Efficient filtration process of water in a tank for recreational and ornamental uses, where the filtration is performed over a small volume of water and not over the totality of the water from the tank

FIELD OF THE INVENTION

The invention relates to a method for filtering water in large reservoirs such as fountains, ponds, pools and lakes with low investment and operating costs.

BACKGROUND

[0002] When water is placed in recreational or ornamental tanks, the water often becomes cloudy despite the good quality and low levels of suspended solids in the water source. The environment adds dust, soil, organic matter etc. to the tank. However, the main source of suspended particles causing turbidity is often the inevitable growth of microorganisms, especially microalgae, which are widely distributed in nature and which have suitable living conditions in these aquatic environments.

[0003] Algae are a diverse group of plants that occur in a wide variety of environmental habitats. They are photosynthetic chlorophyll-containing plants that have very simple reproductive structures and their tissues are not differentiated in roots, stems, or true leaves. The average single size of microscopic unicellular algae is approximately 1 µm. Algae are found all over the world and can cause problems in reservoirs.

[0004] The extermination of algae has long been a problem. Algae are single-celled plant organisms that reproduce in the light of the sun. They are found in vegetation, air, soil and water. Their microscopic spores are continuously introduced into reservoirs and other bodies of water by wind, sandstorms, rainfall etc. They grow rapidly in stagnant water when exposed to sunlight and temperatures above 4 ° C. They can generate mud and / or odors. They can interfere with proper filtration and significantly increase the chlorine requirement in public swimming pools. The presence of phosphates and nitrates in the water promotes their growth.

[0005] Planktonic algae are single-celled microscopic plants that float freely in water. When these plants are abundant or "bloom", they make the water in the tanks green. Less commonly, they can change the color of the water to another, including yellow, gray, brown, or red.

SUMMARY

[0006] According to one aspect of the invention, there is provided a method of filtering water in tanks. The method of filtration is done over a small volume of water, not over the entire water tank. The method includes emitting ultrasonic waves in a tank, adding a flocculating agent to the water, coating the bottom of the tank with a suction device that sucks up the flow of water with flocculated particles to produce an effluent from the suction device, draining the effluent from the suction device into the effluent collection line, filtering the effluent stream from the suction device with equipment leachate collection line

Suction to produce a filtered stream and return the filtered stream to the tank.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory, and are intended to provide a further explanation of the invention as claimed.

SHORT DESCRIPTION OF THE FIGURES

[0008] The following figures, which form part of this application, show the systems and embodiments described below and are not intended to limit the scope of the invention in any way, which scope will be based on the appended claims.

Fig. 1 is a top view of a tank in which the method of the invention is applied.

Fig. 2 is a top view of a tank with a conventional filtration system.

Fig. 3 shows the bottom of a tank where diffuse flocs are observed due to the synergistic action of ultrasound and flocculant.

Fig. 4 shows a top view and a schematic view of the suction device.

Fig. 5 shows a bottom view and a schematic view of the suction device with the suction device.

Fig. 6 shows a front view of the suction device.

Fig. 7 shows a bottom view of the suction device.

Fig. 8 shows a front view of a longitudinal section of the suction device.

Fig. 9 shows a cross-sectional side view of the suction device.

Fig. 10 shows a top view of a detail of the suction device.

Fig. 11 shows a top view of an additional detail of the suction device.

DESCRIPTION OF THE INVENTION

[0009] The invention provides an efficient and economical method of filtering water from reservoirs such as fountains, ponds, public pools and artificial lakes. The suspended solids in the water are precipitated by the synergistic action of flocculating agents and ultrasonic waves and then collected at the bottom by suction with a suction device. The effluent from the suction device is then filtered and returned to the tank, eliminating the turbidity from all the water in the tank and filtering only a very small flow that corresponds to the effluent from the suction device, compared to the flows that are required in traditional filter systems that filter all the water in the tank. In addition, the necessary suction device for carrying out the method according to the invention is described.

[0010] As mentioned above, the water placed in the tanks can become cloudy due to a number of factors. To eliminate suspended solids from tanks,

-3 such as algae, dust, organic matter etc., filtration systems are usually used. Filtration is a method of passing a mixture of solids and liquids, gases, or liquids through a porous or filter material, which may be part of a device called a filter that removes most of the solids in the mixture.

[0011] The applications of the filtration method are diverse and cover many areas of human activity, domestic life and industry where an industrial process involving chemical engineering methods is particularly important.

