GB2600219A

GB2600219A - Water tank

Info

Publication number: GB2600219A
Application number: GB2112056.3A
Authority: GB
Inventors: Vandebeek Luc
Original assignee: Ecobeton Water Technologies NV
Current assignee: Ecobeton Water Technologies NV
Priority date: 2020-09-04
Filing date: 2021-08-23
Publication date: 2022-04-27
Anticipated expiration: 2041-08-23
Also published as: FR3113912A1; NL2029112B1; ES2898641B2; LU500616A1; GB202112056D0; DE102021122297A1; LU500616B1; DE102021122297B4; FR3113912B1; ES2898641R1; BE1028583B1; NL2029112A; GB2600219B; BE1028583A1; ES2898641A2

Abstract

The water tank (WT figure 1) has two separate buffer zones, wherebythe first buffer zone BF1 is provided with a bottom infiltration system, while the second buffer zone BF2 is provided with a water drainage braking system 15. The first buffer zone has a first no porous concrete part 12 and a porous concrete part 13 adapted to allow the flow of water from the first buffer zone through the first second porous concrete part towards the ground or soil. The water drainage braking system 15 has a transit system 16 made from porous concrete wherein the transit system defines an inner chamber 17 which collects water from the second buffer zone BF2.

Description

Water Tank The invention relates to the simple buffer water tank, in which in an efficient manner, part of the water can be infiltrated in the ground, while another part of the water can run into a stream or a canal.

More and more houses and other buildings arc being equipped with water tanks in order to store rainwater. In the event of insufficient water usage, the water tanks remain full of water, and in case of heavy rain, they do not provide a solution for excessive water discharge into waterways.

To assist with the problem of storm water, there is a system that joins plastic modules together with the help of a porous textile material. The construction of such system requires underground works so as to achieve sufficient ground stability. It would be also useful if top layer is suitable to drive on.

Water tanks that are also being used as draining systems are being described, for example in W095/16833. In accordance with this document, the drainage system is being introduced with perforated walls and porous textile material to define storage volume, in which water flows through the walls and the porous textile material, so that the water is being infiltrated in the underground.

Such a system requires a great deal of ground works, in order to ensure that there is a porous ground layer located around the walls with the porous textile material. In addition, in case of wet grounds, such systems are completely inefficient. As a matter of fact, the groundwater flows through the porous side walls in the tank, limiting the space for collecting rainwater.

The usage of porous concrete layers is known for driveways, roads, and parking. The porous concrete has an exceptionally large permeability and is intended to carry water to lower located ground layer. As soon as the ground layer is wet, the efficiency of the porous concrete is being reduced.

DE9412053U1 describes a water tank that is provided with a filter clement and an exit opening at a level that is located above the filter element. Thus, the filter element is not functioning as a means to control the draining of rainwater.

US2012/0111428 describes a water tank manufactured in HDPE, for thc purpose of rainwater collection, in which the water tank is equipped with a filter structure that has a filter film, in order to collect solid particles that are measured from 20mm in the size. Thus, a filter is not operating as a means of disposing of rainwater.

DE10231241 describes a filter element made from porous concrete. The water flows from the bottom to the top through the porous concrete. In addition, as soon as there is too much rainwater that has been accumulated, solid particles are being deposited on the horizontal filter clement, due to which the draining of the rainwater cannot be controlled.

DE4338085 describes a filter installation with horizontal filter elements in order to filter the rainwater. Thus, the installation does not operate as a means of controlling the draining of rainwater from the tank.

All these known systems do not offer efficient solutions to buffer rainwater, to control the draining of rainwater to streams or rivers during and after a rainy period, for example, in case if the ground is too wet, as well as the draining of the water in the ground, if the ground is rather dry.

GB2576406 discloses a buffer tank suitable for controlling the flow of rainwater to streams or river during and after a period of rain. Said buffer tank has however the drawback when placed in certain soil, to be submitted to soil movements, which can cause operating problems, like reduction of buffering and variation of the controlled drainage.

W02007/123342 discloses linear infiltration system functioning as storm sew°, which is not provided with porous concrete water drainage braking system.

KR 100 978075 discloses a water treatment plant with filtering means for the removal of coarse particles.

KR 101 419 909 discloses a water treatment plant with sedimentation step and filtration step.

With the water tank of the invention, the draining of the water along the bottom of a buffer zone of the tank, in accordance with the invention operates as a means to control the soil moisture in the surroundings of the water tank. This is advantageous to avoid the underground movement caused by the drought, for example in clay layers, in which the water tank is located. Moreover, it has been observed that with the water tank of the invention, part of the rainwater falling in the neighbourhood of the water tank can he better infiltrate into the ground and/or was better absorbed by the plants growing in the neighbourhood of the tank.

The invention relates to the water tank (WT) to be placed at least partly in the ground or soil, for example into an excavation or hole whereby the bottom and the wall(s) thereof are at least partly cmn contact with the soil or ground or artificial layer thereof. The water tank has at least the capacity of treatment or buffering of polluted water or rainwater (W1) or part of it, that is substantially free from solid particles with the density greater than 1.1 k2/litre.

