NL2020867B1 - A separation device, and a method of treating water comprising solids - Google Patents

Abstract

A separation device for treating water comprising solids, said solids having a density lower than water, comprises a container with a lumen 5 for separation based on density. To reduce the load of solids in the water for example to reduce the risk of the solids ending up in the environment, the device comprises — a dividing wall comprising a screen for filtering water, said dividing wall dividing the lumen of the container in an upstream first 10 space and a downstream second space, — in the first space, a sedimentation buffer for dense solids and flotation buffer for floating solids, and — a separation zone in an intermediate portion of the first space located between the sedimentation buffer and the flotation buffer for 15 allowing the passage of water from the inlet to the outlet via the screen.

Description

NL B1 2020867

(2?) Aanvraagnummer: 2020867 © Aanvraag ingediend: 3 mei 2018 (© Afsplitsing van aanvraag , ingediend (30) Voorrang:

(7) Aanvraag ingeschreven: 12 november 2019 (43) Aanvraag gepubliceerd:

47) Octrooi verleend:

november 2019 © Octrooischrift uitgegeven:

november 2019 © 2020867 © B1 OCTROOI © Int. CL:

B01D 21/02 (2018.01) C02F 1/24 (2018.01) B03B

5/28 (2018.01) © Octrooihouder(s):

AFM Groep B.V. te Mijdrecht © Uitvinder(s):

Michel Arne Pieke te Mijdrecht

Christiaan Jozef Beeren te Riemst (BE) © Gemachtigde:

ir. W.J.J.M. Kempes te Hilversum

54) A separation device, and a method of treating water comprising solids )57) A separation device for treating water comprising solids, said solids having a density lower than water, comprises a container with a lumen for separation based on density.

To reduce the load of solids in the water for example to reduce the risk of the solids ending up in the environment, the device comprises

- a dividing wall comprising a screen for filtering water, said dividing wall dividing the lumen of the container in an upstream first space and a downstream second space,

- in the first space, a sedimentation buffer for dense solids and flotation buffer for floating solids, and

- a separation zone in an intermediate portion of the first space located between the sedimentation buffer and the flotation buffer for allowing the passage of water from the inlet to the outlet via the screen.

Dit octrooi is verleend ongeacht het bijgevoegde resultaat van het onderzoek naar de stand van de techniek en schriftelijke opinie. Het octrooischrift komt overeen met de oorspronkelijk ingediende stukken.

A separation device, and a method of treating water comprising solids

The present invention relates to a separation device for treating water comprising solids, said solids having a density lower than water, the device comprising a container comprising

- a bottom and side walls providing a lumen for holding water,

- an inlet for supplying water comprising solids to the lumen of the container,

-· an outlet for discharging treated water from the lumen;

said container further comprising

- a sedimentation buffer for holding sedimented solids, said sedimentation buffer being arranged in a bottom portion of the lumen, and

- a flotation buffer for holding floating solids, said flotation buffer arranged in an upper portion of the lumen.

US4849116 discloses an apparatus for separating plastic solids (particulate material) using water, wherein the solids may be more dense or less dense than the water.

The apparatus is not very suitable for handling large volumes of water containing relatively low amounts of solids.

To reduce the load of solids in the water, for example to reduce the risk of the solids ending up in the environment, it is desirable to have a device for treating a flow of water that may contain relatively low amounts of solids so as to result in water having a reduced load of said solids, which device requires a reduced amount of effort for operation thereof.

To this end, a separation device according to the preamble is characterized in that the container comprises

- a dividing wall comprising a screen for filtering water, said dividing wall dividing the lumen of the container in an upstream first space and a downstream second space, wherein

- the inlet is upstream of the screen, and

- the outlet is downstream of the screen;

- the sedimentation buffer being arranged in a bottom portion of the first space, and

- the flotation buffer for holding floating solids is arranged in an upper portion of the first space, and

- a separation zone in an intermediate portion of the first space located between the sedimentation buffer and the flotation buffer for allowing the passage of water from the inlet to the outlet via the screen .