[0012] Filtration has developed with human evolution and more theoretical attention has been paid to it since the 20th century. The classification of the filtration method and equipment are diverse and, in general, the classification categories are not mutually exclusive.

[0013] The variety of filter devices and filters is as wide as the types of porous materials available that can be used as filter materials and the specific conditions in each application: from simple devices such as home coffee filters or filter funnels for laboratory separation, to huge complex systems that are highly automated, such as those used in the petrochemical and refining industries for high catalyst value recovery or drinking water treatment systems for networks urban.

[0014] Filtration is a mechanical or physical operation used to separate solids in liquids (such as liquids or gases) in which filter material is introduced and the fluid may pass through the filter material, but the solids (or at least some of them) are retained . Typically, separation is considered incomplete and depends on the pore size and thickness of the materials, as well as on the mechanics that take place during filtration. Basically, in the filtration method, the filter material has several layers, but other mechanisms are also involved, such as direct capture, diffusion, and centrifugal action where the particles are unable to follow the filter material channels through which the stream lines pass and remain trapped in the air. the fibers of the filter material.

[0015] There are two main ways of filtration:

• Front filtration, which is the best known, passes the fluid perpendicularly across the surface of the filter material. This method is used, for example, in domestic coffee filters. The particles are retained in the filter; the method is limited by the accumulation of particles on the surface of the filter material which becomes eventually clogged;

Tangential filtration, on the other hand, passes fluid tangentially across the surface of the filter material. Fluid pressure allows it to pass through the filter. In this case, the particles remain in the tangential flow and filter blocking is slower. However, this method is only applicable to very small particles, ranging from one nanometer (nm) to one micrometer (μm).

[0016] Furthermore, the types of filtration can be classified according to the pore size of the filter material:

- clarifying filtration: when the pore diameter is between 10 and 450 μm;

- sterilizing filtration: when the pore diameter is greater than 0.22 μm;

- microfiltration: where the pore diameter is between 10 nm and 10 μm;

- ultrafiltration: when the pore diameter is from 1 to 10 nm;

- reverse osmosis: where the pore diameter is between 0.1 and 1 nm.

[0017] The filtration efficiency depends on a set of variables such as pressure, filter materials, viscosity, temperature, particle size and concentration.

[0018] Generally, if the increase in pressure leads to a significant increase in flow rate or filtration, this is indicative of the formation of a granular cake. However, in the case of thick or very thin cakes, an increase in the pumping pressure does not lead to a significant increase in the filter flow. In other cases, the cake has a critical pressure, above which the filtration rate is even reduced. In practice, it is preferable to operate at a constant speed, starting at low pressure, although due to the widespread use of centrifugal pumping systems, normal conditions are pressure and flow fluctuations.

[0019] The theory shows that, in addition to considering the properties of the filter materials, the average flow is inversely proportional to the amount of cake and directly proportional to the square of the filtered area. As a result of these two variables, for the same amount of fluid filtered, it should be noted that the flow is inversely proportional to the square of the cake thickness at the end of the process. This observation means that maximum productivity is theoretically achieved with those very thin thickness cakes whose resistance exceeds that of the filter materials. However, other factors such as cake recovery time, difficulty in discharging, and the cost of a wider filter surface make it practical in practice to operate under denser cake conditions.

[0020] The intensity of the filter stream at any point in time is inversely proportional to the filter viscosity.

[0021] As the filtration temperature increases, the viscosity decreases, and thus the filtration speed increases.

[0022] The effect of particle size on the resistance of the cake and the film is significant. Even slight modifications to the particle exchange affect the coefficient in the equation for the resistance of the cake, and the major changes affect its compressibility.

[0023] For the reasons mentioned above, filtration is not a straightforward process, especially when high flows are filtered.

[0024] Diatomaceous, cassette and sand systems are used in ornamental and recreational reservoirs such as public pools and fountains, the latter being the most common systems.

Sand filters are the elements most commonly used in the filtration of water with a low or medium pollutant load, requiring the removal of particles up to 20 µm in size. The suspended water borne particles are retained as they pass through the sand filter bed. When the filter is loaded with contaminants, reaching a certain charge loss, the filter can be regenerated by washing the effluent.

[0026] The quality of the filtration depends on various parameters, including the shape of the filter, the height of the filter bed, the characteristics and granulometry of the filter mass, the filtration speed, etc.

