Decoupled aquaponics system in mildly salinated water, and process for farming and cultivating in such a system

Abstract

The present invention relates to a decoupled aquaponics system comprising an aquaculture portion (1) and an agriculture portion (2), the aquaculture portion (1) comprising a farming pond (101) filled with water that has a salinity of greater than 2 g / l, and an aquaculture loop for circulating water in the aquaculture portion. The system further comprises a device for collecting water, allowing the extraction of water from the aquaculture portion (1). The agriculture portion (2) comprises a device for the soil-less cultivation of plants, and an irrigation system containing a nutrient solution that is supplied to the device for soil-less cultivation. The aquaponics system also comprises a buffer tank (3), the device for collecting water being configured to discharge water collected from the aquaculture portion (1) into the buffer tank (3). The aquaponics system further comprises a tank for preparing the nutrient solution, said tank for preparing the nutrient solution being at least partially supplied with water from the buffer tank (3). The invention also relates to a process for farming aquatic animals and for cultivating plants in an aquaponics system.

Description

[0001] Decoupled aquaponic system in low-salt water and breeding and cultivation process in such a system

[0002] The present invention relates to the field of aquaponics. The term "aquaponics" is formed by merging the words aquaculture (designating the breeding of aquatic animals or other aquatic organisms) and hydroponics (cultivation of plants using water enriched with mineral matter).

[0003] Generally speaking, an aquaponic system refers to a production system that combines aquaculture and agricultural production, in this case hydroponics. In this context, aquaculture refers to the production of aquatic organisms, particularly aquatic animals (fish, crustaceans, or mollusks), under controlled conditions, whether in fresh, low-salinity, brackish, or marine water.

[0004] One of the general ideas underlying the principle of aquaponics is that the ammonia contained in the urine and excrement of aquatic organisms that are raised in the aquaculture part of the system can form nutrients, nitrates in particular, which can be assimilated by the plant(s) cultivated in the agricultural part.

[0005] The principle of aquaponics has been known for a very long time. However, it is currently attracting significant interest in a context where environmental and nutritional issues are increasing, with, for example, the development of short supply chains for crops and livestock, and, more generally, the need for local production of products grown or raised in an environmentally friendly manner.

[0006] Many aquaponic systems have been developed in this way and are described in the literature.

[0007] Most of the systems considered are so-called "coupled" systems. In a coupled system, water used for aquaculture is then or jointly used for plant cultivation, while water used for plant cultivation is then or jointly used for aquaculture. In other words, either the plants and aquatic animals grow in the same pond, or all or part of the water used for plant cultivation is returned to the aquaculture section.

[0008] Thus, US 10,548,269 describes a coupled aquaponic system, in which animals, typically fish, are raised in salt water, while plants suitable for growing in a salty environment are grown in supports that float on the water in which the aquatic animals are raised. A first plant purifies the water, and a second plant oxygenates it. Oxygenating the water allows the animals in the aquaculture farm to live, and the aquaculture farm provides nutrients for the plants.

[0009] Document WO201617202 discloses another coupled aquaponic system. This document describes and claims a complete aquaponic system comprising devices for circulation, filtration and control of the properties of the fluids circulating in the system from the aquaculture part to the agricultural part and vice versa. The farming of fish or shrimp is envisaged in this document.

[0010] Document WO2019057818 presents yet another aquaponic system. This document discloses a system comprising two systems, respectively aquaculture and hydroponic, which are managed independently.

[0011] The aquaculture system and the hydroponic system communicate with each other, with water from the aquaculture system being treated to extract solid residues and form a nutrient-rich solution for the plants, while water from the hydroponic system is distilled to dilute the water in the aquaculture system. Specifically, a set of treatments allows the extraction of solid residues from the aquaculture system to create a nutrient-enriched solution for the agricultural system, while a distiller allows the demineralization of water from the agricultural system to send it to the aquaculture system and dilute the water there. This implies that the aquaponic system must operate in fresh water, otherwise salt accumulation would occur in the agricultural system.

[0012] According to another configuration envisaged, the aquaponic system can include an agricultural, hydroponic part, without providing for a return of water from the agricultural part to the aquaculture part.

[0013] The article Co-culture of shrimp with commercially important plants: a review by Juan Francisco Fierro-Sanudo, Frederico Paez-Osuna and Gustavo A Rodriguez Montes de Oca published in Reviews in Aquaculture in November 2020 presents a synthesis of more than 158 published studies on shrimp farming carried out in conjunction with plant cultures, in more or less saline environments. This study notably considers an aquaponic system involving the irrigation of various plants grown in open fields.

[0014] However, the aquaponic systems described in the state of the art can be optimized in many aspects. In particular, no system is known that allows very high-density shrimp farming coupled efficiently, particularly with regard to water supply, with agricultural cultivation.

