Patent ID: 12256718

DETAILED DESCRIPTION

The present disclosure relates to water treatment and filtration systems and methods for ponds and aquaculture systems.

The term “about” is used here in conjunction with numeric values to include normal variations in measurements as expected by persons skilled in the art, and is understood to have the same meaning as “approximately” and to cover a typical margin of error, such as ±5% of the stated value.

The term “gravity flow” is used here to refer to flow of water or aqueous media unassisted by a pump.

Water in aquariums, ponds, and aquaculture systems needs to be filtered and treated to maintain adequate water quality for the intended use. Various uses impose different water quality needs, such as a certain level of microbial quality, organic matter, chemical purity, pH, CO2 removal, turbidity or clarity, color, etc. Outdoor ponds typically require removal of coarse debris, such as leaves, sand, dirt, and other impurities that may enter the water from the environment. The water may be treated to remove small contaminants and organic matter, algae and microbes, and may further be condition to oxygenate the water.

Certain types of uses of ponds or tanks, such as fish ponds and aquaculture ponds, may require a relatively high and consistent water quality. One example of such ponds is a koi fish pond. Koi are a variety of carp that originate in Asia and are often kept in outdoor ponds for decorative purposes. While koi are a hardy species and prefer water temperatures below about 77° F. (about 25° C.), they do not thrive at temperatures below about 60° F. (about 10° C.). Therefore, koi ponds are often quite deep (e.g., from about 5 to about 10 ft) to provide an adequate volume of water and a more steady temperature of water in deeper parts of the pond. Because koi are typically kept for their esthetic value, it is preferred that the water in a koi pond is clear and colorless. Good microbial quality, oxygenation, and suitable pH are also important for the health of the fish.

Koi ponds can be sized based on the size of the fish. For example, for smaller koi about 300 gal per fish may be sufficient, whereas large show-quality koi can be allocated as much as 1,000-1,200 gallons of water per fish. With pond depths ranging from about 4 to about 10 feet, pond volumes can range from about 4,000 gallons to about 15,000 gallons or even higher.

The present disclosure relates to filtration systems and methods that can be used to maintain water quality in various ponds, tanks, aquaculture systems, etc., including koi ponds. A schematic flow diagram of a system and method according to the present disclosure is shown inFIG.1. The system1includes a water reservoir10(e.g., a pond or a tank) and a filtration system2that may include a collection box20, a rotary drum filter30, a primary bio-filter40, and a secondary bio-filter50. The system1may be a substantially closed system, where each of the components of the system is in fluid communication with the other components. Water is drawn from the reservoir10into the collection box20through a skimmer intake111, a middle intake112, and a bottom intake113. The collection box20acts to gather water flows from the different intake points for feeding into the rotary drum filter30, and to capture any coarse solid impurities that may be present in the water. The rotary drum filter30is used to filter out smaller particles, and the primary and secondary bio-filters40,50are used for filtration and to aerate and oxygenate the water. Water is returned back into the water reservoir10from the primary and secondary bio-filters40,50. In some embodiments, the system only includes the primary bio-filter40. However, including a secondary bio-filter50that may be of a different type than the primary bio-filter40, may further increase the amount of dissolved oxygen in the water and increase biofiltration of the system.

FIGS.2and3are schematic system flow diagrams according to an embodiment of the present disclosure. The water reservoir10is depicted as a fish pond. The water reservoir may include a water inlet16for filling and make-up water. The water intake may be connected to any suitable water source, such as a municipal water line. The intake of make-up water can be controlled with a valve, and may be adjusted to account for any water losses during the operation of the system. The water reservoir10may have any suitable dimensions, such as a depth of about 2 to about 20 feet, about 3 to about 15 feet, about 4 to about 10 feet, or about 6 to about 8 feet; and a volume of about 1,000 to about 100,000 gallons, about 2,000 to about 50,000 gallons, about 4,000 to about 25,000 gallons, or about 6,000 to about 15,000 gallons. The water reservoir10can be at least partially embedded in the ground such that the water level in the water reservoir10is near or at ground level. The water reservoir10may have a bottom and walls constructed of any suitable material, such as concrete, stone, ceramic, fiberglass, plastic, or a combination thereof. In an upper section of the water reservoir10, near an intended water line, the water reservoir10includes one or more skimmers11for skimming surface water and floating impurities. In an example embodiment, the one or more skimmers11include a movable door that shifts from pressure applied on it by water flow through the water reservoir10. In one example embodiment, a foam pad is positioned behind the skimmer door to enable the door to move upon pressure applied by water flowing through the water reservoir10. The skimmers11are connected to one or more skimmer intakes111leading into the collection box20. The skimmers11may include a weir door and/or a grate to prevent fish from entering the skimmer intake111.