[0027] These filters can be made of polyester resins and glass fibers suitable for the filtration of river and sea water due to their complete corrosion resistance. Also, stainless steel and carbon steel are required for embodiments where better pressure resistance is required.

[0028] The use of filtration systems in ornamental and recreational reservoirs such as ponds and swimming pools is widespread worldwide, however, as their size increases, two problems arise that limit their scale.

[0029] The first limitation is the high investment and operating costs. In fact, there are very few recreational reservoirs with filtered water in the world with a capacity greater than 2,500 m³ (Olympic pool volume), and those closest to these volumes generate high operating costs.

[0030] For example, in the case of a swimming pool in an apartment complex with a volume of 9,000 m³then a filtration rate of 416 l / s is required to meet sanitary regulations for filtration in public swimming pools. These operating volumes are unmanageable for this type of construction project due to the initial investment costs, the area taken up by the filtration systems, the complexity and especially the operating costs.

[0031] There is, however, a second problem which complicates the filtration in large bodies of water and is that it is difficult to evenly filter the entire volume of water. In an ordinary pool or fountain, one suction point and one drain point are enough to obtain a relative homogeneous filtration of all water. As the water volume increases, the effect of the suction point is limited to the surrounding area and has no effect on the total volume. This means that a complex and costly pipe network with a large number of suction and discharge points has to be planned. Such a system has high pressure losses and also causes short circuits in the filtrate flow, i.e. the same water is filtered several times, which reduces the efficiency of the system.

[0032] For the reasons mentioned above, maintaining large bodies of water with filtration systems is not economically viable and is very inefficient, and thus there are no large filtered tanks for ornamental or recreational use in the world.

[0033] There is a Chilean Patent in the prior art with registration number CL 43,534 which is directed to obtaining large bodies of water for recreational use which discloses a method of obtaining (i.e. installing and maintaining) large volumes or tanks.

-6water for recreational purposes, such as lakes and pools with excellent color, high transparency and purity similar to pools or tropical seas, with low cost, especially for bodies of water over 15,000 m³. The invention defines structural features such as oil elimination skimmers, water collection systems, construction details, liner types and colors, additive circulation and injection systems, water supply requirements, pH measurement, salt addition, use of algaeicides and flocculants, flow rate variations fresh water, additives and oxidation methods, and boat-powered extraction vehicle.

[0034] Patent CL 43,534 uses an open water circulation system, therefore it does not consider the water uptake method and does not use any kind of filtration. The problem of the biofilm that forms on the walls and bottom of the tank, which is removed manually in small tanks, but which cannot be achieved in larger tanks, has also not been addressed.

[0035] The object of the invention differs from that of the CL 43,534 patent and, on the contrary, this patent application defines a low cost filtration system that allows water to be recovered without filtering all the water in the tank, as is the case with expensive systems known to date. filtration of water in tanks or drainage of water from a suction system, as is the case in the above-mentioned patent, which means greater water consumption and ultimately the discharge of water with sediment into natural flows.

[0036] In patent CL 43,534 the water is drained and does not contain a filter system, therefore the efficiency of the suction system and of course the filtration itself are not critical. However, sucking the bottom of larger reservoirs efficiently using low water flows (the critical point at which the effluent must be filtered) is a complex problem as the suction device has to pass at high speed to cover large surfaces and thus the sediment cloud is lifted. which makes the water cloudy and reduces system performance. In turn, there are economic and regulatory constraints on the use of large amounts of flocculants for cost reasons given the large amounts of water and sanitation constraints. On the other hand, the properties of this precipitate are not suitable for efficient filtration. The German publication DE 3844374 A1 discloses a method of treating water from large tanks by applying ultrasonic waves to water with subsequent flocculation and filtration.

[0037] A solution has been found to the problem of cost-effective water filtration for larger tanks, without having to filter the entire volume of water as is the case with current systems, with the development and validation of the joint use of flocculants and ultrasound which generates diffuse flocs at the bottom of the tank separated from self and easy to suck with a specially designed suction device that can cover large areas in a short time, and then filtered at high efficiency, due to the quality of the filtrate, with a simple device such as a sand filter or other small and economical filter available on the market using low concentrations of flocculants.