[0015] Thus, the present invention relates to a decoupled aquaponic system comprising an aquaculture part and an agricultural part. The aquaculture part comprises a breeding tank suitable for growing aquatic animals filled with water having a salinity greater than 2g / L, and an aquaculture loop for circulating water between a water outlet of the breeding tank and a water inlet of the breeding tank. The system further comprises a water sampling device for extracting water from the aquaculture part. The agricultural part comprises a device for growing plants above ground and an irrigation system containing a nutrient solution supplying the device for growing plants above ground. The system comprises a buffer tank, the water sampling device being configured to discharge the water taken from the aquaculture part into the buffer tank.The system further comprises a nutrient solution preparation tank, said nutrient solution preparation tank being at least partly supplied with water from the buffer tank.

[0016] A "decoupled aquaponic system" means an aquaponic system whose aquaculture and agricultural parts can be managed and controlled independently.

[0017] Salinity is defined as the amount of salts dissolved in a liquid, i.e. the mass content of salts. The main dissolved salts are chlorine, sodium, magnesium, sulfate, calcium, potassium, etc. The configuration of the aquaponic system allows in particular to extract water from the aquaculture part before its properties become imperfect for the proper growth of the aquatic animals raised, and while its properties are suitable to serve as a basis for the preparation of a nutrient solution suitable for the cultivation of plants in the agricultural part.

[0018] The aquaponic system may include means for measuring the salinity of the water in the aquaculture section and nitrogen parameters, in particular means for measuring nitrates, in the water in the aquaculture section.

[0019] The system may also include means for measuring alkalinity in the water of the aquaculture section.

[0020] The aquaculture loop may include a mechanical filter.

[0021] The aquaculture loop may include a denitrator. A denitrator, or denitrifying device, generally includes an anaerobic filter that allows denitrification of the water.

[0022] The aquaculture loop may include a degassing device and / or an aerobic biological filter. The breeding tank may contain shrimp. The breeding tank may contain more than 6 kg of shrimp per cubic meter of water.

[0023] Such density can be achieved in particular at the end of the breeding period, when the shrimp have reached the desired size for fishing.

[0024] The agricultural part may comprise at least two irrigation systems, namely a first irrigation system supplying a first soilless cultivation system and a second irrigation system supplying a second soilless cultivation system, and in which the first irrigation system contains a first nutrient solution containing water directly from the buffer tank, and in which the second irrigation system contains a second nutrient solution containing water directly from the buffer tank and optionally containing drainage from the first irrigation system.

[0025] The drainage of the first irrigation system corresponds to the solution recovered at the outlet of this first irrigation system.

[0026] The aquaponic system may comprise first plants grown in the first soilless cultivation system, namely fruit plants, preferably tomatoes, and comprising second plants grown in the second soilless cultivation system, namely leafy plants.

[0027] Leafy plants include leafy vegetables, that is, vegetables whose consumed part (or at least a consumed part) consists of leaves. This includes cruciferous or brassica plants, aromatic plants, and certain shoots (for example, beetroot shoots).

[0028] The term "fruiting plants" means all plants that produce fruit, preferably edible fruit.

[0029] Fruit plants and leafy plants are grown on growing media suitable for soilless cultivation.

[0030] Possible growing media for fruit plants and / or leafy plants include growing media, including fibrous media, floating media, and any other form of media suitable for root development.

[0031] For example, fruit plants and leafy plants are respectively grown on a fibrous substrate or on an impermeable floating support having through holes adapted to receive roots of said leafy plants.

[0032] For example, fruit plants may be grown on a fibrous substrate, and leafy plants may be grown on an impermeable floating medium having through holes adapted to receive roots of said leafy plants.

[0033] The system may include a sensor adapted to measure electroconductivity in the fibrous substrate.

[0034] The invention also relates to a method of raising aquatic animals and cultivating plants in an aquaponic system, the method comprising:

[0035] - the breeding of aquatic animals in an aquaculture area containing water with a salinity greater than 2g / L,

[0036] - the cultivation of plants, supplied with nutrient solution by an irrigation system,

[0037] Plant cultivation is carried out above ground and the process involves:

[0038] - the at least daily measurement of salinity in the water of the aquaculture part, and - the at least daily measurement of nitrates in the water of the aquaculture part, and, if the salinity exceeds a given salinity threshold, and / or if the nitrates exceed a given nitrate threshold:

[0039] - water extraction from the aquaculture part,

[0040] - the addition of new water to the aquaculture part, to compensate for the extracted water, the method further comprising the preparation of the nutrient solution, said nutrient solution comprising water extracted from the aquaculture part.

[0041] The aquatic animals more specifically considered include fish and crustaceans, notably shrimp, especially Penaeus Vannamei shrimp.

[0042] The method may include storing the water extracted from the aquaculture portion in a buffer tank.

[0043] The given salinity threshold can for example be between 3g / L and 8g / L. and the given nitrate threshold can for example be between 100 mg / L and 300 mg / L.

[0044] The preparation of the nutrient solution may include: the supply of water extracted from the aquaculture part, the supply of inputs, optionally, the supply of fresh water, and the mixing of the water extracted from the aquaculture part, the inputs and optionally fresh water.

