WO2012025911A2

WO2012025911A2 - Method for manufacturing a tank, and storage tank

Info

Publication number: WO2012025911A2
Application number: PCT/IB2011/054015
Authority: WO
Inventors: Thierry Labrosse
Original assignee: Thierry Labrosse
Priority date: 2010-08-24
Filing date: 2011-09-14
Publication date: 2012-03-01
Also published as: WO2012025911A3

Abstract

The invention relates to a method for manufacturing a tank for storing a liquid, comprising the steps of: placing a membrane (3), suitable for forming a sealed bag after being unfolded, on a surface forming a tank bottom; and simultaneously filling the inside (4) and the outside (5) of the membrane with a solid granular filler while gradually unfolding the sides of the bag in order to form the sides of the tank. The invention further relates to a buried, partially buried, or mounded tank characterised in that it comprises a membrane (3) and a solid filler inside and outside the tank.

Description

PROCESS FOR CONSTRUCTING RESERVOIR

AND STORAGE TANK

The present invention relates to a construction technique of a buried tank, partially buried or mound for the storage of liquids and in particular water.

There are conventional metallic or prefabricated and buried or superficial plastic tanks. These tanks have a rigid structure but have the disadvantage of being sensitive to bad weather, buoyant, expensive and fragile to crush and, especially for the superficial tanks, to be vandalized.

In addition, there are underground tanks of very large capacity constituted by natural or excavated excavations whose walls are made impermeable, either by cementing and asphalt coating, or by coating plastic sheets with a system of filling and filling. appropriate pumping generally for liquids including volatile liquids and liquids not yet degassed such as hydrocarbons and petroleum products. Generally, these systems have a solid structure but have high costs that increase the cost of stored products particularly if it is the storage of drinking water. The present invention aims to provide a weather resistant tank and less likely to suffer damage.

To do this, the present invention firstly proposes a method for constructing a reservoir for storing a liquid, characterized in that it comprises the steps of:

applying a membrane adapted to form a sealed bag after unfolding on a surface forming a bottom of the tank,

simultaneously filling the inside and outside of the membrane with a solid granular filler by progressively unfolding the sides of the pocket to achieve the sides of the tank.

Advantageously, the method comprises a step of partially closing the upper part of the membrane by a roof so as to form an inclined plane and a vent and / or a chimney allowing the entry of water, the exit or the entrance of the 'air.

Preferably, the method comprises a step of covering the tank thus formed by backfill on a more or less thick layer depending on the resistance to surface traffic that is desired.

Preferably, the method comprises a step of laying a strainer and a draw tube before filling the membrane.

Since the reservoir is a buried or semi-buried reservoir, the method advantageously comprises, prior to the installation of the membrane, a digging step of a dig, the laying of the membrane being done on the bottom of the dig.

According to a particular embodiment, the flattened membrane is a membrane without welds made from a film / plane the method comprising a preliminary step of beach of the membrane to form a bottom and sealed sides by progressively unfolding the sides of the membrane. membrane.

Advantageously, before laying the membrane on the bottom, a geotextile material adapted to protect the membrane against hard objects (such as rocks, roots), the movements of the soil or the aggressions of animals or insects or microorganisms that could perforate or degrade the membrane. The invention also proposes a tank of the buried or partially buried or tiled type, characterized in that it comprises a membrane and a solid charge internal and external to the tank.

Advantageously, the membrane is formed, either of several layers of membranes installed together to form a sealed multilayer envelope, or of a single waterproof membrane composed of several synthetic layers of different polymers similar to the films used in the packaging industry called multilayer film .

Alternatively, the membrane is a monolayer membrane.

According to a particular embodiment, the membrane is made by using several plates, sheets or films welded together or glued with glues or with adhesive strips, so as to produce an envelope with the exact shapes of the reservoir.

The material of the membrane is advantageously chosen from composite materials, polymers, metals, metal alloys, sealed or semi-synthetic natural products combining a natural product and a synthetic product.

According to a particular embodiment, the membrane comprises an outer lining with a geotextile material or other equipment adapted to provide a mechanical protection of the membrane or the envelope.

According to one embodiment of the invention, the solid charge is sand.