The use of ultrasound in larger tanks allows very effective and easy suction with the suction device, not only because of the formation of large and dispersed flocs easy for suction and filtration, but also allowing the use of ultrasound which allows control of biofilm growth in tanks and eliminate the environment where algae stick to the walls and bottom of the tanks. Biofilm consists of layers of bacteria formed on the surfaces of the host, creating adhesion points for algae that are difficult to remove from the surface of the tank. In these cases, the ultrasound waves prevent the formation of the basal layer of the biofilm to avoid that most floating planktonic bacteria become sessile bacteria with high adhesion ability to grow on the surface. The biofilm basal layer begins to build up as fast as 20 minutes to 3 hours after the surface immersed in the pond is cleaned.

[0039] When using ultrasonic waves in the flocculation method, the method of the invention actually removes algae cells, particles, dust and turbidity in general from the water, greatly improving the flocculation efficiency due to the action of ultrasound in the coagulating flocculants. To achieve a 90% removal of algae, particles, dust and turbidity, sonication reduces the amount of flocculants by two-thirds. The method according to the invention has a great advantage over the previous method of filtering water from tanks with very low investment and operating costs and high water filtration efficiency.

[0040] Indeed, compared to traditional tank filtration systems, excellent results are obtained for the level of water transparency at significantly lower investment and operating costs as it uses a synergistic system between flocculation and sonication of suspended particles which are easily sucked off by the suction device with due to the formation of large flocs that are individually melted and easy to suck off without the presence of biofilms, and also for efficient filtration thanks to the quality of the sediment thanks to a small, standard, cost-effective filter that is readily available on the market. This is achieved by using a very low level of flocculants. Ultimately, filtration of only a small percentage of the total water volume corresponding to the suction effluent achieves a result equal to or better than with traditional systems that filter the entire water tank.

[0041] The invention provides efficient and economical filtration of water from a tank, the filtration being performed on a small volume of water, rather than on the entire volume of water in the tank, the method comprising:

a.emitting ultrasonic waves in a tank, the ultrasonic emitter being below the surface of the water, so all the water in the tank receives the emitted ultrasonic waves, and the ultrasonic waves are emitted at a frequency of 20 to 100 kHz, and power ranging from 10 to 45 watts;

b. adding a flocculating agent to the water to flocculate suspended solids in the water;

c. sucking off a stream of water from the bottom of the tank containing flocculated solids with a suction device to provide an effluent stream from the suction device;

d. draining the leachate stream from the suction device to the leachate collection line;

e. filtering the effluent stream from the suction device from the effluent collection line to produce a filtered stream; and

f. returning the filtered stream to the tank.

[0042] Preferably, in step a) of the invention, the ultrasound waves are emitted over a period of 12 to 24 hours, more preferably 20 to 24 hours.

[0043] The ultrasonic waves may be emitted by the emitting devices. These devices emit ultrasonic waves in a radial form in the range of 180 ° and a distance of 150 meters, therefore the devices emitting ultrasonic waves are below the water surface and are distributed in a radius of 100 to 150 m, so all the water in the tank receives the ultrasonic waves emitted.

[0044] Typically, the ultrasonic wave emitters are at the periphery of the tank; however, in the case of a tank with a diameter greater than 300 meters, a central island or other central platform may be formed which allows the provision of emitting devices in the center of the reservoir, positioned such that the entire surface is subjected to ultrasonic waves according to the coverage range of the emitting device used.

[0045] The object of step a) of this invention is a method:

- reducing the amount of microalgae, which is the main component of water-suspended solids; facilitating the extraction method and increasing the efficiency of the subsequent filtration by an eco-friendly method at low cost, which reduces the use of chemical products and maintains the ultimate goal of low operating costs;

- elimination of the biofilm formation that usually forms on the walls and bottom of the tank and which is a source of algae growth, which makes the use of the suction device more efficient and reduces the need for manual wall cleaning, generating a synergistic effect;

- reducing the amount of flocculant and facilitating the removal of algae and coagulation of particles from the bottom by means of a suction device;

- facilitating the suction with the suction device due to the synergistic action of the ultrasonic waves and the flocculant, since this allows for larger flocs and easy suction without generating the cloud of suspended particles formed when the suction device covers the bottom of the tank;

- facilitate filtration with simple sand filters without additional flocculation; and

- eliminating the turbidity of the water in the tank together with the flocculant.

Preferably, in step b) of the process according to the invention, the flocculating agent is an ionic polymer. More preferably, said ionic polymer is a biodegradable cationic polyelectrolyte.