[0045] Inputs can be supplied directly, for example in the form of powders, or supplied in a stock solution. Stock solution refers to a solution rich in inputs, which can be obtained by mixing inputs in water from the aquaculture section (via the buffer tank) or in fresh water.

[0046] Throughout this document, the concept of fresh water refers to water with a salinity of less than 1 g / L of salts.

[0047] The method may comprise preparing two nutrient solutions, namely a first nutrient solution and a second nutrient solution, the preparation of the first nutrient solution comprising: providing water extracted from the aquaculture part, providing inputs contained in a mother solution, and mixing the water extracted from the agricultural part and the mother solution, and diluting with fresh water; the method comprising irrigating, by a first irrigation system, first plants with the first nutrient solution, the preparation of the second nutrient solution comprising: providing water extracted from the aquaculture part providing drainage from the first irrigation system; mixing the water extracted from the aquaculture part and drainage from the first irrigation system and optionally adding inputs;the method comprising irrigating, by a second irrigation system, second plants with the second nutrient solution.;

[0048] Inputs may include one or more of the following:

[0049] - Calcium nitrate;

[0050] - potassium nitrate;

[0051] - monopotassium phosphate;

[0052] - one or more organic inputs;

[0053] - iron chelate;

[0054] - mixture of trace elements;

[0055] - manganese;

[0056] - nitric acid;

[0057] - hydrochloric acid;

[0058] - sulfuric acid;

[0059] - orthophosphoric acid.

[0060] Other features and advantages of the invention will become apparent in the description below.

[0061] In the attached drawings, given as non-limiting examples: Figure 1 represents, according to a principle diagram, an aquaponic system in accordance with an embodiment of the invention; Figure 2 represents, according to a principle diagram, the aquaculture part of an example of an aquaponic system in accordance with an embodiment of the invention, for example the aquaponic system of Figure 1; Figure 3 represents, according to a principle diagram, the agricultural part of an example of an aquaponic system in accordance with an embodiment of the invention, for example the aquaponic system of Figure 1.

[0062] An aquaponic system according to the present invention comprises an aquaculture part 1, an example of which is shown in Figure 2, and an agricultural part 2 (hydroponic) shown in Figure 3.

[0063] According to the invention and as described in more detail below, the aquaculture part 1 and the agricultural part 2 are in interface in that water from the aquaculture part 1 is used for irrigation of the plants in the agricultural part 2. However, there is no direct return of water from the agricultural part 2 to the aquaculture part 1. The aquaculture part and the agricultural part can be managed, in particular with regard to the properties of the water they contain, as described below, independently. The system proposed in the invention is thus a decoupled aquaponic system. Furthermore, the aquaculture part and the agricultural part can be managed independently. By independently it is understood that the respective control systems of these parts are independent, the properties of the water leaving the aquaculture part 1 to be used for irrigation in the agricultural part 2 can nevertheless influence the management of the agricultural part 2.

[0064] In the example shown, when water is extracted from the aquaculture part 1, it is discharged into a buffer tank 3. The buffer tank 3 supplies (in whole or in part, as described with reference to Figure 2) the agricultural part 2. Finally, any effluent from the agricultural part is removed from the system to be released or treated as needed. Figure 2 thus represents the aquaculture part 1 of such an aquaponic system.

[0065] The aquaculture part comprises a breeding tank 101. The breeding tank contains aquatic animals, preferably crustaceans, preferably shrimp. More particularly, the system which is the subject of the present invention is particularly suitable for breeding shrimp, in particular Penaeus Vannamei shrimp (also called Litopenaeus Vannamei). The breeding tank 101 allows the growth of shrimp in so-called low salinity water, greater than 1 g / L but less than 10 g / L.

[0066] Salinity is defined as the quantity of salts dissolved in a liquid, i.e. the mass content of salts. The main dissolved salts are chlorine, sodium, magnesium, sulfate, calcium, potassium, etc. It thus includes in particular the content of ions: Chloride (cl-), Sodium (na+), Sulfate (SO42-), Magnesium (Mg2+), Calcium (Ca2+), Potassium (K+), etc. Salinity is measured from the electrical conductivity of water, at a given temperature and pressure. In particular, the electrical conductivity of water can be measured using a conductivity meter. This conductivity thus reflects the presence of ions in the solution, in particular Chloride (ch), Sodium (na + ), Sulfate (SO4 2 '), Magnesium (Mg 2+ ), Calcium (Ca 2+ ), Potassium (K + ), etc.

[0067] The present invention, one embodiment of which is detailed with reference to Figures 1 to 3, aims in particular to enable shrimp farming with a very high shrimp density. The density in the farming tank can thus be greater than 6 kg of shrimp per cubic meter of water, advantageously greater than 10 kg / m3 and up to 20 kg / m3 or even more. Reduced in number of Penaeus Vannamei shrimp, the shrimp density can thus be greater than 0.4 shrimp per liter of water in the farming tank, and up to more than 1.2 shrimp per liter of water in the farming tank at the end of the farming period, when the shrimp have reached the desired size for fishing.