The water reservoir10may further include at least one wall drain12that directs water into the middle intake112. An exemplary design of the wall drain12is shown inFIGS.8A and8B. The wall drain12may include a back wall213and side walls214defining a cavity211, a face plate215surrounding a front opening, and one or more outlets212positioned on the back wall213or side walls214of the wall drain12. When the wall drain12is installed, one or more of the outlets212can be connected to the middle intake112based on the most convenient flow path, and any remaining outlets212can be capped. A most convenient flow path is one with the least number of turns in the line that could lower the flow rate in the line and make cleaning more difficult. Accordingly, the wall drain12can be positioned inside a wall of the water reservoir10, allowing the middle intake112to be connected to the wall drain12in multiple orientations (e.g., an upward, downward, left, or right orientation). Thus, the multiple outlets provide at least five different options to connect to the collection box20via the middle intake112. The face plate215may be used to attach the wall drain12to a wall of the water reservoir10.

The wall drain12can be positioned at any location on a wall of the water reservoir10. However, preferably the wall drain12is positioned in at or near a midpoint of the water height in the water reservoir10. For example, if the water reservoir10is designed for a water depth of about 8 feet, the wall drain12can be positioned about 4 feet from the bottom of the water reservoir10. Drawing water from the water reservoir10through a wall drain12positioned near the midpoint of the water depth improves water mixing in the water reservoir10and helps avoid dead zones where harmful bacteria could colonize.

The water reservoir10also includes at least one bottom drain13that directs water into the bottom intake113. An exemplary design of a bottom drain13according to an embodiment is shown inFIGS.9A-9C. The bottom drain13preferably includes a lid that prevents fish from entering the bottom intake113but that lets water and debris to flow through the drain.

The skimmers11, wall drain12, bottom drain13, skimmer intake111, middle intake112, and bottom intake113may be sized so that approximately equal volumes of water are drawn from each section (top, middle, and bottom) of the water reservoir10. In one exemplary embodiment, the lines used for the skimmer, middle, and bottom intakes111,112,113are 2 to 6 inch diameter, for example 4-inch diameter, PVC pipe or similar. Water flow from the water reservoir10to the collection box20can be arranged as gravity flow. Total flow rate through the skimmer, middle, and bottom intakes111,112,113may be from about 500 to about 20,000 gallons per hour, about 1,000 to about 18,000 gallons per hour, or about 4,000 to about 16,000 gallons per hour. The flow rates are given for a system that includes a single collection box, rotary filter, and primary and secondary bio-filter. However, the flow rate can be increased if the system includes multiple collection boxes, rotary filters, and bio-filters. Recommended turnover rates for aquariums and aquaculture ponds, including koi ponds, vary from about once every one to three hours. In some embodiments, the filtration system is sized to provide a turn-over rate of the water in the water reservoir of about once every 0.8 to 2 hours, or about once every hour. As will be described herein, the filtration system2relies on gravity to circulate water throughout the pond and also includes passive elements that do not require power to operate. As such, the disclosed filtration system is capable of lasting many years without requiring much maintenance, as is the case with current pond filtration systems.

As will be described in further detail herein, a pump (such as pump411) may be positioned to return water from the filtration system2to the water reservoir10(also referred to as a pressurized return) to minimize or eliminate bubbles from entering into the water reservoir10, which would otherwise occur in a non-pressurized return system. The existence of bubbles in the water reservoir10may destroy the serene environment of the water reservoir10.

The skimmer, middle, and bottom intakes111,112,113lead the water flow from the water reservoir10into a filtration system2. The filtration system2is shown in further detail inFIG.4.

The first component of the filtration system2is a collection box20. An exemplary embodiment of a collection box is shown inFIGS.5A-5C. The collection box20can be used to balance the incoming flows from the water reservoir and to capture any larger debris. In particular, the collection box20allows the multiple pond inputs (e.g., the skimmer intake111, the middle intake112, and the bottom intake113) to be consolidated and balanced. The collection box20may also be used to flush the system to remove passive sediment that has been built up over time.

The skimmer, middle, and bottom intakes111,112,113lead the water flow from the water reservoir10into the collection box20. Each of the intakes connects to an inlet at the bottom26of the collection box20. The inlets may include risers (e.g., pipes) that extend from the inlets at the bottom of the collection box20upward and have an open top through which water can flow into the interior of the collection box20. The bottom26of the collection box20may be fitted with bulkhead fittings that connect each intake line to a riser. The bulkhead fitting may include a bottom piece placed under the bottom26of the collection box20with a threaded portion extending through the bottom26and into the collection box20, and a top piece placed inside the collection box20and threadingly coupled with the bottom piece. A rubber gasket can be included underneath the top piece to seal the connection. The risers can be friction-fitted onto the bulkhead fittings.