Preferably, in step b) of the process according to the invention, the flocculant agent is added to the water in the tank at a concentration of 0.005 to 2 ppm at least once every 6 days, preferably in a concentration of 0.01 to 0.5 ppm at least once every 4 days; more preferably at a concentration of from 0.0125 to 0.04 ppm every 24 hours.

Preferably, in step c) of the process according to the invention, the flow of water with flocculated particles is in the range of 1 to 30 l / s. More preferably, the flow of water with flocculated particles is in the range of 10 to 20 l / s.

[0049] On the other hand, in step c) of the invention, when the bottom of the tank is covered with a suction device, it can be moved by various traction means, such as a boat on the surface of the tank; wagon on rails at the bottom of the tank; a motorized, automated and / or remotely controlled robot; or with cable and wheel system.

[0050] In step e) the water flows are variable depending on the size of the suction device which in turn is related to the volume of the reservoir. Preferably, in step e) of the process according to the invention, the effluent stream from the suction device is filtered in the range from 1 to 30 l / s, more preferably in the range from 10 to 20 l / s.

[0051] The effluent stream from the suction device is pumped by a mobile pump connected to the suction device by means of a flexible suction hose placed along the edge of the water surface of the tank on a movable or fixed platform or on a boat. The effluent from the suction device is discharged to the effluent collection line; from said effluent collection line, water is pumped by a centrifugal pump for filtration, at a flow of preferably from 1 to 30 l / s, more preferably at a flow of 10 to 20 l / s; and at a pressure of 100 to 300 kPa (1 to 3 bar) towards the filter. Said filter may be a sand filter, a diatomaceous filter or a cartridge filter, according to the flow of the effluent that is sucked by the suction device.

[0052] In step f) the filtered water is returned to the tank by means of a recirculation pump located at the periphery of the tank and connected by a hose or pipe to the supply line; using the injectors, the filtered water is returned to the tank from said feed line to complete the recirculation cycle and thus save water in the system.

[0053] It is important to remember that the purpose of the suction device is to clean the bottom of the tank in the method according to the invention, as is the case with suction devices in traditional swimming pools, but also with the emission of flocculants and ultrasound, the traditional filtration system of public swimming pools becomes completely replaced. In other words, the suction device not only eliminates the material naturally located on the bottom (leaves, branches, soil, etc.), but also all suspended particles, in the case of public swimming pools, are eliminated by filtering all the water four times a day. In the case of the invention, the suspended particles become flocs by means of ultrasound and flocculants

-10 (larger particles easy to suck) and are sucked off through the suction device and then filtered, reducing the elimination costs by two orders of magnitude. This means that instead of filtering all the water with conventional systems, only the effluent stream from the suction device is filtered.

[0054] Optionally, the filtrate according to the invention may contain water from the skimmers or grooves to eliminate, in particular, the surface layer of water in the reservoir which may contain oils and floating particles. The cleaned stream by means of skimmers may be included in the effluent collection line for its filtration, as in step e) of the invention, since the skimmers only eliminate the surface water layer with a very low flow, for example from 1 to 5 L / s. This does not affect the performance of economic filters available on the market that are used in the process of the invention. It should be noted that in some traditional filter systems the water is introduced into the skimmer filter, but in this case it corresponds to larger streams, which is intended not only to eliminate the surface layer but also to filter all the water. The method according to this patent concerns only the surface layer filtration, so that the streams are filtered in two lower orders of magnitude.

[0055] In this invention, a suction device is necessary that is capable of covering large areas under the water in the reservoir, such as those that can cover 1 hectare (ha) in 3 hours, i.e. can move at a speed of 0.93 m / s; this suction device has not been found on the market, therefore the suction device has been specially designed to carry out step c) of the method according to the invention; this device covers at least an area 100 times larger than the bottom of the tank over the same period of time, better than any other existing device.

[0056] As can be seen in Fig. 4 to 11, the suction device used in step c) of the method according to the invention essentially comprises a structural frame (10); coupling means (20) for the pump system; wheel means (30) with a horizontal axis for movement above the bottom of the tank; rotary sliding means (40) with a vertical axis for displacing the surrounding tank walls; suction means (50) that include a plurality of suction lines that suck a stream of water with flocculated particles from the bottom of the tank towards the coupling means (20); cleaning agents (60) that include a line of brushes; pivot means (70) between the circular means (30) and the structural frame (10) for adapting the suction device to elevations in the bottom of the tank; the structural frame (10) includes rotatable means (80) for attachment to a traction means, such as a remotely operated robotic submersible car; and attachment means (90) between the suction means (50), the cleaners (60) and the structural frame (10).

