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Document Type and Number:
WIPO Patent Application WO/2022/111812
Kind Code:
A multi-technique aquaponic production unit comprising a covered dome structure greenhouse of which shape allows passive air flow, ventilation and sunlight capture with no regard to orientation, that dome structure housing within a fish rearing pond/sump, a solids separation/bio filter system with a zeolite material component, a plant cultivation area, a solids collection sedimentation tank/pond, an earth exchange ventilation system.

Application Number:
Publication Date:
June 02, 2022
Filing Date:
November 27, 2020
Export Citation:
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International Classes:
A01G9/14; A01G31/02; A01K63/04
Foreign References:
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1. A multi-technique aquaponic production unit comprising a covered dome structure greenhouse of which shape allows passive air flow, ventilation and sunlight capture with no regard to orientation, that dome structure housing within:

- a fish rearing pond / sump,

- a solids separation / bio filter system with a zeolite material component,

- a plant cultivation area,

- a solids collection sedimentation tank/pond,

- an earth exchange ventilation system.

2. The unit according to claim 1 , further comprising one or more aeration pumps housed within the dome structure greenhouse, supplying air to all bodies of water housed within de dome structure, such as a fish pond or a grow bed, through a grid of air conduits that terminate with defuses, air stones and / or aeration porous hoses.

3. The unit according to claim 1 or 2, further comprising a water heat exchange module connected to a heater unit, both being housed within the dome structure greenhouse, wherein the heating unit is supplied with heating water from a separate tank, wherein the heating unit is preferably a gas heating unit to make use of C02 discharge of said unit for plant growth, and wherein cold water is preferably supplied from a chiller unit or an outer cold water source to said heat exchange module when water cooling is needed for cold water fish rearing.

4. The unit according to any of claims 1 - 3, further comprising a multitude of vents distributed along the sides of the dome structure greenhouse above ground level and in the top part of the dome to facilitate passive air flow throughout the dome structure housing.

5. The unit according to any of claims 1 to 4, further comprising a shading system housed within the dome structure greenhouse which decreases the sun light above the fish pond and the plant cultivation area when needed in an adjustable degree and comprises a mesh net and/or semi translucent colored fabric as the main sun visor. 6. The unit according to any of claims 1 to 5, comprising an outer shading system fitted on the dome structure greenhouse and comprising a mesh net with 10-90% degree shade which doubles as a pest barrier protecting the upper canopy of one or more vents in addition to providing shading.

7. The unit according to any of claims 1 to 6, wherein the pond / sump further comprises a main submersible water pump, being the main source of nutrient rich water throughout the unit.

8. The unit according to any of claims 1 to 7, wherein the solids separation / bio filter system further comprises one or more containers with a zeolite material component at their bottom and a water inlet which are placed on each beginning of a plant cultivation area, wherein water is pumped into the one or more containers by submersible pumps housed within the pond/sump.

9. The unit according to claim 8, wherein the containers are provided in such a way that

- water pumped into the containers falls to the bottom of the container where the zeolite material is housed so that the mechanical impact on the zeolite and container surfaces causes the solids to separate from flowing water;

- the flowing water exits the container through one or more L shaped elbow fittings that prevent heavy solids from overflowing with the exiting water;

- the accumulating solids (sludge) exits said container through a bottom drain to the sludge tank/pond;

- the zeolite material constantly leeches out micro nutrients into the stream of water; and

- the zeolite porous surface provides sufficient surface area for cultivating the majority of the nitrification bacteria colony in the system.

10. The unit according to any of claims 1 to 9, wherein the plant cultivation area further comprises

- a pre-fabricated set of metal or composite legs (corners and middle sections) that have a dish like base with pre-drilled holes on the upper sides,

- a set of pre-cut square section metal or composite girder that make up the front, back and side frames of the beds,

- a set of mechanical fasteners to assemble components; a pre-fabricated one or more plane of wood, plastic, composite or metal to make up the floor of the bed, side panels and the bottom one or more shelves,

- a multitude of plastic fittings for water inlet/outlet, drip and drain,

- a pre-cut plastic liner fitted inside the grow bed;

- pre-cut buoyant material planes for the DWC technique and/or the NFT ;

- non-soil media for the ebb-flow technique;

- a pre-cut rigid material: plastic, wood, composite or metal cover to be the tuber/root container rack.

11. The unit according to any of claims 1 - 10, wherein the plant cultivation area further comprises a multi technique (DWC, NFT, Ebb-flow) hydroponic system that shares one infra structure with a raised grow bed comprising pest prevention designed bases.

