FR2904559A1 - Cooling tower waste e.g. sludge, disinfecting installation for destruction of e.g. legionella pneumophila, has platform defining lower space in which vapor is injected, and upper space in which vapor arrives after its passage via platform - Google Patents

Abstract

The installation (10) has a sealed enclosure (12) with a platform (14) that is permeable to water vapor and on which waste layer (100) rests, where the platform is formed of a metallic rail. A conduit (16) injects the vapor into the enclosure, and a temperature sensor (18) detects temperature of the waste resting on the platform. The platform contacts with a wall of the enclosure over its periphery to define, in the enclosure on both sides of the platform, a lower space in which the vapor is injected, and an upper space in which the vapor arrives after passage of the vapor via the platform. An independent claim is also included for a method for disinfecting cooling tower waste.

Description

 The invention relates to an installation and a method for disinfecting waste cooling towers for the destruction of possible pathogens.

Cooling towers, in particular those of nuclear or thermal power stations, are suitable environments for the development of certain pathogens, in particular bacteria (especially Legionella pneumophila) and amoebae (especially Naegleria fowleri).

These pathogens affect both the water circulating in these cooling towers, the residues of these towers such as cleaning residues, namely sludge, other waste such as scale and all facilities forming the interior lining these towers, including parts that are regularly replaced during maintenance procedures and may be metal, plastic (including PVC) or other. Usually, the treatment to destroy pathogens, especially in water, is a chemical treatment.

WO 95/21129 relates to the treatment of sludge from wastewater to eliminate dangerous bacteria. For this purpose, it is intended in particular to place these sludge in a series of autoclaves in which steam heated to a temperature of 120 to 135 ° C is injected for 10 to 15 minutes. Then, the sludge is subjected to a drying step prior to evacuation.

It is also known to thermally treat with water the waters whose pathogenic agents are desired to be destroyed. However, in the case of amoebae of the Naegleria fowleri type, they can be in an encysted form allowing it to survive over particularly long periods (several years) and to be relatively resistant. The only known effective treatments against amoebas, and in particular Naegleria fowleri, are chemical treatments.

In addition, in general, in the case of a waste treatment that may be composed of different materials, it is often necessary to perform a preliminary sorting between these different materials, in order to adapt the disinfection conditions to the nature of the waste, at least according to the type of material that constitutes it, and possibly according to the shape of the materials (size, consistency more or less compact or soft ...).

Also, it is sometimes implemented, in order to destroy several types of pathogens, several treatments adapted to each category of pathogen.

The present invention aims to provide an installation and a disinfection process to overcome the disadvantages of the prior art and in particular offering the ability to disinfect all types of waste from cooling towers, simply and safely, by means of a physical inactivation and not a chemical inactivation, so as to inactivate in particular Legionella pneumophila bacteria and amoebae Naegleria fowleri.

For this purpose, according to the present invention, there is provided a facility for disinfecting waste cooling towers for the destruction of at least some of the possible pathogens, comprising:

a sealed enclosure containing support means permeable to steam and on which the waste is able to lay in a layer,

means for producing steam and means for injecting steam making it possible to bring the vapor into the chamber, and

- Temperature measuring means adapted to detect the temperature of the waste disposed on said support means.

Thus, thanks to these support means, it is possible to dispose the waste in a layer of relatively regular thickness, which, combined with the vapor permeability of the support means, allows them to be easily fully brought into contact with each other. with this steam, whereby the waste homogeneously reaches a temperature sufficient to eliminate pathogens, and in particular Legionella pneumophila and Naegleria fowleri. In addition, thanks to the measuring means, which directly report the temperature of the waste, it is thus possible to ensure that this sufficient temperature is reached.

According to an advantageous advantageous arrangement of this installation, said support means come into contact with the wall of the enclosure over their entire periphery so as to delimit in the enclosure, on either side of said support means, a lower space in wherein the steam is injected and an upper space in which the steam reaches after passing through said support means. In this way, the steam is forced through the support means and thus through the waste which is thus brought to the temperature sufficient to destroy the pathogens more quickly.

According to a first preferred embodiment of the installation according to the invention, said support means comprise at least one floor that is permeable to steam.