[0057] As shown in Fig. 5, the wheel means (3) comprises stainless steel horizontal axes (31) in which are semi-rigid polyurethane protective rollers (32) and support wheels (33) made of a self-lubricating plastic such as such as high-density polyethylene, to support and move the structural frame (10). Additionally, these wheel means (30) comprise stainless steel secondary axles (34) in epoxy resin bearings (35) positioned on the sides of the suction means (50) and the means.

Cleaners (60); on these secondary axes (34) are secondary wheels (36) made of a self-lubricating plastic, such as high density polyethylene, to support and move the suction means (50) and the cleaning means (60). Moreover, the rotary skid means (40) comprises vertical axles and lateral guard wheels made of a self-lubricating plastic such as high-density polyethylene.

[0058] As shown in Fig. 6, the coupling means (20) comprise a hose nozzle (21) for a flexible hose connected to the pump system, PVC couplings (22) and flexible corrugated pipes (23) which are connected to the suction means and which allow the distribution of the suction force from the pump system

As shown in Fig. 7, the suction means (5) comprises a complex suction channel (51) made of stainless steel which connects suction inlets (52) made of stainless steel pipes, argon-welded with a continuous weld bead to said channel. a suction device (51); and PVC joints (53) and flexible corrugated tubes (54) connected to coupling means (20).

As shown in Fig. 8, pivot means (70) connect the structural frame (10), wheel means (30) and suction means (50) about horizontal axes (31). In addition, it should be emphasized that the rotatable means (80) connect the traction means (not shown in this figure) to the structural frame (10).

[0061] In Fig. 9 it is indicated that the fastening means (90) comprises cables, e.g. plastic cords, which suspend the suction means (50) and the cleaning agents (60) on the structural frame (10) not more than 2 cm from the bottom. tank.

[0062] As shown in Fig. 10, the structural frame (10) consists of intertwined arcs (11) to define an interior space which comprises suction means (50) and cleaning means (60) suspended by the fastening means (90). The braided arches (11) of the structural frame (10) are fastened with plastic screws. Mounted at the lower ends of said intertwined arcs are pivot means (70) which pivot about horizontal axes (31). Between each support wheel (33), securing rollers (32) and secondary wheels (36), such as between the pivot means (70) and the pivot means (80), are high-density polyethylene washers (not shown in the figures).

[0063] Fig. 11 shows the distribution of the suction inlets (52) in the suction means (50) and the cleaners (60) as a center line of the brushes.

APPLICATION EXAMPLES

[0064] In order to carry out the method of the invention that allows efficient filtration of water in reservoirs such as fountains, ponds, pools and lakes with low investment and operating costs, the following steps were carried out:

A reservoir (A) was built, similar to an artificial lake, located on the central coast of Chile, with an area of ​​about 6000 m² and a volume of 90,000 m³as shown in Fig. 1. In Fig. 1, a top view of the tank (A) has the structure necessary for

Carrying out the method according to the invention. Fig. 2 is a top view of the same tank constructed as necessary for conventional filtration in which all the water in the tank is filtered. The difference in structure of conventional filtration and filtration according to the method of the invention can be seen in Figs. 1 and 2; the structure of Fig. 1 is simpler and more economical than the structure of Fig. 2. In particular, Fig. 2 presents the necessary equipment for traditional filtration, where there is a huge need for pipes to the rim of the tank as a filtration area to handle all the necessary filters. You can see all the infrastructure needed for traditional filtration, which generates very high operational and infrastructure costs; on the other hand, Fig. 1 shows the simplicity of the structure needed for the filtration of the water according to the invention, thus saving in operating costs and infrastructure costs.

[0065] The method according to the invention was carried out in the following steps:

In stage a), ultrasonic waves were emitted by means of devices emitting ultrasonic waves (8), hereinafter referred to as sonicators, trademark LG Sonics model XL with double frequency in 20 and 100 kHz and power of 45 W, produced by LG SOUND, Gerrit van der Veenstraat 752321 CD, Leiden, The Netherlands; with this device, the formation of biofilms was prevented and the use of flocculant was reduced by 75%. Said sonicators (8) are placed 10 to 30 cm below the water surface by means of floats and are on the rim of the tank as shown in Fig. 1.