12. The unit according to claim 11 , wherein the plant cultivation area is provided to to cultivate tubers and root vegetables, with added bucket-like containers to be placed above water level of a DWC technique, filled with non-soil based media appropriate for desired crop, wherein the humidity will be maintained in said containers via drip system or wick system in addition to the water flowing into the bed underneath the container.

13. The unit according to any of claims 1 - 12, wherein the plant cultivation area further comprises:

- one or more bottom shelves that are used for further produce such as: Mushroom growing, composting plant leftovers, rearing beneficial/ feed insects;

- boxes, drawers or tub like containers. 14. The unit according to any of claims 1 - 13, wherein the earth exchange ventilation system further comprises for each vent:

- a multitude of tube like pipes or ducts that have a vent opening outside said dome structure greenhouse at one end and another one or more vents opening inside the dome structure greenhouse;

- one or more suction fans fitted on the inside vents;

- a pest preventing grid with air filtration insect prevention inserts fitted on the outside vent;

- an optional water vapor system for cooling purposes in extreme dry hot climates being supplied from a separate freshwater tank through a pump coupled with a filter.

15. The unit according to any of claims 1 - 14, wherein the ducts/pipes of the earth exchange ventilation system are placed under the pond/sump to achieve a cold trap effect that cools the incoming air and removes excess humidity by condensation.

Improved Aquaponic Unit

Aquaponics is the integration of recirculating aquaculture and hydroponics into one production system. In an aquaponic unit, water from a fish tank cycles through filters, plant grow beds and then back to the fish tank. In the filters, the fish waste is removed from the water, first using a mechanical filter that removes the solid waste and then through a biofilter that processes the dissolved wastes. The biofilter provides a location for bacteria to convert ammonia, which is toxic for fish, into nitrate, a more accessible nutrient for plants. This process is called nitrification. As the water (containing nitrate and other nutrients) travels through plant grow beds the plants uptake these nutrients, and finally the water returns to the fish tank purified. This process allows the fish, plants, and bacteria to thrive symbiotically and to work together to create a healthy growing environment for each other, provided that the system is properly balanced.

Ammonia (NH3) from the fish waste is transformed to Ammonium (NH4). Nitrosomonas bacteria transforms NH3-NH4 to Nitrite N02-, Nitrobacter Bacteria transforms N02- to Nitrate N03-. The main factors that affect nitrification rates are temperature, pH, and dissolved oxygen (DO) concentration.

The temperature for optimum growth of nitrifying bacteria is between 77-86 Q F (25- 30 Q C). Growth rate decreases by 50% when the temperature is decreased from the optimal to 64 Q F (18 Q C) and nitrifying activities cease when the temperature falls below 32 Q F (0 Q C) or above 120 Q F (49 Q C). It should be noted that Nitrobacter is less tolerant of low temperatures than Nitrosomonas. In cold water systems, care must be taken to monitor the accumulation of nitrites. The optimum pH range for Nitrosomonas and Nitrobacter is between 7.8-8.0 and 7.3- 7.5, respectively. Nitrosomonas growth is inhibited at pH below 6.5. All nitrifying activity is inhibited if pH drops to 6.0 or less. However, the optimum pH for plant nutrient availability in hydroponics is between 5.5 - 6.5. It is recommended that the pH of aquaponic systems be maintained at around 7.0.

Nitrifying bacteria are aerobic and their activity is affected by the DO in the aqueous phase. Maximum nitrification rates exist if DO levels exceed 80% of saturation. Nitrification ceases when DO concentration drops to 2.0 mg/L or less. The activity of Nitrobacter is more strongly affected by low DO than that of Nitrosomonas. In addition, nitrifying activity can be enhanced by adding bacteria from an existing colony, including commercial nitrifying microbes, media from an existing aquaponics system, etc.

Conventional aquaponic systems comprise an aquaculture part (aquatic animal rearing) and a plant cultivation hydroponic part (soilless planting method) which exist in a symbiotic relationship. Such systems utilize three main techniques of hydroponics:

Firstly, raft or deep-water culture (DWC) systems comprise a bed with continuous water flow from / to a fish pond with one or more filter units that are inserted before and / or after the fish pond. The plants are seated in a floating raft with the roots placed under water. Fig. 1 shows an embodiment of such a system.

Secondly, NFT (nutrient film technique) systems comprise one or more pipes or covered channels, wherein the plants are seated in openings in the pipe or channel cover. The roots are partially covered in a thin film of nutrient rich water continually running from and to the fish pond. One or more filter units are inserted before and / or after the fish pond. Fig. 2 shows an embodiment of such a system.