According to an alternative or complementary embodiment, the solid filler comprises aranulates such as, alone or in combination, glass beads, volcanic or porous gravel such as pumice, clinker, quartz gravel.

According to a particular embodiment, the reservoir comprises one or more membranes or additional enclosing envelopes comprising one or more complementary materials.

Advantageously, the reservoir comprises one or more recovery pumps for evacuating leaks of liquid or gas associated with one or more removable or fixed measuring sensors for monitoring said leaks.

Advantageously, the stored liquid capacity is between 15 and 80% of the volume of the tank.

Other features and advantages of the invention will be apparent from the following description of non-limiting embodiments of reservoirs according to the invention accompanied by the drawings which represent:

in FIG. 1: a schematic view of a dig adapted to a reservoir of the invention,

in Figure 2: a sectional view of a tank according to the invention;

in FIG. 3: represents a perspective view of the geomembrane filled with a reservoir according to the invention;

in FIGS. 4A to 4C: sectional views of three embodiments of a reservoir according to the invention;

in FIGS. 5A and 5B: sectional views of a reservoir of the invention in a first configuration respectively in use and submerged; in Figure 5C: a sectional view of a reservoir of the invention in a second configuration;

in FIGS. 6A to 6C: sectional views of reservoir variants according to the invention;

in FIG. 7: a view in perspective and in transparency of an example of an improvement of the invention;

To achieve the reservoir of the invention, the first operation is to dig a dig 1, according to Figure 1, the theoretical dimensions of the reservoir defined by the study. A geomembrane membrane 3 is then placed in the excavation and the interior and exterior are filled at the same time with a solid filler such as sand 4 or aggregates.

The geomembrane is shaped in a pocket comprising a bottom and walls, the bottom and the walls being made in a sealed manner.

The geomembrane makes a waterproof pocket to conserve water without leakage. According to FIG. 2, the tank comprises a roof 14 which partially closes the upper part of the geomembrane so as to form a slope inclined plane and a vent or chimney 8 allowing the entry of water 9 and an outlet or inlet of air and then covers the tank thus formed by embankment on a more or less thick layer depending on the resistance to the surface traffic to be resisted or the use that one wants to make of the surface above the tank of the invention that can be reused as parking, garden, road.

The tank is equipped with a vent or chimney 8 allowing the entry and exit of air necessary for filling and emptying the tank. Recovery of the liquid present in the reservoir can be carried out by a gravity network 13 when the reservoir is situated in height relative to the point of capture or by a pump 11 associated with a well preferably installed during the filling of the sand 4.

According to the invention, the free spaces between the grains of the sand constitute the actual useful volume of the tank and correspond to a percentage of approximately 40% of the total volume but variable depending on the size and quality of the grains of sand or aggregates 4 selected to fill the tank pocket.

Despite the fact that the reservoir is full of sand and despite the phenomena of capillarity, can be recovered by pumping or gravity flow an amount of water approximately 15 to 80% of the total volume depending on the type of sand or aggregates used.

Fine sands give a quantity of recoverable water of the order of 20 to 26%. With 20 mm diameter gravel (15 25), 38% of available water is obtained. By using volcanic or porous gravel (pumice, clinker, ...) it is envisaged to obtain a percentage higher than 60%. With porous sand or gravel (volcanic), it can be estimated that the maximum volumes of water available for pumping are close to 72%.

The reservoir of the invention has no dimensional limit neither in width nor in height nor in depth but to facilitate the understanding of these advantages and the proportions to be taken into account, we describe below the case of a tank with a total volume of 1000 m ³ . A 1000 m ³ (5 x 10 x 20 m) tank, fully filled with 1000 m ³ of sand, can store about 400 m ³ of water in the sand, and about 250 m ³ of this water will be available for pumping or gravity flow.

The theoretically perfect form of a reservoir will be the sphere but its realization is complex. The most functional form is the cube or parallelepiped (cube / rectangle) which is an easier form to manufacture and is used for figures.

