FR3074795A1 - METHOD AND DEVICE FOR RECOVERING, SANITIZING, AND REUSING WATER AGAINST WASHING OF SWIMMING POOL - Google Patents

Abstract

The treatment device (1) of the backwash water (28) from a pool sand filter (20) (40) comprises a sedimentation tank (2) delimited by side walls (3), a bottom (5) equipped with a discharge orifice (7) for extracting solid waste (18) after sedimentation of the backwashed contaminated water (28), an inlet adapted to receive the contaminated backwashed water (28) from the sand filter (20), and an outlet (15) adapted to eject out of the tank (2) the water sucked by a suction device (16) immersed in the tank (2). The tank (2) further comprises an orifice (6) adapted for the addition, within the tank (2), of flocculant-type water treatment products capable of agglomerating soil and waste ( 18) of the backwash water (28), and the suction device (16) is able to suck water "sufficiently clean and clear" (17) after flocculation for reinjection directly into the pool (40) without additional filtering.

Description

The present invention relates to the recovery as well as the sanitation of the backwashing water of a swimming pool sand filter. and its re-use as bathing water for greater economy and environmental protection.

It finds general application in the field of maintenance of swimming pools and their filters and more particularly when sand filters are used for the filtration of bathing water.

We know that swimming pools, both private and public, see their waters contaminated by many external elements provided by bathers, or the environment of the swimming pool for example. To allow continuous swimming, the water in the pools is therefore filtered, in particular by sand filters. Over time, the sand filters become clogged and their effectiveness decreases. A backwashing is then planned. It consists of injecting water in the opposite direction of filtration to remove the impurities contained in the filter. Backwashing water is often discharged into the environment with waste or sewage, which increases the volume of water that treatment plants must treat.

Are already known devices for recovering and treating backwashing waters which attempt to remedy these drawbacks.

For example, in document US9539529-B2, the backwashing water is directed to a sedimentation tank in which it is stored for a minimum of 24 hours. During this interval, the unfiltered particles still in suspension sediment on the bottom of the tank. The decanted water is then returned to the hydraulic circuit of the pool and passes through the sand filter before being reinjected into the pool. A mechanical filter is placed upstream of the sedimentation tank to filter large waste and particles before filling the tank. Even if such a device reuses the backwashing water by going back through the sand filter, it is not completely satisfactory insofar as it does not treat the microparticles in suspension and thus the water leaving the sedimentation tank. cannot be re-injected directly into the swimming pool because "insufficiently clean and clear". The "insufficiently clean and clear" water, not being completely rid of its waste, participates in the clogging of the sand filter and therefore increases the frequency of backwashing operations. In addition, the mechanical filter placed upstream of the tank is not practical since it is necessary to clean it after each filling of the sedimentation tank.

The present invention improves the situation.

It relates to a device for treating the backwashing water coming from a swimming pool sand filter comprising a sedimentation tank delimited by side walls, a bottom equipped with a drain orifice for extraction. solid waste after sedimentation of the dirty backwashing water, an inlet adapted to receive the dirty backwashing water from the sand filter, and an outlet adapted to eject the water sucked out of the tank by a device suction immersed in the tank.

According to a general definition of the invention, the reservoir further comprises an orifice adapted for the addition, inside the reservoir, of water treatment products of the flocculant type capable of agglomerating the soiling and the waste from the backwashing water, and the suction device is capable of sucking water "sufficiently clean and clear" after flocculation to reinject it directly into the pool without additional filtering.

In the context of the invention, "sufficiently clean and clear" water is substantially crystalline water intended for swimming. It is devoid of waste and microparticles. It may contain chlorine, bromine, salt or the like on which the flocculant has no effect. However, the bacteriological aspect of water is not taken into account here.