Thirdly, ebb-flow or raised bed systems comprise a grow bed with a substrate that has a timed flow / drain cycle to provide water and oxygen for the plant’s root system. Nutrient rich water continually runs from and to the fish pond, and one or more filter units are inserted before and / or after the fish pond. Fig. 3 shows an embodiment of such a system. In conventional systems, a sump tank is placed at the lowest point of the system to collect the hydroponic nutrient depleted water; it houses the water pump that pumps back the water to the fish pond. It has to be proportional to the grow area and technique used, in ebb-flow systems it needs to be at least the same size of the grow beds combined. It has to hold at least 25%-33% of the fish pond water size; therefore it takes a significant space when using a greenhouse or limited space. The manure samples from commercial farms averaged 2.83% nitrogen (N), 2.54% phosphorus (P), 0.10% potassium (K), 6.99% calcium (Ca), and 0.53% magnesium (Mg) on a dry-weight basis. In addition to low potassium and magnesium levels, Iron and other micro nutrients are usually scarce if present at all, the only source would being the fish feed, adding from traditional fertilizers sources would disrupt the Nitrification cycle by lowering the PH level to acidic which would be devastating to the nitrification bacteria crucial for the transformation of NH3,NH4 and N02 that are toxic for the fish, into the non-toxic N03 to be available as the main nutrient for the plants, also adding fertilizers to the system releases minerals and salts that would alter the salinity of the water (TDS, E.C...etc.) and that would eventually render the water un-inhabitable by fish and hinders nutrient uptake through the root system for plants.

Using conventional designs, however, causes the emergence of some inherited problems. First, the apparatuses for the aquaponic systems are fixed in design to serve a one technique of plant cultivation even when combined as a multi-technique system, as there will be a designated system design for each technique that can’t be used for another crop set. Secondly, most of the apparatuses of said systems are fixed with permanent infrastructure components and are not made to be easily erected, relocated nor expanded. Thirdly, shadows cast by gutters, trusses and equipment in the roof of the greenhouse can lead to uneven light conditions in the crop. As the sun moves from the east to the west during the day, the shadows of the greenhouse structure will also move. An east-west alignment creates structural shadows in the same part of the crop through the day which can affect crop productivity and plant health in this area. Further, greenhouses, which are classified as lightweight structures, are highly vulnerable to wind loads. In addition, cold countries adopted advanced greenhouse technology, increased light transmission, saved energy for heating and optimized all production means to achieve maximum yield; they used glass as covering material which gives rise to high initial cost. Southern or Mediterranean greenhouses adapted to the local conditions, with moderate investments and little (if any) climate control system besides natural ventilation; this produced suboptimal conditions for plant production and as a consequence lower yields than high-tech greenhouses; they used mostly plastic film as covering material. Further, conventional deep-water culture (DWC) apparatuses have a close proximity to the ground and hard to protect from pests.

It is thus an object of the invention to provide an improved aquaponic system. Improved aquaponic systems should thus take into consideration the environmental stability and the means to control it, as the energy consumption and construction cost for such a controlled environment is usually high.

These and other objects are achieved by an aquaponic system according to the independent claim. Advantageous embodiments of the improved aquaponics system according to the invention are described in the dependent claims. Further characteristics of the invention will become apparent from the description of the embodiments and the accompanying figures.

The invention will now be described by means of figures depicting exemplary embodiments.

Figs. 1 - 3 shows conventional aquaponics systems from the prior art;

Fig. 4 shows the water circulation between the pond and the hydroponic component in an exemplary embodiment of the invention;

Fig. 5 shows a trickle filter in an exemplary embodiment of the invention;

Fig. 6 shows a schematic embodiment of the invention as a deep water culture aquaponic system;

Fig. 7 shows a schematic embodiment of the invention as a nutrient film technique aquaponic system; Fig. 8 shows a schematic embodiment of the invention as an ebb-flow aquaponic system;

Fig. 9 shows a schematic embodiment of the invention as a tuber-root vegetable system;

Fig. 10 shows a schematic embodiment of an improved aquaponics system according to the invention as a block diagram;

Figs. 11 - 12 show schematic side views of an improved aquaponics system according to the invention;

Fig. 13 shows schematic side, front, and back views of the grow beds in an improved aquaponics system according to the invention.

The improved aquaponic system according to the invention comprises a domed greenhouse scalable from 10s of square meters to 100s of square meters as shown in Figs. 11 - 12, an aquatic culture system and a hydroponic system housed within as shown in the schematic block diagram of Fig. 10, as well as a trickle filter shown in Fig.

5 and a multi technique cultivating apparatus as shown in Fig. 13.