[0068] The expression "breeding pond" can of course collectively designate a set of several ponds where shrimp or other aquatic animals are raised. An aquaculture loop allows water to circulate, in a closed circuit, between a water outlet 102 of the breeding pond 101 and a water inlet 103 of the breeding pond 101.

[0069] The aquaculture loop comprises a number of devices for treating the water in the aquaculture section. The aquaculture loop shown thus comprises a mechanical filter 104 for mechanically filtering the water from the breeding tank 101. The purpose of mechanical filtration is to separate solid elements of a given size or larger present in the water. The mechanical filter 104 may be of different types. In particular, it may be a mesh filter. It may be a drum filter, which comprises a rotating filter for capturing and separating solid elements from the water. Preferably, the mechanical filter is a filter suitable for removing particles larger than 100 micrometers, preferably larger than 60 micrometers. These solid elements are then removed from the aquaculture loop, thus becoming solid effluents 105 of the aquaponic system. The solid effluents 105 also include sludge.Solid effluents, rich in nitrogen, can be recovered, particularly as organic fertilizers.

[0070] In conjunction, where appropriate, with the biological filter described below, the mechanical filter makes it possible to maintain the breeding in clear water. Clear water is understood to mean water whose mass concentration of suspended solids is less than 100 mg / L, preferably less than 80 mg / L, even more preferably less than 50 mg / L. Once filtered, the water from the breeding tank is sent to a recovery tank 106. The recovery tank 106 constitutes a water reserve facilitating the management of the quality and quantity of the water present in the aquaculture part 1 of the aquaponic system.

[0071] A denitrator 107 is planned, in parallel with the recovery basin 106.

[0072] The denitrator 107, or denitrifying device, is a device that allows the formation of nitrogen from nitrates present in the water. It therefore makes it possible to limit, stabilize, or slow down the progression of the quantity of nitrates in the water of the aquaculture part. It is based on the colonization of a neutral substrate by bacteria that use a carbon source, typically alcohol such as ethanol, to transform nitrates into nitrogen. In a denitrator, the denitrifying bacteria catalyze the reduction of the nitrate ion (NO3-) into nitrogen (N2) according to the following reaction: NOs' + 6H + + 5 e' -> / 2 N2 + 3H2O. The denitrator thus makes it possible to control the quantity of nitrates and more generally the nitrogen parameters present in the water. This makes it possible to limit the quantity of water to be replaced in the aquaculture section according to the methods described below.

[0073] The aquaculture loop also includes an aerobic biological filter 108. The aerobic biological filter 108 allows nitrification, that is to say the transformation by nitrifying organisms of ammoniacal nitrogen into nitrates during two successive reactions. The first reaction is a nitrosation reaction, which is the transformation of ammonia (NH4+) into nitrite ion (NO2-) by nitrous bacteria. The second reaction is a nitration reaction, which is the transformation of nitrite ions into nitrate ions (NO3-). Nitrate ions are assimilable by plants and less toxic than ammonium. The aerobic biological filter 108 therefore makes it possible to adapt the quantity of organic matter present in the water from the recovery tank 106.

[0074] Finally, a degassing device 109 allows, if necessary, the release of gases dissolved in the water before the water is reintroduced into the breeding tank 101 via the water inlet 103. Various degassing devices are possible. The most common degassing devices operate by mechanical agitation of the water. The degassing device 109 allows in particular the release of carbon dioxide dissolved in the water. It allows the pH of the water to be raised if necessary, without increasing its alkalinity.

[0075] Water management, in order to maintain desired characteristics, also involves extracting water from the aquaculture section to the buffer tank 3, and supplying water as compensation from a new water source 110. Water extraction, using a sampling device, is carried out punctually as needed. Water extraction can be carried out from different areas of the aquaculture section, i.e. not necessarily from the breeding pond

[0076] The fresh water source 110 corresponds to a reservoir or a water network allowing the introduction into the aquaculture part (at the level of the aquaculture loop or the breeding basin 101) of water whose properties make it possible to compensate for any drifts in the properties of the water present in the aquaculture part. For example, network water, or borehole or spring water, can be supplemented in a dedicated basin to form fresh water having the desired properties. The properties of the water include in particular salinity, pH, nitrogen parameters (in particular nitrates), and alkalinity.

[0077] For example, between 1% and 10%, and for example 3% of the water present in the aquaculture loop can be extracted each day from the aquaculture part, an equivalent or substantially equivalent quantity of new water being added as compensation. The added quantity also makes it possible to compensate for evaporation and / or possible leaks from the system. The quantity of water extracted depends on the evolution of the properties of the water in the aquaculture part, these can nevertheless be regulated to a certain extent by the devices it contains (for example, as explained above, the denitrator 107 can control the increase of nitrates in the water, at least to a certain extent), or by the addition of suitable products.

[0078] The water requirements of the agricultural (hydroponic) part can also be taken into consideration for the water extraction of the aquaculture part.

