FR2826952A3 - Used water treatment or purification unit has number of holders for aerobic bacteria that can be introduced through manhole - Google Patents

Abstract

The unit, having a preferable volume of 3 - 10 cu m, consists of a chamber (1, 2, 3) made from concrete and set below ground level. It has a top (4) with a manhole (5) and cover (6), and a number of holders (16) for aerobic bacteria that can be introduced through the manhole and moved to the required position inside the chamber. The unit, having a preferable volume of 3 - 10 cu m, consists of a chamber (1, 2, 3) made from concrete and set below ground level. It has a top (4) with a manhole (5) and cover (6), and a number of holders (16) for aerobic bacteria that can be introduced through the manhole and moved to the required position inside the chamber. Once inside the chamber the aerobic bacteria holders are positioned between vertical walls, where they are accessible to oxygen from an aerator with a tube (17) and membrane (18) located between the holders and the bottom of the chamber. The holders are made from a material with a density of less than 1, and they are kept below the level of the manhole cover by a separator.

Description

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The present invention relates to a water purification tank or (used) water treatment tank.

Small water treatment or purification tanks with a volume of 1 to 50 m3 are increasingly used to purify water discharges from houses located in areas outside the legal areas provided for habitat or specific neighborhoods too far from the central treatment plant. In fact, the use of micro-wastewater treatment plants is compulsory in Flanders for single-family homes or habitable entities that are not connected to the sewer pipes or whose connection to the sewers is impossible or too expensive.

- un support pour des bactéries aérobies, et un système d'aération pour faire passer au moins de l'oxygène au travers du support, ledit support se trouvant dans une zone spécifique de la cuve. The known water purification tank comprises: - a tank, - a cover with a manhole which can be closed by means of closure,

a support for aerobic bacteria, and an aeration system for passing at least oxygen through the support, said support being in a specific zone of the tank.

The aeration system includes a porous membrane to allow the passage of oxygen or air from the bottom to the top of the bed of aerobic bacteria.

After a while, the membrane is damaged, so that all of the oxygen passes through a specific area of the reaction bed or so that substantially it does not enter the reaction bed. This causes a malfunction or work of the aerobic bacteria and therefore of the purification tank.

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The replacement of the defective membrane in the known tank requires the use of large machines, since the cover of the tank must be lifted, since afterwards the support with aerobic bacteria is lifted and that a new support with a new membrane is introduced in one piece into the tank.

In addition, afterwards the cover must be correctly placed to ensure sufficient closure.

In the tank according to the invention, the support consists of several packages or support assemblies, each package or support assembly having a shape adapted to allow the package or assembly to be introduced into the specific zone of the tank via the manhole. ; at least one package or support assembly introduced into the specific area being movable in the specific area of the tank.

For example, the holder has two packages or sets.

Preferably, the support consists of at least three packages or support assemblies (for example 4.5, 6 or even more than 6), of which at least two (preferably all) are movable in the specific area.

The specific zone is for example between two substantially vertical walls and / or between a wall and one or more walls of the tank, and / or several walls.

The aeration system has an aeration membrane which is located along the bottom of the specific area. The specific zone and / or the substantially vertical walls thereof comprise at least one support means for the packages or support assemblies so that a bottom zone is defined for the aeration membrane between the bottom and the packages or support assemblies, the bottom zone having a height which is greater than the total height or equivalent thickness or diameter of the aeration membrane. Thanks to the use of this support means, the flattening of the membrane by the weight of the packages or support assemblies with aerobic bacteria can be avoided.

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According to one embodiment, the packages or support assemblies are made of a material which has a density of less than approximately 1. The specific zone is provided with at least one means to prevent the packages or support assemblies from touching the cover, that the tank is filled with water.

According to a detail of an embodiment, the packages or support assemblies are interconnected by at least one means to avoid lateral movements of one package or assembly relative to another.

To facilitate the replacement of packages or assemblies, at least one package or support assembly is provided with an aeration tube, the latter being connected to the aeration membrane. Preferably, the aeration membrane is connected to a package or support assembly by a connection means so that the membrane is substantially horizontal in the specific area.

According to a particular embodiment, the connection means is adapted so that the membrane can be moved from a substantially horizontal position to a substantially vertical position during an upward movement of the package or support assembly by the hole d 'man.

According to one embodiment, each package or support assembly has a substantially parallelepiped shape with a cross section which is less than the opening of the manhole.

Other forms are possible for packages or sets.

