FR2981926A1 - Station, useful for treating waste water from washing of vehicles, comprises deoiler arranged downstream from centrifugal machine, and UV generator arranged downstream from deoiler to neutralize proliferation of organisms in de-oiled water - Google Patents

Abstract

The station comprises a surge tank (3) for storing waste water to be treated, a centrifugal machine (4) arranged downstream from the surge tank for separation of solid particles from the waste water to obtain the solid particles and the clarified water, a deoiler (5) arranged downstream from the centrifugal machine for separating oils from the clarified water to obtain the oils and the de-oiled water, and a type C UV generator (6) arranged downstream from the deoiler to neutralize organisms in the de-oiled water. The generator includes a UV gun comprising a central channel. The station comprises a surge tank (3) for storing waste water to be treated, a centrifugal machine (4) arranged downstream from the surge tank for separation of solid particles from the waste water to obtain the solid particles and the clarified water, a deoiler (5) arranged downstream from the centrifugal machine for separating oils from the clarified water to obtain the oils and the de-oiled water, and a type C UV generator (6) arranged downstream from the deoiler to neutralize organisms in the de-oiled water. The generator includes a UV gun comprising a central channel for a passage of the de-oiled water and two lamps with UV rays extending on both sides of the central channel. The surge tank comprises a cylindrical conical bottom cistern including an exit opening at a lower end of the conical bottom for connecting a waste water routing pipe between a container and the centrifugal machine. The centrifugal machine is a centrifuge scraper. The station comprises: a storage tank (7) that stores the treated water and is arranged in downstream from the generator; and a controller to order an activation of the centrifugal machine, the deoiler and the generator when a volume of water in the storage tank is lower than a threshold. The storage tank includes a volume detector to measure the volume of water in the storage tank. The controller is ready to order opening or closing of a valve connected to an urban water circuit to fill the storage tank. The deoiler includes superimposed wings. Each wing extends between two lateral walls opposite from the deoiler, and is tilted towards a basic wall from the deoiler according to an angle of 40[deg] compared to a horizontal plane parallel with the basic wall. An independent claim is included for a method for treating waste water.

Description

FIELD OF THE INVENTION The present invention relates to the general technical field of the treatment of polluted effluents with a view to their purification, such as industrial or urban waste water. The present invention finds particular but not limited application in the treatment of truck wash water on washing areas. The present invention can also be used in the treatment of public fountain water, car wash water or even buses. PRESENTATION OF THE PRIOR ART A wastewater treatment method is known in which all the liquids to be treated are collected in a buffer tank. These liquids are then subjected to a centrifugal treatment to separate the sludge from the wastewater to be treated: on the one hand, sludge is obtained on the one hand and partially treated wastewater on the other hand. These partially treated wastewater is then subjected to de-oiling treatment to separate the oils from the wastewater to be treated: on the one hand, oils are obtained on the one hand and treated water on the other hand. A disadvantage of this process is its low efficiency. Another disadvantage of this process is the unsatisfactory degree of purity of the treated water. An object of the present invention is to provide a device and a wastewater treatment method to overcome at least one of the aforementioned drawbacks.

SUMMARY OF THE INVENTION To this end, the invention proposes a wastewater treatment plant, remarkable in that it comprises: a buffer tank for the storage of the wastewater to be treated, a centrifuge downstream of the reservoir buffer for the separation of solid particles from the wastewater to be treated, so as to obtain, on the one hand, solid particles and, on the other hand, clarified water, - a de-oiler downstream of the centrifuge for the separation of the oils from the clarified water, so as to obtain on the one hand oils and secondly deoiled water, and - at least one type C ultraviolet radiation generator downstream of the de-oiler to neutralize the proliferation of organisms in de-oiled water. The fact that the treatment plant comprises an ultraviolet radiation generator makes it possible to limit the proliferation of bacteria contained in the wastewater.