Thanks to the device according to the invention, the treatment of the backwashing water is more effective than that described in document US9539529B2 because, thanks to the use of flocculant, the microparticles in suspension also precipitate. The water thus treated does not pass through the sand filter, no additional impurity is stored there, which reduces the frequency of backwashing necessary for the proper functioning of the sand filter. In addition there is no mechanical filter upstream of the sedimentation tank which eliminates the strain due to the cleaning of said filter. Thus, surprisingly, the Applicant has observed the possibility of obtaining “clean and clear” water from a soiled water of backwashing without using an additional filtration system consuming energy, without adding new filters in the hydraulic circuit and with an efficiency of around 95%. This results in a saving of water which affects several levels. The user can on the one hand save money, on the other hand, the environment is preserved because the water consumed and the waste discharged into nature decrease. This reduction in waste results in a reduction in the volumes of wastewater treated by treatment plants and avoids congestion or even unnecessary saturation of the latter. In fact, the backwashing water thus freed of its impurities is reusable in the swimming pool circuit without the need to circulate through the sand filter and without requiring a new addition of chemicals, such as chlorine and salt for example, which will be kept during the treatment of backwashing water. Finally, fresh water reserves are preserved, especially in regions suffering from water rationing. During each sand filter backwash, for a private family pool it is possible to recover approximately 1m3 of water. Much larger quantities will be recovered and saved for larger pools such as public pools or large pools. The invention applied to millions of swimming pools around the world would make it possible to recover and save millions or even billions of cubic meters of fresh water, which is also very useful for other uses, in a context of scarcity of the resource.

According to particular embodiments, the device comprises one or more of the following characteristics, taken in isolation or in any technically possible combination:

- The bottom of the tank is in the form of a hopper, the side walls narrowing towards the waste discharge orifice;

the treatment product is a flocculant belonging to the group formed by polymers, copolymers of acrylic acid and polyacrylamide;

- The device further comprises a device for rinsing the tank;

the outlet of the tank is connected to the hydraulic circuit of the swimming pool;

the suction device comprises a perforated cylinder mounted substantially horizontally at a height chosen inside the tank;

- The device further comprises at least one pump arranged in series between the clear water suction device and the swimming pool.

The invention also relates to a method of treating the backwashing water implemented by a device for treating the backwashing water from a swimming pool sand filter comprising a sedimentation tank. delimited by side walls, a bottom fitted with a drain orifice for the extraction of solid waste after sedimentation of the soiled backwashing water, an inlet adapted to receive the soiled backwashing water from the sand filter , and an outlet adapted to eject from the tank the water sucked in by a suction device immersed in the tank.

According to another aspect of the invention, the method comprises the following steps:

- the sedimentation tank is filled with backwashing water laden with waste from the sand filter;

- a selected dose of flocculant is added to the tank through the orifice provided on the sedimentation tank;

- allowed to stand for a period chosen to allow the deposition of suspended particles and microparticles at the bottom of the sedimentation tank under the effect of the flocculant and gravity; and

- we suck the water "sufficiently clean and clear" to reinject it directly into the pool without additional filtering.

In practice, after the step of suctioning clean and clear water, the solid waste is discharged via the drain opening.

For example, the sedimentation stage lasts approximately 24 hours for a capacity tank of the order of m3.

Other advantages and characteristics of the invention will appear on examining the description and the drawings in which:

- Figure 1 schematically shows the water treatment device integrated into the hydraulic circuit of a swimming pool, after sedimentation of the backwashing water, in accordance with the invention;

- Figure 2 schematically shows the treatment device of Figure 1 further equipped with a rinsing device connected to the hydraulic circuit of the pool according to the invention.

- Figure 3 is a front view of the device for treating the backwashing water according to the invention; and

- Figure 4 is a side view of the processing device of Figure 3.

Referring to Figures 1 to 4, there is shown a device 1 for treating the backwashing water 28 adapted to recover, sanitize and reuse the backwashing water 28 from a sand filter 20 d 'a swimming pool 40.

Generally, the bathing water 48 contained in the swimming pool 40, due to its use, includes impurities or waste such as silt, dead skin, plants, sun products and make-up, insects ... It should therefore be filtered to ensure bathing in good hygienic conditions. The swimming pool equipment includes a skimmer 41, a drain 42 and a bottom cleaner 43 connected respectively to a pump 46a via three individual pipes at 51.52 and 53 and which join upstream of the pump 46a for form a single pipe 54 at the inlet of the pump 46a. The three pipes 51, 52 and 53 are fitted with taps, respectively 45a, 45b and 45c to stop / circulate the bathing water 48 in the sand filter 20. The bathing water 48 is then injected into the sand 20 via a pipe 21, also called a water inlet line, mounted downstream of the pump 46a. The filtered water 27 by the sand filter 20 is then redirected via the outlet line 22 to a discharge nozzle 44 which opens into the pool 40. A tap 45f makes it possible to stop / circulate the filtered water 27 towards the pool 40.