According to a detail of a water purification tank according to the invention, the manhole is at least partially above the specific zone, preferably above a part thereof which is eccentric , preferably distant, from the vertical central axis of the specific area. The specific zone is defined between two vertical walls which extend into the tank and two side walls which extend between the two vertical walls. These side walls are preferably parts of the side or walls of the tank. The manhole is

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 then preferably above the specific zone at such a distance from a first side wall that a single package or support assembly (advantageously with the ventilation membrane) can be moved towards this first side wall to allow placement of packages or additional support assemblies in the specific area via the manhole (5).

The subject of the invention is also: a water purification process, in which a purification tank according to the invention is used and in which the packages or support assemblies carry aerobic bacteria to purify the water, and a method for replace the aeration membrane and / or one or more packages or support assemblies of a purification tank according to the invention, in which - the manhole is open, at least one package or support assembly is made free of other packages or support assemblies, - the released package or support assembly is removed from the tank through the manhole, - a new support package or assembly is placed in the specific area and - this new support package or assembly is connected to the others support packages or sets.

 Preferably, in the latter method, all the packages or support assemblies are removed from the tank through the manhole, before removing the aeration membrane.

 For example, several packages or support assemblies are introduced subsequently into the specific area, the first package or support assembly introduced into the specific area being provided with a substantially horizontal ventilation membrane.

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Details and characteristics of an embodiment will emerge from the following description, in which reference is made to the accompanying drawings.

In these drawings:
Figure 1 is a vertical sectional view of a tank according to the invention (with the cover in the open position);
Figure 2 is a top view of the tank (without cover) of Figure 1;
Figure 3 is a top view of the tank with the cover;
FIGS. 4A to 4F show the removal of carrier packages of bacteria;
FIGS. 5A to 5D show the placement of new carrier packages of bacteria in the tank; - Figures 6 to 9 are schematic views from above of possible embodiments of the tank according to the invention.

 The tank 1 comprises: a cylindrical tank with a side wall 2 and a bottom 3 (for example made of concrete); - a cover 4 which has a manhole 5; - a plate 6 for closing the manhole 5; two vertical partitions 7,8 which divide the tank into three zones or chambers, namely a decantation zone or chamber 9, a reaction zone or chamber 10 and a zone or chamber 11 according to (or post) decantation or decantation after reaction; - an inlet 12 for bringing the water (which must be purified) into the settling zone 9; - A passage (such as a tube) 13 for the supply of settling water from zone 9 to the reaction zone 10; - A passage 14 for the supply of water from the reaction zone 10 into the zone after decantation; - an evacuation 15 to allow the evacuation of purified water out of the chamber after decantation 11.

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The reaction zone 10 is an zone in which water is treated with aerobic bacteria and in which air is introduced to improve the treatment.

In this reaction zone, three parallelepipedal packets carrying bacteria 16A, 16B, 16C are placed. These packages serve as carriers for bacteria.

The package 16A is connected to an air line 17 and to an aeration membrane, the membrane being substantially horizontal in the tank. The membrane 18 has a sufficient length to obtain aeration of the three packages 16.

The water W circulates in the tank in the following manner: - between the inlet 12 and the passage 13 which is substantially the most distant from the inlet 12; between the passage 13 and the passage 14 which is substantially the most distant from the passage 13 (the passage 14 is preferably located in an area which is free of support and / or ventilation package); between passage 14 and outlet 15 which is substantially as distant from passage 14.

After the sewage or used water has passed through the settling or digestion or digestion zone (zone 9), the water flows by gravity into the compartment in which the fixed bed is located (zone 10). Organic waste is mineralized by the supply of oxygen via the aeration membrane (18, air coming for example from a silent compressor). This aerobic system releases a quantity of energy, which contributes to the metabolism and the development of colonies of specific bacteria which cling to the fixed bed. The aeration step can be continuous, substantially continuous or non-continuous. For example, the fixed bed is ventilated for specific periods of 5 to 20 minutes with intermediate breaks of 5 to 60 minutes of non-ventilation or poor ventilation.

The ventilation can optionally be controlled by computer.

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 The secondary sludge with the wastewater is then separated in the post-settling tank (zone 11). The purified water can then be discharged via the outlet 15 into surface water, into open ditches, etc.

The walls or partitions 7,8 are provided with profiles 20,21 serving as supporting elements for the packages or assembly 16. The height H of the profiles 20,21 is greater than the diameter of the membrane 18, so as to avoid the flattening of the membrane.