Preferred but non-limiting aspects of the device according to the invention are the following: the ultraviolet radiation generator comprises an ultraviolet gun consisting of a central channel for the passage of de-oiled water and at least two ultraviolet lamps extending on both sides of the central canal; - The buffer tank consists of a conical bottom cylindrical tank including an outlet opening at the lower end of the conical bottom for the connection of a sewage conveyance conduit between the reservoir and the centrifuge; the centrifuge is a scraper centrifuge; - The treatment plant further comprises a treated water storage tank downstream of the ultraviolet radiation generator; the storage tank comprises a volume detector for measuring the volume of treated water in the storage tank, the station further comprising a controller for controlling the activation of the centrifuge, the de-oiler and the ultraviolet radiation generator when the volume of water in the storage tank is below a threshold; - The controller is able to control the opening or closing of a valve connected to an urban water circuit to fill the storage tank; the de-oiler comprises a plurality of superimposed fins, each fin extending between two opposite side walls of the de-oiler and being inclined towards a bottom wall of the de-oiler at an angle of between 30 ° and 45 ° relative to a parallel horizontal plane; at the bottom wall, and preferably at an angle equal to 40 ° with respect to the horizontal plane; this maximizes the turbulence in the separator compartment S, which promotes the dissociation of the oil from the liquid to be treated. The invention also relates to a vehicle wash area remarkable in that it comprises a treatment station as defined above for the treatment of waste water from washing vehicles. The invention also relates to a remarkable wastewater treatment process in that it comprises the following steps: - the storage of the wastewater to be treated in a buffer tank, - the separation of solid particles from the wastewater to be treated using a centrifuge disposed downstream of the buffer tank, so as to obtain, on the one hand, solid particles and, on the other hand, clarified water; separation of the oils from the clarified waters by using a de-oiler arranged downstream of the centrifuge, so to obtain on the one hand oils and on the other hand deoiled water, - the neutralization of organisms present in de-oiled water using an ultraviolet radiation generator disposed downstream of the de-oiler. BRIEF DESCRIPTION OF THE DRAWINGS Other advantages and characteristics of the device according to the invention will become more apparent from the following description of several variant embodiments, given by way of non-limiting examples, from the appended drawings in which: FIG. 1 illustrates an embodiment of the wastewater treatment device according to the invention; FIG. 2 illustrates an example of a centrifuge that can be used in the treatment device illustrated in FIG. 1; FIG. An example of a de-oiler that can be used in the treatment device illustrated in FIG. 1 is FIG. 4 schematically illustrates the steps of the treatment method according to the invention. DETAILED DESCRIPTION OF THE INVENTION The device and method according to the invention will now be described in more detail with reference to the figures. In these different figures, the equivalent elements of the device and the method bear the same numerical references. Referring to Figure 1, there is illustrated an embodiment of the wastewater treatment plant according to the invention. In this figure, the treatment station is used for the treatment of wastewater from a washing area. Those skilled in the art will appreciate that the treatment station according to the invention is not limited to this application example. General features of the washing area The washing area comprises one (or more) treatment lane (s) 1 equipped with two treads 110 forming a raceway for the passage of a vehicle such as a heavy vehicle.

The washing area may be equipped with a raised device (not shown) movable in translation in two opposite directions along the corridor. The elevated device may include one or more spray systems for washing the vehicle from an aqueous solution.

The washing area also comprises a filtration grid 120 connected to a concrete window 2 for collecting wastewater flowing from the vehicle during washing thereof. Advantageously, the filtering grid may extend between the two treads 110.

In this case, the two treads 110 may be inclined so as to form a concave angle to allow the runoff of wash water in the filter grid. The view 2 wastewater collection is connected to the treatment station according to the invention. Treatment station The treatment plant comprises a buffer tank 3, a centrifuge 4, a de-oiler 5, an ultraviolet radiation generator 6 and a storage tank 7. Buffer tank The buffer tank 3 is connected to the wastewater collection line 2 via a pipe 91 for conveying wastewater. The flow of wastewater between the collection eye 2 and the buffer tank 3 can be obtained: - by gravity in the case where the buffer tank 3 is at a lower altitude than the view 2 collection of wastewater, or for example - using a circulating pump (not shown) for moving the wastewater through the conveying conduit 91. The buffer tank 3 can store the wastewater to be treated prior to their treatment, for example when the centrifuge 4, the de-oiler 5 and / or the ultraviolet radiation generator 6 are inactivated, or when the volume of treated water contained in the storage tank 7 is maximum. Advantageously, the buffer tank 3 may comprise a tank - for example cylindrical - including a conical bottom. This allows an accumulation of solid particles at the lower end of the conical bottom. The buffer tank 3 may include an outlet opening at the lower end (i.e. the lower end) of the conical bottom. This allows suction of the wastewater contained in the tank from the bottom so as to remove the solid particles present in the tank. Centrifuge The centrifuge 4 is disposed downstream of the buffer tank 3. The centrifuge 4 is connected to the outlet opening of the buffer tank 3 via a channel 92 for conveying water. The water supply channel 92 may comprise a circulation pump for moving the wastewater to be treated between the buffer tank 3 and the centrifuge 4. This water circulation pump has for example a flow rate of 15m 3 / h. Alternatively, the centrifuge may be a centrifugal pump. The centrifuge 4 makes it possible to separate a suspension in its liquid part and in its solid part. In an alternative embodiment, the centrifuge 4 is a centrifugal pump scraper. This makes it possible to improve the clarification yield of the treatment station.