According to a second preferred embodiment of the installation according to the invention, said support means comprise at least one endless belt arranged at least partially in the enclosure and associated with drive means allowing the continuous advancement of the endless belt, and control means of said drive means. In this way, the installation can be used continuously, the waste being disinfected during their stay on the endless carpet at an upstream end of which the waste is brought and at the other end downstream of which the waste is removed. This continuous mode of operation is obviously very interesting to treat large quantities of waste because it provides a significant return. According to a third preferred embodiment of the installation according to the invention, said support means comprise at least one mobile carriage, said enclosure comprises at least one movable panel for the entry and / or exit of the carriage with respect to the enclosure, and said installation further comprises positioning and guiding means allowing the carriage to traverse the installation and to be placed in a treatment position in the enclosure. In this case, it works batch of waste to be treated.

Also, preferably, the installation further comprises means for programming the duration and the treatment temperature, connected to said temperature measuring means. In this way, it is possible to automate the disinfection monitoring that is performed when the waste has been brought to the programmed temperature for the programmed time.

In addition, preferably, the installation comprises one or more of the following provisions:

- means of supplying waste to dispose of waste to be treated on said support means and disinfected waste disposal means for emptying the disinfected waste out of the enclosure;

means for draining the condensate that forms in the enclosure; upstream of the feed means, means for treating the waste, in particular means for raking, grinding, dehydrating the waste and / or mixing with other waste and / or with a structuring material.

Optionally, if one wants to disinfect the waste with respect to one or other pathogens that Legionella pneumophila and Naegleria fowleri, these other pathogens are not sensitive to heat but being sensitive to a chemical treatment, said steam injection means or the waste is associated with at least one source of a chemical adjuvant, in particular an oxidizing or biocidal adjuvant. In addition, in order to treat a larger quantity of waste in the enclosure without increasing its floor area, it is possible for said enclosure to have more than one disinfection chamber (at least two) able to contain each of the support means for the simultaneous treatment of several layers of waste, these separate rooms can be placed next to one another and / or above one another, superimposed.

In the case of superimposed disinfection chambers, it is understood that said support means comprise several floors (each forming a platform) or carpet (possibly endless) superimposed on each of which rests a layer of waste subjected to steam.

These floors may be permeable and serve as a direct support for the waste layer or these floors may be impervious to steam and serve as a separator between two separate disinfection chambers. In the latter case, according to one embodiment, this impermeable floor is able to be surmounted by a trolley which contains the layer of waste and whose walls, in particular the bottom, are permeable to steam.

The present invention also relates to a method of disinfecting waste cooling towers that may contain pathogenic elements. For this purpose, the process is characterized in that it comprises the following step: said waste is subjected to steam so that it has a minimum temperature of 60 ° C for a minimum of 5 min, that disinfection is carried out which destroys any presence of Legionella pneumophila type bacteria and amoebae type Naegleria fowleri.

In this way, it is understood that by a single heat treatment carried out under pre-established temperature conditions, and for a minimum duration, it is ensured that all the waste is disinfected.

Preferably, one or more of the following arrangements are implemented:

the minimum temperature of the waste is 65 ° C., advantageously 70 ° C. or 75 ° C. the minimum duration during which the waste is subjected to steam is 10 minutes, advantageously 15 minutes or 20 minutes;

- the temperature of the waste is measured in several locations;

the method also comprises the following step: the waste is layered beforehand on vapor-permeable support means contained in an enclosure;

said support means are placed in contact with the wall of the enclosure over their entire periphery so as to delimit in the enclosure, on either side of said support means, a lower space in which the steam is injected and an upper space in which the steam reaches after passing through said support means, and the steam is injected under said support means; in this way, the steam is forced through the support means and through the waste; - Waste disposal means are also used for disposing the waste on said support means and disinfected waste disposal means for emptying the disinfected waste out of the enclosure;

the process also comprises the following step: an initial treatment of the waste is carried out, before submitting them to the steam, in particular crumbling, grinding, dehydration or mixing with other waste and / or with a structuring material;

the process also comprises the following step: at least one chemical adjuvant, in particular an oxidizing or biocidal adjuvant, is combined with steam or waste before sending said vapor to the waste;

- The method is carried out continuously by means of at least one endless belt forming the support means, arranged at least partially in the enclosure and associated with drive means for continuous advancement of the endless belt, and control means of said drive means;

the process is carried out by batches of waste by means of at least one mobile carriage forming the support means, able to come into the enclosure and associated with guiding and positioning means enabling the carriage, via at least one wall; mobile speaker, to enter and leave the enclosure respectively before and after the disinfection step;

- the waste belongs to the group of materials consisting of sludge, scale, plastics, metals or a mixture of them;

- The waste is arranged in a layer of a thickness between about 3 and 80 centimeters, preferably between 5 and 30 centimeters, and preferably between 10 and 20 centimeters.