The reservoir is made from a membrane 3 of synthetic material which forms the envelope or the sealed bag of the reservoir. This envelope could be made either by several layers of membranes installed together to form a multilayer envelope, or by a single membrane composed of several synthetic layers of different polymers similar to the films used in the packaging industry called multilayer film, of in order to bring the physicochemical qualities of several plastics, such as chemical inertness, oxygen barrier, metal screen, protection against perforation, etc .... improving the overall strength of the envelope and also reducing the total thickness of the envelope, and therefore the cost of manufacture.

The membrane or geomembrane may also be a polymer monolayer membrane.

According to Figure 3, the tank is manufactured from a single-width synthetic material membrane folded as a package package, so as to obtain the desired shape without cutting or welding.

The folding 30 creates lost surfaces and therefore increases the cost but it allows a quick installation without equipment nor welding or gluing.

Folding provides a bottom and four sealed sides, the folding 30 being for example on the short sides of the rectangular tank to achieve a kind of box without cover forming a sealed pouch using folded flaps on the short sides. This embodiment has the advantage of requiring no tools and to use a membrane delivered in the form of a simple rectangular sheet. The membrane can also be made by using several plates, sheets or films inter-related or bonded with glues or with adhesive tapes, so as to achieve an envelope with the exact shapes of the tank studied reducing the losses due to folding.

The membranes are usually made of synthetic materials, of the polymer type such as polyethylene, PVC, polypropylene or elastomer. However, it is also possible to use films or sheets or plates made of composite, metal, metal alloy, natural waterproof or semi-synthetic product combining a natural product and a synthetic product to manufacture the membrane or the sealed envelope of the tank. The tank membrane is fragile and can be torn at or after installation. Therefore, a geotextile or other equipment can be used to provide and obtain better mechanical protection of the membrane or the envelope. In order to protect the tank membrane, a geotextile can be placed outside the enclosure to protect it from hard objects, such as rocks, roots that could puncture the envelope, either at the time of installation or more late in the development of the roots, movements of the soil or aggression of animals or insects or micro-organisms that could perforate or degrade the envelope.

In order to protect the membrane, it is also possible to install a geotextile or a protective film containing active chemical agents of the repulsive or insecticidal or bactericidal or other type, outside the envelope to protect it against animal aggression, insects or microorganisms that could perforate the envelope in the short or medium or long term.

The reservoir is initially intended to store water in dry areas with sand, which allows reuse of sand that has been extracted to carry out the excavation in which the membrane is placed.

However, one can also use this tank for the storage of ^other liquids, such as hydrocarbons, solvent, chemicals, liquid waste and even gas through a membrane or envelope and the filling and discharge openings adapted to the pressures and stresses thermal, physical and chemical product stored. The greater the internal pressure generated by the gases in the stored product, the deeper the tank will have to be installed, in order to cancel the pressures on the envelope by the weight of the embankment located above.

The tank is usually filled with sand that is suitable for storing water. However, as previously seen, the sand may be replaced or combined with other aggregates or fillers.

In the case of other liquids, the sand may have physicochemical or other undesirable interactions requiring the sand to be replaced by another granulate, such as glass beads, quartz gravel or other, better adapted to the liquid or gas stored in the sand. the reservoir or interactions sought or unwanted.

When the leakage of the liquid stored in the tank must always be avoided for environmental protection or for ^other reasons, a second or third envelope is carried out, is added around the tank to achieve one or more additional membranes or envelopes containment.

In the case of a liquid or pollutant gas stored in a tank, it is possible to install around the first membrane or envelope forming the tank a second or third containment and containment envelope with one or more piezometers large enough to install a recovery pump allowing to evacuate leaks of liquid or gas and to allow the installation of a removable or fixed measuring sensor to monitor any leaks.

The buried tank of the invention is insensitive to external aggression and bad weather and can better withstand storms, cyclones, drought, floods, vandalism or accidental pollution, and aging is greatly slowed down.

In the event of flooding, the tank will automatically fill with the ventilation chimney, and the water already present in the tank, thanks to the presence of the solid charge, will mix only very slowly with the waters coming from the flood. guaranteeing a better quality of water as soon as the pumping can begin again; which will bring health security unusual during floods because wells and surface water are very often polluted.

The reservoir can even be installed directly in a river provided that the sandbank selected to bury the reservoir presents very low risks of hydraulic erosion and displacement by river currents.