The water tank (WT) of the invention is at least provided with: - a tub (1) with a bottom (10) adapted to be in contact with the ground or soil (ground and soil means also artificial porous layer, such as sand layer), and with at least one side wall (11a, 11b, 11c, 11d) adapted to be at least partly in contact with the ground or soil, - a first partition wall (20) which divides the water tank (WT) at least into first buffer zone (BF1) with a first water buffer volume of at least 500 litres, and a second buffer zone (BF2) with a second water buffer volume of at least 500 litres, whereby the first buffer zone (BF1) is provided with an inlet system (2) through which the polluted water or rainwater can flow in the first buffer zone (BF1) above a minimum inlet level (PO), in which the first partition wall (20) is provided with a first discharge system (21) through which water can flow from the first buffer zone (BF1) to the second buffer zone (BF2), whereby the discharge system (21) is located on a first exit level (P1) under the inlet level (PO) of the first buffer zone (BF1), whereby the second buffer zone (BF2) is provided with a second discharge system (3) through which water of the second buffer zone (BF2) can flow outside of the second buffer zone (BF2), whereby the second discharge system (3) is located on a second exit level (P2), which is located under the first exit level (P1), whereby the bottom (10) of the water tank (WT) which is located in the first buffer zone (BF1) is divided into (a) a first not water permeable concrete part (12) with a first not porous concrete upper surface (12A) that is facing the first buffer zone (BR), whereby no water can flow from the first buffer zone (BF1) through the said first not water permeable concrete part (12) towards the ground or soil, and (b) a second water permeable porous concrete part (13) adapted for the flow of water from the first buffer zone (BF1) through the said second water permeable porous concrete part (13) towards the ground or soil, said second water permeable porous concrete part (13) having a porous concrete upper side (13A) that is facing the first buffer zone (BF1) and that is located at least 10 cm above the first concrete not porous upper surface (12A), whereby the porous concrete upper side (13A) of the second part (13) has a surface facing the first buffer volume of at least 200cm2, whereby the second buffer zone (BF2) is provided along its bottom with a water drainage braking system (15) that comprises and/or is provided with a transit system (16) produced at least from a porous concrete, said transit system (16) defining an inner chamber (17) in order to collect water from the second buffer zone (BF2) flowing through the porous concrete of the transit system (16), in which the transit system (16) comprises a discharge system or discharge means (18) for the disposal (outside the water tank) of water that flows in the inner chamber (17) of the transit system (16), whereby the transit system (16) produced at least from a porous concrete comprises an upper section (16A) made from a porous concrete with an upper porous surface of at least 100 cm2 that is located at least 100 cm (H) under the second exit level (P2), whereby at least the upper section (16A) produced at least from a porous concrete of the transit system (16) is being produced from a hardened porous water-draining concrete, that is being produced by hardening a mixture of at least cement, aggregates with particle size of 6 mm to 14 mm, and water in order to reach an open-pore volume of 8 to 12% in the hardened porous water-draining concrete, in which the hardened porous water-draining concrete has a water permeability of 0.05 litre/m2/s to 5 litre/m2/s, preferably of 0.1 litre/m2/s to 3 litre/m2/s, and most preferably between 1.1 to 1 litre/m2/s, whereby the said water permeability of the hardened porous water-draining concrete is measured by the filling of the second buffer zone (BF2) with water reaching the second exit level (P2) with an empty inner chamber (17) for the transit system (16), and afterwards by the determination of the water quantity that flows through the porous concrete of the transit system (16) and its upper section (16A) produced from porous concrete in 30 seconds within the inner chamber (17) of the transit system (16).

The water tank according to the invention contains two separate buffer zones (13F1 and BF2), that substantially have separate operations and distinct functions. The first buffer zone makes the first buffer volume. Part of the water of the first buffer zone (BF1) can be infiltrated through the bottom of the first buffer zone in the ground or soil in a controlled manner (for example in the soil layer located below the bottom), whereas as soon as the water level in the first buffer zone is above an exit level, water of the first buffer zone flows in the second buffer zone through an exit opening.

Water of the second buffer zone flows in a controlled way outside the second buffer zone through a transit system, to a stream or a canal or ditch or river.

By using the water tank of the invention, a large water volume can be buffered and if necessary, can be pumped, for example to water the garden.

Water of the first buffer zone (BF1) is first of all being used to infiltrate water in the ground or soil (adjacent to the tank) (especially in the soil layer below the bottom of the tank), which is beneficial in order to retain a minimum soil moisture. In the event of rain, the infiltration of rainwater is therefore also being improved.

with respect to the rain water infiltration in a dry ground layer.

Water of the second buffer zone (which can also be pumped to water plants) flows in a controlled way to a canal or a stream or a river, which is beneficial for the canal/river animal/plant life, especially for the plants that grow along the bottom of the canal or river. The presence of these plants is therefore also advantageous for the water infiltration along the bottom of the canal and stream or river.

In the surroundings of the water tank of the invention, the rainwater infiltration in the top soil layer, as well as in the bottom soil layer is increased or improved in the surroundings of the water tank, which is beneficial for the adjacent garden plants during long dry period, and what is also beneficial for maintaining a minimum ground water level in the surroundings of the water tank.

The water tank of the invention has preferably one or several of the following characteristics: * The second water permeable porous concrete part (13) has a water permeability of 1 litre/m2/s to 10 litre/m2/s, preferably of 2 litre/m2/s to 8 litre/m2/s, ideally between 3 to 6 litre/m2/s, in which the water permeability of the second water permeable porous concrete part (13) is measured by the filling of the first buffer zone (BF1) with water reaching until the first exit level (P1) with an empty collecting chamber (LO) under the second part (13), and afterwards through the determination of the water quantity that flows through the second part (13) in 30 seconds within the collecting chamber (LO).

