FR2999562A1 - Plant, useful for treating i.e. domestic waste water, has tank including ventilation enclosure and clarification enclosure, where water to-be purified passes through enclosures, and clarification enclosure is connected with output pipe - Google Patents

Abstract

The sewage treatment plant comprises a tank including a ventilation enclosure and a clarification enclosure, where the water to-be purified passes through the enclosures. The clarification enclosure is connected with an output pipe by a siphon zone (20) delimited by a siphon partition (2). A lower end of an input passage (210) passes through the siphon zone. A filter material (3) is placed in the downstream of the input passage in the siphon zone, so that the suspended matters are blocked by the filter material. The sewage treatment plant comprises a tank including a ventilation enclosure and a clarification enclosure, where the water to-be purified passes through the enclosures. The clarification enclosure is connected with an output pipe by a siphon zone (20) delimited by a siphon partition (2). A lower end of an input passage (210) passes through the siphon zone. A filter material (3) is placed in the downstream of the input passage in the siphon zone, so that the suspended matters are blocked by the filter material. The filter material is partially placed above the siphon zone, where the filter material is pozzolana. A bacteriological treatment unit is arranged in the downstream of the input passage in the siphon zone. The clarification enclosure is delimited with the ventilation enclosure by a common partition wall and by an exit wall (113). The siphon partition extends starting from its lower end in the vicinity of a lateral wall, and delimits a storage space of the filter material. The filter material is provided in a vat removably placed in the storage space. An external wall comprises a set of projecting elements in bearing surfaces against which the filter material exerts a force directed towards the bottom of the station.

Description

Individual water purification station, including a siphoid partition delimiting a siphoid zone in which a filter material is disposed. The field of the invention relates to the design and manufacture of wastewater treatment equipment. More specifically, the invention relates to an individual treatment plant, of the type incorporating a ventilation tank and a clarification tank, the latter using a siphoid wall. In the context of non-collective sanitation, we distinguish houses connected to the collection network of their municipality and those that are not. Until recently, homes not connected to the collection network were equipped generally, or even at best, with a septic tank for the treatment of domestic wastewater (excluding rainwater) associated with a filter sandbox.

The evolution of standards and regulations now requires homes not connected to the collection network of their municipality to have an individual sanitation system, aimed at returning to the natural environment treated water of a predetermined satisfactory quality. The texts currently in force define individual sanitation, otherwise referred to as non-collective sanitation (CNR), as "any sanitation system carrying out the collection, pretreatment, purification, infiltration or discharge of wastewater. buildings not connected to the public sewerage network ". In this context, a solution for individuals not connected to the collection network of their community is to resort to the installation of a micro-wastewater treatment plant. A micro-wastewater treatment plant can be defined as a solution for treating domestic wastewater, operating at a reduced scale according to the same principle as an urban wastewater treatment plant, by implementing a process called activated sludge "or" fixed culture ".

The "activated sludge" treatment process consists in using the microorganisms or bacteria present in the water to be treated in order to degrade the organic matter present in the said waters, without resorting to the addition of chemicals. . Such a treatment makes it possible to reject the treated water directly in the natural environment or, alternatively, to use it in irrigation. Among the effluents discharged by a dwelling, two categories can be distinguished, namely: - "gray water", corresponding to water coming from sinks, washing machines, showers, etc .; - the "water-valves", corresponding to the waters rejected by the toilets. All of these effluents contain: - organic materials; - nitrogen and phosphorus materials; - pathogenic microorganisms; suspended solids which can cause diseases, organic pollution and eutrophication.

Conventionally, the micro-purification stations are designed to carry out the following treatment phases: - the decantation, aiming to retain the heaviest materials at the bottom of the tank and to bring the lightest surface to the surface; aeration, according to which the "sludge" in suspension undergoes a treatment of purification, this by creating sequentially aerobic periods and periods of anoxia, which will allow to generate a phenomenon of digestion of organic matter as well as a reduction of nitrates and nitrites; - the clarification (possibly preceded by a pre-clarification), aimed at separating the persistent light sludge from the purified water: in this phase, the remaining sludge is returned to the settling basin or the reaction basin, while the purified water is extracted from the micro-station to be generally dispersed in the soil. The advantages of micro-stations include the following: - they implement ecological treatment processes and do not use chemicals to treat wastewater; - The ground surface of the micro-station is significantly limited and does not require underground spreading, which allows to install even in small areas, possibly with a difference in altitude; - Sludge emptying frequency is low compared to that of a septic tank; - it does not give off odors.

