043]    Advantageously, for a given material selection to construct dump  200 , once the location of pivot pin  220  is optimally defined—the apparatus operates reliably passively without human intervention or without a dedicated motor or drive system, and requires minimal maintenance. While there is a range of positions (between bottom  225  and top  226 ) for mounting (fulcrum) pivot pin  220  in which dump  200  is operable, according to a preferred embodiment of apparatus  100  it is desirable to position pin  220  such that, for the particular capacity (i.e., dumper dimensions) or the unit and the density of the material from which dump  200  is manufactured, the assembly&#39;s center of gravity does not shift until the compartment (in this example  205 ) accumulating the wastewater is substantially full. Advantageously, selecting or adjusting the position of pin  220  so as to trigger dumping when the compartments are full tends to provide the greatest flushing effect. Notably, each compartment  205 ,  210  has an interior, the shape of which has a centroid  205   a,    210   a,  respectively. The centroids  205   a,    210   a  are laterally spaced from the pin  220  and its associated pivot axis  220   a.  The centroids  205   a ,  210   a,  are preferably equally positioned or spaced from the pin  220  or pivot axis  220   a,  although such is not absolutely necessary for operation of the apparatus  100 . The compartments  205 ,  210  preferably have identical or near identical shapes, although an apparatus with compartments  205 ,  210  whose shapes are not identical is possible. While compartments  205 ,  210  are illustrated as being pyramidal, other shapes are possible. Further, while illustrated as having a square or rectangular open top, the open tops of the compartments  205 ,  210  may have other shapes. 
         [0044]    It is to be understood that the shape of dump  200  is conveniently selected to be a simple double V profile, but that other shapes that similarly permit the reliable passive shifting of the point of balance without human or automated intervention could be incorporate into alternate designs without materially changing the principles of its operation. 
         [0045]    Referring to  FIG. 3  there is illustrated a preferred embodiment of a wastewater collection and discharge system denoted generally as  300 , wherein apparatus  100  is installed in series with a wastewater emitter discharge line  310  and well house drain line  315 . At a hydrocarbon well house where any conventional wastewater separation and emission device  305  pushes or supplies wastewater into a discharge line  310 , any suitable isolation valve  311  may be used in combination with a small discharge pump to facilitate moving the wastewater upwards to a higher elevation inside the well house so as to take advantage of any additional head pressure that may be available to flush ice from drain line  315 . Discharge line  310 , whether under pressure or not, delivers wastewater (whether as a series of drips or continuous stream) to apparatus  100  which operates taking advantage of a shifting center of gravity such that the point of balance alternates between the two compartments  205 ,  210  of dump  200  which releases substantial quantities of swirling wastewater into drain line  315  so as to resist any tendency for drain line  315  to freeze up outside well house wall  325  or to block drain exit  316 . Any suitable bypass valve  318  may be installed in drain line  315  to permit operators to divert wastewater to an alternate disposal means should circumstances require it. 
         [0046]    Referring back to  FIG. 4 , bottom or floor  400  of tub chamber  110  may be sloped downwardly, both end to end and side to side, to facilitate inducing a swirling motion in the wastewater directed through outlet  140 . The outlet may be integral to the tub chamber  100  and communicate with the bottom or floor  400 . Further illustrated is an alternate embodiment of tub chamber  110  according to which recessed upper edge  410  permits top  120  to slidingly engage lengthwise to form the upper boundary of the space within tub chamber  110 . 
         [0047]      FIGS. 5-8  show a wastewater disposal system  500  according to yet another illustrated embodiment. 
         [0048]    The wastewater disposal system  500  includes a chamber  502 , a dump  504 , and optionally a cover  506 . 
         [0049]    The chamber  502  is formed one or more walls  508  and a floor  510  which separate an interior  512  of the chamber  502  from an exterior  514  thereof. The chamber  502  may an outlet  516  at least proximate a bottom  518  thereof, which may be integral with the floor  510 . As best illustrated in  FIG. 8 , the floor  510  may slope relatively downward with respect to a top  520  of the chamber  502 . In particular, the floor  510  may be sloped downwardly toward the outlet  516 , for example from a rear of the chamber  502  toward a front of the chamber  502  where the outlet  516  is positioned proximate the front of the chamber  502 . The outlet  516  may be configured to couple to a drain line ( FIG. 3 ) positioned to carry the collected wastewater from a well house ( FIG. 3 ). The chamber  502  may optionally be open proximate the top  520  thereof. 