Since the packages or assemblies are made of a material having a density of less than 1, the partition 7 is provided in its upper part with profiles 22, 23. These profiles are spaced from each other by a distance at least equal to the width B of a packet 16. The upper part of the partition 7 which is located below the manhole 5 is free of profiles 22,23 over a length Bl, so that the placement of packages in the tank is possible. These flaps or sections 22, 23 serve as a means of preventing the packages 16A, 16C from touching the cover when the tank is filled with water. The package 16B is connected to the packages 16A and 16C by connection elements 24, whereby the package 16B also does not touch the cover when filling the tank of the tank with water.

The plate 6 is fixed on a protuberance 50 to ensure the closing of the opening 5. The protuberance 50 has a passage 51 for the introduction of an aeration duct 17 into the tank.

Steps for replacing the membrane will now be described.

The manhole 5 (see FIG. 4A-the cover is not shown, although the manhole 5 is drawn) is opened and the connection elements 24 are removed.

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 The package 16B which is under the manhole 5 is lifted to be withdrawn from the reaction zone 10 (see FIG. 4B).

The package 16C is then moved under the manhole 5 (see Figure 4C) and lifted (Figure 4D).

The package 16A which is then connected with the membrane to be replaced is then moved to be brought under the manhole 5. (see FIG. 4E) The package 16A is then lifted. During this upward movement, the membrane 18 touches the cover 4, whereby the means holding the horizontal membrane in the tank is broken, so that the membrane moves in a vertical position and so that the package 16A and the membrane can be removed from the tank (see Figure 4G).

To place new packages or assemblies 16 in the reaction zone 10, at least one package 16A is placed in the tank 1 with the membrane 18 in a substantially horizontal position. To introduce the membrane 18 into the tank 1 via the manhole 5, the package 16A is slightly inclined. As soon as the membrane 18 and the end of the package 16A are located in the reaction zone, the package 16A is straightened in the vertical position. The package 16A is then lowered into the tank until the end of the package is supported on the profiles 20, 21, so that the membrane extends between the support profiles 20, 21. The package 16A is then moved so that the package 16A is located under the profile 23 and so that new packages or assemblies can be introduced into the tank through the manhole 5. (see FIG. 5A) The package 16C is then lowered into the tank through the manhole 5 and moved below the profile 22 (see Figure 5B).

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Finally, the package 16B is lowered into the tank through the manhole 5 (see FIG. 5C). The packets are linked together by connection elements 24 (see FIG. 5D).

Packets 16A, 16B and 16C are shown in Figure 5E.

The tank 1 has for example a water treatment volume of between 1 and 25 m3, preferably from 3 to 10m3. The total height of the tank is for example less than 3 m, in particular between 1.5 m and 2.5 m.

Advantages of the tank in FIG. 1 are: - simple placement and easy replacement of the support packages and the aeration membrane.

- Compact system (concrete tank placed underground).

- Low difference in level between input and output.

 - Low energy cost.

- Low maintenance cost - Low investment costs - No odor problem - Possibility of partially replacing the fixed bed - Less earthwork required to replace the fixed bed - Possibility of extending the manhole with a nozzle to further reduce the earthwork to be carried out for the replacement of the fixed bed (16A, 16B, 16C).

Figures 6 to 8 are views of particular embodiments.

In Figure 6, the tank 1 is provided with a single inner wall 7 to define a reaction zone 10 and a settling zone 9 in the tank. A nozzle 100 then connects the reaction zone 9 of the tank 1 to a post-settling tank 101.

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In FIG. 7, the tank 1 has a single interior wall 8 to define a reaction zone 10 and a post-decantation zone 11 in the tank 1. A pipe 102 connects a decantation tank 103 with the reaction zone 10 of the tank 1.

traits interrompus dans les figures. e Dans la figure 9, la cuve 1 comporte deux parois 7,8 qui ne sont pas parallèles. In FIG. 8, the reaction zone 10 is defined in the tank 1, so that the tank 1 is connected to a settling tank 103 (via the tube 202) and to a post-settling tank 101 (via the tube 100). The manhole 5 is represented by

broken lines in the figures. e In Figure 9, the tank 1 has two walls 7,8 which are not parallel.

A package or support assembly 16A, 16B, 16C is a porous element allowing the passage of gas from top to bottom and the passage of liquid. Several packages or support assemblies are placed side by side to form the fixed bed. The packages or support assemblies advantageously have a height corresponding substantially to the height of the fixed bed.

