FR2880551A1 - Rising filtration waste water treatment cell has flushing water evacuated into adjoining tank through rapid-opening valve equipped with grille-cleaning brush - Google Patents

Abstract

The treatment cell, designed to treat waste water by rising flow filtration, has an outlet (9) to discharge flushing water from the cell controlled by at least one rapid-opening valve (18) that is fitted with a brush (20) to prevent blockage of its fine-mesh grille (19). The grille, which is curved and designed to retain the filter medium (4) during the flushing sequence, is situated between the filter medium and the flushing water outlet. The brush covers the moving part of the valve and cleans the grille as it moves between its open and normally-closed positions. A complete water treatment system can include a number of cells set side by side.

Description

2880551 -

  The present invention relates to the field of wastewater treatment by ascending filtration and cocurrent on fixed biological culture.

  The present invention relates more particularly to a treatment cell for the upward filtration of wastewater, of the type consisting of at least one quick-opening valve for discharging the washing water of the filter material into an adjoining sheet, said valve having a device for cleaning the thin anti-waste material grid disposed between the filter material and the outlet of the wash water.

  The prior art already knows from the international application W098 / 40146 a device for the treatment of wastewater with a view to their purification by biological means, by ascending filtration and co-current. Said device comprises a submerged filter bed, supported by a support floor, means for supplying the water to be treated and / or washing water, and means for supplying treatment and / or washing air in a lower chamber provided under the floor, means for discharging the treated water downstream of the filter bed, and means for backwashing the filter bed with a backwashing liquid.

  However, no description of the washing water evacuation of said device is presented.

  It is also proposed in the French patent application FR 2 557 558 a submerged filter filled with granular material for the treatment of water by upward filtration and against the current. However, said patent application does not mention any particularity of said filter for washing water discharge.

  The present invention intends to provide an improvement in the prior art by proposing a wastewater treatment cell by upward filtration whose washing is carried out by raising the water level and having at least one opening valve. fast to evacuate wash water to an adjoining tarpaulin.

  To do this, the present invention is of the type described above and is remarkable, in its broadest sense, in that said valve allows the rapid evacuation of washing water in the adjoining tarpaulin and the cleaning of the grate Fine anti-loss of material.

  Advantageously, the treatment cell comprises a curved grid, fine mesh, for retaining the filter media during washing sequence, said grid being disposed between said filter medium and the outlet of wash water.

  When the treatment cell is equipped not only with the quick-opening valve but also with the grid designed to retain the filtering material, the said quick-opening valve will advantageously be provided with a brush ensuring when opening or closing said valve, a scan of said grid to clean said grid residues fixed thereon during the washing sequences.

  Advantageously, the curved grid, fine mesh is provided with an opening disposed against the wall of the cell to evacuate the residues during the closing of the valve.

  Advantageously, the treatment cell comprises an adjoining wastewater collection tank.

  Advantageously, the treatment cell further comprises a support floor consisting of nozzles allowing the supply of operating or washing air and water to be treated or washed. Advantageously, the treatment cell further comprises an anti-loss deflector. material disposed between the filter medium and the outlet of the treated water.

  The present invention also relates to a method of operating the treatment cell as described above. The method is notable in that the quick open valve is normally closed and sealed during operation of said cell and said valve is automatically and rapidly opened at the end of each wash sequence.

  The present invention also relates to an upwash wastewater treatment system comprising a plurality of treatment cells as described above, said cells being arranged juxtaposed to each other.

  Preferably, each cell comprises a tulip of admission by gravity of the water to be treated, said intake tulip being disposed in a water supply manifold common to all the cells juxtaposed, so as to ensure equidistribution of the water to be treated on all of said cells.

  Advantageously, a dirty water cover is disposed adjacent and common to all the juxtaposed cells.

  The invention will be better understood from the following description, given purely for explanatory purposes, of an embodiment of the invention, with reference to the appended figures: FIG. 1 illustrates a sectional view of an upflow filtration wastewater treatment cell according to the invention; FIG. 2 illustrates a partial view of the outlet of the washing waters of the treatment cell, said treatment cell comprising a quick-opening valve implemented during the washing sequences of the filter medium; Figures 3a and 3b schematize the opening of the quick-opening valve of Figure 2; Figure 4 illustrates a partial sectional view of a floor-support constituting the processing cell of Figure 1; - Figures 5a to 5c show schematically the realization of the support floor of Figure 4; and FIG. 6 illustrates a partial view of the outlet of the treated water of the treatment cell, said treatment cell comprising a deflector against material loss.

  FIG. 1 illustrates a sectional view of a treatment cell (1), according to the invention, of wastewater by upward filtration.

  Said treatment cell comprises a floor-support (2) constituted by at least one plate traversed by nozzles (3).

  The said nozzles (3) are arranged through the floor (2) so as to have a part (head of the nozzles) opening into a filter media (4) resting on the floor and a part (tail of the nozzles) opening into a chamber ( 5) under the floor (2).