* the total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is greater than the total water permeability of the upper section (16A) of the transit system (16), whereby the total water permeability of the second part (13) of the first buffer zone (BF1) is measured by the filling of the first buffer zone (BF1) with water reaching the first exit level (21) with an empty bottom collecting chamber (LO) under the second part (13), and afterwards through the determination of the water quantity that flows through the second part (13) in 30 seconds within the bottom collecting chamber (LO), while the total water permeability of the transit system (16) is measured by the filling of the second buffer zone (BF2) with water reaching the second exit level (P2) with an empty inner chamber (17) for the transit system (16), and afterwards through the determination of the water quantity that flows through the porous concrete of the transit system (16) and its upper section (16A) produced from porous concrete in 30 seconds within the inner chamber (17) of the transit system (16).

* the total water permeability of the second part (13) of the bottom of the first buffer zone (BFI) is at least two times greater than the total water permeability of the transit system (16).

* the total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is between 3 to 10 times greater than the total water permeability of the transit system (16).

* the second part (13) of the bottom of the first buffer zone (BF1) forms a protrusion (13U) with respect to the upper surface (12A) of the first part (12) of the bottom of the first buffer zone (BF1).

* the protrusion (13U) has an elongated shape with a substantially horizontal axis (13X) and with a rectangular or trapezoidal section in a plane perpendicular to the substantially horizontal axis (13X).

* the protrusion (13U) has a trapezoidal section in a plane perpendicular to the substantially horizontal axis (13X).

* with respect to the first part (12) of the bottom of the first buffer zone (BF1) in horizontal position, the protrusion (13U) has (a) two inclined side surfaces (13F, 13G) and (h) a substantially horizontal upper surface (13A) which extends between the upper edges (13H, 131) of the two inclined side surfaces (13F, 13G), whereby the inclination of both inclined side surfaces (13F, 13G) is such that along a vertical section perpendicular to the substantially horizontal axis, the width (B1) of the trapezoidal section along the substantially horizontal upper surface or upper side (13A) of the protrusion (13U) is smaller than the width (B2) of the trapezoidal section along the horizontal plane of the upper surface (12A) of the first part (12).

* the first partition wall (20) comprises a water permeable part (20D) that is produced at least partially from the water permeable concrete, whereby water can flow between the first buffer zone (BF1) and the second buffer zone (BF2) through the above-mentioned water permeable part (20D) of the partition wall (20), whereby said water permeable part (20D) of the first partition wall (20) is at least partially located under the second exit level (P2), whereby the above-mentioned water permeable part (20D) of the first partition wall (20) has a total water permeability between the total water permeability of the transit system (16) and the total water permeability of the second part (13) of the first buffer zone (BF1), whereby the total water permeability of the water permeable part (20D) of the first partition wall (20) is being measured after the sealing of the transit system (16) and the filling of the second buffer zone (BF2) up to the second exit level (P2), with an empty first buffer zone (BF1), and afterwards through the determination of the water quantity that flows in 30 seconds through the partition wall (20) of the second buffer zone (BF2) to the first buffer zone (BFI).

* the transit system (16) comprises a pipe (18) that is connected to the inner chamber (17) and that flows through the outside wall (11d) of the water tank (WT), whereby said pipe (18) is adapted for the flow of water from the inner chamber (17) outside the water tank (WT).

* the water tank (WT) comprises a second partition wall (30) in order to define the sedimentation zone (BZ) in the water tank (WT), whereby the water tank (WT) contains an inlet (31) in order to let the polluted water or rainwater flow in the sedimentation zone (BZ), where the second partition wall (30) has an overflow system (32) that forms the met system (2) for the first buffer zone (BF1).

* the sedimentation zone (BZ) comprises a flexible water permeable filter container (40), which is removably mounted in the sedimentation zone (BZ).

* the flexible water permeable filter container (40) has a bottom (40B) and at least one side wall (40C) with a free upper edge (40D) whereby the at least one side wall has an upper part (40C1) along the upper edge (40D), whereby the above-mentioned upper part (40C1) of the at least one side wall (40C) has a water permeability that is greater than the water permeability of the bottom (40B) and than the water permeability of a part (40C2) of the at least one side wall (40C) that is located adjacent to the bottom (40B).

* the upper edge of the at least one side wall of the filter container is located on a level that is higher than the inlet level (PO).

* the water tank is provided with a movable cover (50) which has at least a utility access hole or manhole (51, 52, 53).

* combinations of at least two of these characteristics.

The invention relates as well to a water installation which comprises (a) a water tank, in accordance with the invention, with a water inlet system (2), and (b) a sedimentation tank (BZT) that is provided with an inlet (60) in order to collect water and an exit pipe (61) to direct or drain water from the sedimentation tank (BZT) towards/in the first buffer zone (BF1) of the water tank through the inlet system (2).

The invention further relates to the use of the water tank, in accordance with the invention along a water stream or sewage system, or canal, or river, in order to buffer polluted water or rainwater before the water will partially run into the water stream or sewage system. or canal, or river, whereby the water is being collected in the first buffer zone (BF1), before it will partially flow to the second buffer zone, whereby water of the first buffer zone (BF1) can flow through the second water permeable porous concrete part (13) of the bottom (12) in the ground layer under the bottom of the water tank, while water that flows in the second buffer zone (B P2) is being drained through transit system (16) in the water stream or sewage system, or canal, or river.

Embodiments of a tank in accordance with the invention will now be described with reference to the attached drawings.

