FR2952632A1 - Purification station for the treatment of wastewater, comprises vertically extending external wall, an inner wall defining an access volume partially contained in the volume defined by the external wall, and horizontal platforms - Google Patents

Abstract

The purification station comprises an external wall (12) closed on itself and extending vertically, an inner wall (13) defining an access volume partially contained in the volume defined by the external wall, and horizontal platforms arranged in the intermediate volume defined between the inner wall and the outer wall and defining a first level and a second level located above the first level. A part of the external wall extending to the upper end of the second level is buried in soil. Functional spaces are located at the lowest level of the station. The purification station comprises an external wall (12) closed on itself and extending vertically, an inner wall (13) defining an access volume partially contained in the volume defined by the external wall, and horizontal platforms arranged in the intermediate volume defined between the inner wall and the outer wall and defining a first level and a second level located above the first level. A part of the external wall extending to the upper end of the second level is buried in soil. Functional spaces are located at the lowest level of the station for receiving treatment facilities of wastewater to form a storm water basin (25), an aeration basin or a treated water tank. A bottom constituted by an invert unit is connected to the outer wall, and the storm water basin extends over the entire surface of the invert unit. The external wall has a first closed circular or oval curve in horizontal projection. The inner wall extends vertically, and has a second closed circular or oval curve in horizontal projection. The outer wall and inner wall are coaxial to each other, and one of functional spaces is defined by intermediate vertical walls defined in axial planes. The upper end of the external wall is located at the soil surface. The access volume extends above the soil surface. The upper end of the access volume is closed by a partly transparent structure. The functional spaces receive a facility including a grit chamber and a skimming tank for pretreatment of water and for membrane filtration of water.

Description

The present invention relates to a treatment plant for the treatment of wastewater. The known purification plants consist of a plurality of treatment plants arranged in series and borrowed in turn by the water to be treated. They conventionally comprise, upstream, a pre-treatment facility intended to eliminate the coarsest solid or particulate elements. Pretreatment generally involves rough preliminary purification of the raw water, using grids prohibiting the passage to the most voluminous detritus (this preliminary purification is commonly called "screening"). This operation can sometimes be supplemented by a finer sieving operation, using grids with bars of smaller spacing. The pretreatment also includes a grit removal and de-oiling-degreasing operation, intended to extract water sands, greases and floating materials such as hydrocarbons. This operation is carried out in a settling basin, in which the sands are recovered in the bottom, and the greases and floating materials are scraped on the surface. The pretreatment step is usually followed by biological treatment. In so-called "aeration basins" equipped with aerators, we develop aerobic bacteria that proliferate in the presence of oxygen. These microorganisms absorb pollutants dissolved in water, and in particular organic matter. In another large basin called clarifier, is then decanted by separating the treated water from the mass of the remaining bacteria. Because of the many facilities they include, conventional sewage treatment plants have a very large footprint, which requires them to be located at the end of collection systems and outside cities. Such removal entails high costs related to the length of the supply manifolds. In addition, the effluents treated in these stations are generally discharged directly into the natural environment, without being able to be exploited in ancillary applications such as municipal watering, cleaning of roads, etc., The present invention aims to propose a purification plant improved, can be integrated inside the cities, compact, and allowing an efficient treatment of waste water. This objective is achieved by means of a treatment plant for the treatment of wastewater according to the invention because it comprises an outer wall closed on itself and extending vertically, an inner wall defining a volume at least partially contained in the volume defined by the outer wall, a plurality of horizontal platforms disposed in the intermediate volume defined between the inner wall and the outer wall and defining at least a first level and a second level located above of the first level, and thanks to the fact that in addition, a part of the outer wall extending at least to the upper end of the second level, is buried in the ground, and a plurality of functional spaces for receive wastewater treatment facilities is spread over the first and second level. In this application, wastewater mainly includes domestic and industrial wastewater and possibly rainwater.

The fact that a part of the outer wall extending at least to the upper end of the second level is buried in the ground means that at least the first and second level of the treatment plant are located under the ground level. The treatment plant according to the invention is therefore at least partly and preferably completely buried. It can also include the number of levels in the basement desired. The wastewater treatment plant can thus occupy only a small area, harmonize with the urban environment and thus integrate in the heart of the cities and no longer outside of them. Advantageously, the treatment plant according to the invention can house all the facilities necessary for the treatment of wastewater. Thus, according to a preferred embodiment, the purification station houses at least one pretreatment plant including a preliminary purification unit (degrill) and a grit-de-oiling unit, an aeration tank and a treatment plant. libation water Ln IL, the treatment plant may also comprise a tarpaulin of treated water.