Other advantages and characteristics of the invention will become apparent on reading the following description given by way of example and with reference to the appended drawings in which:

- Figure 1 shows schematically a first embodiment of a disinfection system according to the present invention; - Figure 2 shows schematically a second embodiment of a disinfection system according to the present invention;

- Figure 3 shows an alternative embodiment of the installation according to the second embodiment; and - Figure 4 schematically shows a third embodiment of a disinfection system according to the present invention.

A disinfection installation 10 as represented in the case of the first embodiment of FIG.

12 closed: here an upper cover 12a closes the top opening of a chest 12b formed of a bottom wall vertically belted by a side wall.

This enclosure 12 contains, as a waste support means 100, a floor 14 formed of a metal grid (for example stainless steel) whose edge joins the side wall of the trunk 12b, being in contact with it so that waterproof.

A pipe 16 serves as a steam injection means and opens into the chamber 12 under the floor 14. The floor 14 to allow through its thickness

(arrows 17) forced passage of the steam that is injected into the chamber 12 from the pipe, this floor 14 is permeable to water vapor.

For this purpose, preferably, the floor 14 is solid and it is made of a material permeable to water vapor, or the floor 14 carries openings through the entire thickness of the floor (this is the case when it consists of a metal grid). These openings have a size of between 0.5 and 10 millimeters, and preferably an average dimension of the order of 1.5 millimeters.

The pipe 16 is connected to a boiler (not shown) producing water vapor whose pressure can vary between 0 and 2 bar.

A layer of waste 100 of uniform thickness (between 3 and 30 cm) is distributed over the entire surface of the upper face of the floor 14. This homogeneous thickness of the waste layer 100 makes it possible to obtain an increase in temperature uniform on all treated waste, the diffusion of this heat by steam facilitating the rise in temperature to reach the minimum temperature destroying pathogens. In order to monitor the temperature evolution within the waste layer 100 and to control that temperature reaches a minimum value, several temperature probes 18 are placed directly in the waste layer 100.

These temperature probes 18 are connected to a temperature control box 20 comprising in particular a display screen 20a on which each of the temperatures measured by the different temperature probes 18 can be viewed, as well as an adjustment knob 20b making it possible to adjust the minimum temperature that it is desired to reach in the waste layer 100. In addition, this temperature control unit 20 comprises a detection system which signals that the set of temperature probes reaches this minimum temperature: a light signal or For example, a hearing aid (alarm) is used for this purpose.

Condensation is formed during the steam treatment, condensate draining means are provided: for this purpose, a chimney 22 opening into the cover 12a, which remains in principle open, and a drain pipe 24 are used. opening into the trunk 12b, for example at the bottom, provided with a valve or a valve that is open once the steam injection is complete.

The disinfection installation 10 makes it possible simultaneously to carry out the disinfection treatment for a batch of waste corresponding to the layer of waste 100 disposed on the floor 14.

This waste layer 100 may be disposed manually or automatically on the floor 14, when the cover 12a is removed.

For example, as shown in Figure 1, can be used as a waste feed means, a distribution hopper 30 containing the waste to be treated 102 and equipped in its lower part, a tilting door 32 Advantageously, this hopper 30 is as wide as the floor 14 and it can advance (arrow 34) along the length of the enclosure 12 by means of guiding means 36 which can take the form of, for example, a rail or a rack.

According to the disinfection method according to the present invention, once the waste layer 100 has been brought to the minimum temperature (60 ° C, preferably 70 ° C or even 75 ° C or 80 ° C) for a minimum duration ( contact time) of 5 min (preferably 10 min or 15 min or 20 min), the disinfected waste is removed from the floor 14 by evacuation means (not shown) manual or automated.

Optionally, one (or more) initial treatment of the waste is carried out before placing them in the layer 100 and subjecting them to steam in the enclosure 10.

In particular, during this initial treatment can be carried out a crumbling and / or grinding to reduce the size of waste and facilitate their temperature rise.

Also, this initial treatment may include a dehydration step to improve the vapor permeability.

In addition, the initial treatment may comprise a step of mixing with one or more other products, such as waste and / or with a structuring material.

By structuring material is meant in the present patent application a material which gives a more airy structure to very compact waste, including wet mud type of small particle size, and which by increasing the permeability of waste facilitates the penetration of the steam and its contact with the entire volume of waste. By way of nonlimiting examples, mention may be made of wood chips and / or pieces of plastic material.

