FR2810310A1 - Industrial waste water treatment apparatus comprises coagulating or flocculating agents and effluent mixed in container and supplied to flocculation vat in bottom of clarifying tank - Google Patents

Abstract

An effluent purification apparatus comprises: (1) a clarifying tank (I); (2) a pump delivering effluent (II) intermittently to a container (III) on top of (I); (3) metering pump(s) supplying coagulating or flocculating agents (IV) to (III); and (4) a conduit taking (II) and (IV) from (III) to a flocculation vat in (I). A sludge bed forms in the vat. (II) flows downwards and is clarified by contacting the bed.

Description

The present invention relates to a device for physicochemical and bacteriological purification of water.

Most industrial effluents are currently discharged to treatment plants for treatment and purification.

For this purpose, contracts are concluded between the industrials discharging effluents and the water treatment companies.

The cost of treating these effluents can be very high for industrialists and can in some cases exceed the cost of water consumption. The responsibility for the treatment of effluents is thus sent back to industrialists, who may consider equipping themselves with their own means of treating used effluents.

However, current effluent treatment devices are poorly suited to the treatment of spent effluents at the level of a company that discharges small volumes of water, compared to a local authority, for example.

Current devices include several elements that sequentially perform the operations of homogenization of effluents, degreasing, coagulation, flocculation. These devices are expensive and use large floor areas.

For these reasons, it is difficult for an industrialist to equip himself with his own purification plant for its effluents.

The object of the invention is to provide an effluent treatment device which has a small footprint, a cost of acquisition and economic operation while having a high degree of purification.

For this purpose, the effluent purification device according to the invention comprises - a clarification tank, - a pump that pulsates the effluent into an enclosure placed on the upper face of the clarification tank, - at least one dosing pump for adding, in said enclosure, a reagent that coagulates or flocculates the effluent, a vertical supply duct bringing the effluent added with reagents from said enclosure to the lower part of a flocculation tank disposed within the clarification tank, in which a bed of sludge is formed which the effluent passes from bottom to top and in contact with which it clarifies.

By introducing the effluent at the base of the sludge bed, the aggregation of pollutants, organic and inorganic present in the effluent, on the flocks constituting the sludge bed is maximum. In addition, the arrival of the effluent in a pulsed manner allows to put the flocs in motion and increases their aggregation capabilities. This device therefore allows a very effective flocculation in a reduced time.

 As a corollary, the consumption of chemical reagents is reduced because of the maximization of the flocculation process.

The device according to the invention allows a reduction of the BOD of more than 70%, as well as an excellent filtration of metals.

One of the major criteria for pollution of an effluent is the BOD or biological oxygen demand, which is the oxygen consumption of the microorganisms present in the effluent to assimilate the organic substances of this effluent.

Particularly advantageously, the flocculation tank comprises a prolonged frustoconical upper portion of a cylindrical lower portion into which the supply duct opens.

Due to this particularly advantageous configuration of the flocculation tank, the effluent with added reagents is introduced into a zone whose volume is relatively small, namely the cylindrical portion of the flocculation tank. In this small volume, flocculation is particularly intense.

Furthermore, thanks to the inclined surface of the frustoconical portion, the sludge formed by the accumulation of flocs can flow out of the flocculation tray under the effect of an increase in the load.

Flocculation takes place dynamically and is self-regulating. Indeed, whatever the load to which the device is subjected, flocculation is always effected optimally on the one hand by ensuring intense flocculation at the cylindrical portion and on the other hand by discharging out of the tray. flocculation excess mud.

According to a particularly advantageous characteristic of the invention, the supply duct comprises a first tube, one end of which opens into the chamber and the other end of which has radial homogenization openings above it. the surface of the frustoconical tray and a second tube, of diameter greater than the diameter of the first tube, whose upper end covers the circumferential homogenization openings of the first tube and whose lower end opens into the lower part of the frustoconical tray.