In the drawings it shows: -Fig 1 a top view of a first embodiment of a water tank in accordance with the invention without the cover with utility access hole; -Fig 2 a view in cross section of the water tank of Fig 1, along the line II -II; - Fig 3 a view in cross section along the line III -III of the water tank of Fig 1; - Fig 4 a view in cross section along the line IV -IV of the water tank of Fig 1; -Fig 5 a view in perspective of the water tank of Fig 1; - Fig GA to 6F views of processing steps for the water that flows in the water tank of Fig 2; -Fig 7 a view in cross section of a second embodiment which is similar to the embodiment of Fig 2; -Fig 8 a view of the second embodiment of Fig 7 along the line VIII -VIII; - Fig 9 a top view of third embodiment of a water tank in accordance with the invention which is similar to the embodiment of Fig 1; and - Fig 10 a view in cross section of the water tank of Fig 9 along the line X -X. Fig 1 shows a first embodiment (top view, without cover 50) of a water tank in accordance with the invention with two separate buffer zones (BF1, BF2).

The water tank (WT) in accordance with Fig 1 is used to buffer water, as well as to treat water (W1), in order to infiltrate a part of it (W2) (for water present in the first buffer zone (BF1), along the bottom of it) and to let another part of water (W3) (water present in the second buffer zone (BF2)) to flow to a stream or a canal, or a river, through a drainage braking system (15).

The water (W1) is preferably a rainwater or polluted water (W1) or part of it that is substantially free from solid particles with a density greater than 1.1 kg/litre,. The above-mentioned water can be a water issuing from a sedimentation tank, in which heavy solid particles can be removed.

The water tank (WT) is at least equipped with: - a tub (I) with a bottom (1()) and with four vertical side walls (I Ia. I lb. 11c, Ild), - a first partition wall (20) which divides the water tank (WT) at least into a first buffer zone (BF1) with a first water buffer volume of at least 500 litres (for example with a buffer volume of 1 to 5 m3), and a second buffer zone (BF2) with a second water buffer volume of at least 500 litres (for example with a buffer volume of 1 to 5 m3), whereby the first buffer zone (BF1) is provided with an inlet system (2) causing the polluted water or rainwater to flow or enter in the first buffer zone (BF1) above a minimum level or substantially upto a maximum inlet level (PO), in which the first partition wall (20) is provided with a first discharge system or first overflow system (21) through which water can flow from the first buffer zone (BF1) to the second buffer zone (BF2), whereby the discharge system (21) is located on a first exit level (P1) under the inlet level (P0) of the first buffer zone (BPI).

The second buffer zone (BF2) is provided with a second discharge system or second overflow system (3) through which water of the second buffer zone (BF2) can flow outside the second buffer zone (BF2), whereby the second discharge system (3) is located on the second exit level (P2), which is located in its turn under the first exit level (P1).

The bottom (10) of the water tank (WT) which is located in the first buffer zone (BF1) is divided into (a) a first not water permeable or not water permeable concrete part (12) with a first not porous concrete upper surface (12A) that is facing the first buffer zone (BF1), and (b) a second water permeable porous concrete part (13), with a porous concrete upper side (13A) that is facing the first buffer zone (BF1) and that is located at least 10 cm (AH) above the first concrete not porous upper surface (12A). The porous concrete upper side (13A) of second part (13) has a surface of at least 200 cm2 that is facing the first buffer volume.

The second buffer zone (BF2) is being provided along the bottom (10) of a water drainage braking system (15) that comprises and/or is provided with a transit system (16) produced at least from a porous concrete, that defines an inner chamber (17) in order to collect water from the second buffer zone (BF2), in which the transit system (16) comprises a discharge system or discharge means (pipe 18) for the disposal of water that flows in the inner chamber (17) of the transit system (16).

The transit system (16) produced at least from a porous concrete comprises the upper section (16A) made from porous concrete, with a porous concrete upper surface of at least 100 cm2 that is located at least 100 cm (AH1) under the second exit level (P2). The upper section (16A) produced at least from porous concrete of the transit system (16) is being produced from a hardened porous water-draining concrete, that is being produced in its turn by hardening a mixture of at least cement, aggregates with particle size of 6 mm to 14 mm, and water in order to reach an open-pore volume of 8 to 12% in the hardened porous water-draining concrete, in which the hardened porous water-draining concrete has a water permeability of 0.05 litre/m2/s to 5 litre/m2/s, preferably of 0.1 litre/m2/s to 3 litre/m2/s, and ideally between 1.1 to 1 litre/m2/s. The water permeability is being measured by the filling of the second buffer zone (BF2) with water reaching the second exit level (P2) with an empty inner chamber (17) for the transit system (16), and afterwards through the determination of the water quantity that flows through the upper section (16A) produced at least from porous concrete in 30 seconds within the inner chamber (17) of the transit system (16).

The water tank of Fig 1 comprises two separate buffer zones (BF1 and BF2), that have substantially separate operations. The first buffer zone forms the first buffer volume. Part of the water of the first buffer zone (BF1) can be infiltrated through the bottom of the first buffer zone in the ground in a controlled way, whereas as soon as the water level in the first buffer zone (BF1) is above an exit level (P1), water of the first buffer zone flows in the second buffer zone through the exit opening (21).

Water of the second buffer zone flows in a controlled way outside the second buffer zone (BF2) through a transit system (16), to a stream or a canal.

By using the water tank of Fig 1, a large volume of water can be buffered and if necessary, can be pumped, for example to water the 35 garden.