The sand filter 20 comprises a tank 26 partially filled with sand 29, an inlet line 21 for bathing water 48, an outlet line 22 for filtered water 27, a pipe 23 for evacuation backwashing water 28, an upper pipe 34 connected to an upper nozzle 36 and a lower pipe 35 connected to a lower nozzle 37. In practice, the bathing water 48 from the pool 40 passes through the sand filter 20 and the impurities it contains are trapped in the sand 29 which acts as a sieve. The bathing water 48 injected under pressure, via the upper pipe 34 and the upper nozzle 36, circulates through the sand 29 before being sucked out of the sand filter 20 through the lower nozzle 37 and the pipe lower 35. Gravity makes the filtering process easier. However, the sand filter 20 becomes clogged after filtering a certain amount of particles and no longer performs its role properly. A backwashing is then carried out to allow the sand filter 20 to regain optimum efficiency. The backwashing consists in supplying the sand filter 20 with water, via the inlet line 21 of bathing water 48 which, due to the action of the multi-way valve, will be directed to the lower pipe 35 before being expelled by the lower nozzle 37 thus making it possible to evacuate the impurities retained in the sand 29 in the direction of the upper nozzle 36 then of the upper pipe 34. In fact, the mesh formed by the sand 29 contained in the tank 26 decreases in diameter as the water progresses from the upper nozzle 36 to the lower nozzle 37, which makes it possible to retain the impurities during the filtration process. By injecting water in the opposite direction, during backwashing, the mesh of sand 29 sees its diameter increase and will allow the passage of impurities. The impurities will be evacuated in the backwashing water 28 via the evacuation pipe 23.

To implement the backwash, the pump 46a which injects the bathing water 48 into the sand filter 20 is stopped, then the position of the multi-way valve 24 is changed via the selector 25, to direct the flow of water, from the "filtration" position to that of "backwashing". After reactivation of the pump 46a, a quantity of bathing water 48 is injected under pressure into the sand filter 20 via the lower nozzle 37. The water loaded with the particles present in the sand 29 then follows the reverse path of the bathing water 48 through the sand filter 20 during filtration to be finally sucked by the upper nozzle 36 in the upper pipe 34. The water, after passing through the multi-way valve 24, is then directed via the evacuation pipe 23 of the backwashing water 28 to the treatment device 1.

The main element of the device 1 is a sedimentation tank 2, (hereinafter called "tank"), of polyhedral shape and delimited by four faces / side walls 3, a ceiling 4, and a bottom 5. In alternative the shape of the tank can be spherical, conical or pyramidal with the top facing down.

In practice, the tank 2 is placed on the ground by feet 9. Elements of the hydraulic circuit of the pool 40 can thus be placed under the tank 2 to allow space saving in the case of small technical room cut.

The tank 2 is made of waterproof and resistant materials such as plastic, metallic or similar materials. Advantageously, the interior of the tank 2 is coated with a non-stick material in order to prevent the deposit of waste 18 on the internal walls of the tank 2.

A pipe 23, for example made of high pressure PVC 50mm in diameter, connects an inlet 10 formed in the ceiling 4 of the tank 2 to the multi-way valve 24 of the sand filter 20 to recover the backwash water 28 coming from the sand filter 20. A tap 45d is placed on the evacuation pipe 23 to stop / circulate the backwashing water 28 in the tank 2.

The ceiling 4 is also provided with a rinsing device 13 adapted to rinse the tank 2 after treatment. The rinsing device 13 can be connected to an external water source or to the hydraulic circuit of the swimming pool. The connection can be made by a pipe 33, fitted with a tap 45g, disposed between the rinsing device 13 and the outlet line 22, by any suitable connection system. In practice, the rinsing device 13 is a nozzle provided with 360 ° perforations 14 to allow rinsing of all of the side walls 3 of the tank 2.

In a side wall 3 of the tank 2 is formed an outlet 15 adapted to eject from the tank 2 clean and decanted water, sucked by a suction device 16. The suction device 16 can be produced according to different sizes and shapes. In practice, the suction device 16 comprises a perforated cylinder 11 mounted substantially horizontally inside the tank 2. Preferably, the cylinder 11 is perforated with suction holes on the part facing the ceiling 4 of the tank 2. The cylinder 11 comprises a free end connected to an outlet 15 located at a selected height of the tank, preferably in the lower part of the tank 2 at a chosen distance from the bottom 5 of the tank 2. The outlet 15 opens out to a pipe 12 allowing the evacuation of the treated water from the tank 2. A tap 45e is arranged on the line 12 upstream of a pump 46b which has the function of sucking the treated water.