The configuration of the feed duct makes it possible to produce a homogeneous mixture of the effluent and the reagents before being introduced into the lower part of the flocculation tank.

Advantageously, the lower part of the clarification tank has a frustoconical portion which receives the sludge overflowing from the flocculation tank and a pump discharges the sludge collected in the frustoconical part of the clarification tank.

Thanks to the frustoconical shape of the lower part of the clarification tank, the sludge that emerges from the flocculation tank is collected on a defined surface of the base of the clarification tank. This sludge can be easily extracted by a pump. Load variations can therefore be absorbed without difficulty, the regulation of the sludge bed is carried out autonomously.

Preferably, calibrated openings are provided on the upper part of the clarification tank in order to allow the clarified effluent to flow into a storage tank surrounding the clarification tank.

The storage tank surrounds the clarification tank, which makes it possible to obtain a particularly compact device whose ground occupation is clearly inferior to the devices of the prior art.

Advantageously, the lower end of the supply duct has a divergent frustoconical section in order to improve the dispersion of the effluent in the sludge bed.

According to a preferred embodiment of the invention, a filter material is disposed between the clarification tank and the storage tank, through which the clarified effluent passes before being stored in the lower part of the storage tank.

According to advantageous features that the invention may present, the effluent clarification device comprises a filtration tank containing a filter material, disposed between the enclosure and the flocculation tank, a wall located between the flocculation tank and the filtration tank, a conduit of greater diameter than the supply duct and coaxial with the latter extending between the wall and the filter tank.

Preferably, the upper edge of the frustoconical portion of the flocculation tray is joined to the inner face of the vessel.

Preferably, the filtration tank has, on its underside, openings protected by strainers allowing the filtered water to flow.

The filtering mass makes it possible to reduce the residual pollutants at the outlet of the clarification tank.

According to a particularly advantageous embodiment of the invention, a pump sucks the clarified effluent into the storage tank and introduces it into at least one annular chamber, arranged on the external face of the storage tank, containing a fixing granulate. bacteriological elements.

The clarified effluent is set in motion in an annular chamber which contains a granulate fixing the bacteriological elements. The vortex flow experienced by the effluent in the annular chamber allows a remarkable contact between the granulate and the effluent and consequently an excellent and rapid fixation of the bacteria. The BOD reduction is over 95%.

Preferably, the annular chambers are four in number, each communicating with that adjacent thereto, by a conduit.

Each of the annular chambers contains a granulate having a specific bacterial binding property so that the successive passage through the four chambers achieves a remarkable biological treatment of the effluent.

Advantageously, a recovery pump sucks the clarified effluent at the upper annular chamber and reinjects it to the lower chambers.

This return pump maintains a regular annular speed of the effluent in which the granulate is in suspension.

Preferably, an air intake is arranged. For a good understanding, the invention is described below with reference to the attached schematic drawing showing a preferred embodiment of the effluent clarification device.

Figure 1 is a sectional view of the device according to the invention, Figure 2 shows the effluent purification device according to the invention integrated in a treatment facility.

Figure 3 shows an alternative embodiment of the invention for providing drinking water in isolated sites.

As shown in the cross-sectional view of FIG. 1, the effluent purification device comprises a cylindrical storage tank 1. A cylindrical clarification vessel 2 is concentrically disposed inside the vessel 1. clarification 2 comprises, in its upper part, circular openings 3 calibrated regularly distributed and has, in its lower part, a frustoconical section 4. The concentric tanks 1 and 2 are joined by an annular platform 5 on which a filter material rests 8. The annular platform 5 is pierced with openings 6 regularly distributed. The openings 6 are each surmounted by a strainer 7. A nozzle 9 for injecting air and / or water opens into each strainer. The feed circuit of the nozzles 9 is not shown in the figures.

A flocculation tank 12 is placed inside the tank 2. The tank 12 consists of a frustoconical upper portion 13 of decreasing section downwards, extended by a cylindrical lower portion 14. The flocculation tank 12 is provided on its lower face with feet 15 which rest on the bottom of the tank 2.