Water of the first buffer zone (BF1) is first of all being used to infiltrate the water in the ground (adjacent to the tank), which is beneficial in order to retain a minimum of soil moisture. In the event of rain, the infiltration of rainwater is therefore also improved, with respect to a dry ground layer.

Water of the second buffer zone (BF2) (that also can be pumped to water the plants) flows in a controlled way to a canal or a stream, which is beneficial for the life of animals in the canal/stream and for the plants that grow along the bottom of the canal or stream. The presence of these plants is therefore also advantageous for the water infiltration along the bottom of the canal and stream.

In the surroundings of the water tank of the invention, the rainwater infiltration is increased, which is beneficial for the adjacent garden plants during long dry period, and what is also beneficial for the maintenance of a minimum ground water level in the surroundings of the water tank.

The water tank in accordance with Fig 1 has the following 20 characteristics: The second water permeable porous concrete part (13) has a water permeability of 1 litre/m2/s to 10 litre/m2/s, preferably of 2 litre/m2/s to 8 litre/m2/s, ideally between 3 to 6 litre/m2/s, in which the water permeability is being measured by the filling of the first buffer zone (BF1) with water reaching the first exit level (P1) with an empty collecting chamber (LO -sec Figure 3) under the second part (13), and afterwards through the determination of the water quantity that flows through the second part (13) in 30 seconds within the collecting chamber (LO).

The total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is greater than the total water permeability of the upper section (16A) of the transit system (16), whereby the total water permeability of the second part (13) of the first buffer zone (BF1) is being measured by the filling of the first buffer zone (BF1) with water reaching until the first exit level (21 -P1) with an empty bottom collecting chamber (LO) under the second part (13), and afterwards through the determination of the water quantity that flows through the second part (13) in 30 seconds within the bottom reception chamber (LO), while the total water permeability of the transit system (15) is measured by the filling of the second buffer zone (BF2) with water reaching until second exit level (P2) with an empty inner chamber (17) for the transit system (16), and afterwards through the determination of the water quantity that flows through the upper section (16A) produced from porous concrete in 30 seconds within the inner chamber (17) of the transit system (16).

The total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is between 5 to 10 times greater than the total water permeability of the transit system (16).

The second part (13) of the bottom of the first buffer zone (BF1) forms a protrusion (13U) in relation to the upper surface (12A) of the first part (12) of the bottom of the first buffer zone (BF1).

The protrusion (13U) has an elongated shape with a substantially horizontal axis (13X) and with a trapezoidal section in a plane perpendicular to the substantially horizontal axis (13X).

In relation to the horizontal plane for the first part (12) of the bottom of the first buffer zone (B El), the protrusion (13U) comprises two inclined side surfaces (13F, 130) and a substantially horizontal upper surface (13A) that is located between the upper edges (13W 131) of two inclined side surfaces (13F, 130), whereby the inclination of both inclined side surfaces (13F, 130) is such that along a vertical section perpendicular to the substantially horizontal axis, the width (B1) of the trapezoidal section along the substantially horizontal surface (13A) of the protrusion (13U) is smaller than the width (B2) of the trapezoidal section along the horizontal plane of the upper surface (12A) of the first part (12).

The transit system (16) comprises a pipe (18) that is connected to the inner chamber (17) and that runs through an outside wall (11d) of the water tank (WT), through which water of the inner chamber (17) can flow outside of the water tank (WT).

Under the protrusion (13U), the second part (3) comprise a porous section (13Z) in the bottom (10).

The water tank is provided with a movable cover (50) with a first utility access hole or manhole (51) for the first buffer zone (BF1) and a second utility access hole or manhole (52) for the second buffer zone (BF2).

Operation steps of the water tank of Figure 2 are the following: Fig 6A: flow of rainwater (W1) through the inlet system (2) in the first buffer zone (BF1) and its partial drainage (W2) through a porous part (13) (in order to let the water to be infiltrated in the ground layer under the tank). The water level in the first buffer zone (BF1) increases until it reaches the exit level or overflow level (P1).

(See Fig 6B) In case additional rainwater flows in the first buffer zone (BF1), part of it (W4) will flow through the exit opening (21) in the second buffer zone (BF2). (See Fig 6C).

Through the flow of additional rainwater in BF1, the water level in the second buffer zone BF2 will also be increased. A part of the water (W3) of the second buffer zone is being drained through the water drainage braking system (15) to a stream. (Fig 6D) The water level can increase in the second buffer zone (BF2) until it reaches the exit opcnina (3). Part of the rainwater (W5) can then run through the opening (3) to the stream (See Figure 6E).

As soon as the flow of fresh rainwater (W1) in the first buffer zone (BF1) has stopped, no more water flows through the exit opening (21) and through the exit opening or second overflow opening (3).

Water is being afterwards buffered in the buffer zones (BF1) and (BF2) and can be pumped for various purposes, such as to water plants, use of water for toilets, washing machine, etc. The water level in the buffer zones will also slowly decrease, through ground infiltration (W2) (through a porous element 13) and through water drainage (W3) to the stream (through the transit system 16).

In accordance with the invention, the tank can effectively brake the drainage of rainwater, which is advantageous to overcome flooding problems. During dry season, the water from both buffer zones (BF1, BF2) can be drained, as a result of which the water level in the buffer zone can be lowered slowly. A free buffer volume is being formed in the following manner in order to collect upcoming rainwater (for example, storm rainwater). (Fig 6F) Fig 7 a view in section of second implementation form which is similar to the implementation form of Fig 1 and 2.