The centrifuge 4 may be a manual or automatic centrifuge for the manual or automatic discharge of the solids contained in the drum.

This centrifuge has for example a capacity of 15,000 liters / hour. Referring to Figure 2, the centrifuge 4 comprises a clarification chamber 400 in which is housed a rotary cylindrical drum 410 on the wall 420 which is deposited solids.

The clarified liquid is discharged to a first outlet mouth 41 of the centrifuge 4. The first outlet mouth 41 is connected to the de-oiler 5 disposed downstream of the centrifuge 4.

The solid particles are evacuated to a bucket (not shown) at a second outlet mouth 42 of the centrifuge 4. Alternatively, the solid particles can be discharged to a mobile carriage for transporting the solid particles to an incinerator. example.

The de-oiler 5 and the centrifuge 4 are connected via a conveyance pipe 93 clarified water. Oil separator The de-oiler 5 separates oil or hydrocarbons contained in the wastewater to be treated. The de-oiler preferably comprises: an inlet for introducing the liquid to be deoiled into the de-oiler, and two outlets, a first outlet allowing the passage of the oils and hydrocarbons contained in the liquid to be deoiled, and a second outlet allowing the passage de-oiled liquid.

The treatment station according to the invention may comprise any type of commercial de-oiler. For example, the de-oiler may be a de-oiler of stainless material comprising a coalescer pack of stainless steel. Preferably, the de-oiler has a minimum flow rate of 3000 liters / hour. Referring to Figure 2, there is illustrated an example of de-oiler that can be used in the treatment device according to the invention. As recalled above, other types of commercial de-oiler may also be used in the context of the present invention. The de-oiler 5 comprises a housing 520 composed of a bottom wall 521 and four side walls extending perpendicularly to the bottom wall 521 so as to form a rectangular parallelepiped. Preferably, the device comprises a cover intended to cover the housing 520. The de-oiler also comprises an angled sleeve 510 for introducing into the housing 520 the liquid to be treated. One end 511 of the bent sleeve 510 extends outside the housing 520. This end 511 is intended to be connected to a pipe for bringing the liquid to be treated into the de-oiler. The other end of the bent sleeve 510 extends inside the housing. The sleeve 510 discharges effluent to be treated in an inlet compartment E of the housing 520. The inlet compartment E is delimited by: one of the side walls of smaller dimensions, the two side walls of larger dimensions, - the bottom wall 521 and - a plate 526 disposed inside the housing 520 and extending in a plane perpendicular to the bottom wall 521 and the side walls of larger dimensions. The plate 526 is separated from (ie does not contact) the bottom wall 521 so as to form an opening 527 for the passage of the flow to be treated to a separating compartment S. The separating compartment S is delimited by the plate 527, the side walls of larger dimensions and a double wall 528, 529 forming a rising cuff.

The double wall 528, 529 consists of two parallel partitions, each partition extending in a respective plane perpendicular to the bottom wall 521 and the side walls of larger dimensions.

The partition 528 closest to the separator compartment S is remote from the bottom wall, and the partition 529 farthest from the separator compartment S is in contact with the bottom wall 521 so as to form a channel for the passage of the treated liquid. .

This double wall 528, 529 forming a rising collar makes it possible to direct the flow of treated liquid towards the surface so that it flows into an outlet compartment O. The outlet compartment O is delimited by: one of the side walls of smaller dimensions, - the two side walls of larger dimensions, - the bottom wall 521, and - the partition 529 in contact with the bottom wall 521.

The outlet compartment makes it possible to neutralize the turbulence of the treated fluid before it leaves the treatment device at an outlet mouth 530 positioned on one of the side walls 522 of larger dimensions. The device also comprises a coalescer assembly 540 disposed in the separator compartment S. The coalescer assembly 540 comprises fins 542 inclined fixed on a base. These fins are superimposed one above the other between the bottom and the top of the housing. Referring to Figure 2, the de-oiler comprises three sets of superimposed fins. Preferably, the coalescer assembly 540 is disposed near the plate 527, that is to say at a distance from the plate 527 less than twice the smallest dimension of a fin 542. The fins 542 are extend towards the bottom wall 521 at an angle α of the order of 30 ° relative to a horizontal plane parallel to the bottom wall 521. In the embodiment illustrated in FIG. 2, the fins or blades 542 extend between the larger walls 522, 524 of the housing 520. However, in other embodiments, the fins 542 may extend between the smaller walls 523, 525 of the housing 520.