[0066] As shown in Fig. 3, the suspended particles were coagulated in regular form into large sized flocs that had been dispersed due to the synergistic effect between the emission of ultrasonic waves and the flocculant, allowing easier suction and efficient filtration of the effluent stream from the device suction.

[0067] In step b) the cationic polymer, Crystal Clear ™, which is a biodegradable cationic polyelectrolyte manufactured by AP Aquarium Products, USA, was added at concentrations of 0.08 ppm every 24 hours.

[0068] In step c) the bottom of the tank was covered with the suction device shown in Figs. 4 to 6, which traps flocculated particles, which sucked a stream of 15 l / s of water with these flocculated particles for 2 hours every 2 days. As shown in Fig. 1, the effluent from the suction device (2c) is sucked by a mobile pump (2e) with 6.98 kW (9.5 hp) and connected to the suction device by a flexible plastic hose (2d) by 10.16 cm (4 inches) in diameter and 150 m long, towards a discharge pipe (4) that leads to several concrete drainage chambers (2a), all of which are connected by a discharge pipe (4). This suction device covers the bottom of the tank and is immersed in the water of the tank and covers a hectare in 3 hours at a speed of 0.93 m / s. The mentioned speed is much better than any similar equipment on the market. This specially designed device covers at least 100 times the surface area of ​​the tank bottom for the same period of time than any other device on the market.

[0069] In step e) the effluent from the suction device was filtered by pumping with the VOGT® model Serial N 628 centrifugal pump 5.52 kW (7.5 hp) with a force and flow of 15 l / s, connected to a crane 10.16 cm (4 in.) ID from one or more concrete drainage chambers. An Aguasin® sand filter model QMA-210-E was used; loaded with C-5 support gravel and two filter layers, one with CARENTI C-8 and the other with CARENIT AN. In step e) of the process according to the invention, all the effluent was filtered with a suction device for one and a half hours and thus filtered at 15 liters / sec for 1.5 hours / day.

[0070] In step f) the filtered water was returned to the tank by three recirculation pumps, each with a power of 1.84 kW (2.5 hp) and a flow of 5 1 / s for a total of 15 1 / s recirculation flow.

[0071] The biofilms were not formed, therefore manual cleaning of the walls and the suction device was not necessary; total turbidity of the water was eliminated, and pollutants precipitated with polymers were easily and efficiently completely eliminated, leaving a completely clean bottom. The device, which sucked a flow of 15 lps from the bottom of the tank, left the bottom surface of the tank free of particles, fluff and a layer of residue by gentle cleaning other than simple dredging. The suction device was applied to the lake bottom for 2 hours every 2 days to suck the stream with flocculated particles into the bottom of the reservoir, keeping the water completely crystalline, meeting and exceeding the standards for transparency in direct contact recreational water and the pool regulations in the country of implementation, i.e. NCh 1333, NCh 209, and NCh 409.

Table 1: Comparison table of treated water from the method of the invention compared to the ordinance for recreational water of direct contact NCh 1333 *

<td>Parameters</td><td>Measured pool value</td><td>NCh 1333</td>

<td>pH</td><td> 7.8</td><td>6.5 to 8.3, unless the natural water conditions vary, but never below 5.0 or above 9.0</td>

<td>Temperature, ° C, maximum</td><td> 17.7</td><td> 30</td>

<td>Transparency, minimum *</td><td>35 meters</td><td>Visualization of Secchi disks at a depth of 1.20 m</td>

<td>Visible floating solids and unnatural foams</td><td>Lack</td><td>Lack</td>

<td>Floating oils and fats, mg / 1, maximum *</td><td> &lt;5</td><td> 5</td>

<td>Emulsified oils and fats, mg / 1, maximum *</td><td> &lt;5</td><td> 10</td>

<td rowspan="2">Color, scale unit Pc-Co, maximum *</td><td> 10</td><td> 100</td>

<td>Lack</td><td>No artificial colors</td>

<td>Turbidity, units silica, maximum *</td><td> 0.55</td><td> 50</td>

<td>Faecal coliform bacteria / 100 ml, maximum *</td><td> -</td><td> 1,000</td>

<td>Substances that cause an unpleasant smell or taste</td><td>Lack</td><td>Lack</td>

<td colspan="3">* Chilean official regulations where applicable (Chili is the country where the embodiment of the invention has been made), Regulation NCh 1333</td>

Table 2: Comparison table of treated water from the method according to the invention _________ in comparison with the swimming pool ordinance NCh 209 * _________