In the second implementation form, the first partition wall (20) comprises a water permeable part (20D) that is being produced at least partially from a water permeable concrete, whereby water can flow between the first buffer zone (BF1) and the second buffer zone (BF2) through the above-mentioned water permeable part (20D) of the partition wall (20), in which the water permeable part (20D) of the first partition wall (20) is at least partially located under the second exit level (P2) (for example on the level that is higher than the level of the upper surface (13A) of the water permeable part (13) of the first buffer zone (BF1)).

The above-mentioned water permeable part (20D) of the first partition wall (20) has a total water permeability between the total water permeability of the transit system (15) and the total water permeability of the second part (13) of the first buffer zone (BEI). The total water permeability of the water permeable part (20D) of the first partition wall (20) is being measured after the scaling of the transit system (16) and the filling of the second buffer zone (BF2) up to the second exit level (P2), with an empty first buffer zone (BF1), and afterwards through the determination of the water quantity that flows through the partition wall (20) of the second buffer zone (BF2) in 30 seconds to the first buffer zone (BF1).

In the second implementation form, the water of the first buffer zone (BF1) flows partially through the water permeable part of the partition wall (20) at a water level which is under the water level (P1) of the exit opening (21).

Fig 9 is a top view of a third implementation form of a water tank, in accordance with the invention, which is similar to the implementation forms of Fig 1 and Fig 7.

In the third implementation form the water tank (WT) comprises a second partition wall (30) in order to define a sedimentation zone (BZ) in the water tank (WT), whereby the water tank (WT) has an inlet (31) in order to let the polluted water or rainwater to flow in the sedimentation zone (BZ), in which the second partition wall (30) comprises an overflow system (32) that forms the inlet system (2) in its turn, for the first buffer zone (BF1).

The sedimentation zone (BZ) contains a flexible water permeable filter container (40), which is removably mounted in the sedimentation zone (BZ).

The flexible water permeable filter container (40) has a bottom (40B) and at least a side wall (40C) with a free upper edge (40D) whereby the side wall has an upper part (40C1) along the upper edge (40D), whereby the above-mentioned upper part (40C1) contains at least a side wall (40C) with a water permeability that is greater than the water permeability of the bottom (40B) and of the part (40C2) of at least a side wall (40C) that is located adjacent to the bottom (40B).

The upper edge (40D) of at least the side wall of the filter container is located on the level (P3) that is higher than the inlet level (PO).

The sedimentation zone (BZ) forms a third buffer zone for the water tank. The filter container (40) can be equipped with a cover or a float (40F) in order to avoid liquids or particles with a density of less than 1 kg/litre to flow above the top of the upper edge (40D) of the container. The container can be supported by a grid (41), so that the bottom (40B) of the container (40) is spaced from the bottom (10) of the tank.

The invention relates as well to a water installation which comprises (a) a water tank, in accordance with the invention, and (b) a sedimentation tank that is provided with an inlet (60) in order to collect water and with an exit pipe (61) to drain the water from the sedimentation tank in the first buffer zone (BF1) of the water tank through the inlet system (2).

The invention further relates to the use of the water tank, in accordance with the invention along the water stream or sewage system, or canal, or river, in order to buffer polluted water or rainwater before the water will partially run into the water stream or sewage system, or canal, or river, whereby the water is being collected in the first buffer zone (BF1), before it will partially flow to second buffer zone, whereby the water of the first buffer zone (BF1) can flow through the second water permeable porous concrete part (13) of the bottom (10) in the ground layer under the bottom of the water tank, while the water that flows in the second buffer zone (BF2) is being drained through transit system (15) in the water stream or sewage system, or canal, or river. In the third implementation form, the water permeable filtering system (40) comprises at least: -at least partially flexible water permeable container (40) which is removably mounted in the tub (1), whereby the container (40) has at least a top opening (400), as well as at least partially water permeable bottom (40B) and at least partially water permeable side wall (40C) in order to define an inner volume (BV) for the purpose of the collection of solid particles (D) with a size of 1 mm or more, whereby the water permeability of at least partially water permeable bottom (40B) and of at least partially water permeable side wall (40C) is being adjusted to prevent the passing of solid particles (D) with a size of 1 mm or more.

The tub (1) of the water tank, in accordance with the invention, is provided with a support system (80) for the at least partially flexible water permeable container (40), which makes the bottom (40B) of the at least partially flexible water permeable container (40) to be spaced from the bottom (90) of the sedimentation zone (BZ), in order to form a free zone (50) between the bottom (10) of the sedimentation zone and the bottom (40B) of at least partially flexible water permeable container (40), so that at least a part of the filtered water (WF) can he collected. The support system of the container (40) has for example, a support grid (41) and outriggers (42).

The water tank, in accordance with the third implementation form has a straightforward design, so that it is easy to use and that the plastic particles also can be removed easily in a removable container, without the risk of loss of plastic particles that are collected in the container.

The water tank (WT) is equipped with a cover (16) (for example, concrete cover), which ensures that it has at least a utility access hole (53) that has been resized in order to accommodate the vertical lifting of at least partially flexible water permeable container (40) from outside the tub. In this way a container (40) with waste particles (D) can be easily replaced by an empty container. Thus, there is no loss of time in the water treatment.