Claims (15)

CLAIMS 1. Water purification tank comprising a tank (1,2, 3), a cover (4) with a manhole (5) which can be closed or closed by a closing means (6), a support (16) for aerobic bacteria, and an aeration system (17,18) for passing at least oxygen through the support (16), said support (16) being in a specific zone ( 10) of the tank, characterized in that the support (16) consists of several packages or support assemblies (16A, 16B, 16C), each package or support assembly (16A, 16B, 16C) having a shape adapted to allow the package or assembly to be introduced into the specific zone (10) of the tank via the manhole (5); at least one package or support assembly (16A, 16B, 16C) introduced into the specific zone (10) being movable in the specific zone (10) of the tank. 2. Purification tank according to claim 1, characterized in that the support consists of at least three packages or support assemblies (16A, 16B, 16C), at least two of which are movable in the specific zone (10) of the tank . 3. Purification tank according to claim 1 or 2, in which the specific zone (10) is located between two substantially vertical walls (7,8) and in which the aeration system comprises an aeration membrane (18) which is located along the bottom (3) of the specific zone (10), characterized in that the specific zone (10) and / or the substantially vertical walls (7,8) thereof comprise at least one means of support (20, 21) for the packages or support assemblies (16A, 16B, 16C) so that a bottom zone is defined for the ventilation membrane (18) between the bottom (3) and the packages or assemblies support (16A, 16B, 16C), the bottom zone having a height (H) which is greater than the total height or equivalent thickness or diameter of the aeration membrane (18). <Desc / Clms Page number 12> 4. Purification tank according to any one of the preceding claims, characterized in that the packets or support assemblies (16A, 16B, 16C) are made of a material which has a density of less than about 1, and in that the specific area (10) is provided with at least one means to prevent the packages or support assemblies (16A, 16B, 16C) from touching the cover (4). 5. Purification tank according to any one of the preceding claims, characterized in that the packages or support assemblies (16A, 16B, 16C) are interconnected by at least one means (24) to avoid lateral movements of one package or set compared to another. 6. Purification tank according to any one of the preceding claims, characterized in that at least one package or support assembly (16A) is provided with an aeration tube, the latter being connected to the aeration membrane . 7. Purification tank according to the preceding claim, characterized in that the aeration membrane (18) is connected to a package or support assembly (16A) by a connection means so that the membrane (18) is substantially horizontal in the specific area (10). 8. Purification tank according to the preceding claim, characterized in that the connection means is adapted so that the membrane (18) can be moved from a substantially horizontal position to a substantially vertical position during a movement towards the top of the package or support assembly (16A) through the manhole (5). 9. Aeration tank according to one of the preceding claims, characterized in that each package or support assembly (16A, 16B, 16C) has a substantially parallelepiped shape with a cross section which is less than the opening of the hole. man (5). <Desc / Clms Page number 13> 10. Aeration tank according to any one of the preceding claims, characterized in that the manhole (5) is at least partially above the specific zone (10), preferably above a part of the latter which is eccentric, preferably distant, with respect to the vertical central axis of the specific zone. 11. Purification tank according to the preceding claim, characterized in that the specific zone (10) is defined between two vertical walls which extend in the tank and two side walls which extend between the two vertical walls, and in that the manhole is above the specific zone at a distance from a first side wall such that a single package or support assembly can be moved towards this first side wall to allow the placement of packages or support assemblies additional (16B, 16C) in the specific area (10) via the manhole (5). 12. A method of water purification, in which a purification tank is used according to any one of the preceding claims and in which the packages or support assemblies (16A, 16B, 16C) carry aerobic bacteria. 13. Method for replacing the aeration membrane and / or one or more packages or support assemblies of a purification tank according to any one of claims 1 to 11, in which - the manhole (5) is open, - at least one package or support assembly (16B) is made free from the other packages or support assemblies, - the released package or support assembly (16B) is withdrawn from the tank through the manhole (5), - a new package or support assembly (16B) is placed in the specific zone (10) and this new package or support assembly is connected to the other packages or support assemblies. <Desc / Clms Page number 14> 14. Method according to the preceding claim, characterized in that all the packages or support assemblies (16A, 16B, 16C) are removed from the tank (1) through the manhole (5), before removing the membrane d ventilation (18). 15. Method according to the preceding claim, wherein several packages or support assemblies (16A, 16B, 16C) are introduced into the specific area (10), the first package or support assembly (16A) introduced into the specific area being provided with a substantially horizontal aeration membrane (18).