Abstract:
The wastewater evaporator provides for effluent evaporation in a septic system to eliminate need for a drain field. The evaporator tank contains a plurality of evaporator trays in a vertical array. Solids settle in the septic tank, and liquid effluent flows from the septic tank to the evaporator tank and cascades sequentially from the uppermost to the lowermost tray. The multiple trays increase the surface area of liquid contained therein, thereby greatly enhancing evaporation. An above-surface air pump and vent may be provided for air flow through the evaporator tank. An ultrasonic generator may be installed in each tray to increase the surface area of the effluent to enhance evaporation. An additional intermediate pump tank may be provided between the septic tank and the evaporator tank to control effluent flow and delivery to the evaporator tank. A sump pump in the pump tank periodically delivers effluent to the evaporator tank.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/671,438, filed Jul. 13, 2012. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to water treatment facilities, and particularly to a wastewater evaporator that evaporates wastewater effluent in a septic system to eliminate or minimize the need for an underground drain field. 
     2. Description of the Related Art 
     Homes and businesses in many suburban areas and nearly all rural areas are not connected to a sanitary sewer system, but rely upon individual septic tank and drain field systems. Such septic tank and drain field systems collect wastewater in the tank, and effluents drain out into the drain field where it is absorbed and dissipated into the surrounding soil. 
     Such septic tank and drain field systems work reasonably well, are reasonably economical, and require little maintenance until replacement is needed, generally after many years of service. However, they require soil that is capable of absorbing all of the liquid introduced into the system, which limits the areas where such tank and drain field systems may be installed. Areas with high water tables and very rocky ground with poor absorption are clearly not suited for such systems, which limits the available areas for new home, business, and industrial construction. Government regulations concerning such installations are ever more restrictive as well, and consideration must be given to the need to avoid contamination of well water. 
     A number of evaporative systems for water treatment have been developed in the past. An example of such is found in Japanese Patent Publication No. 59-156,493, published on Sep. 5, 1984. This reference describes (according to the drawings and English abstract) a sewage system incorporating separate tanks for anaerobic and aerobic bacterial treatment of effluent. The treated effluent is then further pasteurized and pumped into an evaporation tank. An ultrasonic generator is installed upon a float in the tank, to agitate the water surface for greater evaporation. 
     Thus a wastewater evaporator solving the aforementioned problems is desired. 
     SUMMARY OF THE INVENTION 
     The wastewater evaporator includes an evaporator tank having a plurality of shallow, vertically stacked evaporator trays therein. The trays are arranged such that when one tray is nearly full, water flows into an overflow drain to the next tray therebeneath until all trays are filled from the uppermost tray in sequence to the lowermost tray. The multiple trays with their collectively large water surface area provide for greater evaporation than would be provided by a single water surface within the tank. An overflow may be provided to drain excess water from the tank. 
     Air is introduced into the tank by an air intake manifold at one side or end of the evaporator trays to flow across and between the trays and the surfaces of the water therein. An above-ground air pump or fan may be provided to force air into the tank, and a vent may be located for the escape of the air. Each of the trays may be provided with an ultrasonic generator to agitate the surface of the water therein, thereby increasing the surface area to enhance evaporation. 
     The evaporator tank receives liquid effluent from a generally conventional septic tank for settling solids. After settling, the liquid effluent flows from the septic tank to a pump tank located between the septic tank and the evaporator tank. The pump tank is used as a holding tank for the liquid effluent to prevent overfilling the evaporator tank. A sump pump or the like is installed in the bottom of the pump tank. The sump pump operates periodically (e.g., once per day) to pump effluent to the trays in the evaporator tank. An alarm system including a water level sensor may be provided for the pump tank to alert personnel of excessively high or low effluent level in the pump tank. The alarm system may be connected to the operation of the pump to activate the pump in the event of high effluent level in the pump tank or to prevent timed pump operation in the event of low effluent level in the pump tank. 
     These and other features of the present invention will become readily apparent upon further review of the following specification and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic side elevation view of the interior of a wastewater evaporator according to the present invention, illustrating its internal configuration and components. 
         FIG. 2  is a schematic side elevation view of a wastewater evaporator according to the present invention incorporating a septic tank and a pump tank in combination with the evaporator tank of  FIG. 1 . 
     
    
    
     Similar reference characters denote corresponding features consistently throughout the attached drawings. 