An extraction duct 17 opens between the feet 15 of the flocculation tank 12, the extraction being provided by a pump 18.

An enclosure 20 is disposed on the upper face of the tank 2. The enclosure 20 is supplied with effluent to be treated by the pump 21 and flocculant or coagulating reagents by the metering pumps 22 and 23.

A vertical supply duct 25 extends from the enclosure 20 to the cylindrical portion 14 of the flocculation tank 12. The supply duct 25 comprises a first tube 26 opening into a second tube 27 of diameter greater than the diameter 26. The tube 26 opens at its upper end into the chamber 20, and its lower end is provided with radial openings 28. The tube 27 covers the openings 28 of the tube 26 and extends to the portion cylindrical flocculation tank 12.

The tank 1 receives, on its outer face, four annular chambers 31, 32, 33, 34 superimposed.

Each chamber communicates with the adjacent chamber via a conduit 35.

A pump 36 is provided which sucks from the bottom of the vessel 1 through a conduit 37 and discharges into the lower annular chamber 31.

A recovery pump 39 sucks from the upper annular chamber 34 and delivers to the two intermediate chambers 32 and 33. An introduction of air is provided downstream of the pumps 36 and 39.

This introduction is done through a compressor that is not shown in the drawing.

The annular chambers are each equipped with a look 41 which allows access to the interior thereof.

The upper annular chamber 34 extends to the top of the storage tank 1 and is provided with an opening 43 opening on the outside.

The operation of the device described above is as follows the effluent to be treated first undergoes a physicochemical treatment and then a bacteriological treatment.

The effluent, coming from a storage zone 45, is sucked by the pump 21 to be introduced into the chamber 20. The suction of the effluent by the pump 21 is carried out intermittently, for example 15 to 30 suction seconds then rest time of 15 to 60 seconds, so that the effluent is introduced into the chamber 20 in a pulsed manner. In the chamber 20, the pumps 22 and 23 inject the effluent with coagulating reagents and flocculants. These reagents can be ferric chloride, aluminum sulphate or polymers and depend on the type of effluent to be treated. The action of the pumps 22 and 23 corresponds to an effluent pulsation period.

Under the effect of the pulsations of the pump 21, the effluent added with reagents is expelled from the enclosure 20 and escapes through the vertical conduit 25.

The openings 28 made in the upper tube 26 of the duct make it possible to homogenize the effluent / reagent solution. At the bottom of the feed conduit 25, the effluent is brought into contact with a bed of sludge consisting of flocs. The flocs are suspended by the pulsations that drive the effluent. In contact with the flocks forming the sludge bed, the organic or inorganic pollutants aggregate on these flocs and as it passes through the bed of sludge, the effluent clarifies. In the event of a charge increase, the excess sludge discharges out of the flocculation tank and collects at the center of the frustoconical part 4 of the clarification tank 2. They are extracted by the pump 18.

The clarified effluent being of a lower density than the flocs forming the sludge bed, it flows out of the clarification tank through the openings 3 formed therein.

The clarified effluent is discharged into the lower part of the storage tank 1 which surrounds the clarifying tank, passing through the filtering mass 8. This filtering mass may consist of grains of quartz, pozzolan, activated charcoal, diatomaceous earth or pumice stone and reduces the residual load of the effluent leaving clarification.

The filtering mass can be washed by the countercurrent introduction of a mixture of water and air through the nozzles 9. The introduction of this mixture takes place, simultaneously and at equal volume, with the extraction excess sludge pump 18 so as not to disturb the dynamics of clarification.