Such a device can be used to separate solids from water wherein the amount of water comprising solids is much more than the volume of the container. The water will pass through the first space and any relatively dense solids will settle and end up in the sedimentation buffer whereas relatively less dense solids will be collected in the flotation buffer. Solids of the latter type may be saw dust, rubber granulate, plastic granulate etc. The risk of the screen being clogged by solids is reduced because the separation of solids takes place at least in part before the water reaches the screen. Thus, the screen in effect serves as a safety device for solids that do reach the screen. The device according to the invention also allows solids to be separated that are smaller than the size of the screen, except that for such particles the screen doesn't act as a fail safe device.

In a device according to the invention, the dividing wall will divides the lumen with a vertical component.

The flow path of water through the first space will have a predominantly horizontal component, with rising and/or settling of particles taking place in a direction transverse to the flow path. Thus the water is passed along the buffers in a substantially horizontal direction. The predominantly horizontal transport of water is typically over at least 1 m, preferably at least 2 m and more preferably at least 3 m.

Preferably at least one of the inlet and the outlet is provided in a sidewall, and more preferably both are provided in a sidewall, which allows the device according to the invention to be used in line with a conduit such as a drainage conduit. This allows the device to perform the treatment passively, more in particular without a pump for transporting the water through the device.

The device according to the invention will typically not need mechanical operation until a buffer needs to be emptied and/or the screen is clogged to an undesirable extent and requires cleaning or replacement.

Typically the cross-sectional area of the first space transverse to the flow path will be at least 5 times the cross-sectional area of the inlet, more preferably at least 12 times, and most preferably at least 30 times. Thus the flow rate of the water through the separation zone is reduced and the time available for solids to rise is increased.

According to a favourable embodiment, the sedimentation buffer is located lower than the screen.

This reduces the risk of sedimented solids from being entrained by a flow of water from the first space to the second space, which could result in clogging of the screen. This may reduce the frequency with which the screen will have to be cleaned.

According to a favourable embodiment, the upper edge of the dividing wall is above the upper edge of the outlet.

Thus the risk can be reduced that in case of varying water levels in the container water comprising solids spills over the dividing wall instead of passing the screen.

According to a favourable embodiment, the container comprises a dividing baffle dividing the flotation buffer in an upstream first flotation buffer and a downstream second flotation buffer.

This helps to prevent that solids captured in the first flotation buffer are entrained by water flowing from the inlet to the outlet to reach the screen where they could result in clogging of the screen. Typically the dividing baffle will extend between opposite sidewall portions of the container.

The dividing baffle will extend downward and its lower end will be higher than the separation buffer.

According to a favourable embodiment, the sedimentation buffer comprises an upstream end and a downstream end, and the dividing baffle of the flotation buffer is upstream of the downstream end.

Thus a local bottleneck in the flow path of the water in the first space is avoided or reduced. A bottleneck causes a local acceleration of the velocity of the water moving from the inlet to the outlet, which could thus entrain solids more easily. By having the dividing baffle upstream of the downstream end of the sedimentation buffer, this risk is reduced and hence the risk of clogging of the screen .

According to a favourable embodiment, a guiding baffle is provided in front of and transverse to the inlet.

This reduces the flow speed of the water and results in a more laminar flow, reducing the risk of currents with relatively high speed that could entrain solids from the sedimentation buffor and/or the flotation buffer and/or also reduces the risk of water passing between the sedimentation zone and the flotation buffer too quickly, which would result in premature clogging of the screen.

According to a favourable embodiment, the screen is a concave screen with respect to the first space.

This has been found to result in the least maintenance necessary due to clogging of the screen.

According to a favourable embodiment, the screen is arranged with a positive inclination from a horizontal plane in direction of the flow path of water through the device at the location of the screen.

Thus the flow velocity of water passing through the screen can be relatively low, reducing the risk of clogging. Also, this allows the surface area to be relatively large even larger than the cross-sectional area perpendicular to the flow path of water through the first space. Positive inclination means that an upper section of the screen is relatively far from the inlet and a lower section of the screen is relatively close to the inlet.

According to a favourable embodiment, the flotation buffer is provided with a float for indicating a load of floating solids in the flotation buffer.