According to a particular embodiment, the outlet 15 can be provided on any other part of the tank 2. The cylinder 11 will then be replaced by any other pipe so as to maintain the suction zone at a chosen distance from the bottom 5 of the reservoir 2, and the perforations oriented towards the top of the reservoir 2 to allow the suction function of the sufficiently clean and clear water 17, also called "clear water" or "treated water", without sucking up waste 18.

The tank 2 further comprises an orifice 6 adapted to allow the addition of water treatment products of the flocculating type inside the tank 2 to agglomerate the soiling and waste 18 of the water against washing 28, in particular the microparticles which, because of their very small size, hardly sediment.

In practice, the flocculant belongs to the group formed by polymers, copolymers of acrylic acid, of polyacrylamide. For example, the flocculant is sold commercially under the reference "Quickflock (registered trademark)", in liquid form, by the German company Bayrol composed of hydrolysed aluminum polyhydroxychloride.

After flocculation, the suction device 16 will allow the suction of water that is sufficiently "clean and clear" 17 to directly supply the pool 40 with bathing water 48 and this without additional filtering.

The bottom 5 of the tank 2 is equipped with a drain orifice 7 for removing the waste 18 contained in the backwashing water 28 after sedimentation of the waste 18.

In practice, the bottom 5 of the tank 2 has a downward slope towards the waste discharge port 7 of the waste 18. For example, the bottom 5 is in the form of a hopper, the side walls 3 narrowing towards the orifice emptying 7. In hot countries, the waste 18 thus removed can be put to dry in the sun in any suitable container to be then thrown in the trash and not in the nature or in the whole in the sewer so as not to clutter the treatment plants.

A device 8 for controlling the water level of the gauge type or the like is provided on a side wall 3 of the tank 2 in order to allow the filling to be stopped before any overflow.

Alternatively, the fluid level control is visual when the material of the tank 2 is transparent such as PVC.

The steps for implementing the recovery, sanitation and reuse process of backwashing water are as follows.

The pump 46a is stopped, the selector 25 is set to the "against washing" position and the pump 46a is reactivated. The evacuation pipe 23 of the backwashing water 28, loaded with impurities, opens into the upper part 4 of the tank 2. The backwashing water 28 is poured into the tank 2. To allow the flocculation of the impurities, it is advisable to add, during the filling of the reservoir 2, a dose of flocculant through the orifice 6 provided for this purpose to allow the homogenization of the mixture. Alternatively, the flocculant can be added before or after filling the tank 2.

The level of fluid contained in the tank 2 is controlled by the control device 8 to stop the supply of water before the tank 2 overflows.

The sand filter 20 is then cleaned. After stopping the pump 46a, the selector 25 of the multi-way valve 24 is put in the "filtration" position to allow the filtration of the bathing water 48 by the sand filter 20.

It is then necessary to let the liquid flocculant act in the tank 2 for a chosen period, for example at least for 24, 48 or 72 hours. For example, a dose corresponding to approximately 0.0001 m3 to 0.00015 m3 of flocculant for a reservoir 2 of the order of approximately 1 m3 and a swimming pool 40 of the order of 50 to 100 m3 corresponding to a private swimming pool of medium size .

The duration of sedimentation allows the flocculant to act and the impurities to come to settle on the bottom 5 of the tank 2, by gravity, thus forming two distinct phases or parts. The upper phase is composed of clean and clear water 17 and of the various elements of treatment of the bathing water such as chlorine, bromine or salt for example on which the flocculants have no effect. The lower phase for its part contains the waste 18 initially contained in the sand filter 20. The interface between the upper and lower phases is located substantially below the suction device 16, which allows the return of the treated water. 17 (sufficiently clean and clear) towards the swimming pool 40, in order to avoid the injection of impurities in the bathing water 48.

In practice, it may be useful to at least partially empty the tank to maintain the level of clear water substantially below the suction device 16.

The reinjection of the clear water 17 into the hydraulic circuit of the swimming pool 40 is then possible by opening the tap 45e, and activating the pump 46b.

In an alternative embodiment, the arrangement and the power of the pump 46a can provide the energy necessary for the suction of the clear water 17, without using the second pump 46b.

Clear water 17 is then reinjected into the pool 40 by means of the discharge nozzle 44.

When the clear water 17 is completely sucked out of the tank 2, it is advisable to deactivate the pump 46b and close the tap 45e.