  Said chamber (5) is intended to receive, before passing through the filter medium (4), the water to be treated and washing, and the treatment air for the development of bacteria on the filter media (4) necessary for the purification process.

  Advantageously, the filter media is in granular form and has a high porosity coefficient in order to allow the development of a large number of microorganisms.

  The filter media thus has the function of simultaneously forming a physical and biological barrier to pollution.

  The water to be treated and the treatment air are respectively conducted in said lower chamber (5) by separate feeds (6, 7), the washing water being fed through another conduit.

  Said treatment cell (1) further comprises two discharge outlets: a first discharge outlet (8) for treated water, and a second discharge outlet (9) for washing water, the said wash water being recovered by a recovery tank (10) adjacent to the treatment cell (1) as will be seen later. - 5 -

  Due to the development of bacteria and the accumulation of suspended solids during filtration operations, the filter media is steadily becoming clogged. Also, it is necessary to perform regular washing to ensure the continuity of the purifying and hydraulic capabilities of the filter constituted by the filter media (4).

  These washes are carried out by washing with water and with air according to the following steps.

  A first step consists in isolating the treatment cell (1) by closing the supply of water to be treated (closure of the corresponding valve 23) and the outlet of the treated water (closure of the corresponding valve 24).

  A second step is to lower as much as possible the water level at the upper surface of the filter medium (opening of a valve (18)).

  The next step consists in admitting air and water at a controlled speed to ensure a good declogging of the filter media (4), the level of the water in the upper part of the media rising, then to empty this reserve of water. dirty water in a recovery tank (10) reserved for storage, said tank being arranged adjacent to the treatment cell (1). Advantageously, said valve (18) is disposed on one of the side walls of the treatment cell (1) so as to interest the largest width of the filter to a height such that disturbances in the filter media are minimized. Furthermore, in order to minimize the settling time of the materials, to ensure emptying of the washing water without risk of re-deposit of the extracted material and thus ensure a flushing effect on the surface of the filter, said valve (18) used is advantageously a quick-opening valve.

  A final step is to reintroduce the dirty water by pumping at the head of primary treatment in which they can be concentrated, extracted and directed to the treatment of sludge.

  After several successive washing sequences (two in general), the filter media (4) is rinsed one last time with water and then put back into service. - 6 -

  Figure 2 schematizes the position of the quick-opening valve (18) in the processing cell (1).

  In order to guard against the loss of filtering material during washing sequences, a curved fine grid (19) of air gaps having a diameter smaller than that of the filtering medium is arranged between the filter medium and the outlet of the water washing with said quick-opening valve (18). Thus, when the quick-opening valve (18) opens to allow the washing water to pass to the recovery tank (10), the filter material possibly entrained with the wash water is blocked by said grid (19). .

  However, the washing sequences also result in clogging of the grid (19), thus increasing the risk of loss of filter media due to its entrainment with the dirty water in the direction of said recovery tank (10). However, in addition to a medium-term deficit of filter media in the cell, the entrainment of the filter media can also generate mechanical damage to equipment downstream. For this purpose, the quick-opening valve (18) is advantageously provided with a cleaning brush (20). Said brush (20) is disposed on said valve (18) so as to rub the grid (19) during the opening and closing of said valve (18). Figures 3a and 3b schematically the opening of the valve (18) and the associated cleaning of the grid (19) by said brush (20).

  In Figure 4 is shown a partial sectional view of the support floor (2) constituting said processing cell (1). It is shown in the figure a single bushing (3) to simplify the description. It is of course obvious that the floor supports a plurality of swirls (3), the number of swirls being a function of the extent of the support floor (2) and the desired distribution of the water to be treated in the filter medium.

  Said nozzle (3) has orifices (16, 17) arranged at the tail and head to allow the passage of the water to be treated, the treatment air and wash water. - 7 -

  Each bush (3) is held firmly fixed in a preform (11). Holding the nozzle (3) in the preform (11) is achieved by interlocking a threaded portion (12) formed on at least a portion of the inner face of the preform (11) with a threaded portion (13). ) formed on the at least part of the outer face of said bush (3).

  Advantageously, said nozzle (3) has a second threaded portion (14) formed at least partly on the tail of the nozzle (3). This second threaded portion (14) serves to receive a locking means, such as a nut (15) for blocking the burr (3) in the preform (11). For this purpose, the second threaded portion (14) is arranged at least on the bushing (3) so that, when fixed on the second threaded portion (14), said nut (15) is positioned against the underside of the support floor (2).

  Figures 5a to 5c show schematically the installation of the bushings in the support floor (2) of the processing cell (1).

  The installation steps consist in first of all, when forming the support floor (2), as many preforms (11) passing through the support floor (2) as on the other side of the floor (3) ) planned. Thus, a plurality of preforms (11) opening into both the lower chamber (5) and the filter medium (4) is formed in the support floor (2).