Alternatively, the risers may be connected to the collection box20via a slip fitting. The slip fitting enables a person to insert or remove the risers into or from the collection box20by simply sliding them in or out of the slip fitting without screwing in or out. An example of a suitable slip fitting is the BFA1040CFS 4″ PVC bulkhead fitting, available from Hayward Flow Control of Clemmons, NC In some cases a threaded fitting may become stuck requiring a greater amount of force or even tools in order to dislodge the threaded connection, whereas a slip fitting can be installed and removed by hand without tools or excessive force being required. Furthermore, a riser may be removed and capped (closed). By capping one or more risers, flow is forced through one or more of the other uncapped risers, allowing the ability to flush the system with an increased flow of water.

The skimmer intake111connects to a first riser21, the middle intake112connects to a second riser22, and the bottom intake113connects to a third riser23. The first riser21has a first height H21, the second riser22has a second height H22, and the third riser23has a third height H23. The first, second, and third heights H21, H22, and H23are preferably lower than the upper edge25of the collection box20. The collection box20may also include a drain24.

The first, second, and third heights H21, H22, and H23may also be different from one another. In one embodiment, the first height H21is the shortest of the first, second, and third heights H21, H22, and H23. In one embodiment, the third height H23is the tallest of the first, second, and third heights H21, H22, and H23. To stop water flow from the water reservoir into the collection box, a taller riser with a height extending above the water level in the water reservoir10can be inserted into the bulkhead fitting. Flow can be stopped from one, two, or all three intakes at a time. Stopping flow from only one or two intakes will increase water flow from the other risers/intakes. This can be used to clean any settled debris from the lines. Alternatively, flow can be stopped from all of the intakes at the same time so that the collection box and/or the filtration system2can be drained and cleaned.

The water level in the collection box20can be kept below the water level of the water reservoir10to facilitate gravity flow when the system is in operation. The first, second, and third heights H21, H22, and H23of the risers21,22,23can be adjusted so that the open ends of the risers21,22,23are generally below the water level in the collection box20.

The second component of the filtration system is a filter. Water flows from the collection box20to the filter through one or more connection lines201. The filtration system is preferably arranged such that the water level in the filter is below the water level in the collection box20and the flow from the collection box20to the filter is gravity flow. In an alternative embodiment, the connection line201includes a pump.

In a preferred embodiment, the filter is a rotary drum filter30. The rotary drum filter30is arranged to filter out particulates from the water. For example, the rotary drum filter30may have a screen size of about 10 to about 100 μm, about 20 to about 80 μm, or about 50 to about 70 μm. The rotary drum filter30may include a cleaning system that is capable of initiating a self-cleaning cycle when the filtration rate of the rotary drum filter30falls below a threshold value.

The filtration system2also includes a primary bio-filter40. An exemplary embodiment of a primary bio-filter40is shown inFIGS.6A-6C. Water from the rotary drum filter30flows into the primary bio-filter40through one or more connecting lines301. In one embodiment, the flow from the rotary drum filter30to the primary bio-filter40is arranged as gravity flow. In an alternative embodiment, the connecting line301includes a pump. The primary bio-filter40provides a housing for a filter media that allows bacteria to colonize in the filter. The bacteria feed on and thereby remove organic matter (e.g., nitrogen-containing organic matter) in the water. An example of suitable filter media is a semi-buoyant polyethylene media MB3 WaterTek available from Water Management Technologies, Inc. in Baton Rouge, LA. The primary bio-filter40may be divided into a main compartment41and a drainage compartment43by a wall42. The wall42may comprise a screen that maintains the filter media on one side while allowing water to pass through, and prevents the filter media from getting into the outlet47or connected return line401that returns the treated water into the water reservoir10.

The primary bio-filter40is outfitted with an aeration system to provide oxygen into the filter. The aeration system may include an aeration pump46and one or more air diffusers45at the bottom of the primary bio-filter40. The air diffusers45may include a membrane (e.g., a rubber membrane) and a check valve that prevents water in the filter from entering the line from the aeration pump46. The air flow rate from the aeration system can be arranged at a suitable level to keep the filter media in the bio-filter in constant motion, and to provide oxygen to the bacteria colonized on the filter media.