On the other hand, the "activated sludge" treatment implies a regular supply of organic matter to allow the bacteria to develop and thus to treat the water. Also, a prolonged absence of water flow in the micro-station will imply the need for reactivation of the bacteria.

According to the prior art, two types of micro-purification station are distinguished: the stations operating an activated sludge purification, as described above; fixed culture stations in which the microorganisms responsible for the treatment are fixed on a support at the bottom of the tank. The invention relates to stations operating a so-called "activated sludge" treatment. Micro-activated sludge purification stations generally give satisfaction according to the current purification criteria. However, it can be deplored in some cases that the water leaving a micro-treatment plant is insufficiently treated, or that the station is subject to a sludge that may be due to a prolonged absence, such as mentioned earlier, or a rejection of a cleaning product that neutralizes bacteria, or a power cut during which the compressor used for the aeration cycle no longer works. There is therefore a need to optimize the operation of the micro-purification stations. In the context of collective sewage treatment plants, ie large ones, siphoid partitions are used to delimit a water withdrawal zone (thus treated), at the base of which is formed a passage of reduced dimensions in which flows a water slightly loaded with suspended matter. This principle is currently very little used in the micro-purification stations, and does not in any case to suppress the phenomena of mud flow. In addition, the micro-stations are schematically water tanks containing a set of mechanisms (air compressor, pump, electrical panel ...) and generally intended to be buried. Once buried, these tanks are under the pressure of the soil which is exerted on the walls of the tank and which creates a risk of lateral and / or vertical crushing of the tank. In addition, Archimedes' principle is verified when water is present in the soil in which the micro-station is buried, which can lead to lifting the tank under the pressure of the water to the point of requiring a civil engineering intervention. Indeed, to limit this risk, civil engineering companies conventionally use concrete as low or high ballast slab, as well as lashing straps that hook the tank to the concrete. In addition, a decompression well may be provided to release the pressure of the water to the surface. At the same time, tank manufacturers use lateral reinforcements, horizontal or vertical, to allow the tank of the micro-station to withstand the pressure. It is understood that the installation of a micro-treatment plant therefore requires special attention in terms of civil engineering to mitigate any risk of recovery of the micro-station under the effect of the pressure of water present in the ground. In any case, these operations are relatively long, tedious and expensive to perform. The object of the invention is in particular to overcome the disadvantages of the prior art. More precisely, the object of the invention is to propose a micro-station for the purification of domestic wastewater by activated sludge, which produces a treated water of satisfactory quality in all or almost all circumstances. Another object of the invention is to provide such a micro-purification station which is simpler and faster to install than the microstations of the prior art. In this sense, the invention aims to significantly limit the civil engineering operations related to the installation of the micro-station 20 purification in the soil. These objectives, as well as others which will appear later, are achieved thanks to the invention which has for object an individual purification station, of the type comprising a tank including at least two enclosures, one of aeration and the other clarification, the water to be purified 25 passing from one to the other, the clarifying chamber being connected to an outlet duct by a siphoid zone delimited by a siphoid partition whose lower end forms a passage of entering the siphoid zone, characterized in that a filter material is disposed downstream of the inlet passage in the siphoid zone so that the water passes through the filter material, the latter being intended to fix the materials suspended in the waters.

Thus, thanks to the invention, an individual purification plant is obtained producing a treated water of better quality than with the individual purification plants of the prior art, this in all circumstances.

Indeed, the combined actions of aeration / clarification on the one hand, and the filter material, on the other hand, leads to an optimal treatment of domestic wastewater. In addition, the individual treatment plants according to the invention eliminate, or at least limit, the risks of starting sludge, 10 by the presence of the filter material. It is further noted that the arrangement of the filter material downstream of the inlet passage in the siphoid zone is particularly effective insofar as the water present in the siphoid zone (which extends to the sampling zone ai level of the outlet duct) are the least loaded with suspended solids. The action of the filter material is therefore largely sufficient with respect to the amount of suspended solids present in the zone downstream of the inlet passage in the siphoid zone. As a result, the filter material becomes clogged less rapidly by being present in this area, and therefore it is only necessary to replace it with a relatively low frequency. Preferably, the filter material is disposed in the upper part of the siphoid zone. This feature helps to improve the above-mentioned effects, since the higher the filter material is placed in the station, the less likely there is suspended matter in the water at the level where it is placed. According to a preferred solution, the filter material is at least partially constituted by pozzolan. Such a material is particularly effective in its ability to fix the suspended solids, to block them and thus to further limit or even prohibit their exit from the station.