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The wastewater evaporator is a system for the removal of liquid effluent from a septic system, precluding any requirement for a drain field in the surrounding soil. The wastewater evaporator is suited for installation in areas with high water tables, rocky ground and other areas with poor drainage; areas where contamination of underground water may be a problem; and other areas where septic drain fields are precluded due to laws and/or regulations. 
     The interior of an exemplary evaporator tank  10  of the wastewater evaporator is illustrated as a side elevation view in  FIG. 1 . The evaporator tank  10  includes a floor  12 , walls  14 , and a top  16  defining an internal volume  18 . The floor, walls, and top are preferably constructed of or lined with liquid impervious or waterproof materials in order to preclude leakage or seepage of effluent from the tank  10 . A plurality of wide, shallow evaporator trays  20  are installed within the evaporator tank  10 . Each of the evaporator trays  20  may extend throughout the majority of the tank  10 , as shown in  FIG. 1 , or they may comprise smaller units for assembly as a series of separate stacks, as shown in  FIG. 2 . 
     Each of the evaporator trays  20  is preferably constructed to be as shallow as practicable in order to provide the greatest number of trays in the vertical array(s) installed within the evaporator tank  10 . The trays  20  are spaced apart from one another by spacers  22  to allow a wide but closely spaced horizontal passage between adjacent trays for the flow of air therethrough. Each of the evaporator trays  20  includes at least one (and preferably more) overflow drain(s)  24 . The overflow drains extend up from the bottom of each tray  20 . This results in the effluent filling each tray  20  to a shallow depth equal to the height of the overflow drain(s)  24 . The edges or rims of the trays  20  are slightly higher than their overflow drains  24  in order to assure that effluent will not overflow the edges of the trays  20 . 
     It will be seen in  FIG. 1  that the overflow drains  24  are staggered between adjacent trays, e.g., the drains  24  of the uppermost tray  20  are installed in the right side portion of the tray, with the drains  24  of the next lower tray  20  being installed in the left side portion of that tray, etc. Effluent enters the evaporator tank  10  through an inlet pipe or line  26  from the septic tank or other effluent supply line, to flow into the uppermost tray  20 . When the effluent reaches a level sufficient to flow into the overflow drains  24  of the uppermost tray, the overflow begins to flow through those drains into the next highest adjacent tray. When the liquid reaches the top of the overflow drains  24  of that next highest adjacent tray, it begins to flow into the next tray below. This process continues with effluent flowing progressively in a cascade from the topmost tray to the lowermost tray and so on to cover the floor  12  of the evaporator tank  10  if sufficient effluent flows into the tank. The large number of evaporator trays  20  multiplies the available effluent surface area by the number of trays, thereby greatly increasing the surface subject to evaporation and correspondingly increasing the rate of evaporation for the effluent in the tank  10 . 
     The rate of evaporation is enhanced by providing a constant supply of air through the evaporator tank  10 . This is accomplished by an air pump  28  (electrically powered fan, etc.) installed above the tank  10 . Air enters through an inlet  30  and is pumped or blown downward into an air inlet plenum  32  and air inlet manifold  34  installed in one end of the tank  10  adjacent to the evaporator trays  20 . Air then passes from the manifold  34  between the trays  20  to evaporate moisture from the trays. Humidified air leaves the evaporator tank  10  through an air outlet vent  36 . The vent  36  may be located anywhere on the tank  20 , so long as it communicates with the internal volume  18  of the tank  10 , but the vent  36  is preferably located at or toward the opposite end of the tank from the air inlet plenum  32  and manifold  34  to facilitate airflow through the assembly. 
     The above-described system works well to remove liquid effluent from sewage and other wastewater by increasing the surface area of the liquid that is subject to evaporation. The system requires only enough power to drive an air fan or blower to circulate air between the evaporator trays. However, the system is still dependent upon the total surface area of the liquid contained within the tank. The rate of evaporation may be increased further by increasing the available liquid surface area. This may be accomplished by installing an ultrasonic agitator  38  in each of the evaporator trays  20 . The agitators  38  serve to agitate and break up the surface of the liquid in each of the trays, thereby increasing the surface area for greater evaporation. Electrical power to drive the ultrasonic agitators  38  is provided by an electrical cable  40  or the like that extends into the tank  20 , e.g., down the air passage from the air pump or fan  28  and through the air inlet manifold  34  and lines to the individual ultrasonic agitators  38  in each of the trays  20 . 