The bottom 5 of the tank 2, containing the solid waste 18, is drained by the waste discharge port 7 of the waste 18 located on its lower part.

In practice, the tank 2 is not completely rid of the impurities which remain attached to the walls 3. It is then advisable, after having closed the drain orifice 7 for the waste 18, to rinse the walls 3 via the rinsing device 13 provided for this purpose. The rinsing device 13, connected to an external water supply or to the hydraulic circuit of the swimming pool 40, allows, through 360 ° perforations, the rinsing of the walls 3 of the tank 2. In the case where the rinsing device 13 is connected via line 33 to the outlet line 22, the tap 45g must be opened to supply said device 13 with rinsing water. If the device 13 is connected to an external water source, it will be necessary to activate the water supply. During rinsing, the drain port 7 is kept open to allow the evacuation of the water used for rinsing. Once the tank 2 has been rinsed, the 45g tap should be closed or, if necessary, the external water supply cut off.

The tank 2 then returns to its initial state and can therefore be used again for a next recovery cycle, sanitation, and reuse of the backwash water 28.

One or more steps of this process can be automated, in particular by the use of electric valves, fluid level detectors or even a device for automatically discharging the flocculant.

Claims (10)

1. Treatment device (1) for backwashing water (28) from a swimming pool sand filter (20) (40) comprising a sedimentation tank (2) delimited by side walls (3), a bottom (5) equipped with a drainage orifice (7) for the extraction of solid waste (18) after sedimentation of the soiled backwash water (28), an inlet adapted to receive the soiled backwash water washing (28) from the sand filter (20), and an outlet (15) adapted to eject from the tank (2) the water sucked in by a suction device (16) immersed in the tank (2), characterized in that the reservoir (2) further comprises an orifice (6) adapted for the addition, inside the reservoir (2), of water treatment products of the flocculating type capable of agglomerating the soiling and the waste (18) of the backwashing water (28), and the suction device (16) is capable of sucking water "sufficiently clean and clear" (17) after flocculation to reinject it directly into the pool (40) without additional filtering. 2. Device according to claim 1, characterized in that the bottom (5) of the tank (2) is in the form of a hopper, the side walls (3) narrowing towards the waste discharge orifice (7). 3. Device according to one of the preceding claims, characterized in that the treatment product is a flocculant belonging to the group formed by polymers, copolymers of acrylic acid and polyacrylamide. 4. Device according to one of the preceding claims, characterized in that it further comprises a rinsing device (13) of the reservoir (2). 5. Device according to one of the preceding claims, characterized in that the outlet (15) of the tank (2) is connected to the hydraulic circuit of the swimming pool (40). 6. Device according to one of the preceding claims, characterized in that the suction device (16) comprises a perforated cylinder (11) mounted substantially horizontally at a height chosen inside the tank (2). 7. Device according to one of the preceding claims, characterized in that it further comprises at least one pump (46b) arranged in series between the suction device (16) of clear water (17) and the swimming pool ( 40). 8. Method for treating the backwashing water (28) implemented by a device (1) for treating the backwashing water (28) coming from a swimming pool sand filter (20) (40) ) according to one of claims 1 to 7 and comprising a sedimentation tank (2) delimited by side walls (3), a bottom (5) equipped with a drain orifice (7) for the extraction of waste ( 18) solids after sedimentation of the dirty backwashing water (28), an inlet (10) adapted to receive the dirty backwashing water (28) coming from the sand filter (20), and an outlet (15) adapted to eject from the tank (2) the water sucked in by a suction device (16) immersed in the tank (2), characterized in that the method comprises the following steps: - the sedimentation tank (2) is filled with the backwashing water (28) loaded with waste (18) coming from the sand filter (20); - a chosen dose of flocculant is added to the tank (2) through the orifice (6) provided on the sedimentation tank (2); - allowed to stand for a period chosen to allow the deposition of suspended particles and microparticles at the bottom (5) of the reservoir (2) of sedimentation under the effect of the flocculant and gravity; and - the water is sufficiently clean and clear (17) to be reinjected directly into the pool (40) without additional filtering. 9. Method according to claim 8, characterized in that after the suction step of clean and clear water (17), the solid waste (18) is discharged via the drain opening (7). 10. Method according to claim 8 or claim 9, characterized in that the sedimentation step lasts approximately 24 hours for a tank (2) of capacity of the order of m3.