The at least partially flexible water permeable container (40) is for example a bag, such as a sandbag or a "big bag" of 1 m3 or more (for example a bag, that is usually intended for sand transportation), with the inner volume (BV) that contains a substantially square section. The bag or big bag (40) has a substantially square top opening (400), where the top opening (400) is associated with at least two bands, in which each band stretches between two corners of the substantially square opening (400). Each band can therefore achieve a connection between two corners of the top opening (400).

The water tank of the invention can be placed in ditches, canals, etc, for controlling the water flow in said ditches or canals, while enabling passages of vehicles, people and bikes on the cover of said water tanks.

Claims

CLAIMSI. Water tank (WT) to be placed at least partly in the ground or soil, said water tank having at least the capacity of treatment of polluted water or rainwater (W1) that is substantially free from solid particles with the density greater than 1.1 kg/litre, whereby the water tank (WT) is at least provided with: -a tub (1) with a bottom (10) adapted to be in contact with the ground and with at least one side wall (11a, 1lb, 11c, Ild) adapted to be at least partly in contact with the ground or soil or layer thereof, -a first partition wall (20) which divides the water tank (WT) at least into first buffer zone (BF1) with a first water buffer volume of at least 500 litres, and a second buffer zone (BF2) with a second water buffer volume of at least 500 litres, whereby the first buffer zone (BF1) is provided with an inlet system (2) through which the polluted water or rainwater can flow in the first buffer zone (BF1) above a minimum inlet level (P0), in which the first partition wall (20) is provided with a first discharge system (21) through which water can flow from the first buffer zone (BF1) to the second buffer zone (BF2).whereby the discharge system (21) is located on a first exit level (P1) under the inlet level (PO) of the first buffer zone (BF1), whereby the second buffer zone (BF2) is provided with a second discharge system (3) through which water of the second buffer zone (BF2) can flow outside of the second buffer zone (BF2), whereby the second discharge system (3) is located on a second exit level (P2), which is located under the first exit level (P1), whereby the bottom (10) of the water tank (WT) which is located in the first buffer zone (BF1) is divided into (a) a first not water permeable concrete part (12) with a first not porous concrete upper surface (12A) that is facing the first buffer zone (BF1), whereby no water can flow from the first buffer zone (BF1) through the said first not water permeable concrete part (12) towards the ground or soil, and (b) a second water permeable porous concrete part (13) adapted for the flow of water from the first buffer zone (BF1) through the said second water permeable porous concrete part (13) towards the ground or soil, said second water permeable porous concrete part (13) having a porous concrete upper side (13A) that is facing the first buffer zone (BF1) and that is located at least 10 cm above the first concrete not porous upper surface (12A), whereby the porous concrete upper side (13A) of the second part (13) has a surface facing the first buffer volume of at least 200 cm2, whereby the second buffer zone (BF2) is provided along its bottom with a water drainage braking system (15) that comprises and/or is provided with a transit system (16) produced at least from a porous concrete, said transit system (16) defining an inner chamber (17) in order to collect water from the second buffer zone (B P2) flowing through the porous concrete of the transit system (16), in which the transit system (16) comprises a discharge system or discharge means (18) for the disposal of water that flows in the inner chamber (17) through the porous concrete of the transit system (16), whereby the transit system (16) produced at least from a porous concrete comprises an upper section (16A) made from a porous concretewith an upper surface of at least 100 cm2 that is located at least 100 cm (I-I) under the second exit level (P2), whereby at least the upper section (16A) produced at least from a porous concrete of the transit system (16) is being produced from a hardened porous water-draining concrete, that is being produced by hardening a mixture of at least cement, aggregates with particle size of 6 mm to 14 mm, and water in order to reach an open-pore volume of 8 to 12% in the hardened porous water-draining concrete, in which the hardened porous water-draining concrete has a water permeability of 0.05 litre/m2/s to 5 litre/m2/s, preferably of 0.1 litre/m2/s to 3 litre/m2/s, and most preferably between 1.1 to 1 litre/m2/s, whereby the said water permeability of the hardened porous water-draining concrete is measured by the filling of the second buffer zone (13F2) with water reaching the second exit level (P2) with an empty inner chamber (17) for the transit system (16), and afterwards by the determination of the water quantity that flows through the porous concrete of the transit system (16) and its upper section (16A) produced from porous concrete, in 30 seconds within the inner chamber (17) of the transit system (16).
2. Water tank according to claim 1, characterized in that the second water permeable porous concrete part (13) has a water permeability of 1 litre/m2/s to 10 litre/m2/s, preferably of 2 litre/m2/s to 8 litre/m2/s, and ideally between 3 to 6 litre/m2/s, whereby said water permeability of the second water permeable porous concrete part (13) is measured by the filling of the first buffer zone (BF1) with water reaching the first exit level (P1) with an empty collecting chamber (LO) under the second part (13), and afterwards by the determination of the water quantity that flows through the second part (13) in 30 seconds within the collecting chamber (LO).
3. Water tank according to claim 1 or 2, characterized in that the total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is greater than the total water permeability of the upper section (16A) of the transit system (16), whereby the total water permeability of the second part (13) of the first buffer zone (BF1) is measured by the filling of the first buffer zone (BF1) with water reaching the first exit level (21) with an empty bottom collecting chamber (LO) under the second part (13) and afterwards by the determination of the water quantity that flows through the second part (13) in 30 seconds within the bottom collecting chamber (LO), while the total water permeability of the transit system (16) is measured by the filling of the second buffer zone (BF2) with water reaching the second exit level (P2) with an empty inner chamber (17) for the transit system (16), and afterwards through the determination of the water quantity that flows through the porous concrete of the transit system (16) and its upper section (16A) produced from the porous concrete in 30 seconds within inner chamber (17) of the transit system (16).