At this point, the effluent has undergone physicochemical treatment and is therefore clear. It is stored in the lower part of the storage tank. The effluent is then sucked by the pump 36 and is discharged, after being added with air, into the annular chamber 31 in a tangential manner, so as to create a vortex flow inside this chamber. The chamber 31 contains a granulate which fixes the bacteria present in the effluent. Inside the annular chamber, the granulate is suspended and agitated by vortex flow. This suspension and agitation of the granulate allow a remarkable fixation of the bacteriological pollutants present in the effluent. The pump 39 draws the effluent towards the annular chambers 32, 33 and 34 which communicate via the ducts 35. It maintains a constant velocity in them by reinjecting the effluent sucked into the upper chamber 34 in the intermediate chambers 32. and 33. Each of the chambers 31, 32 and 33 contains a specific granulate (activated carbon, sand or calibrated polystyrene beads) having an action on a specific bacterium, so that when the effluent is extracted from the annular chamber 34 by opening 43 it underwent a complete bacteriological treatment.

The effluent may be subjected to a subsequent treatment, for example addition of disinfectant product represented by the reference 45 of FIG. 2. FIG. 3 represents an embodiment of the invention intended to supply drinking water in sites isolated.

The device according to the invention is fed by a hand pump 50. The tank 2 is divided by two horizontal walls 51 and 52 which define an upper part 47, an intermediate part 48 and a lower part 49.

The upper part has an enclosure 20 into which a conduit 25 opens through an opening in the wall 52.

The supply duct 25 connects the enclosure 20 to the flocculation tank 12 which is located in the lower part of the tank 2.

The lower end of the duct 25 has a diverging frustoconical section 57.

The flocculation tank 12 rests on the bottom of the tank 2 and its frustoconical upper portion 13 adjoins the inner wall of the tank 2.

The frustoconical portion 13 of the flocculation tank is pierced with spill openings 55.

The wall 51 is pierced with a circular opening on which a concentric evacuation duct 56 is connected to the supply duct 25.

The exhaust duct 56 has radial discharge openings 59 at its upper end and terminates in a filter tank 60 filled with a filter material such as sand. A pipe 66 makes it possible to fill the tank 60 with filtering material. The bottom of the filtration tank 60 is provided with openings 61 protected by strainers 62.

Each strainer 62 is provided with a cleaning nozzle 65 connected to the pump 50. Each of the upper, intermediate and lower portions of the tank 2 is provided with a drain valve 61, 62, 63. The hand pump 50, thanks to a three-way manual valve 67, can suck a fluid from a borehole 68 or from the intermediate portion of the tank 2. This pump discharges, through a three-way manual valve 68, in the upper part of the tank 2 or in a duct 70 which supplies the cleaning nozzles 65.

The operation of this embodiment of the invention is now described. The valves 67 and 68 are oriented so as to draw non-potable water from a borehole 68 and to discharge this water into the upper part of the tank 2. The water is decanted and the particles are deposited on the wall 52. A flocculating or coagulating reagent is introduced into the chamber 20 by a pump, not shown. When a sufficient volume of water is introduced into the upper part 47, the water flows into the chamber 20 and into the supply conduit 25 which opens into the flocculation tank 12.

At the bottom of the supply duct 25, the water is brought into contact with a bed of sludge consisting of flocks. The diverging frustoconical section of the feed duct 25 allows excellent dispersion of the water in the sludge bed. The water is clarified in contact with the fluidized sludge bed. The excess sludge is discharged from the flocculation tank 12 through the openings 55 and flows into the bottom of the tank 2. This sludge can be extracted by the valve 63.

Under the effect of the pulsations of the pump 50, the clarified water escapes from the lower part 49 through the evacuation conduit 56 and discharges via the openings 59 into the filtration tank 60. The tank being filled with a filter material such as sand, the clarified water undergoes a filtration operation. The water exits the tank 60 through the openings 61 protected by the strainer 62 and is stored in the intermediate portion 48. The water can be withdrawn by the valve 62 to be consumed. The water may also be subjected to a second clarification cycle by orienting the valves 67 and 68 so that the pump 50 sucks at the intermediate portion 48 water which has undergone a first clarification cycle and delivers this water at the top 47 to undergo a new clarification cycle. The valves 67 and 68 may furthermore be oriented such that water is sucked at the intermediate portion 49 and discharged through the conduit 70 into the cleaning nozzles 65. The cleaning nozzles 65 open into the the strainers 62 and the water sent against the current cleans the filter media. During this operation, the valve 63 is open. The invention thus provides a particularly compact effluent purification device and an economic cost of acquisition while having excellent physicochemical and bacteriological purification capabilities.