The installations can be divided according to the needs, on the different levels of the treatment plant. In particular, several basins can be arranged at different levels and thus be superimposed.

According to a preferred embodiment of the invention, a functional space, located at the lowest level of the treatment plant, is arranged to form a storm basin. This storm basin has the function of delaying the influx of rainwater into the sewerage network. It is particularly useful for absorbing precipitation peaks due to thunderstorms, particularly in urban areas where the soil waterproofing coefficient is important, and the risk of flooding, which is very high. Most often, the storm basin is independent and remote from the surrounding wastewater treatment plants. Unlike conventional installations of treatment plants, which are precisely sized according to the size of the city and the number of Equivalent-Inhabitants to be considered, a storm basin is sized according to rainfall data, watershed area, soil permeability, etc. In case of heavy rainfall, the volume of rainwater to be stored is often much higher than the volume of domestic or industrial wastewater produced at the same time. Usually, the dimensions of the storm basin are therefore greater than those, for example, the aeration basin of the treatment plant located in the same area. For this reason, it was considered to install the storm basin at the lowest level of the buried wastewater treatment plant. It is at this level, indeed, that the recovery of efforts is the most important. The thrust of the water on the side walls of the basin is taken up by the thrust of the earth on the outer face of the outer wall, and the weight of the water is supported by the bottom wall of the purification plant, which rests directly on the ground. According to one embodiment of the invention, the purification plant comprises a bottom consisting of a raft connected to the outer wall and the storm basin extends over the entire surface of this raft. In this way, the volume of the storm basin can be maximum.

According to the method of the invention, vertical intermediate walls are provided in the defined intermediate volume.

between the outer wall and the inner wall, and define functional spaces for receiving wastewater treatment plants. They can for example extend between two horizontal platforms. Thanks to these vertical intermediate walls, several functional spaces housing processing facilities, communicating or not between them, can be arranged on one and the same level of the treatment plant. According to one embodiment of the invention, the outer wall and the inner wall are coaxial and at least one functional space is delimited by vertical intermediate walls defined in axial planes. This configuration facilitates the organization of the space inside the treatment plant. According to one embodiment of the invention, at least one of the functional spaces is arranged to form a ventilation tank, and another functional space receives booster tanks of the aeration basin. For example, the aeration tank and the boosters can be located at the second level of the treatment plant and be adjacent. According to one embodiment of the invention, at least one of the functional spaces can be arranged to form a sheet of treated water. For example, this tarpaulin of treated water may be located at the second level of the treatment plant. According to one embodiment of the invention, at least one of the functional spaces receives water pretreatment facilities, in particular a grit chamber and a degreaser. These pre-treatment facilities may for example be located at a third level of the treatment plant. According to a preferred arrangement, at least one of the functional spaces receives membrane filtration installations of water. These advantageously replace the clarifiers used in conventional treatment plants, which are too large, unsuitable for their integration into a compact structure such as that of the present invention. In addition, the membrane filtration makes it possible to obtain a water of better quality, more pure than that obtained with usual dairifiers. According to an exemplary embodiment, these membrane filtrates of the water 1) are located at a trolsenle level of the purification station.