The result of the treatment is thus significantly improved compared to the solutions of the prior art, this by a very modest industrial cost. According to possible variants, the filter material belongs to the following group: zeolite; - sand; - sponge; - honeycomb material. According to a particular embodiment, the station also includes bacteriological treatment means. This characteristic concerns certain applications. Indeed, the level of polluting bacteria in both bathing and drinking water is an increasingly important subject and the normative and regulatory texts will evolve, with regard to bathing water, towards more and more rigorous criteria. In this case, the bacteriological treatment means is preferably present downstream of the inlet passage in the siphoid zone. According to an advantageous characteristic of an individual purification station according to the invention in which the clarification chamber is delimited by a partition wall common with the ventilation enclosure and by an outlet wall connected by two side walls. , the siphoid partition is preferably arranged facing one of the side walls. In this case, the siphoid wall extends from its lower end in the vicinity of said side wall and deviates from it upward to define a storage space of said filter material. Advantageously, the filter material is present in a tray 30 removably disposed in said storage space. The filter material is thus easily accessible, and can be easily and quickly replaced when needed.

According to another advantageous characteristic, the outer wall of the purification plant has projecting elements each having a substantially flat bearing surface against which a backfill material is likely to exert a force directed towards the bottom of the station. Other features and advantages of the invention will appear more clearly on reading the following description of a preferred embodiment of the invention, given by way of illustrative and non-limiting example, and the appended drawings among which: - Figure 1 is an exploded perspective view of an individual treatment plant according to the invention; FIG. 2 is a view from above of an individual purification station according to the invention; - Figure 3 is a partial view of a purification plant according to the invention, schematically in the interior of the clarification chamber. Referring to Figures 1 and 2, an individual treatment plant according to the invention is generally in the form of a vessel 1 including, according to the present embodiment, two enclosures, namely: aeration 10; In the upper part of the station, a tank is provided to receive an electrical panel intended to supply a compressor (not shown) from which extends an air duct opening into the tank. Ventilation enclosure 10. The compressor of the ventilation enclosure is programmed to perform successive cycles of aeration of the water present in the ventilation enclosure. It is recalled that the purpose of the aeration chamber is to carry out successive aerobic and anoxic phases in order to induce digestion of the organic matter present in the water to be treated.

As can be seen in FIG. 1, a duct 100 opens into the aeration chamber, the water to be treated arriving in the station via this duct 100. The ventilation chamber is separated from the settling chamber / clarification by a partition wall 12 in which is formed an orifice 120 communicating with a pipe 111, extending towards the bottom of the clarification chamber. When the level increases in the aeration chamber, this due to the arrival of water via the conduit 100, until reaching the orifice 120, the water 10 passes from the ventilation enclosure to the Decantation / clarification chamber 111. The settling chamber / clarification includes a pump 112, activated by successive cycles programmed, to: - let the suspended solids in the non-operating phase of the pump; - Pump the sludge (thus undigested) and return to the ventilation chamber, through a pipe (not shown). An outlet pipe 110 extends from the settling / clarifying chamber, to allow the outlet of the treated water. This duct 110 is provided in the upper part of the settling chamber / clarification. Therefore, it is necessary that the water level increases sufficiently in the settling chamber / clarification, to reach the level of the outlet duct. As the water level increases in the settling / clarification enclosure, the heavier suspended solids decant during the non-operating phase of the pump 112, while only the finest and lightest suspended solids go up with the water level. In addition, a siphoid zone 20 constitutes a compulsory passage of water circulation in the station, connecting the internal volume of the clarifying chamber to the outlet duct. This siphoid zone, in which the waters are weakly charged with suspended matter, is delimited by a siphoid partition described in more detail later. Thus, as illustrated in FIG. 3, the lower end 21 of the siphoid partition 2 forms an inlet passage 210 for the waters that rise in the siphoid zone as symbolized by the arrows F. According to the principle of the the invention, a filter material 3 is disposed downstream of the inlet passage 210 formed by the lower end of the siphoid partition 2, this filtering material extending in such a way that the water necessarily passes through the filtering material; being intended for fixing suspended solids in waters. According to a preferred embodiment, the filter material is constituted by pozzolana (or volcanic rock). According to possible variants, this filtering material may also consist entirely or partially of: zeolite; - sand; - the sponge; an industrial material of the honeycomb type. With reference to FIG. 3, it is noted that the settling / clarifying chamber is delimited by: the partition wall 12 mentioned above; the outlet wall 113, from which the outlet duct extends; lateral walls 114, connecting the partition wall 12 and the outlet wall 113. According to the present embodiment, the siphoid wall 2 is arranged so as to face one of the side walls 114. More specifically, the siphoid partition extends from its lower end 21 in the vicinity of one of the side walls 114 and 30 goes up towards the upper part of the settling / clarification enclosure, this deviating from the corresponding lateral wall 114, to delimit a storage space 22 of the filter material 3. Above this storage space, the siphoid partition 2 extends to form a box 23 provided with a bottom, inside which leads the conduit Release. This box defines a sampling area strictly speaking.