In some embodiments the primary bio-filter40includes a leaf guard to prevent undesirable outside material or animals from getting into the primary bio-filter40. In some embodiments the leaf guard is made of a mesh screen.

The filtration system2may also include a secondary bio-filter50. An exemplary embodiment of a secondary bio-filter50is shown inFIGS.7A-71. Water from the rotary drum filter30flows into the secondary bio-filter50through one or more connecting lines302. The connecting line302can include a pump312.

Like the primary bio-filter40, the secondary bio-filter50can also provide a housing for filter media that allows bacteria to colonize in the filter to increase biofiltration of the system. However, the secondary bio-filter50may be set up with a different configuration than the primary bio-filter40to encourage growth of different types of bacteria and more oxygenation. In one embodiment, the secondary bio-filter50is a bakki shower. A bakki shower includes one or more through-flow boxes that can be stacked on top of one another to simulate water flow across and through a bed of rocks. Rather than being immersed in water as in the primary bio-filter40, the filter media in the bakki shower is covered by a thin film of moving water. The filter media typically used in a bakki shower is a porous ceramic material that resembles highly porous rocks. Water is brought into the bakki shower through the top, where it can be dispersed and allowed to trickle through the bed of media. In some embodiments, the disclosed bakki shower system is a highly efficient filter that allows for a high oxygen transfer while minimizing typical shower splashing.

In one embodiment, the secondary bio-filter50is a bakki shower comprising two or more stacked filter housing units51. Each filter housing unit51defines an interior space for housing media. In a stacked arrangement, only the bottom filter housing unit51has a closed bottom, whereas upper filter housing units51have an open bottom or a bottom with one or more openings to facilitate flow of water. The media can be supported on a perforated media tray52placed at the bottom of the filter housing unit51. The filter housing unit51may further include a diffuser plate53placed at or near the top of the unit to disperse water. In the exemplary embodiment shown, the diffuser includes a first section511and a second section512, where the first section511includes perforations (e.g., holes) distributed at a first density and the second section512includes perforations (e.g., holes) distributed at a second density, where the second density is greater than the first density. The first section511may extend from a first end of the diffuser plate53about ¼ to about ½ of the way toward the second end, and the second section512may extend from the end of the first section511to the second end.

Each filter housing unit51may also include a skirt54, shown inFIGS.7C,7F and7G. The skirt54has a center opening540that is smaller in diameter than the outer perimeter541of the skirt. The skirt54defines a splash guard542and a support ledge548that surround the center opening540. When filter housing units51are stacked, the upper filter housing unit51can be supported on the support ledge548.

In an embodiment, the splash guard542comprises a slanted wall543that includes a plurality of openings544. The openings may be shaped to minimize splashing of water from the filter. For example, the openings may be shaped as ovals, ellipsoids, rounded rectangles, or rectangles having a longitudinal axis extending outwardly from the center opening540. In another embodiment, the filter housing unit51further includes a splash reducing material546that is placed under the openings544of the splash guard542. For example, a splash reducing material546, such as a highly porous polymeric filter material (for example MATALA® filter media available from Matala USA in Laguna Hills, CA), can be disposed on top of the diffuser and below the splash guard542along the walls of the filter housing unit51.

The filter housing units may be covered by a roof assembly55(shown inFIGS.7H and7I) supported on the support ledge548of the skirt54. The roof assembly55includes a roof550having slanted first and second roof portions551,552, and first and second end walls553,554. The roof assembly55includes a water inlet56at one of the end walls553,554. The roof assembly55functions to distribute the water flow into the bio-filter, and keeps sun light, which may promote algae growth, and rain fall away from the opening of the filter housing unit51. The diffuser plate53may be coupled with the roof550to form the roof assembly55. The diffuser plate53may include a flange515at the first and second ends of the diffuser plate53to facilitate coupling with the roof550.

A typical bakki shower arrangement is provided with a water outlet at one of the sides of the bottom unit. The water outlet can be a simple opening or a pipe, or a water-fall type outlet (shown as57inFIGS.7A and7B). According to an embodiment, the bakki shower has one or more water outlets57at the bottom of the lower stacked filter housing unit51. The bakki shower can be arranged on top of or above the primary bio-filter40, and the flow of water from the bakki shower directed into the primary bio-filter40. Flow from the bakki shower into the primary bio-filter40can be arranged as gravity flow. The primary bio-filter40has an input end48with one or more inlets410, where the connecting line301brings water from the rotary drum filter30, and an output end49with one or more outlets47. The water from the secondary bio-filter50can be directed into the primary bio-filter40near the output end. For example, the outlet57of the bakki shower (secondary bio-filter50) can be connected to an outlet line570that ends in the primary bio-filter40adjacent the wall42of the primary bio-filter40.