Other features and advantages of the invention will become apparent on reading the following description of exemplary embodiments of the invention given by way of illustration and not limitation. This description refers to the accompanying drawing sheets in which: Figure 1 is an axial sectional view of a purification plant according to the present invention, in the direction 1-1 of Figure 3; Figure 2 is an axial sectional view of the purification plant of Figure 1, in the direction II-II of Figure 3; Figure 3 is a radial sectional view of the purification plant of Figure 1, in the direction III-III; Figure 4 is a radial sectional view of the purification plant of Figure 1, in the direction IV-IV; and FIG. 5 is a radial sectional view of the purification plant of FIG. 1 along the V-V direction. A purification plant according to a preferred embodiment of the invention will now be described with reference to FIGS. 1 to 5. According to this embodiment, the purification station 10 is an underground structure, comprising an outer wall 12, of total height Hi taken in the vertical direction Y and whose outer face is in contact with the ground 11. In the example, the outer wall 12 is strictly vertical. According to alternative embodiments, it could also be chosen inclined by going flaring upwards or staggered. This outer wall 12 is made of concrete. It can be achieved by the technique of molded walls and earth moving within the wall thus obtained, by the so-called Berlin wall technique, by sheet piling systems or any other technique suitable for the realization of deep foundations. In the example illustrated, the upper end 12a of the outer wall 12 is located at the surface of the ground 22, which corresponds here to the natural terrain TN. As is more particularly apparent from FIGS. 3 to 5, the tile king has, in a horizontal plane, the shape of a circular circular smoke tip of diameter d1. This shape makes it possible to obtain a self-supporting structure which is more efficient in terms of the distribution of the forces As an alternative having similar advantages, and in particular depending on the topology of the site, the outer wall 12 can also have, In horizontal projection, an oval shape, however, the outer wall may also have any other suitable shape, for example rectangular or square.The structure also comprises a bottom wall 17, which may be constituted by a base connected sealingly In this way, a watertight box of diameter d1 and height H2 is formed by the outer wall 12 and the base 17. This box protects the buried wastewater treatment plant 10 from the groundwater. 1 and 2, the purification plant 10 further comprises an inner wall 13 extending vertically from the raft 17 to a height H3. H3 of the inner wall 13 is greater than the height H2 defined above. In this way, as indicated in FIGS. 1 and 2, the purification station extends above the surface of the ground 22, and the aerial part of the purification plant forms an entrance room, from which is accessible a spiral staircase 18 to access the various facilities housed in the treatment plant. In the example shown, the inner wall 13 is vertical and has, in horizontal projection, the shape of a second circular closed curve. In particular, as shown in Figures 1 and 2, the outer wall 12 and the inner wall 13 are coaxial, main axis A-A. Alternatively, the inner wall 13 could obviously take an oval shape or any other suitable form, for example rectangular or square. In addition, the outer wall 12 and the inner wall 13 may not be coaxial. The inner wall 13 defines between itself and the outer wall 12 an intermediate volume 40.

As shown in FIGS. 1 and 2, several horizontal platforms are arranged in the intermediate volume 40, defining several levels of the treatment plant. As illustrated in all the figures, these platforms are supported by a series of vertical columns. .

Cians nraie, ùiiL preiliiete pi iteiui-street 151, espucee of the raft 17 a distance HP, delimits with radier 17 prerrlier level 41, which corresponds to the lowest level of the purification plant. As illustrated in Figures 1 and 2, the first horizontal platform 151 forms a solid circular slab, pierced with one or more openings for the passage of conduits and pumping facilities.

An access volume 14 located above the platform 151 is delimited by the platform 151, on the one hand, and the inner wall 13, on the other hand. This access volume 14 is partly contained in the interior volume of the sealed box formed by the outer wall 12 and the raft 17, and it extends at its upper end 14a, above the surface of the ground 22. L Helical staircase 18 extends, from platform 151, over a large part of the height of the access volume 14. The upper end 14a of the access volume 14 can advantageously be closed by an at least partially transparent structure 15 In the example, this structure is a glass dome.

Alternatively, it can also take the form of a cone or a pyramid. Such a structure makes it possible to diffuse as much as possible of the natural light inside the purification plant, via the skylight constituted by the access volume 14, and thus to save energy. A second level 42, located above the first level 41, is defined between the first platform 151 and a second platform consisting of three platform portions 152a, 152b, 152c, slightly spaced apart in the vertical direction Y. Each of these Platform portions 152a, 152b, 152c have an annular sector shape, and the annular sectors thus formed are, in horizontal projection, complementary to one another. The portions of platforms 152a, 152b, 152c are, in the example, interconnected by vertical intermediate walls 20. Finally, a third horizontal platform 153, spaced from the floor 17 by a distance H2, delimits, between itself and the platform portions 152a, 152b, 152c, a third level 43. In the example, the third platform 153 consists of an annular slab extending horizontally from the upper end 12a of the outer wall to the internal wall 13 of the treatment plant. In the example, the third platform 153 is located at the surface of the ground 22.