It goes without saying that the invention is not limited to the embodiment described above by way of example, but that it embraces all variants.

Claims (3)

<B> CLAIMS </ B> 1. Effluent purification device comprising a clarifying tank (2), characterized in that it comprises - a pump (21, 50) pulsatingly delivering the effluent into a chamber (20) placed on the upper face of the clarification tank (2), - at least one addition metering pump (22, 23), in said chamber (20), a coagulating or flocculating reagent of the effluent, - a conduit (25) leading to the effluent supplemented with reagent (s) from said enclosure to the lower part of a flocculation tank (12) disposed inside the clarification tank, in which a bed of sludge is formed which the effluent crosses from bottom to top and in contact with which the effluent clarifies. 2. Effluent purification device according to claim 1, characterized in that the flocculation tank (12) comprises a frustoconical upper portion (13) extended by a cylindrical lower portion (14) into which the conduit (25) opens. ). 3. effluent purification device according to claim 1 or claim 2, characterized in that the conduit (25) comprises a first tube (26), one end of which opens into the chamber (20) and whose the other end is provided with radial homogenisation openings (28) and a second tube (27) having a diameter greater than the diameter of the first tube (26), the upper end of which covers the homogenization openings (28) of the first tube and whose lower end opens into the lower part of the frustoconical tray (12). <B> 4. </ B> Effluent purification device according to one of claims 1 to 3, characterized in that the lower part of the clarification tank (2) has a frustoconical portion (4), which receives the sludge overflowing from the flocculation tank. 5. Effluent purification device according to one of claims 1 to 4, characterized in that a pump (8) discharges the sludge collected in the frustoconical part of the clarification tank. 6. effluent purification device according to one of claims 1 to 5, characterized in that calibrated openings (3) are provided on the upper part of the clarification tank (2) to allow the clarified effluent to pour into a storage tank surrounding the clarification tank (2). 7. Effluent purification device according to one of claims 1 to 6, characterized in that the lower end of the supply duct (25) has a diverging frustoconical section. <B> 8. </ B> Effluent purification device according to one of claims 1 to 7, characterized in that a filter material (8) is arranged between the clarification tank (2) and the tank of storage <B> (1), </ B> through which the clarified effluent passes through before being stored in the lower part of the storage tank <B> (1). </ B> 9. Purification device effluent according to one of claims 1 to 7, characterized in that it comprises - a filtration tank (60) containing a filter material disposed between the enclosure (20) and the flocculation tank (13), - a wall (51) located between the flocculation tank (13) and the filtration tank (20), - a discharge duct (56) of greater diameter than the supply duct 25 and coaxial with the latter extending between the wall 51 and the filter tank (20). 10. Effluent purification device according to claim 9, characterized in that the upper edge of the frustoconical portion (13) of the flocculation tank (12) is joined to the inner face of the vessel (2). 11. effluent purification device according to claim 9 or claim 10, characterized in that the filter tank 60 has, on its underside, openings (61) protected by strainers (62) allowing the water filtered to flow. 12. Effluent purification device according to one of claims 1 to 8, characterized in that a pump (36) sucks the clarified effluent into the storage tank (1) and introduces it into at least one chamber ring (31) disposed on the outer face of the storage vessel containing a granulate fixing bacteriological elements. 13. effluent purification device according to claim 12, characterized in that the annular chambers are four in number (31, 32, 33, 34), each communicating with that adjacent thereto, by a conduit (35). . <B> 14. </ B> Effluent purification device according to one of claims 12 or 13, characterized in that a recovery pump sucks the clarified effluent at the upper annular chamber and reinjects it to the lower rooms.