Reference will now be made to FIG. 2 which represents a second embodiment embodying the principles described above in connection with the first embodiment of FIG. 1 with regard to the disinfection installation 10. The disinfection installation 110 of FIG. Figure 2 shows the same reference signs increased by a value 100 than those of Figure 1 when it comes to the same elements.

In the case of the second embodiment of a disinfection installation 110, in order to allow the implementation of the process according to the present invention in a continuous manner, the waste layer

100 rests on an endless belt 114 which advances through drive means consisting of rollers 115.

Here, the enclosure 112 is delimited by the box 112b which can be secured to its cover 112a. The hopper 130 is disposed at an opening of the cover 112a which is located above the upstream zone (left of FIG. 2) of the belt 114. This hopper 130 is associated with a first conveying system 138 for the continuous supply of waste to be treated 102.

The hatch 132 (represented here in a sliding version) of the hopper 130 makes it possible to modify the flow rate of the waste to be treated 102 which penetrates into the chamber 12 in the upstream zone of the belt 114.

The advancing speed of the belt 114 by the rollers 115 and the longitudinal dimension of the enclosure 112 are such as to ensure a contact time between the waste layer 100 and the carpet 114 sufficient to allow the steam coming from the pipe 116 to raise the waste from the layer 100 to the minimum temperature for the minimum duration.

Preferably, as shown in FIG. 2, the upstream and downstream ends of the carpet 114 are in contact with the lateral walls of the trunk 112b of the enclosure 112. It is jointly provided that the transverse edges of the endless belt are also in contact with the other two side walls of the trunk 112b of the enclosure 112. To perfect this contact to obtain a seal forcing the passage of steam through the endless belt 114, it is advantageously available, at least on the walls side of the trunk 112b (or along the transverse edges of the belt 115), sealing elements such as rubber seals, a flexible skirt ...

Thus, it is ensured that the steam coming from the pipe 116 passes through (arrows 117) the endless belt 114 carrying the waste layer 100.

In this Figure 2, there is the chimney 122 and the drain pipe 124, provided with a valve or a valve, for discharging liquids resulting from the condensation of steam.

There is also the temperature control box 120 comprising the display screen 120a and the adjustment knob 120b, the temperature control box 120 being connected to a plurality of temperature sensors 118 which are placed in this case above the waste layer 100.

It is important that the adjustment of the height position of these temperature probes 118 is possible in order to allow positioning as close as possible to the layer of waste 100. not

Also, in this case, preferably, the control system of the housing 120 allows an automatic correction of the temperature measured by the temperature sensors 118 to take into account the distance that separates them from the waste layer 100 and ensure that the detection system takes into account the temperature of the materials composing this layer of waste 100.

If it is desired to increase the treatment capacities of the disinfection installation 10 of the first embodiment (FIG. 1) or the disinfection installation 110 of the second embodiment (FIG. 2), it is possible to envisage providing the means for support of the waste layer 100 on several superimposed levels.

In the case of the first embodiment of FIG. 1, it is therefore conceivable to place several floors 14 on top of one another with one or more pipes 16 allowing the steam to come under pressure under the floors 14.

In the case of the second embodiment of FIG. 2, if it is envisaged to arrange several endless belts 114 on top of one another, the arrangement of the variant constituted by the disinfection installation 210 can be achieved. shown in Figure 3. The disinfection facility 210 of Figure 3 bears the same reference signs increased by a value 100 than those of Figure 2 when it comes to the same elements.

The disinfection system 210 of FIG. 3 repeats the principles described above in connection with the disinfection system 110 of FIG. 2.

However, here the disinfection system 210 processes continuously and at the same time three layers of waste 100, a layer being treated by each of the three levels A, B and C which are separated in a sealed manner from one another by delimiting chambers. independent. Each level A, B or C functions in the same way as the disinfection system 110 of the second embodiment of FIG. 2:

a first conveyor system 238 carries the waste to be treated 102 above a distribution hopper 230, the lower part of which is equipped with a hatch 232 to regulate the flow rate of the waste to be treated 102; -The opening of the hopper 230 is located in the upstream zone of the upper face of an endless belt 214 whose edges are in sealing contact with the side walls of the chest 212b of the enclosure 212;

the downstream zone of the upper face of each endless belt 214 (driven by rollers 215) brings the waste layer 100 to the inlet of an evacuation system 242 carrying the disinfected waste 104 to the second system of conveying 240.