The reservoir shown in Figure 4A is buried, it is invisible and inaccessible, which reduces vandalism, the risk of drowning and accidental or accidental pollution by people.

The inaccessibility of the reservoir associated with the presence of the solid charge inside also greatly reduces the risk of animal pollution caused by rodents, snakes, frogs, insects and other animals that can no longer access the water made inaccessible by the load and the depth of the tank.

In the case of sand, the ^absence between the sand grains upper free space several millimeters greatly reduces the usual proliferation of fauna and flora contaminant that usually encountered in stagnant water, and the reservoir thus reduces significantly the risks of malaria, cholera, bilharzia and other diseases related to stagnant water.

The semi-buried or tiled tanks of Figures 4B and 4C are also protected reservoirs although easier to access by removing the embankment.

Despite the need to build a volume much higher than recoverable storage capacities and despite the loss of available volume occupied by the load, the cost of manufacturing and construction of the reservoir remains very economical for the following reasons:

- it does not require any masonry or reinforced concrete construction,

- the waterproof membrane necessary for making the envelope can be transported on the back of a man or in a cart for large tanks,

- all the work can be done without expensive equipment neither truck nor earthmover nor generator, - the construction of a tank is adapted to the HI O techniques requiring a large workforce for the earthwork, the transport and the filling of sand.

- Maintenance costs are very low and can be reduced to washing or replacing clogged sand at the entrance to the chimney or gravity sand filters placed before the tank.

The walls of a tank are usually subjected to internal or external pressures or combined, and the liquid located inside a tank applies on the walls an internal pressure proportional to the depth of the tank.

In the case of an empty and buried tank, the soil and / or water contained in the soil, in the event of flooding or rising groundwater, applies an external pressure which may even raise the reservoir if the latter is empty and light.

For the tank of the invention, whether the tank is full or empty, and whatever its depth, the sand located inside and outside the membrane cancels almost all internal and external pressure efforts, and the amplitude of the deformations of the membrane will be only a few tenths of millimeters bringing very low physical constraints, and therefore a long life.

Experience has shown that simple buried plastic packaging pouches can last for more than 50 years despite a thickness of only 60 to 80μ, and the aging studies of buried PVC pipes have shown that their lifespan even under regular hydraulic stress, could have lifetimes exceeding 70 years. The sun can not degrade the envelope since the latter is buried, and the usual fragility of ultraviolet membranes is greatly reduced.

The membrane of a reservoir ^has failed only very low hydraulic pressures to support and an absence of accidental overpressures of hammer type, it can be reasonably estimated that the lifetime of a reservoir of the invention made from a simple moisture-resistant polymer geomembrane will exceed 50 years.

In areas with significant risk of earthquakes, the tank can be built from a flexible and elastic elastomeric membrane providing high resistance to tearing that can be caused by the telluric earthquake waves.

Only very large earthquakes can cause tearing of the membrane, and even in this case, the reservoir will probably keep at the bottom a significant amount of water available providing a minimum water reserve very important for the survival of populations after this type of disaster that usually destroys all drinking water supplies.

In tsunami-prone areas, the reservoir can be buried deeper, and its mass associated with the freshwater already present in the reservoir will allow it to maintain a supply of drinking water even if the tsunami tears the entire upper part of the reservoir. of the tank.

Such a situation is shown in FIG. 5B in the case of a tank with a chimney 8 and a sand filter 16 with a water inlet.

The lower part will remain watertight, and the fresh water present in the reservoir will mix only very slowly with the sea water brought by the tsunami which will remain only a few hours above the tank, which will limit the mixture of water. sea / fresh water.

A surface of open water, such as lake, pond, river, impluvium, loses by evaporation a significant quantity of water which, in dry, hot and windy weather, can be greater than 2 cm per day and provoked in a few months. complete drying of the water tank. Even when the water is in the soil, evaporation is certainly reduced but not negligible, and we speak of evapotranspiration. The tank is similar to a water table incorporated in the ground but its evapotranspiration can be done only through the ventilation chimney also called vent and will be strongly limited by the membrane which closes largely the tank in part high. This will bring the system tank a sharp reduction of water losses caused by evaporation or ^{evapotranspiration} in comparison to all the other usual storage systems that are open impluviums / or underground tanks and / or closed, which evaporation a lot of water in dry, hot and windy weather and which can even be completely dry during major periods of drought.