[0079] The following properties of the water present in the aquaculture loop are monitored by measurements at a suitable frequency. The monitoring of the properties can be done using any suitable method known to a person skilled in the art in the state of the art. Depending on the property in question, its measurement can be carried out, for example, weekly, bi-weekly, daily, twice a day, or "continuously" (i.e. the measurement is sufficiently frequent to observe a regular variation, without a sudden "jump" in the measured value, so that at any time the measured value can be known precisely).

[0080] For example, the following properties of the water in the aquaculture section can be measured at a suitable frequency, for example continuously, at one or more points in the aquaculture section, in particular in the breeding tank (or in the various tanks forming the breeding tank):

[0081] - dioxygen (02) dissolved in water;

[0082] - pH;

[0083] - the temperature;

[0084] - salinity;

[0085] Daily measurements can be taken for:

[0086] - nitrogen parameters (NH4+ / NO2- / NO3-);

[0087] - total alkalinity.

[0088] Less frequently, for example every other day or twice a week, measurements can be taken for cation concentrations: Na+ / K+ / Mg2+ / Ca2+. A weekly measurement of the redox potential can be taken.

[0089] Obviously, the frequencies mentioned above are for information purposes only and can be adapted, in particular depending on the particular aquaponic system considered, or in particular if possible deviations observed in the properties of the water require more regular monitoring of these properties. The aquaponic system can include permanently installed sensors for this purpose, or sensors installed by an operator to take a measurement (for example, manual sensors).

[0090] Ranges of values ​​have been defined for the above-mentioned water properties, or for certain pairs of properties. For example, the pair formed by salinity and nitrates is very relevant because the toxicity of nitrates for shrimp depends on salinity.

[0091] Maintaining within the defined ranges may require certain measures, for example the activation of the denitrator 107 or the addition of certain products, in particular mineral salts, to the water, for example in the recovery basin 106.

[0092] The added products can therefore be: sodium bicarbonate, soda, calcium oxide or calcium carbonate to compensate for a decrease in alkalinity and / or pH.

[0093] Furthermore, the extraction of water from the aquaculture part to the buffer tank 3 is advantageously carried out according to certain properties of the water. Indeed, it is necessary to maintain water whose quality allows shrimp to be raised at high density (or, where appropriate, other aquatic animals) in the water, while providing an effluent of interest for hydroponic cultivation, particularly rich in nitrates, but relatively low in salt.

[0094] Thus, it may be decided to extract water from the aquaculture part 1, sending it to the buffer tank 3, when the water reaches or exceeds a given salinity threshold. This threshold is for example between 3g / L and 10g / L, and advantageously between 3g / L and 8g / L.

[0095] Similarly, it may be decided to extract water from the aquaculture part 1, by sending it to the buffer tank 3, when the nitrates reach or exceed a given nitrate threshold. This threshold is for example between 100 mg / L and 300 mg / L, and advantageously between 150 mg / L and 250 mg / L, for example 200 mg / L or approximately 200 mg / L.

[0096] Throughout the patent application, "approximately" or "in the order of" means the indicated value plus or minus 10%.

[0097] In this patent application, unless otherwise indicated, all limits of the ranges of values ​​indicated are included in the range considered.

[0098] In certain salinity or nitrate ranges, the ratio between these two properties can be taken into account in the decision to extract water from the aquaculture section.

[0099] Furthermore, alkalinity can be monitored and controlled by adding more or less bicarbonate to the water in the aquaculture area.

[0100] In addition, it may be decided to extract water from aquaculture section 1, sending it to buffer tank 3, as long as the total alkalinity, defined by the CaCO3 equivalent content of the water, does not exceed a given threshold. This threshold may be between 100 and 300 mg / L, it may be 150 mg / L or about 150 mg / L. When the total alkalinity is above this threshold, it may be decided to reduce the water extraction and decrease the sodium bicarbonate inputs so that the total alkalinity falls below the given threshold.

[0101] Replacing extracted water with new water with suitable properties can restore the water's properties to a desired level. For example, if water is extracted because its salinity becomes too high, new, low-salinity water or even fresh water can be introduced to compensate for the extracted water.

[0102] The new water supplied can therefore be mains water, borehole water or spring water, supplemented by adding various salts, in particular:

[0103] - aquaculture salt (commercially available for the formation of artificial seawater),

[0104] - ethylenediaminetetraacetic acid.

[0105] The aquaculture loop shown in Figure 2 corresponds to a particularly optimized loop. Obviously, the present invention is not limited to this exemplary embodiment, and certain alternative embodiments (in particular not including all the devices present in the aquaculture loop described, or including other devices) can be envisaged without departing from the scope of the present invention.

[0106] Figure 3 represents the agricultural part 2, hydroponic, of an aquaponic system according to an embodiment of the invention, such as that represented in Figure 1.

[0107] The interface with the aquaculture part is carried out via buffer tank 3.