         [0050]    The dump  504  is received in the interior  512  of the chamber  502 . The dump  504  is formed of at least one wall  522  that separates an interior  524  of the dump  504  form an exterior thereof. The dump  504  has a top  526 , which is open, and a bottom  528  which is closed. The dump  504  is pivotally coupled to oscillate back and forth in the interior  512  of the chamber  502  about a pivot axis  530  which is generally horizontal with reference to the ground or gravitational force when the wastewater dump system  500  is in use. The dump  504  may be pivotally coupled directly to the cover  506 . Alternatively, the dump  504  may be pivotally coupled directly to the chamber  502 . 
         [0051]    A shape of the interior  524  of the dump  504  has a centroid (illustrated by cross)  532  that is radially offset from the pivot axis  530 , toward the top  526  of the dump  504 . In particular, the interior of the dump  504  may have a parabolic shaped cross-section (best illustrated in  FIG. 7 , an apex of the parabolic shaped cross-section being a bottom  528  of the dump  504 . 
         [0052]    The cover  506  may be selectively positionable to open and close the top  520  of the chamber  502 . The cover  506  may have an inlet  534  formed therein, for example proximate a top  536  of the cover  506 . The inlet  534  may be an integral part of the cover  506 . The inlet  534  may be configured to couple to a discharge reception ( FIG. 3 ) to transfer a trickle of dripping wastewater from a hydrocarbon well house wastewater emitter ( FIG. 3 ) to the inlet  534 . The inlet  534  may have a first opening  534   a  that provides a fluid path or fluid communication to the discharge reception. The inlet  534  may optionally have a second opening  534   b  that provides a fluid path or fluid communications with the atmosphere to equalize pressure and facilitate the flow of wastewater. The cover  506  may include a pair of opposed brackets  506   a  (only one visible in  FIG. 6 ), which extend respectively downwardly from the cover  506  and which are received in the interior  512  of the chamber  502  when in use. The brackets  506   a  may include journals or similar structures  506   b  that rotationally receive respective ones of opposed bearings  504   a  (only one visible in  FIG. 6 ) of the dump  504  to pivotally couple the dump  504  within the interior  512  of the chamber  502 . 
         [0053]    In operation, the dump  504  oscillates or pivots back and forth in the interior  512  of the chamber  502  as wastewater alternatingly accumulates and is dumped from the interior  524  of the dump  504 . In a first position, the dump  504  is substantially upright (illustrated in  FIG. 7 ) in the interior  512  of the chamber  502  with the top  526  of the dump  504  aligned with the inlet  534  to accumulate wastewater from the inlet  534  in the interior  524  of the dump  504  with the top  526  of the dump  504  spaced relatively above the pivot axis  530 . In a second position, the dump  504  is substantially tilted in the interior  512  of the chamber  502  with at least a portion of the top  526  of the dump  504  spaced relatively at or below the pivot axis  530  to dump at least some wastewater accumulated in the interior  524  of the dump  504  into the interior  512  of the chamber  502 . As wastewater accumulates in the interior  524  of the dump  504 , the accumulated wastewater conforms to the shape of the interior  524 . Thus, the wastewater has a centroid that is radially spaced relatively above the pivot axis  530 . Consequently, the dump  504  with the accumulated wastewater becomes top heavy, and is passively pivoted by the accumulation of wastewater in the interior  524  of the dump  504 , subsequently dumping of wastewater from the interior  524  of the dump  504  as the weight of the accumulated waste water causes the dump  504  to tip or tilt. 
         [0054]    The various embodiments described above can be combined to provide further embodiments. All of the U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet are incorporated herein by reference, in their entirety. Aspects of the embodiments can be modified, if necessary to employ concepts of the various patents, applications and publications to provide yet further embodiments. 
         [0055]    These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.