The water that is incorporated in the reservoir necessarily passes through the sand contained in the reservoir, and is therefore automatically filtered by the sand grains with the same efficiency as a sand filter.

This is improved for the example of FIG. 5A for which the sand filter 16 placed under a slight bowl collecting the runoff prefilters the water intended to fill the tank, the stack 8 arranged at a higher height not receiving any water. runoff.

The presence of a mineral support, such as sand, associated with water facilitates the proliferation of natural purification microorganisms usually called non-pathogenic common bacteria that participate in the filtration of water. Without being comparable to the performance of a slow sand filter, a process approved by the WHO, the reservoir, thanks to the presence of sand, will improve the quality of the water by mechanical filtration and also thanks to the microorganisms which will settle naturally on sand and will trigger a biological filtration process that will improve the quality of the stored water.

Thanks to the very low losses of water by evaporation and the very strong reduction of the risks of proliferation of pathogenic micro-organisms, the reservoir makes it possible to preserve stagnant water for several months, or even several years.

In the case where the water to be incorporated in the tank are charged and polluted sediment or sticky contaminants, can be pre-filter upstream ^the water before filling the tank. If the polluted water is not filtered, the reservoir will gradually clog at the vent or chimney can be used as ^water inlet or an inlet specific ^water. When the tank is clogged, simply dig up the backfill around the vent or chimney or specific water inlet, open the top of the membrane, change or wash or dry and clean the layer of sand clogged by sediments brought by the raw water to a depth of approximately 100 cm, re-apply a layer of new sand or washed or cleaned and close the membrane and put backfill on it.

As seen above, the tank can be used to store other liquids, hydrocarbons, solvents, flammable liquids and even gas through a membrane or envelope with inputs and outputs adapted to liquids or gases stored.

In case of fire, the presence of sand or glass beads or other aggregates suitable for flammable liquids will reduce the risk of explosion and facilitate the work of firefighters to extinguish the fire. Even in case of fire, the majority of the tank shell will remain intact since the fire is confined to the surface and reclamation costs after ^the fire will be reduced and faster.

FIGS. 4A to 4C show three embodiments of a tank according to the invention.

In FIG. 4A, the reservoir is a buried reservoir, and the outer layer of sand 5 is a buffer layer between the membrane 3 and the ground in which the excavation receiving the reservoir is dug.

The interior of the tank is filled with a load of sand here.

The embankment 15 is disposed between the roof 14 of the reservoir and the ground level to fill the excavation above the reservoir.

The chimney 8 goes up through the embankment to make a water inlet and an air inlet / outlet zone.

According to Figure 4B, the tank is a semi buried tank.

The lower part of the tank is arranged in a restricted excavation, the gap between the walls of the excavation and the membrane being here also filled with sand 5.

On the other hand, the reservoir protrudes from the excavation and the embankment 15 covers the upper part and the top of the sides of the tank. The embankment may include a layer of sand against the membrane, this layer of sand being covered by the embankment resulting from digging the excavation.

The example of FIG. 4C is a tank made under a hillock for which the embankment 15 coincides with the load 5 used to fill the outside of the tank.

The mound in this case covers the sides and the roof of the tank, and the chimney 8 protrudes from the top of the tank and is flush with the top of the mound.

The tank shown in FIGS. 5A and 5B comprises a water inlet device 16 separated from the ventilation duct 8 of the tank.

This water inlet device is made in a depression 17 allowing the runoff to fill the tank.

The device 16 includes a washable sand filter 18, and a water supply pipe 19, connected to the sand filter 18 and provided with multiple openings distributing the water in the tank.

The sand filter is, in the case of Figure 6A, a concrete wall tank filled with a layer of gravel tray bottom and a layer of sand in the upper part of the tray.

Between the sand and the gravel is arranged a geo-fence retaining the sand.

The tank for producing the sand filter on the ground is advantageously of a height of the order of 0.5 to 1m with a length of 1 to 10m depending on the dimensions of the tank to be fed and a width in the upper part from 1 to 1, 5m.