In FIG. 3, the evacuation system 242 comprises gutters and gutters connected to the downstream zone of the upper face of each endless belt 214 of each of the three levels A, B and C, and a central descent pipe gathering the disinfected waste 104 resulting from the three levels A, B and C to the second conveyor system 240.

At each of the three levels A, B and C, the disinfection facility 210 also comprises a pipe 216 placed under the endless belt 114 corresponding to the arrival of water vapor that will penetrate the layer of waste 100, via the endless belt 214 (arrows 217), and temperature probes 218 disposed near the waste layer 100 being processed. For temperature monitoring, the disinfection facility 210 may comprise a single housing 220 (display screen 220a, adjustment button 220b connected to all of the temperature sensors 218 and detection system).

For the collection and discharge of the condensate, there are provided several chimneys 222 (one per level) and several drain pipes 224 (one per level) each provided with a valve or a tap.

Referring now to Figure 4 which shows a third embodiment, in its variant form with superposition of two treatment areas. The disinfection plant 310 of FIG. 4 bears the same reference signs increased by a value 300 as those of FIG. 1 when it is the same elements.

In this third embodiment, as in the case of the first embodiment, a batch or sheeting process is carried out. On the other hand, the main difference lies in the fact that instead of disposing of the waste layer 100 directly on a fixed floor 14 permeable to steam, a movable support is used in the form of a rolling carriage 314.

This carriage 314 moves in the disinfection installation 310 along a path, for example on rails, in order to pass in successive zones each corresponding to one of the preceding waste treatment.

Thus, such rails serve as positioning and guiding means enabling in particular the carriage 314 to be placed in a treatment position in the enclosure 312. In addition, there are provided control means (not shown) and control means. traction

(not shown) of the carriage to move it from one area to another

First, coming from an entry zone 350, the carriage arrives in a filling zone 351 of the carriage 314, passing under a hopper 330, provided with a bottom hatch 332, and fed with waste by a first conveying system 338 for continuously feeding waste to be treated 102. It is understood that when the hatch 332 is opened, thanks to the width of the hopper 330 which is identical to that of the carriage 314, it is possible to complete the filling of the hopper. carriage as it passes under the hatch 332 (arrow 360 in Figure 4).

Then, the trolley 314 filled with waste arrives at the location of a charging zone 352 of the enclosure (situation shown in dashed lines).

This enclosure 312 situated in the zone of the enclosure 353 delimits a closed space which opens at the front and at the back by doors, respectively 312a and 312b, which are movable (arrows 361 and 362) to leave pass the carriage 314, respectively to the inlet (left in Figure 4) or the outlet (right in Figure 4) of the enclosure 312.

More specifically, in the illustrated version which has in the chamber 312 two separate disinfection chambers 312c and 312d superimposed, separated by an impervious floor 365, the loading area 352 is equipped with a lifting table 364.

In its low position, shown in solid lines in the figure

4, the lift table 364 allows the carriage 312 to access, after opening the front door 312a, in the lower disinfection chamber 312c. In its high position, represented in dotted lines on 4, the lifting table 364 allows the carriage 312 to access, after opening the front door 312a, in the upper disinfection chamber 312d.

The two disinfection chambers 312c and 312d have the same equipment, namely a pipe 316 opening into the impermeable floor 365, for the arrival of the water vapor which will penetrate the layer of waste 100, via the walls, and Particularly the bottom, the carriage 314 which are vapor permeable (arrows 317), and temperature probes 318 disposed near or in the waste layer 100 being processed.

When the carriage 314 enters one of the disinfection chambers 312c and 312d of the enclosure 312, it is then placed in the treatment position in which, after closing the front door 312a, it is possible to implement the method of disinfection according to the present invention. This setting treatment position is preferably automatically by means of positioning and guiding, including rails.

For example, the walls of the carriage 314 are made with metal grids or pierced walls (for example stainless steel).

In order to force the passage of steam in the waste layer 100, the carriage preferably has sealing means along its contour, such as a flexible rubber-type seal which forms a bead coming from, in the position of treatment, bearing against the walls of the disinfection chamber 312a or 312b in which is the carriage 314.

For temperature monitoring, the disinfection facility 310 may comprise a single housing 320 (display screen 320a, adjustment button 320b connected to all of the temperature sensors 318 and detection system).