[0108] Agricultural section 2 is advantageously used for growing traditional vegetables, in particular tomatoes, and / or mesclun, and / or aromatic plants.

[0109] The agricultural part comprises, in the example shown, a first irrigation system 201 intended for growing first plants, and a second irrigation system 202 intended for growing second plants. The crops grown in the agricultural part are soilless crops. The concept of irrigation system thus refers to a device allowing the irrigation of plants, that is to say the supply of nutrient solution to their roots, via their growing medium.

[0110] An irrigation system may therefore include, depending on the type of soilless cultivation system considered, and for example, a basin, more or less deep, a set of open pipes of the gutter type containing the nutrient solution, or even a drip or "dripper" type system to bring the nutrient solution to the level of the cultivation medium, for example a cultivation substrate.

[0111] In the example shown, the first irrigation system 201 is intended for irrigating fruit plants (as first plants) grown in a first soilless cultivation system, and the second irrigation system 202 is intended for irrigating "leafy" plants (as second plants), grown in a second soilless cultivation system.

[0112] The fruit plants most particularly considered within the framework of this aquaponic system are tomatoes, particularly cherry tomatoes.

[0113] Cultivated leafy plants may include cruciferous plants. Cruciferous plants of particular interest include arugula (Eruca sativa), Chinese mustard (Brassica Juncea), pak choi (Brassica rapa L. subsp. Chinensis), and mizuna (Brassica rapa joponica).

[0114] For the cultivation of fruit plants, especially tomatoes, a nutrient solution (first nutrient solution) must be prepared for use in irrigation. Tomatoes are used herein as a preferred example, but this does not exclude the cultivation of other fruit plants, mutatis mutandis.

[0115] Tomatoes are advantageously grown on a fibrous growing substrate, for example rock wool in blocks, and in particular rock wool blocks with vertically oriented fibers (the vertical direction being defined when the block is in the position of use to accommodate the roots of the tomatoes). This type of substrate proves to be very draining, which prevents the accumulation of salts from the irrigation water in the substrate. The first irrigation system 201 may comprise a dripper which distributes water over the growing substrate. The first irrigation system 201, in the example presented, is not “recirculating”, that is to say that the first nutrient solution is not recycled to be supplied again to the tomatoes.

[0116] By adjusting the amount of water supplied, a large proportion of the water supplied is consumed by the tomatoes. For example, only about 30% of the volume of the nutrient solution supplied is recovered at the outlet of the first irrigation system 201 in the form of so-called drainage solution. Obviously, the nutrient solution having irrigated the tomatoes and which is recovered at the outlet of the first irrigation system no longer has the same properties as the initial nutrient solution.

[0117] The first nutrient solution is obtained on the basis of water from buffer tank 3, i.e. water extracted from agricultural part 1 under the conditions described with reference to figure 2. This water is particularly rich in nitrogen parameters, notably nitrates.

[0118] In the example shown, two separate nutrient solutions are produced for growing tomatoes. These two solutions are obtained by diluting the same mother solution with water from the buffer tank 3 and fresh water. Mother solution 203 comprises fresh water and inputs 204. The mother solution therefore makes it possible to provide the inputs in a form that is simple to implement to form the desired solution.

[0119] Inputs may include one or more of the following:

[0120] - calcium nitrate;

[0121] - potassium nitrate;

[0122] - monopotassium phosphate;

[0123] - one or more organic inputs

[0124] - iron chelate

[0125] - a mixture of trace elements

[0126] - manganese

[0127] - nitric acid

[0128] - hydrochloric acid;

[0129] - sulfuric acid

[0130] - orthophosphoric acid.

[0131] A first solution for fruit plants 205 is obtained by diluting the mother solution with water from the buffer tank 3 and fresh water 207 so as to obtain a first percentage of fresh water in the first solution for fruit plants 205.

[0132] A second solution for fruit plants 206 is obtained by diluting the mother solution with water from the buffer tank 3 and fresh water 207 so as to obtain a second percentage of fresh water in the second solution for fruit plants 206.

[0133] The second percentage of fresh water is greater than the first percentage of fresh water.

[0134] As a simple example, the first percentage of fresh water can be between 10% and 40% by volume, the second percentage of fresh water can be between 41% and 70% by volume.

[0135] Of course, alternatively, the first solution for fruit plants 205 and the second solution for fruit plants 206 can be respectively obtained by adding the inputs to water from the buffer tank 3 and then diluting the mother solution thus obtained with fresh water, with the respective desired dilution rate.

[0136] Other methods for preparing nutrient solutions can of course be envisaged within the framework of the present invention.

[0137] The selection of the fruit plant solution used to irrigate tomatoes, between the first fruit plant solution and the second fruit plant solution, results from a very fine management of the growing conditions, and can thus be a function of one or more of the following elements:

[0138] - the time of day (given by the hour);

[0139] - weather forecasts for the coming hours and / or days;

[0140] - the weight of the growing media (in this case the substrate blocks);

[0141] - the air temperature around the tomatoes;

[0142] - brightness; and

[0143] - electroconductivity in the substrate.