     The evaporator tank  10  is installed downstream from a septic tank, to accept the liquid effluent from the septic tank after the solids have settled out in the septic tank. An additional pump tank may be installed between the septic tank and the evaporator tank  10 , to better control the inflow of liquid effluent into the evaporator tank  10 ,  FIG. 2  of the drawings provides a schematic view of such a system, including a septic tank  42 , a pump tank  56 , and an evaporator tank  10 . It will be noted that the arrangement of the components in the evaporator tank  10  of  FIG. 2  is somewhat different from the exemplary evaporator tank  10  shown in  FIG. 1 , but both  FIG. 1  and  FIG. 2  illustrate the various components of the evaporator tank  10  using like reference numerals for like components. 
     The septic tank  42  of  FIG. 2  is generally conventional, having an intake pipe  44  with a liquid effluent drain  46  extending from the tank  42 . The septic tank  42  preferably includes a baffle  48  therein to retain solids in a portion of the tank  42 , while allowing liquid effluent to pass through a passage  50  in the baffle  48  to a liquid effluent portion  52  of the tank  42 . A filter  54  or the like may be installed in the liquid effluent portion  52  of the tank to further restrict the flow of solids from the tank  42  to the liquid effluent drain  46 . 
     The effluent outlet drain line or pipe  46  from the septic tank  42  connects to a pump tank  56  that serves as an intermediate reservoir or holding tank to control flow to the evaporator tank  10 . Liquid effluent flows from the liquid effluent portion  52  of the septic tank  42 , through the liquid effluent drain  46  extending from the septic tank  42  to the pump tank  56 . 
     Liquid effluent flows from the pump tank  56  to the evaporator tank  10  through the effluent supply line  26  that connects the pump tank  56  to the evaporator tank  10 . The effluent level within the pump tank  56  will vary, depending upon output from the septic tank  42  as well as the rate of input and evaporation in the evaporator tank  10 . Accordingly, a pump  58  (e.g., sump pump, etc.) is installed in the pump tank  56  to supply liquid effluent to the evaporator tank  10  periodically through the effluent supply line  26 . Generally, the pump  58  may be operated on a timed basis, e.g., once every twenty-four hours or so, to substantially empty the pump tank  56  of accumulated effluent and “dose” the trays  20  of the evaporator tank  10 . 
     However, the pump  58  may be actuated by some other means, e.g., a liquid effluent level sensor  60 . The effluent level sensor  60  may be of any conventional principle of operation, e.g., a float system, capacitance system, pressure transducer at the bottom of the tank, etc. The level sensor  60  may be connected to an above-surface alarm device  62  to alert personnel in the event that the effluent level reaches too high a level in the pump tank  56 . The alarm  62  may be an audible and/or visual device, and may be contained in a control station or other structure. The level sensor  60  may also operate to prevent actuation of the pump  58  during its regular timed schedule of operation in the event that insufficient effluent has collected in the pump tank  56 . 
     Liquid effluent flows from the pump tank  56  into the evaporator tank  10  through the effluent supply line  26  extending between the pump tank  56  and the evaporator tank  10 , as described further above. The evaporator trays  20  fill in a cascade from top tray to bottom tray, as described further above. Any additional effluent flowing into the evaporator tank  10  will cause the lowermost tray  20  to overflow into the bottom of the evaporator tank  10 . Accordingly, a return pump  64 , e.g., sump pump, etc., is preferably provided in the bottom of the evaporator tank  10  to return excess effluent to the pump tank  56  through a return line  66 . An access hatch  68  may be provided in the top of the evaporator tank  10  to provide access to the interior  18  of the tank  12  as needed, e.g., servicing or replacement of the return pump  64 , etc. The access hatch  68  is normally sealed in place in the top of the evaporator tank  10  until access is needed to the interior of the tank  10 . A similar access hatch (not shown) may be installed in the top of the pump tank  56 . 
     Accordingly, the evaporator tank and septic system therewith provide for the installation of such systems where dispersal of effluent into the ground is not feasible due to physical conditions and/or governmental regulations. The water of the effluent is evaporated from the evaporator trays within the evaporator tank and thence expelled from the evaporator tank to the atmosphere as humidified air, rather than flowing into the surrounding soil as in a conventional septic system. The resulting elimination of ground pollution greatly expands the potential locations for installation of such a system, thus permitting the construction of residences and businesses in locations where they were not previously feasible due to the prohibitive costs of a dedicated sewer system. 
     It is to be understood that the present invention is not limited to the embodiments described above, but encompasses any and all embodiments within the scope of the following claims.