Preferably, the device comprises a skimmer 550 (or "skimmer" according to the English terminology) disposed in the upper part of the housing 520 to recover the floating oil layer on the surface of the liquid contained in the separator compartment S.

The housing 520 includes a through-light 553 on one of 522 of its walls. This light is in contact with the skimmer 550 to allow the oil to be fed outside the de-oiler. This makes it possible to limit the risks of oil saturation of the de-oiler and thus to limit the maintenance operations to be carried out on the de-oiler. The first outlet of the de-oiler allowing the passage of the de-oiled liquid is connected to the ultraviolet radiation generator via a routing pipe for the passage of de-oiled water from the de-oiler to the ultraviolet radiation generator. Ultraviolet radiation generator The ultraviolet radiation generator 6 purifies the water to be treated by neutralizing the proliferation of bacteria and other organisms such as fungi or algae. This generator may be a type C ultraviolet radiation generator (wavelength between 100 and 280 nanometers).

The ultraviolet radiation generator 6 may have a bactericidal effect or a bacteriostatic effect depending on the amount of ultraviolet radiation generated; more precisely, the ultraviolet radiation generator can: destroy the living cells contained in the wastewater to be treated (bactericidal effect), or sterilize the living cells contained in the wastewater to be treated (bacteriostatic effect). The presence of an ultraviolet radiation generator 6 eliminates the use of bactericide or fungicide to neutralize the proliferation of bacteria and other undesirable organisms (fungi, algae, etc.) in the treated liquid. Thus, in the context of the present invention, the disinfection of the water to be treated is not accompanied by the formation of reaction products with the organic materials contained in the water. It should be noted that the use of fungicide and / or bactericide has many disadvantages for the treatment of wastewater intended for use in pressurized water spraying systems. In particular, the use of fungicide and / or bactericide: - decreases the life of pressurized water projection systems such as high pressure lances; - presents a risk for the user. Thanks to the use of an ultraviolet radiation generator 6, the present invention overcomes the disadvantages associated with the use of fungicide and / or bactericide in the water to be treated. Advantageously, the ultraviolet radiation generator 6 may comprise an ultraviolet gun consisting of a central channel for the passage of the water to be purified and at least two ultraviolet lamps extending on either side of the central channel. This makes it possible to improve the quality of the purification of the waters to be treated.

The ultraviolet radiation generator 6 is connected to the storage tank 7 located downstream of the ultraviolet radiation generator 6 via a tube 95 for conveying the treated water.

Storage tank The storage tank 7 allows the storage of treated water prior to their subsequent use, for example to clean a vehicle at the washing area.

The treated water contained in the storage tank 7 can also be used to clean one of the elements constituting the treatment station such as the centrifuge. In this case, the water used for cleaning the centrifuge is returned by a water delivery system (eg a pipe) to the buffer tank for treatment. The storage tank 7 may be an open or closed vessel of a capacity that may vary depending on the application. In the embodiment illustrated in Figure 1, the storage tank 7 has a capacity of 5 m3.

Controller The activation and deactivation of different elements of the treatment station such as the centrifuge 4, the various pumps of the station, the de-oiler 5 and the ultraviolet radiation generator 6 can be controlled by a controller of the treatment station. . For example, in one embodiment, the storage tank 7 includes a volume detector for measuring the volume of treated water in the storage tank 7. The controller controls the activation of the centrifuge 4, the de-oiler 5, and of the ultraviolet radiation generator 6 when the volume of water in the storage tank is below a threshold.

This management of the activation of the various elements of the station makes it possible to limit the amount of energy used by the treatment station for the treatment of wastewater.

Advantageously, a water pipe of the urban network can be connected to the storage tank to allow filling of said storage tank with water from the urban network. This may be useful for example in the case of high heat inducing an increase in the evaporation of the liquid contained in the storage tank, or when the storage tank no longer contains enough treated water to allow water supply of the car wash. In this case, the controller may be programmed to control the opening (or closing) of the electronic valve connected to the water line of the urban network when the volume of water contained in the storage tank is lower (or higher) at a threshold predetermined by the user. A process of treatment using the treatment station 20 illustrated in FIG. 1 will now be described. In a first step, the method comprises a step of storing the wastewater to be treated, for example in the buffer tank of the treatment station. This makes it possible to regulate the flow of water to be treated by the various elements (centrifuge, de-oiler, type C ultraviolet radiation generator) of the treatment station. In another step, the method comprises separating the solid particles from the wastewater to be treated. This separation is carried out using the centrifuge of the treatment plant. This makes it possible to obtain, on the one hand, solid particles or sludges and, on the other hand, clarified waters. The solid particles or sludge are removed from the treatment circuit, for example using a bucket.