[0144] Regarding the electro-conductivity in the substrate, it is remarkable to note that it is here controlled upwards, and not downwards as is the case in conventional agricultural crops. Indeed, generally electro-conductivity is measured to control the quantity of nutrients present in the water. In conventional agricultural systems, which use fresh water, a drop in electro-conductivity is thus expected and monitored, in order to know when the water must be renewed or enriched. In the context of agricultural part 2 of an aquaponic system in accordance with the present invention, the water used has a certain salinity, which is the property of water that mainly influences its electro-conductivity.Thus, it is above all the increase in salinity, which can be problematic for cultivated plants, which is monitored via the increase in electro-conductivity that it causes, in order to take the necessary corrective measures (for example, the addition of soft water or soft nutrient solution, i.e. with a salinity of less than 1g / L of salts, or with a low salinity, typically less than 2g / L).

[0145] For the cultivation of leafy plants, a second nutrient solution must be obtained. The second nutrient solution 208 is obtained on the basis of water from the buffer tank 3, i.e. water extracted from the agricultural part 1 under the conditions described with reference to FIG. 2.

[0146] The leafy plants may be grown on impermeable supports that float or are arranged on the surface of the second nutrient solution, and having through-holes adapted to receive roots of said leafy plants. The second irrigation system 202 may thus advantageously comprise a basin, in particular a shallow basin filled with the second nutrient solution. Shallow depth means a water height of less than 20 cm, advantageously less than 10 cm.

[0147] The growing supports may in particular be formed of rafts (generally called by the corresponding English term "raft") which are formed of a floating shelf comprising adapted through-orifices intended to receive roots of said cruciferous plants, which can thus reach the second nutrient solution on which the raft floats. For example, the rafts known and used successfully in the embodiment described here comprise approximately 1000 orifices per square meter. The support being moreover impermeable, in that it becomes little or not at all saturated with second nutrient solution and in that the roots of the second plants do not develop there or little, there is no risk of accumulation of mineral salts in the growing support.

[0148] In addition to the water from the reservoir 3, the second nutrient solution may also optionally comprise the first nutrient solution from the first irrigation system 201, after this first nutrient solution has irrigated the tomatoes. This drainage water from the first irrigation system may represent, for example, up to 50% of the volume of the second nutrient solution 208 which is formed. Acids are then added to obtain a pH located within a desired pH range for growing the cultivated leafy plants.

[0149] If the second nutrient solution is formed without water from the first irrigation system, inputs are added to the water from buffer tank 3 (and therefore from the aquaculture section). The inputs may include one or more of the following:

[0150] - iron chelate;

[0151] - one or more organic inputs;

[0152] - a mixture of trace elements;

[0153] - manganese;

[0154] - nitric acid;

[0155] - hydrochloric acid;

[0156] - sulfuric acid;

[0157] - orthophosphoric acid.

[0158] Organic inputs include organic liquid fertilizers.

[0159] It should therefore be noted that the cultivation of fruit plants is optional in the proposed system. An aquaponic system according to certain embodiments of the invention may be devoid of fruit plant cultivation in its agricultural portion, and / or the cultivation of fruit plants may be seasonal.

[0160] The second irrigation system 202 causes a recirculation of the second nutrient solution. Thus, the second nutrient solution can be used to irrigate the second plants until its nitrate and / or phosphorus content falls below a threshold set respectively for these elements.

[0161] Typically, the second nutrient solution may be used until the nitrate content is below a threshold of between 50 mg / L and 0 mg / L, preferably between 30 mg / L and 0 mg / L; and / or the second nutrient solution may be used until the phosphorus content is below a threshold of between 10 mg / L and 0 mg / L, preferably between 5 mg / L and 0 mg / L. In the embodiment shown in the figure, and as described above, the first irrigation system 201 is not “recirculating”. It is however possible, in an alternative embodiment, to provide for recirculation of all or part of the effluent to form a new quantity of nutrient solution for fruiting plants, which will be supplied to the tomatoes (or other fruiting plants). In this case, the cultivation of leafy plants may be optional.

[0162] The effluent leaving the agricultural part leaves the aquaponic system and can be released or treated as needed, for example by a local sewage treatment plant 4.

[0163] According to an alternative embodiment, the effluent can (in whole or in part) be treated so that its properties are compatible with a return to the aquaculture part. For example, a physicochemical treatment of the effluent can be carried out to give it certain properties close to those of the new water brought into the aquaculture loop. This allows the treated effluent to be integrated into the new water brought into the aquaculture loop. The treatment of the effluent can include the addition of a base. The invention thus developed proposes a decoupled aquaponic system, the configuration and operating mode of which allows the breeding of aquatic animals, in particular shrimp, at very high density in low salinity water, which allows the soilless cultivation of leafy plants and / or fruit plants, of high quality and with a high yield.