In accordance with the present invention, a 1-calf horn corresponds to the Vespuce delimited by three platforms, each of which

these platforms extending, in horizontal projection, over the entire space defined between the outer wall 12 and the inner wall 13. As indicated above, a platform can indifferently consist of a single annular or circular portion , or a plurality of complementary platform portions. In the latter case, the platform may consist of any number of platform portions offset relative to each other in the vertical direction, and these platform portions may have any suitable shapes, allowing space to be modulated. as required. According to an alternative embodiment not shown, portions of intermediate horizontal platforms may further be provided between the platforms defining the levels of the purification plant, so as to form for example half-levels or quarter levels. In the exemplary embodiment illustrated, the purification plant 10 comprises only three levels 41, 42, 43. This example is however not limiting, and the number of levels of the station can obviously vary according to the needs.

The first level 41 is arranged to form a storm basin 25 intended to delay stormwater inflows, especially in case of significant thunderstorms. In the example, the storm basin 25 extends over the entire surface of the slab 17. For this, an opening or indentation 24 is formed at the lower end of the inner wall 13. The lower part of the intermediate volume 40 communicates with a central space 30 located under the first horizontal platform 151 and delimited by the inner wall 13. As is apparent from Figure 1, the raft 17 is covered with a coating 26 whose upper surface, which constitutes the bottom of the storm basin 25, converges slightly towards the central axis AA. In the example, a slope of 2% naturally guides the water received in the storm basin to a well 28 located in the central space 30 and connected to a pumping system 29 for raising the water of the pool. Thunderstorm 25, itree 30 of the epurdLron station 10 (see Figure 3

The second and the third level 42, 43 each comprise several functional spaces distributed in the intermediate volume 40. On the same level, the functional spaces are delimited by vertical intermediate walls 20. Thus, they have very different dimensions and shapes, are closed or not, and communicate with each other or not. Advantageously, some intermediate walls 20 may extend in axial planes, thus delimiting functional spaces having, in horizontal projection, an annular sector shape. Such axial intermediate walls make it possible to facilitate the organization of the functional spaces within the same level of the purification plant and more generally within the entire structure, while retaining a certain geometry. At each level, at least one of the functional spaces communicates with a platform 47, 48 forming a bearing located in the access volume 14, by one or more doors or openings 46a, 46b, 46c provided in the inner wall 13. L The access of the users to the bearings 47, 48 is provided by the helical staircase 18. In the present description, functional spaces of the purification plant intended to receive wastewater treatment installations have been described. It goes without saying that the wastewater treatment plant will also be able to house other spaces with a function other than the treatment of wastewater. The arrangement of the treatment facilities within the purification plant 10 will now be described in more detail. As illustrated in FIG. 3, the inlet 50 of the effluents to be treated is situated at the third level of the purification station, this level being located substantially at the same height as the sewer collectors. A preliminary scrubber 52 makes it possible, at the inlet 50, to immediately evacuate the coarser debris. Downstream of this grid 52, the system comprises a "by-pass" (or overflow) 54. In the case where the flow rate of the effluents to be treated becomes too great, for example in the event of heavy rainfall, a pipe connected to this "by-pass" makes it possible to convey a portion 35 gravity loops, to the basin d oi age 2S located at the lowest level 41 of station 10 "epulation. The water stored temporarily in the storm basin is recovery, after the rainy episode, to the inlet 50 of the purification plant, by the pumping means 29 described above, and then follows the conventional course described below .In the event of normal operation, the effluents The pretreatment plants are dewatering and de-oiling tanks 60 as shown in Figure 1. By decantation, the sands are treated directly to other pre-treatment facilities on the third level of the treatment plant. sents suspended in the water sink to the bottom of the tanks, and oil and other floating materials from the hydrocarbon type, back to the surface. With a worm system or a bottom-end scraper, sand can be recovered at the bottom of the tank, while oils and other floating materials can be scraped off the surface by, for example, a scraper or surface scraper, which pushes unwanted material towards a sump. After this pretreatment phase, the water is conveyed by gravity to three functional spaces in the form of annular sectors, separated from each other by intermediate vertical walls 20, and covering three quarters of the surface of the second level 42 located between the outer wall 12 and the inner wall 13. These functional spaces are arranged to form aeration basins 64, 65, 66 (see Figure 4). As shown in FIG. 4, these aeration tanks 64, 65, 66 are equipped with aerators 68 intended to supply the oxygen necessary for the proliferation of aerobic bacteria intended to absorb pollutants dissolved in water, and in particular organic materials. A functional space 70, adjacent to the spaces arranged in aeration basins, houses the boosters 72 necessary for the operation of these basins. By means of lines 75, the treated water in the aeration basins 64, 65, 66 is conveyed to pumping systems 76 placed in an additional functional space 74 of the second level and shown in FIG. these pumping systems 76, the water is raised to a functional space 80 located at the third level 43 of the purification plant 10, and receiving filtration facilities Itllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll These facilities use a technology known today as ultrafiltration. By a filtration system using microporous membranes, the water from the aeration tanks 64, 65, 66 is cleared of the remaining bacteria, but also viruses, parasites, pollen, etc. A functional space 84, adjacent to this space 80, houses the boosters 86 necessary for the operation of the microporous membranes. The water obtained with this technology has a purity significantly higher than that obtained by means of a conventional clarifier, which, moreover, has dimensions far too important to be integrated into a compact buried station such as that of the present invention. . The water treated by ultrafiltration is then rerouted to the second level 42 of the purification plant, in a functional space 90 arranged to form a sheet of treated water. The water contained in this tarpaulin can be reused especially for municipal watering, cleaning of roads, etc.