The domed greenhouse forms the outer shell that is the barrier between the aquaponic system and the outer environment. The unique qualities of the dome-shaped housing give it an advantage in terms of temperature, humidity and ventilation control (with less electric power). Temperature is distributed equally across the volume of air inside the dome, air flows naturally (with vents present) from bottom to top along the sides of the dome (as shown in Fig. 12), condensation water slides along the sides away from the cultivation area, with the vents closed the even distribution of temperature prevents frost effect inside the dome. Buoyancy-driven ventilation and wind induct ventilation are utilized in the dome design. The dome shape captures the sun light at any angle and is superior in wind resistance in comparison with any other design.

Figs. 11 - 12 show the earth exchange ventilation system in a side view of the domed greenhouse structure. The driving force for natural ventilation is the pressure difference across the ventilation openings caused by wind and/or thermal effects. Underground vents specifically placed along the circumference of the dome provides constant air flow to the top vent of the dome, an optional one or more fan can be used to assist if needed.

Soil temperature is one of the most important factors affecting design and performance of earth - tube heat exchanger systems. Soil temperatures vary with soil type, depth, moisture content, time of year, and geographic location. The time of year when the ground temperature is at the extreme is also important in the design and performance of a system. Soil temperature fluctuations lag behind surface temperature changes due to the heat storage capacity of the soil. The soil surface reaches maximum temperature during the heat of the summer, but soil 3 - 3.7 m deep may not reach its peak temperature until almost three months later. This thermal lag at the 10 ft. (3 m) depth helps both the heating and cooling performance of these systems.

For hot humid regions the pipe passes underneath and makes contact with the bottom of the pond to make use of the cooling effect of the pond water thermal mass, it makes the pipe act as a cold trap which reduces humidity and cools air flowing through it. Thermal mass and thermal lag are particularly useful where there is a big difference between day and night outdoor temperatures. Thermal mass can be used to store heat when it is warm so that that energy can then be released / used when temperatures drop.

The thermal difference between the inside of the greenhouse the outside environment causes Buoyancy-driven ventilation in the vents that causes air to flow from the cooler outer environment to the warmer inside environment. Several side vents (windows) might be provided to give additional control of ventilation and the door might also double as a vent when needed. The dome air volume acts as a thermal mass that helps buffer the fluctuation between day/night and seasonal temperature. The larger the air volume the slower it heats or cools. The dome structure might be covered with plastic covering materials in accordance with GAP (Good Agricultural practices) recommendations. Multilayer rather than single-layer films are recommended since they allow addition of the positive properties of each of the components that form the film. Diffusive films are preferred over clear films because they improve light uniformity and increase light interception by the crop. EVA films on the outer surface of the cover are to be avoided in dusty areas due to higher losses in light transmission.

Anti-drip films improve transmission and reduce dripping from the inner surface, but usually lose their anti-drip properties before the end of their life span. In Mediterranean climates, a permanent NIR filter may have useful applications during the summer but could be detrimental during the winter. Movable screens or seasonal whitewashing with NIR filter has good potential; this technique is currently under investigation. UV-blocking films are a promising technique to reduce pest infestation, but their commercial availability is still limited.

Other materials such as glass, poly carbonate, acrylic, etc. might be applied as well.

The dome greenhouse can be completely covered with insulated material; with an artificial source of lighting to be provided when the cover material is not translucent.

The hubs are simple singe bolt 4-6 struts connection; the bolts double as hanging fixture points for the shading system, vine lines, light fixtures, sprinkler system, fans, and sensors and extra grow containers.

The shading system is sun barrier/ visor suspended above both the ponds/sump and the plant cultivation area to provide control on the amount of sun light that hits the surfaces of water bodies and plants. It doubles as a ventilation tool as it partially separates the canopy area of the dome structure from the lower ground volume of air which causes a hot air area above the shade material. The heat difference between the hot canopy air and the cooler outside environment causes air to flow out through the top vent creating a vacuum that pulls the lower cooler ground air to the top canopy space (Buoyancy-driven ventilation). This in turn causes a vacuum that pulls outside fresh air through the earth exchange and/or the above ground vents to the interior of the greenhouse dome. An exterior shading system of a mesh net with 10-90% grade of shade can be used to cover the top vent to protect from pests and provide additional shading.

The pond is inserted in the ground to a depth of 2.5- 3.5 meters to utilize earth Isolation quality and to double as a sump; it is the main aquaculture component of the aquaponic system. The pond is dug out and lined with durable liner material (for example, HDPE sheets), or reinforced concrete. Stacks of sand bags can be used to wall the sides before lining if site earth is too loose, or the pond can be a plastic (HDPE) or fiber glass container inserted in the ground. The pond doubles as a sump tank that resides at the lowest point of any water body or channel in the system, it acts as the reservoir of excess water in the system and it doubles as a rearing pond.