The filter material 3 is present in a tray 30 removably disposed in the storage space. It should be noted that the filtering material may be disposed at any level downstream of the inlet passage in the siphoid zone, that is to say in the siphoid zone itself, or even in the sampling zone, and even in the outlet duct. According to another advantageous characteristic of an individual purification station according to the invention, the outer wall of the tank 1 has projecting elements 4, each having a bearing surface 40, essentially flat, against which a material 15 backfilling is likely to exert a force directed towards the bottom of the station and thus towards the bottom of the excavation in which the station is installed. Preferably, the protruding elements 4 form at least one belt around the vessel, and preferably three belts distributed over the height of the vessel as shown in FIG. 1. With reference to FIGS. 1 and 2, the projecting elements 4 have a triangular section, including a bearing surface 40 overlying a lower surface 41. The bearing surface 40 of the projecting elements may be horizontal or slightly inclined downwardly. According to a particular embodiment, the bearing surface 40 forms, with the lower surface 41 of the same projecting element, an angle of approximately 45 °. Note that, according to the present embodiment, the outer ends of the projecting elements are arranged one above the other so as to fit in the same vertical plane.

However, it is also conceivable that the tank has a different external shape, for example cylindrical, pyramidal ... In addition to promoting the maintenance of the station at the bottom of the excavation once it is backfilled, it is noted that these projecting elements also contribute to the strengthening of the structure of the tank vis-à-vis risks of vertical or horizontal crushing. Furthermore, as shown in Figure 3, the projecting elements 4 of the outer wall also appear inside the station.

As a result, the partition wall 12 has side edges 121 of complementary shape to the projecting elements. In addition, the tray containing the filter element also has a shape adapted to the shape of the projecting elements. Therefore, it is put in place and retained without tools or fixing means, coming to rest vertically against the inclined portion of the siphoid wall on the one hand and, on the other hand, against the lower surface of an element projection.

Claims (10)

REVENDICATIONS1. Individual purification plant, of the type comprising a tank (1) including at least two enclosures, one aeration (10) and the other clarification (11), the water to be purified from one to the other. the other, the clarification chamber (11) being connected to an outlet duct (110) by a siphoid zone (20) delimited by a siphoid partition (2) whose lower end (21) forms an inlet passage ( 210) in the siphoid zone, characterized in that a filter material (3) is disposed downstream of the inlet passage (210) in the siphoid zone (20) so that the water passes through the filtering material (3). ), the latter being intended to fix the suspended matter in the water. 2. individual treatment plant according to claim 1, characterized in that the filter material (3) is disposed in the upper part of the siphoid zone (20). 3. individual treatment plant according to claim 1, characterized in that the filter material (3) consists at least partially of pozzolan. 4. Individual treatment plant according to claim 1, characterized in that the filter material (3) belongs to the following group: - zeolite; - sand; - sponge; - honeycomb material. 5. individual treatment plant according to claim 1, characterized in that it includes a bacteriological treatment means. 6. individual treatment plant according to claim 5, characterized in that said bacteriological treatment means is present downstream of the inlet passage (210) in the siphoid zone (20). 7. individual treatment plant according to claim 1, wherein the clarification chamber (11) is delimited by a partition wall common with the ventilation chamber (10) and by an output wall (113) connected by two side walls (114), characterized in that the siphoid partition (2) is arranged facing one of the side walls (114). 8. individual treatment plant according to claim 7, characterized in that the siphoid partition (2) extends from its lower end (21) in the vicinity of said side wall (114) and deviates from it. ci up to delimit a storage space (22) of said filter material (3). 9. individual treatment plant according to claim 8, characterized in that the filter material (3) is present in a tray (30) removably disposed in said storage space (22). 10.An individual purification plant according to claim 1, comprising an outer wall, characterized in that the outer wall has projecting elements (4) each having a substantially flat bearing surface (40) against which a backfill material is likely to exert a force directed towards the bottom of the station.