Runoff can be supplied by means of a supply channel.

FIG. 5B represents the reservoir of FIG. 5A submerged for example in the case of flooding a river or a Tsunami.

In such a case, the chimney and the sand filter are covered with water and form water entries E. Exchanges with the interior of the tank are however made difficult because the sand forms a porous wall reducing very strongly trade between any surface liquids, sea, muddy river water and filtered water liquid present inside the tank, which slows down the contamination of the water tank by the water covering the ground.

Once the water is removed, it will be sufficient to clean the sand filter 18 or change the sand it contains to return to normal operation of the tank.

Figure 5C is a variant of Figure 5A for which the roof 14 ^* of the tank is closed, the chimney 8 'being placed in communication with the top of the tank by a pipe 20 passing through the roof and protruding from the ground.

This configuration makes it possible to replace the chimney of the tank by a vent that can be shifted, which makes it possible to reuse the entire surface of the tank as parking, road, road, garden or other.

According to this example, the entry of water into the tank is carried out by a buffer tank 21 fed for example by a gutter descent 22, the buffer tank 21 being configured as a sand filter and possibly a gravel 24 which feeds the reservoir at through a water pipe 19 with multiple openings.

To increase the longevity of the tank in the case where roofing water and / or runoff water is collected, it is indeed necessary, to avoid clogging the tank too quickly, to install before a washable filter, easy access, gravity sand filter, which fixes almost all the particles coming from the waters of roof and protects the tank of a progressive blockage.

The buffer tank 21 comprises an upper portion forming a water reserve, an intermediate portion comprising sand 23 and a lower portion 24 comprising gravel.

A geomembrane holding the sand and letting the water pass separates the sand from the gravel.

A colander strainer 28 provided with a handle is placed on the sand to retain the largest impurities.

The dimensions of the filter can be 500 to 600mm and a height of about 1m. FIG. 6A shows a reservoir of the complete invention buried in a dig 1, with its chimney 8, a sand filter 16 for the water inlet, a strainer 12 and a bailing tube 25.

The example of FIG. 66 schematizes a reservoir further comprising a confinement envelope 27, for example a geotextile such as a non-woven felt-type non-woven material containing a second load 4 'such as gravel, pozzolan, clinker, pumice stone that increases the water retention capacity of the reservoir, the sand surrounding the second load to filter water, block access to parasites such as mosquitoes or pathogenic microorganisms and protect the geomembrane against the aggressions of the gravel and in particular the punching.

The example of FIG. 6C is similar to FIG. 6A, the sand being replaced by a porous volcanic sand which also increases the water holding capacity of the reservoir.

In all of the examples shown, the filling with sand on both sides of the membrane protects it from direct contact with potentially aggressive objects buried and holds it in place.

FIG. 7 represents in perspective and in transparency an example of an improvement of the invention consisting in realizing a recirculation of the water in the tank.

The mass of sand contained in the reservoir is already a clarification system in itself since the sand will filter the water as soon as it enters the reservoir by blocking the suspended matter on the first centimeters of sand.

The clarification that allows the tank of the invention can however be improved by maintaining a permanent circulation of the water contained in the tank as shown in Figure 7.

This re-circulation can be obtained from a manual or electric pump 40, so as to take the water in the bottom of the tank and reinject it at the top by a conduit 41 connecting the water inlet 42 to the water outlet 43. A valve or valve 44 blocks the outlet of the water 43 and sends the re-circulated water to the water inlet 42 to return it to the tank by the distributor 47.

In order to prevent stagnant water in certain recesses or areas of the tank and lack of oxygen, the suction strainer must ensure water recovery over the entire bottom surface, and the strainer usually made with a single hose should preferably of rectangular shape 46 or network to ensure recovery over the entire horizontal surface of the bottom.

The water inlet pipe at the top of the tank must also distribute the water distribution over the entire surface of the tank and its shape should allow to inject water uniformly and no longer at a single point or on a single line as is usually the case for a tank without recirculation.

According to the example of FIG. 7, a tube 47 pierced with multiple outlets or a porous mat is used.