4. Water tank according to the preceding claim, characterized in that the total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is at least two times greater than the total water permeability of the transit system (16).
5. Water tank according to the preceding claim, characterized in that the total water permeability of the second part (13) of the bottom of the first buffer zone (BF1) is between 3 to 10 times greater than the total water permeability of the transit system (16).
6. Water tank according to any one of the preceding claims, characterized in that the second part (13) of the bottom of the first buffer zone (BF1) forms a protrusion (13U) with respect to the upper surface (12A) of the first part (12) of the bottom of the first buffer zone (BF1).
7. Water tank according to the preceding claim, characterized in that the protrusion (13U) has an elongated shape with a substantially horizontal axis (13X) and with a rectangular or trapezoidal section in a plane perpendicular to the substantially horizontal axis (13X).
8. Water tank according to the preceding claim, characterized in that the protrusion (13U) has a trapezoidal section in a plane perpendicular to the substantially horizontal axis (13X).
9. Water tank according to the preceding claim, characterized in that, with respect to the the first part (12) of the bottom of the first buffer zone (BF1) in horizontal position, the protrusion (13U) has (a) two inclined side surfaces (13F, 130) and (b) a substantially horizontal upper surface (13A) which extends between the upper edges (13H, 131) of the two inclined side surfaces (13F, 130), whereby the inclination of both inclined side surfaces (13F, 130) is such that along a vertical section perpendicular to the substantially horizontal axis (13X), the width (B1) of the trapezoidal section along the substantially horizontal upper side (13A) of the protrusion (13U) is smaller than the width (B2) of the trapezoidal section along the horizontal plane of the upper surface (12A) of the first part (12).
10. Water tank according to at least claim 3, characterized in that the first partition wall (20) comprises a water permeable part (20D) that is produced at least partially from water permeable concrete, whereby water can flow between the first buffer zone (BF1) and the second buffer zone (BF2) through the above-mentioned water permeable part (20D) of the partition wall (20), in which said water permeable part (20D) of the first partition wall (20) is at least partially located under the second exit level (P2), whereby the above-mentioned water permeable part (20D) of the first partition wall (20) has a total water permeability between the total water permeability of the transit system (16) and the total water permeability of the second part (13) of the first buffer zone (BF1), whereby the total water permeability of the water permeable part (20D) of the first partition wall (20) is being measured after the sealing of the transit system (16) and the filling of the second buffer zone (BF2) up to the second exit level (P2), with an empty first buffer zone (BF1), and afterwards through the determination of the water quantity that flows in 30 seconds through the partition wall (20) of the second buffer zone (BF2) to the first buffer zone (BF1).
11. Water tank according to any one of the preceding claims, characterized in that the transit system (16) comprises a pipe (18) that is connected to the inner chamber (17) and that runs through a wall (11d) of the water tank (WT), whereby said pipe (18) is adapted for the flow of water from the inner chamber (17) outside of the water tank (WT).
12. Water tank according to any one of the preceding claims, characterized in that the water tank (WT) comprises a second partition wall (30) in order to define a sedimentation zone (BZ) in the water tank (WT), whereby the water tank (WT) contains an inlet (31) in order to let the polluted water or rainwater to flow in the sedimentation zone (BZ), in which the second partition wall (30) comprises an overflow system (32) that forms the inlet system (2) for the first buffer zone (BF1).
13. Water tank according to the preceding claim, characterized in that the sedimentation zone (BZ) comprises a flexible water permeable filter container (40), which is removably mounted in the sedimentation zone (BZ).
14. Water tank according to the preceding claim, characterized in that the flexible water permeable filler container (40) that has a bottom (40B) and at least one side wall (40C) with a free upper edge (40D), whereby the at least one side wall has an upper part (40CI) along the upper edge, whereby the above-mentioned upper part (40C1) of the at least one side wall (40C) has a water permeability that is greater than the water permeability of the bottom (40B) and than the water permeability of a part (40C2) of the at least one side wall (40C) that is located adjacent to the bottom (40B).
15. Water tank according to the preceding claim, characterized in that the upper edge of the at least one side wall (40C) is located on the level, which is higher than the inlet level (PO).
16. Water tank according to any one of the preceding claims, characterized in that the water tank is provided with amovable cover (50) with at least a utility access hole or manhole (51, 52, 53).
17. Water installation that comprises at least (a) a water tank according to any one of the preceding claims with a water inlet system (2) and (b) a sedimentation tank (BZT) that is provided with (bl) an inlet (60) in order to collect water and (b2) an exit pipe (61) to direct or drain water from the sedimentation tank (BZT) in the first buffer zone (BF1) of the water tank through the water inlet system (2).
18. The use of a water tank according to any one of the preceding claims 1 to 16, along a water stream or sewage system, or canal, or river, in order to buffer polluted water or rainwater before the water will partially run into the water stream or sewage system, or canal, or river, whereby the water is being collected in the first buffer zone (BFI), before it will partially flow to the second buffer zone, whereby water of the first buffer zone (BF 1) can flow through the second water permeable porous concrete part (13) of the bottom (12) at least in the ground or soil layer under the bottom of the water tank, while water that flows in the second buffer zone (BF2) is being drained through transit system (16) in the water stream or sewage system or canal, or river.