Fig. 4 shows a separator filter for a system according to the invention. Water circulates between the pond and the hydroponic component, a one or more separator filter (swirl or vortex) is inserted between the fish pond and the hydroponic system. The swirl filter has two outflowing conduits: one for the sludge and the other for the water with suspended solids. The sludge tank/pond collects and sediments sludge from the vortex filter, excess water would overflow to the fish pond/sump. The sludge tank functions as a degassing and a mineralization stage also. Sludge is collected from this tank periodically to keep the system functional and balanced. It could be used to make fish manure.

Fig. 5 shows a trickle filter for a system according to the invention. The suspended solids flow to the hydroponic system through the trickle filter.

Fig. 13 shows a schematic embodiment of the hydroponic component of a system according to the invention, which is the plant cultivation area. It comprises a multi technique raised bed system. It is elevated 60 - 90 cm above the ground with a 25 - 40 cm deep bed made of a kit to be assembled on site with mechanical fasteners and customizable components. Each leg has a dish type base (15-20 cm in diameter) to be filled with pest repellant. The beds being elevated also keep pests from reaching grow area. Space underneath the beds is utilized for multiple uses including but not limited to cultivating seedlings, mushroom growing area, beneficial / feed insect rearing area, etc.

The multi technique raised bed system is made of metal, plastic or composite material, lined with a durable plastic liner (ex.: HDPE) , fully detachable and easy to assemble, minimal prep-work needed, scalable to need, up to 50 meters in length by attaching modules (segments), width can be adjusted to desired size.

The raised beds can be used for multiple technologies:

Fig. 6 shows use of the beds in a deep-water culture system: The beds are fitted with floating rafts where a multitude of plants are seated one or more at a time in a net cup within a hole in the raft material and the bed has water flow in full depth of the bed.

Fig. 7 shows use of the beds in a NFT (Nutrient Film Technique) system: The beds are fitted to raft like inserts. A multitude of plants are seated one or more at a time in a net cup within a hole in the raft material; the inserts are lowered to preferred root space/ height, held up by spacers. Water flow / drain position is adjusted to a thin film of fluid constantly flowing.

Fig. 8 shows use of the beds in an ebb-flow system: The bed is filled with substrate to the full depth and water flow is timed to create the ebb-flow (flood - drain) effect. The plants are inserted within the substrate.

Fig. 9 shows use of the beds in a tuber-root vegetable system: The bed is fitted with a cover, the cover has openings for each plant’s root system to reach the below bed of water. Each plant is seated in a raft like position in a net cup; an additional container is fitted around each plant to contain the periodically increased substrate around the root or tuber. If a grow bag is used as the container, then the above mentioned net cup would be optional. A drip system or a wicking watering device is fitted for each container to maintain humidity within, excess water will drip in the bed underneath. Each bed comprises one or more trickle filter to provide nutrient rich water; the trickle filter contains a Zeolite battery. The Zeolite would be the source for the micro nutrients and the grow media for bacteria colonies.

Power of gravity drives the water returning from the cultivation beds to the fish pond which doubles as a sump tank for the system.

An oxygenation / aeration system is crucial for fish, plants and bacteria colonies in the system. For this, one or more air blowers are connected with specialized plumbing and fixtures (diffusers) to distribute oxygen rich air to all water bodies of the system.

A minimum of 2 mg/I DO (Dissolved Oxygen) is tolerated for both fish and bacterial heath in the system. One or more air blower / pump is used to pump the appropriate amount of air through a grid of hoses or lines that terminate in the form of a diffuser, air stone and / or porous pipe under water to ensure a bubbling effect while maintaining air pressure throughout the system to ensure even distribution.

The shelf area underneath the grow beds shown in Fig.14 are used as growing area for mushrooms, seed sprouting, rearing beneficial/feed insects (black soldier fly, earth worms, etc.) and or composting plant leftovers, this area will act in addition to its primary function of additional production as an extra source of C02 and additional thermal mass within the greenhouse.

Additional optional components are described in the following:

A water heating system (optional) to raise the temperature of the water in the system, gas operated (natural/propane), solar powered or other. If gas is used in the heater: gas burning generates C02+FI20 inside the dome environment so it doubles as a water heater and C02 generator; a water cooling system or a cold water stream can be used if cooling the water is necessary for cold water fish. A control/monitoring system: A module that is connected to a number of sensors that measure water and air parameters as well as vegetation growth and fish activity and growth. A fish harvest system: Comprises of a reusable net that is inserted in the pond prior to the fish and pulled out mechanically with the fish at harvest size.