<td>Parameters</td><td>Measured pool value</td><td>NCh 209</td>

<td>pH</td><td> 7.8</td><td> 7.2-8.2</td>

<td>Residual free chlorine (ppm)</td><td> 0.5</td><td> 0.5 - 1.5</td>

<td>Copper (algicide) (mg / L)</td><td> 0.38</td><td>Maximum 1.5</td>

<td>Bromine (disinfectant) (mg / L)</td><td> -</td><td> 1 -3</td>

<td>Foams, fats and suspended particles</td><td>Lack</td><td>Lack</td>

<td>Anaerobic bacteria (colonies / mL)</td><td>Lack</td><td> &lt;200</td>

<td>Faecal coliform bacteria</td><td>Lack</td><td>Lack</td>

<td>Total coliform bacteria (colonies / 100 mL)</td><td>Lack</td><td> &lt;20</td>

<td>Algae, larvae or other living organism</td><td>Lack</td><td>Lack</td>

<td>15 cm black disc visibility</td><td>35 m</td><td>1.4 m</td>

<td colspan="3">* Chilean official regulations where applicable (Chili is the country where an embodiment of the invention has been made), Regulation NCh209</td>

[0072] Filtration of large volumes of water is technically complex and involves a high barrier cost to the expansion of the crystalline water bodies.

[0073] The suction device eliminates suspended solids flocculated by the flocculating agent and provides sonication in an efficient and economic way, reducing the streams to be filtered almost 100 times, reducing the investment costs for filters, pipes and energy costs during operation, compared to traditional filtration systems tank. This allows you to reduce the use of disinfectants, flocculants, algaeicides and eliminate biofilms, eliminating the need to manually clean the tank walls and improving the operation of the suction device.

[0074] Apart from the high cost, conventional filtration systems do not clean the bottom of the tank.

[0075] The technology described in this document, which significantly lowers investment and operating costs, makes it possible to eliminate one of the main barriers to the construction of larger clear water reservoirs for recreational and ornamental purposes.

[0076] The main advantages of the implemented method are the significant savings in energy and chemical products, together with environmental protection and the benefits of investment and maintenance costs, which are shown in the comparative table below:

Table 3: Comparison table of approximate costs between a traditional filtration system * and a suction device

<td></td><td>Description</td><td>Flux through the pumps</td><td>Installation costs</td><td>Operating expenses, monthly</td>

<td>Traditional filter</td><td>• 20 VOGT® centrifugal pumps model Serial N 628, running at 15 l / s, with a 5.595 kW (7.5 HP) motor • 20 AGUASIN sand filters model QMA-210; • 129,600 kg of sand (Carenit C2, C3, C4, C5, C8 y AN);</td><td>300 L / s</td><td>US $ 362,180 ⁺</td><td>US $ 16,075</td>

<td rowspan="7"></td><td>• 20 batteries with 250 mm valves;</td><td rowspan="7"></td><td rowspan="7"></td><td rowspan="7"></td>

<td>• Working installation;</td>

<td>• A warehouse with an area of ​​1000 m² with special bases for supporting a total weight of 300 tons, with vibration of operating filters;</td>

<td>• 1998 m. Water pipelines;</td>

<td>• Total energy consumed for one month, 24 hours * 30 days * 20 * 5.595 kW / hour (80 568 kW / hour)</td>

<td>• Operators;</td>

<td>• Maintenance</td>

<td rowspan="9">The method according to the invention</td><td>• Windglider boat</td><td rowspan="9">15L / s</td><td rowspan="9">US $ 18,200</td><td rowspan="9">US $ 910</td>

<td>• Suction pump with 9.5 HP engine</td>

<td>• 3 sonicators, model LGSONIC XL</td>

<td>• Suction device</td>

<td>• 7.5 HP suction pump</td>

<td>• 449 m of water piping</td>

<td>• 3 recirculation pumps with a power of 1.84 kW (2.5 HP)</td>

<td>• Hoses, accessories</td>

<td>• Fuel</td>

<td rowspan="3"></td><td>• Flocculant</td><td rowspan="3"></td><td rowspan="3"></td><td rowspan="3"></td>

<td>• Operator</td>

<td>• Maintenance</td>

<td colspan="5">* T = 4 (minimum pool filtration speed) NCh209 regulation is included</td>

<td>+ Land cost</td><td colspan="4">for a warehouse with an area of ​​1000 m² is not taken into account</td>