Claims (3)

REVENDICATIONS1. Treatment plant (10) for the treatment of wastewater, characterized in that it comprises - an outer wall (12) closed on itself and extending vertically, an inner wall (13) defining a volume of access (14) at least partially contained in the volume delimited by the outer wall (12), a plurality of horizontal platforms (151, 152a, 152b, 152c, 153) disposed in the intermediate volume (40) defined between the inner wall (13) and the outer wall (12) and defining at least a first level (41) and a second level (42) located above the first level (41), in that a portion of the outer wall (12) ) extending at least to the upper end of the second level (42) is buried in the ground, and in that a plurality of functional spaces for receiving wastewater treatment plants are distributed over the first and second level (41, 42). 2. Treatment plant according to claim 1, characterized in that one of the functional spaces located at the lowest level is arranged to form a storm basin (25). 3. Sewage treatment plant according to claim 1 or 2, characterized in that it further comprises a bottom (17) consisting of a raft connected to the outer wall (12) and in that the storm basin (25). ) extends over the entire surface of said slab (17). Treatment plant according to any one of claims 1 to 3, characterized in that the outer wall (12) has, in horizontal projection, the shape of a first circular or oval closed curve 35. Treatment plant according to any one of claims 1 to 4, characterized in that the inner wall (13) extends vertically and has, in horizontal projection, the shape of a second closed circular or oval curve. 6. Sewage treatment plant according to any one of claims 1 to 5, characterized in that vertical intermediate walls (20) are provided in the intermediate volume (40), said vertical intermediate walls (20) defining functional spaces. intended for receiving wastewater treatment facilities. 7. Sewage treatment plant according to claim 6, characterized in that the outer wall (12) and the inner wall (13) are coaxial and in that at least one of the functional spaces is delimited by vertical intermediate walls. (20) defined in axial planes. 8. Treatment plant according to any one of claims 1 to 7, characterized in that the upper end (12a) of the outer wall (12) is located at the floor surface (22). 9. Sewage treatment plant according to any one of claims 1 to 8, characterized in that the access volume (14) extends above the soil surface (22). 10. Purification plant according to any one of claims 1 to 9, characterized in that the upper end of the access volume (14) is closed by an at least partially transparent structure. 11. Wastewater treatment plant according to any one of claims 1 to 10, characterized in that at least one of the functional spaces is arranged to form a ventilation tank (64, 65, 66), and another functional space (70) receives blowers (72) from the aeration basin (64, 65, 66) .2012.A purification station according to any one of claims 1 to 11, characterized in that at least one of the functional spaces is arranged to form a treated water cover (90). 13. Wastewater treatment plant according to any one of claims 1 to 12, characterized in that at least one of the functional spaces receives water pretreatment facilities (52, 60), in particular a sand trap and a degreaser. 14. Wastewater treatment plant according to any one of claims 1 to 13, characterized in that at least one of the functional spaces receives membrane filtration installations of water (82).