A float can reliably indicate the thickness of the layer of floating solids in the flotation buffer.

Finally, the present invention relates to a method of treating water for removing solids from a flow of water, wherein a separation device according to any of the claims 1 to 9 is used, the method comprising the steps of:

- supplying water comprising solids having a density lower than water via the inlet to the first space of the container,

- performing a density separation in the first space, wherein floating solids are received in the flotation buffer and any sedimenting solids are received in the sedimentation buffer;

- passing of water subjected to the density separation through the screen to the second space, and

- discharging treated water from the second space via the outlet.

Thus solids can be removed effectively and in a simple manner.

This method is in particular useful if the water is rain water contaminated with solids. Rain water will be received intermittently, that is, after a period of rain, and with the method according to the invention it is not necessary to operate a pump to pass the water through the device.

According to a favourable embodiment, the method comprises the step of removing of at least one of i) sedimented solids from the sedimentation buffer and ii) floating solids from the flotation buffer .

Thus they can be safely disposed off, and the device is ready for (passive) operation.

According to a favourable embodiment, the solids comprise plastic solids .

This is an important application of the method according to the invention.

The present invention will now be illustrated with reference to the drawing where

Fig. 1 shows a perspective top view on a separation device;

Fig. 2A to Fig. 2C show cross-sectional views through the separation device of Fig. 1; and

Fig. 3 shows a perspective view on a mounting frame for screens for the device according to Fig. 1.

Fig. 1 shows a perspective view on a separation device 100 for separating solids from a flow of water, for example plastic particles and sand entrained by rain water.

The device 100 comprises a container 101 which container 101 comprises a bottom 110, side walls 120 defining a lumen 130 for water.

The side walls 120 are provided with an inlet 121 for supplying water comprising plastic solids to the lumen 130 of the container 101. The side walls also comprise an outlet 122 for discharging treated water from the lumen 130.

The container 101 comprises a dividing wall 150 comprising a plurality of screens 151 for filtering water flowing from the inlet 121 to the outlet 122. The screens 151 are mounted on a frame 152. Advantageously a profile of resilient material is provided to seal the frame 152 against the side walls 120. The dividing wall 150 divides the lumen 130 of the container 101 in an upstream first space 130' and a downstream second space 130.

A guiding baffle 170 is provided in front of the inlet 121. This reduces the speed of the water entering the lumen 130.

It is possible to supply the water to be treated via the top which may serve as the inlet. However, this is more likely to induce eddies that reduces the effectiveness of the separation in the first space 130'.

The device 100 comprises an access opening 190, the role of which will be elucidated later.

Fig. 2Ά to Fig. 2C show cross-sectional views through the separation device 100 of Fig. 1, except that the screens 151 are not shown .

The device 100 comprises a sedimentation buffer 220 for receiving sedimenting solids, said sedimentation buffer 220 being arranged in a bottom portion of the lumen 130. The sedimented solids will typically be sand and/or plastic particles having a density higher than water.

The device 100 also comprises a flotation buffer 240 for receiving rising solids (plastic particles having a density lower than that of water). The flotation buffer 240 arranged in an upper portion of the lumen 130. In the embodiment shown here a dividing baffle 241 is provided dividing the flotation buffer 240 in an upstream first flotation buffer 240' and a downstream second flotation buffer 240. Particles in the first flotation buffer 240' are not likely to be entrained by water flowing from the inlet 121 to the outlet 122 and thus not likely to reach the screen 151 where they could result in clogging or, if they are smaller than the openings in the screens 151 in being passed to the outlet 122.

Between the sedimentation buffer 220 and the flotation buffer 240 there is a separation zone 250. Relatively dense particles settle into the sedimentation buffer 220 and relatively less dense particles rise into the flotation buffer 240, and water having a reduced load of solids is passed to and through the screens 151 of the dividing wall 150 .

The dividing wall 150 is a concave dividing wall 150, here a parabolic dividing wall 150, which affords a large surface area of screens 151 and hence a low flow speed through the screens 151. This helps to reduce the risk of clogging of the screens 151. Also, with the inlet 121 in the sidewall 120, the device 100 is very suitable to be integrated in a rain water drainage system, and does not require a pump for operation until the moment that solids are extracted from the device 100.