The association of a permanent or intermittent but regular re-circulation of water with a distributor in the upper part and a water intake strainer in the lower part both uniformly distributed on a horizontal plane to avoid stagnation of water in remote areas of points of arrival and pumping enables ^the elimination of a large majority of pathogens and ensures better water clarification performance making it possible to obtain clean water by adding to the output tank reverse osmosis.

If the reverse osmosis was installed directly on the rainwater, it would clog in just a few hours, and the installation of cartridge filters before the reverse osmosis would require changing filters weekly or very frequently.

The reverse osmosis is not the only system for potabilizing water, and a satisfactory result can be obtained with nanofiltration or ultrafiltration type membranes. The re-circulation of the stored water increases the improvement of the clarification and thus brings an improvement to the reservoir.

The invention is not limited to the examples shown but encompasses any variant within the scope of the claims

Claims

1. A method of constructing a reservoir for storing a liquid, characterized in that it comprises the steps of:

applying a membrane (3) adapted to form a sealed pocket after unfolding on a surface forming a bottom of the tank,

simultaneously filling the inside (4) and outside (5) of the membrane with a granular solid charge by progressively unfolding the sides of the pocket to achieve the sides of the tank.

2. Method according to claim 1 characterized in that it comprises a step of partial closure of the upper part of the membrane by a roof (14) so as to form an inclined plane (10) and a vent and / or a chimney (8) allowing the entry of water (9), the outlet or the inlet of air.

3. Method according to claim 1 or 2 characterized in that it comprises a step of covering the reservoir thus formed by embankment (15) on a thicker layer depending on the resistance to surface traffic that is desired. .

4. Method according to claim 1, 2 or 3 characterized in that it comprises a step of laying a strainer (12) and a drawing tube before filling the membrane.

5. Method according to any one of the preceding claims characterized in that, the tank being a buried or semi-buried tank, the method comprises prior to the installation of the membrane 3 a step of excavation 1, the laying of the membrane 3 being on the bottom of the excavation 1.

6. Method according to any one of the preceding claims, characterized in that the flattened membrane is a seamless membrane made from a flat film, the method comprising a preliminary step of folding the membrane to form a bottom and sealed sides. by progressively unfolding the sides of the membrane.

7. Method according to any one of the preceding claims, characterized in that before laying the membrane on the bottom, a geotextile material is placed adapted to protect the membrane against hard objects (such as rocks, roots), movements soil or aggression of animals or insects or micro-organisms that could perforate or degrade the membrane.

8. Tank type buried or partially buried or tiled characterized in that it comprises a membrane (3) and a solid charge internal and external to the tank.

9 - Tank according to claim 8 characterized in that the membrane is either formed of several layers of membrane installed together to form a sealed multilayer envelope or a single waterproof membrane composed of several synthetic layers of different polymers similar to the films used in the packaging industry called multilayer film.

10. Tank according to claim 8, characterized in that the membrane is a monolayer membrane.

11. Tank according to claim 8, characterized in that the membrane is made using several plates, sheets or films welded together or glued with glues or with adhesive strips, so as to achieve a shell with the exact shape of the tank.

12. Tank according to one of claims 8 to 11, characterized in that the material of the membrane is selected from composite materials, polymers, metals, metal alloys, waterproof or semi-synthetic natural products combining a natural product and a product synthetic.

13. Tank according to any one of claims 8 to 12, characterized in that the membrane comprises an outer lining with a geotextile material or other equipment adapted to provide a mechanical protection of the membrane or the envelope.

14. Tank according to any one of claims 8 to 13, characterized in that the solid charge is sand.

15. Tank according to any one of claims 8 to 13, characterized in that the solid charge comprises aggregates such as alone or in combination with glass beads, volcanic or porous gravel such as pumice, clinker, quartz gravel.

16. Tank according to any one of the preceding claims characterized in that its capacity of stored liquid is between 15 and 80% of its volume.

17. Tank according to any one of claims 8 to 15, characterized in that it comprises one or more membranes or additional enclosing envelopes (27) comprising one or more complementary materials.

18. Tank according to any one of claims 8 to 15, characterized in that it comprises one or more recovery pumps for discharging leakage of liquid or gas associated with one or more removable or fixed measuring sensors of monitoring said leaks.