The clarified waters are conveyed to an oil separator for the implementation of a step of separation of the oils and hydrocarbons from the clarified waters. This makes it possible to obtain, on the one hand, oils and hydrocarbons that are evacuated and, on the other hand, de-oiled waters.

The de-oiled water is then treated by an ultraviolet radiation generator to neutralize the organisms present therein. Once the neutralization step has been carried out, the treated water is stored in a storage tank for later use, for example in a washing station. The treatment station and method described above can be used for the treatment of wash water from a truck wash area. This treatment station and its method are adaptable to existing or future installations. The reader will have understood that many modifications can be made to the oil-water separation device described above without materially going out of the new teachings presented here. For example, in an alternative embodiment, the treatment station comprises a membrane filter for clarification and disinfection of water by ultrafiltration prior to storage in the storage tank. This membrane filter comprises membranes for separating all particles smaller than 10-20 μm in size such as algae, parasites, bacteria, viruses, germs or organic molecules. This membrane filter may be provided upstream or downstream of the ultraviolet radiation generator.

It is therefore obvious that the examples which have just been given are only illustrations that are in no way limitative.

Claims (10)

1. A wastewater treatment plant, characterized in that it comprises: - a buffer tank (3) for the storage of wastewater to be treated, - a centrifuge (4) downstream of the buffer tank for separation of solid particles of the wastewater to be treated, so as to obtain on the one hand solid particles and on the other hand clarified water, - a de-oiler (5) downstream of the centrifuge for separating the oils from the clarified water, so as to obtain on the one hand oils and secondly deoiled water, and - at least one type C ultraviolet radiation generator (6) downstream of the de-oiler to neutralize the proliferation of organisms in de-oiled water. A treatment plant according to claim 1, wherein the ultraviolet light generator (6) comprises an ultraviolet gun consisting of a central channel for the passage of de-oiled water and at least two ultraviolet lamps extending from and else of the central channel. 3. Processing station according to one of claims 1 or 2, wherein the buffer tank (3) consists of a conical bottom cylindrical tank including an outlet opening at the lower end of the conical bottom for the connection of a wastewater conveying conduit between the reservoir and the centrifuge. 4. Treatment station according to one of claims 1 to 3, wherein the centrifuge (4) is a scraper centrifuge. 5. Treatment plant according to one of claims 1 to 4, which further comprises a storage tank (7) treated water downstream of the ultraviolet radiation generator. The treatment station of claim 5, wherein the storage tank (7) comprises a volume detector for measuring the volume of water treated in the storage tank, the station further comprising a controller for controlling the activation of the centrifuge (4), the de-oiler (5) and the ultraviolet radiation generator (6) when the volume of water in the storage tank is below a threshold. 7. Treatment station according to claim 6, wherein the controller is adapted to control the opening or closing of a valve (8) connected to an urban water circuit to fill the storage tank (7). 8. Treatment plant according to one of claims 1 to 7, wherein the de-oiler (5) comprises a plurality of superimposed fins (542), each fin extending between two opposite side walls of the de-oiler and being inclined towards a bottom wall (521) of the de-oiler at an angle of between 30 ° and 45 ° relative to a horizontal plane parallel to the bottom wall (521), and preferably at an angle equal to 40 ° relative to the horizontal plane. 9. A vehicle wash area characterized in that it comprises a treatment station according to one of claims 1 to 8 for the treatment of waste water from the washing of vehicles. 10. Wastewater treatment process characterized in that it comprises the following steps: the storage (1000) of the wastewater to be treated in a buffer tank, the separation (2000) of solid particles from the wastewater to be treated using a centrifuge disposed downstream of the buffer tank, so as to obtain, on the one hand, solid particles and, on the other hand, clarified waters, the separation (3000) of the oils from the clarified waters by using a de-oiler arranged downstream of the centrifuge, so as to obtain, on the one hand, oils and on the other hand de-oiled water, the neutralization (4000) of organisms present in the de-oiled water by using an ultraviolet radiation generator disposed downstream of the de-oiler.