To indicate the level of solids in the flotation buffer 240, a float 180 is provided which will sink deeper the more the flotation buffer 240 is filled.

Fig. 3 shows a perspective view on the mounting frame 152 suitable for mounting screens 151 for the device 100 according to Fig. 1. The container 101 will typically be made of concrete or plastic, and the frame 152 will be placed in the container 101.

Should the screens 151 need cleaning, personnel can enter the container via the access opening 190. Cleaning may be done using a 10 high-pressure hose from the backside of the screens 151.

A device 100 according to the present invention can be modified with in the scope of the appending claims in many ways. For example, it may be provided with a cover.

Claims (12)

Conclusions A separation device (100) for treating water comprising solid particles, wherein the solid particles have a density lower than water, the device (100) comprising a container (101) comprising the following - a bottom (110) and side walls (120) providing a lumen (130) for holding water, - an inlet (121) for supplying water comprising solid particles to the lumen (130) of the container (101), - an outlet (122) for discharging treated water from the lumen (130); wherein the container further comprises the following - a sedimentation container (220) for holding sedimented solid particles, the sedimentation buffer (220) being in a lower portion of the lumen (130), and - a flotation buffer (240) for holding floating solid particles, the flotation buffer (240) being located in an upper portion of the lumen (130); characterized in that the holder (101) comprises the following: - a partition wall (150) comprising a strainer (151) for filtering water, the partition wall (150) containing the lumen (130) of the container (101) in an upstream first space (130 ') and a downstream second space (130 ") wherein the inlet (121) is upstream of the screen (151), and the outlet (122) is downstream of the screen (151); - the sedimentation buffer (220) is located in a lower part of the first space (130 "), and - the flotation buffer (240) for holding floating solid particles is located in an upper portion of the first space (130 "), and - a separation zone (250) in an intermediate portion of the first space (130 ') located between the sedimentation buffer (220) and the flotation buffer (240) for passage of water from the inlet (121) to the outlet (122) through the screen (151). The separation device (100) of claim 1, wherein the sedimentation buffer (220) is then the sieve (151). The separation device (100) according to claim 1 or 2, wherein the upper edge of the separation wall (150) is above the upper edge of the outlet (122). The separator (100) of any preceding claim, wherein the holder (101) comprises a partition (241) that divides the flotation buffer (240) into an upstream first flotation buffer (240 ") and a downstream second flotation buffer (240"). The separator (100) of claim 4, wherein the sedimentation buffer (220) comprises an upstream end and a downstream end, and wherein the partition (241) of the flotation buffer (240) is upstream of the downstream end. The separation device (100) according to any one of the preceding claims, wherein a guide partition (170) is provided for and transversely of the inlet (121). The separation device (100) according to any of the preceding claims, wherein the screen ((151) is a concave screen (151) with respect to the first space (130 "). The separation device (100) according to any preceding claim, wherein the screen (151) is arranged with a positive slope from a horizontal plane in the direction of the flow path of water through the device (100) at the location of the screen (151) . The separation device (100) according to any of the preceding claims, wherein the flotation buffer (240) is provided with a floating body (180) for indicating a load of floating solid particles in the flotation buffer (240). A method of treating water for removing solid particles from a water stream, wherein a separation device (100) according to a -10 of claims 1 to 9, wherein the method comprises the following steps: - supplying water comprising solid particles with a density lower than that of water via the inlet (121) to the first space (130 ") of the container (101), - performing a density separation in the first space (130 '), wherein floating solid particles are included in the flotation buffer (240) and any sedimenting solid particles are included in the sedimentation buffer (220); - carrying water through the screen (151) to the second space (130 ") which has undergone the density separation, and - discharging treated water via the outlet (122) from the second space (130 "). The water treatment method of claim 10, wherein the method comprises the step of removing at least one of i) sedimented solid particles from the sedimentation buffer and ii) floating solid 15 particles from the flotation buffer (240). A method of treating water according to any one of claims 10 or 11, wherein the solid particles comprise plastic solid particles. 1/4