  The second step consists in removing pre-shaped elements covering the preforms (11) at the ends in order to prevent their obstruction during the construction of the support floor (2), and then to insert the busings (3) into said preforms (11). Unlike the processing cells of the prior art, the insertion of the bushings is operated, not by the upper part of the support floor (2), but by the lower part of said support floor (2). With regard to non-definitive fixing of the nozzles in the preforms, this mode of insertion has the advantage of allowing the replacement, if necessary, of the broken, damaged or damaged nozzles (3), without the need to empty the nozzle. filter medium (4).

  The next step then consists in fixing said bushings (3) in the preforms (11) by screwing the threaded portion (13) formed on the bushings (3), on the complementary threaded portion (12) of the preforms (11) formed. during the production of the preforms (11).

  A final step is to block the bushings (3) in the preforms (11) by clamping the nut (15) on the tail of said bushings (3).

  In order also to avoid the entrainment of the filter medium with the treated water, which can generate mechanical parts degradation downstream of the treatment cell (1) (premature wear, deterioration, etc.), said cell treatment (1) advantageously comprises a deflector (21) anti-loss of material fixed on the side wall of the treatment cell and disposed between said filter and the outlet of the treated water. The deflector (21) thus forms a screen area located between the outlet of the treated water and the filter medium directly disposed under the outlet of the treated water (see Figure 6).

  The figures shown illustrate a single wastewater treatment cell operating by upward filtration. It is of course obvious that the present invention is not limited to a single cell, said invention also being related to a wastewater treatment system having a plurality of such processing cells.

  Preferably, said processing cells are juxtaposed with each other in order to ensure optimal purification.

  In order to ensure equidistribution of the water to be treated on all of said treatment cells, each cell comprises a metal tulip (22), said tulip (22) being arranged in a water intake manifold common to all the juxtaposed cells.

  The aim of the intake tulip (22) is to avoid a multiplication of concrete chutes and to simplify the individual supply.

  The water to be treated is admitted by overflow into said tulip (22) and flows by gravity through a pipe to the lower part of the treatment cell (chamber (5)) The diameter of this tulip (22) is function the height of discharge and the maximum flow rate to be admitted to the filter media. These two characteristics are advantageously defined at the time of the calculation of the piezometric line for the first and at the time of the start of the processing cells for the second. To do this, each tulip (22) will be keyed to an identical level to ensure equidistribution of the total flow in each of the treatment cells.

  It should be noted that in a system comprising a plurality of processing cells, said system will comprise a single covering covering adjacent and common to said processing cells.

  The invention is described in the foregoing by way of example. It is understood that the skilled person is able to realize different variants of the invention without departing from the scope of the patent.

Claims (11)

-i0-CLAIMS   Treatment cell (1) for waste water by upward filtration, of the type comprising an evacuation of the washing water from said cell (9), characterized in that the washing water is discharged in a tarpaulin (10). adjacent to said cell, by actuating at least one quick-opening valve (18), equipped with an anti-clogging brush (20) of the thin anti-loss of material grid (19).   2. Treatment cell (1) according to the preceding claim, characterized in that it comprises a curved grid (19), fine mesh for retaining the filter medium (4) during washing sequence, said grid being arranged between said filter medium and the outlet of the washing water The cleaning of this grid (19) being performed by the quick-opening valve.   3. Treatment cell (1) according to claims 1 and 2, characterized in that the anti-clogging brush (20) lining the movable portion of the valve (18) provides a scan of the grid (19) thin anti-loss of material when said valve (18) opens or closes, and thus allows the cleaning of said gate (19).   4. Treatment cell (1) according to any one of the preceding claims, characterized in that the grid (19) is provided with an opening disposed against the wall of the cell (1) for the evacuation of residues during valve closure (18) with rapid opening.   5. Treatment cell (1) according to any one of claims 1 to 4, characterized in that it comprises a tarpaulin (10) of adjacent waste water.   6. Treatment cell (1) according to any one of claims 1 to 5 characterized in that it further comprises, - a floor support (2) consisting of nozzles (3) for the supply of air from operation or wash and in water to treat or wash.   7. Treatment cell (1) according to any one of claims 1 to 6 characterized in that it further comprises, a deflector anti-loss of material (21) disposed between the filter media (4) and the output of treated water (8).   8. Operating method of the processing cell (1) characterized in that the valve (18) is normally closed and sealed during operation of the cell (1) and that said valve (18) is opened automatically and quickly during washing sequence.   An upflow filtration wastewater treatment system comprising a plurality of treatment cells (1) according to any one of claims 1 to 7, said cells (1) being disposed juxtaposed to one another.   10. Wastewater treatment system according to the preceding claim, characterized in that each cell (1) comprises a tulip (22) for admission by gravity of the water to be treated, said tulip (22) being disposed in the collector supply of water, common to all the cells (1) successive, so as to ensure equidistribution of the water to be treated on all of said cells (1).   11. treatment system according to claim 9 or claim 10, characterized in that said system comprises a covering sheet (10) dirty water, adjacent and common to all cells (1) juxtaposed.