In alternative embodiments, water may be returned from the bakki shower as a rain return in which the bakki shower is suspended over the water reservoir such that water supplied to the bakki shower can rain through the shower. Alternatively, the bakki shower may be set up as a waterfall return in which the bakki shower positioned adjacent to the water reservoir, allowing water to return from the bakki shower to the water reservoir through a water spillway.

The flow rate through the system is affected by multiple factors. Gravity flow can be adjusted by increasing or decreasing the difference in water levels between the water reservoir10and the components of the filtration system2. For example, the water level in the collection box20can be maintained about 1 to about 6 inches, or about 2 to about 5 inches below the water level in the water reservoir10. Flow rate is also affected by the size of the outlets, drains, piping, inlets, and the use of pumps. Features that cause turbulence in the water flow, such as barriers and corners in the lines will act to slow the flow rate. Minimizing such features will help increase flow rate in the system. The flow rate can also be increased by arranging a pressure return system for the filtration system2as shown inFIGS.2and3. In a pressure return system, the flow from the rotary drum filter30is split between the primary and secondary bio-filters40,50, such that flow from the rotary drum filter30to the primary bio-filter40is by gravity flow, and a pump312is used in connecting line302to pump water into the secondary bio-filter. The water from the secondary bio-filter50is flown into the primary bio-filter40by gravity. The return line401includes a return pump411that is sized to control the turnover rate (e.g., filtration rate) of the system.

Referring now toFIGS.9A-9C, an embodiment of the bottom drain13is shown. The bottom drain13may include a receiving portion130having a wall131that extends from a bottom139to a top edge133. The wall131may be generally cylindrical in shape. The bottom drain13may include a slanted sub-floor132that facilitates flow of water into an outlet135positioned adjacent the lowest portion of the slanted sub-floor132. The slanted sub-floor132may be set at a suitable angle α132relative to the bottom138, such as about 15 to about 50 degrees, about 20 to about 45 degrees, or about 25 to about 35 degrees. The bottom drain13can be mounted at the bottom14of the water reservoir10such that the top edge133of the receiving portion130is flush with the bottom14. The top edge133may include a lip134that facilitates installation and placement of the bottom drain.

The outlet135may comprise a pipe section136protruding laterally outwardly from the wall131. The pipe section136can be connected to the bottom intake113. The receiving portion130may further include a lid mounting stub137that couples with a mounting post141of the lid140. The lid mounting stub137may extend upwardly from the bottom138and protrudes through the slanted sub-floor132, for example, from the center of the slanted sub-floor132. The lid mounting stub137may include threading138for coupling with corresponding threading142on the mounting post141so that the mounting post141may be removed. In one example embodiment in which the mounting post141protrudes above the top edge133, if the lid140is removed (e.g., for cleaning, maintenance, or other reasons), a top portion of the mounting post141may be exposed above the top edge133. In such an example, removing the mounting post141by way of the threading138would avoid inadvertent damage that may be caused to the mounting post141or bottom drain13. Alternatively, the mounting post141may be friction fitted onto the lid mounting stub137.

The mounting stub137has a height H137, and the mounting post141has a height H141. In one embodiment, the height H137of the mounting stub137is such that the top of the lid mounting stub137interjects the plane of the slanted sub-floor132, or that no portion of the lid mounting stub137extends more than 4 inches, more than 3 inches, or more than 2.5 inches above the slanted sub-floor132. The combined heights H137and H41are such that when the lid140is mounted on the receiving portion130, a gap remains between the lid140and the wall131of the receiving portion130.

The bottom drain13further provides an air flow path146A defined by an air inlet146connected to the lid mounting stub137; the hollow interior of the lid mounting stub137; the lid mounting post141; an opening in the lid; and a porous rubber membrane145placed at the top of the lid140. The air inlet146can be disposed below the slanted sub-floor132and protrude through the wall131, connecting to an air supply. The air inlet146may extend outwardly at an angle (3130from the center of the bottom drain13(e.g., from the lid mounting stub137) relative to the outlet136, as shown inFIG.9C. The angle may be about 80 to about 180 degrees, or about 90 to about 130 degrees.

While certain embodiments have been described, other embodiments may exist. While the specification includes a detailed description, the scope of the present disclosure is indicated by the following claims. The specific features and acts described above are disclosed as illustrative aspects and embodiments. Various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the spirit of the present disclosure or the scope of the claimed subject matter.