Claims

Demands 1. A decoupled aquaponics system comprising an aquaculture section (1) and an agricultural section (2), the aquaculture section (1) comprising a rearing tank (101) adapted for the growth of aquatic animals filled with water having a salinity greater than 2g / L, and an aquaculture loop for circulating water between a water outlet (102) of the rearing tank (101) and a water inlet (103) of the rearing tank, the system further comprising a water sampling device for extracting water from the aquaculture section (1), characterized in that the agricultural section (2) comprises a soilless plant cultivation device and an irrigation system containing a nutrient solution supplying the soilless plant cultivation device, and in that the system comprises a buffer tank (3), the water sampling device being configured to discharge water sampled from the aquaculture section into the buffer tank (3). (1),the system further comprising a nutrient solution preparation tank, said nutrient solution preparation tank being at least partly supplied by water from the buffer tank (3).

2. Aquaponic system according to claim 1, comprising means for measuring the salinity of the water in the aquaculture part (1) and the nitrates in the water in the aquaculture part (1).

3. Aquaponic system according to claim 1 or claim 2, wherein the aquaculture loop includes a mechanical filter (104) 4. Aquaponic system according to any one of the preceding claims wherein the aquaculture loop includes a denitrifier (107).

5. Aquaponic system according to any one of the preceding claims, wherein the aquaculture loop includes a degassing device (109) and / or an aerobic biological filter (108).

6. Aquaponic system according to any one of the preceding claims, wherein the rearing tank (101) contains shrimp.

7. Aquaponic system according to claim 6, wherein the rearing tank (101) contains more than 6kg of shrimp per cubic meter of water.

8. An aquaponic system according to any one of the preceding claims, wherein the agricultural part (2) comprises at least two irrigation systems, namely a first irrigation system supplying a first soilless growing system and a second irrigation system supplying a second soilless cropping system, and in which the first irrigation system (201) contains a first nutrient solution containing water directly from the buffer tank (3), and in which the second irrigation system (202) contains a second nutrient solution containing water directly from the buffer tank (3) and optionally containing drainage from the first irrigation system (201).

9. Aquaponic system according to claim 8, comprising first plants cultivated in the first soilless culture system, namely fruiting plants, preferably tomatoes, and comprising second plants cultivated in the second soilless culture system, namely leafy plants.

10. System according to claim 9, wherein the fruiting plants and the leafy plants are respectively grown on a fibrous substrate or on an impermeable floating support having through holes adapted to receive the roots of said leafy plants.

11. A method for rearing aquatic animals and cultivating plants in an aquaponic system, the method comprising: - the rearing of aquatic animals in an aquaculture area (1) containing water with a salinity greater than 2g / L, - the cultivation of plants, supplied with nutrient solution by an irrigation system, the process being characterized in that the cultivation of the plants is carried out without soil, and in that the process comprises: - the measurement at least daily of salinity in the water of the aquaculture section (1), and - the measurement at least daily of nitrates in the water of the aquaculture section (1), and, if the salinity exceeds a given salinity threshold, or if the nitrates exceed a given nitrate threshold: - water extraction from the aquaculture section (1), - the addition of fresh water in the aquaculture section (1), in compensation for the water extracted, the process further comprising the preparation of the nutrient solution, said nutrient solution comprising water extracted from the aquaculture section (1).

12. Method according to claim 11, comprising storing the water extracted from the aquaculture part in a buffer tank (3).

13. A process according to claim 11 or claim 12, wherein the given salinity threshold is between 3g / L and 8g / L and the given nitrate threshold is between 100 mg / L and 300 mg / L.

14. A method according to any one of claims 11 to 13, wherein the preparation of the nutrient solution comprises: - the supply of water extracted from the aquaculture section (1), - the supply of inputs, - optionally, the supply of fresh water, and - the mixture of water extracted from the aquaculture part (1), inputs (204) and optionally fresh water (207).

15. A process according to any one of claims 11 to 14, the process comprising the preparation of two nutrient solutions, namely a first nutrient solution (205, 206) and a second nutrient solution (208), the preparation of the first nutrient solution (205, 206) comprising: - the supply of water extracted from the aquaculture section (1), - the supply of inputs (204) contained in a parent solution (203), and - the mixing of water extracted from the agricultural portion (2) and the stock solution (203), and a dilution with fresh water (207); the process comprising irrigating, by a first irrigation system, first plants with the first nutrient solution, the preparation of the second nutrient solution (208) comprising: - the supply of water extracted from the aquaculture section (1) - the provision of drainage for the first irrigation system; - the mixing of water extracted from the aquaculture part (1) and drainage from the first irrigation system and optionally the addition of inputs the process including the irrigation, by a second irrigation system, of second plants with the second nutrient solution.

16. A process according to claim 13 or claim 14, wherein the inputs (204) comprise one or more of the following inputs: - Calcium nitrate; - potassium nitrate; - monopotassium phosphate; - one or more organic inputs; - iron chelate; - mixture of trace elements; - manganese; - nitric acid; - hydrochloric acid; - sulfuric acid; - orthophosphoric acid.

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