For the collection and evacuation of the condensate, several chimneys 322 (one per disinfection chamber) and several drain pipes 324 (one per disinfection chamber) are provided, all of these being provided with a valve or a tap. . It is therefore possible, in the enclosure 312, at the same time, offset or successively the treatment of two batches of waste present in carriages 314 located one above the other in the two disinfection chambers 312c and 312d of the enclosure 312.

When the disinfection treatment is completed, the rear door 312c is opened and the trolley (s) leaves (successively) at an unloading zone of the enclosure 354 equipped with another lifting table 364. .

Then, the carriage advances and arrives in an unloading area of the carriage 355 equipped with a second conveyor system 340 allowing the discharge of the disinfected waste 104 out of the enclosure 312. To facilitate the initial loading and unloading, it is expected advantageously that the carriage 314 has tilting front and rear walls.

In the embodiment shown, the filling area of the carriage 351 is placed upstream of the enclosure 312, but it is quite clear that in a variant (not shown) the trolley waste feed means (here the hopper 330 and the first conveying system 338) are placed in the vicinity (for example partly above) of the enclosure 312 to fill the carriage (s) 314 while it (they) is (are) already positioned (s) in the disinfection chamber (s) 312a (312b) of the enclosure 312.

Similarly, in the embodiment shown, the unloading area of the carriage 355 is placed downstream of the enclosure 312, but it is quite clear that in a variant (not shown) the means for evacuating waste of the carriage (here the second conveyor system 340) are placed in proximity (for example partly below and / or beside) of the enclosure 312 to empty the carriage (s) 314 while it (s) ) is (are) still positioned in the disinfection chamber (s) 312a (312b) of the enclosure 312.

It will be understood that in the context of the present invention, a variant of this disinfection system 310 according to the third embodiment is devised, which consists in providing only one disinfection chamber in the enclosure 312, without a lifting table 364 in areas 352 and 355.

Also, in the context of the present invention, another variant of this disinfection system 310 according to the third embodiment, which consists in placing the zones 352, is conceived. (loading of the enclosure) on the one hand and the zones 354 and 355 (unloading the enclosure and unloading the carriage) on the other hand on the same side of the enclosure 312, that is to say, the same the side of the zone of the enclosure 353, this side forming both the upstream and the downstream or the inlet and the outlet of the enclosure 312.

The first conveying system 138, 238 or 338 allowing the supply of waste to be treated 102 in the enclosure 112 or 212 and the second conveying system 140, 240 or 340 allowing the evacuation of the disinfected waste 104 out of the enclosure 112, 212 or 312 may take a number of forms; endless belts or belt conveyors or conveyors, with buckets, with screws, with support trays ...

The installation and the disinfection process which has just been exposed makes it possible to destroy the pathogenic agents constituted by the bacteria of the Legionella pneumophila type and the amoebae of the Naegleria fowleri type.

However, in order to complete this disinfection process in order to reach other pathogens, it is possible to associate with the vapor and / or the waste one or more chemical adjuvants, for example an oxidizing or biocidal adjuvant. In this case, it suffices, for example, to mix this chemical adjuvant with the water supplying the boiler with steam.

Tests were conducted with an oil boiler producing 200 kg / hour of steam at a pressure of 0.5 bar at a temperature between 100 and 140 ° C.

In order to verify that the temperature in the treated materials reached the prescribed minimum value, the tests were conducted using six temperature probes.

The results of these tests are shown in Table I below. No. Thickness Efficiency Efficiency

Material type Test duration (cm) Legionella Naegleria pneumophila treatment

Not proven

2 Tartar tartra 15 8 to 12 min at 100 ° (below the threshold Effective detection before treatment)

5 Sandy mud

17-20 7.5 to 18 min Efficiently effective (hand-swept) 100 °

9 Wet scale (condenser) 10 5 to 26 min> 80 ° Effective Effective

PVC slats Not proven

12 scaled 10 10 min at 100 ° (below the effective detection threshold before treatment)

14 Sludge mud

5 10 to 20 mm> 70 ° Effective Effective swept

15 Sandy mud 10 10 to 18 min> 90 ° Effective Effective

2/3 sandy muds

fraîches17 + 1/3 liquid sludge 10 4.5 to 28 min> 70 ° Effective Effective

fresh

TABLE I

Regarding the results shown in Table I, it should be noted that the steam disinfection treatment according to the conditions of the invention is therefore effective on the bacteria Legionella pneumophila and amoeba Naegleria fowleri.

In particular, these tests revealed the sensitivity of Naegleria fowleri type amoebae to heat, and in particular to water vapor. More specifically, it turns out that a steam disinfection treatment of more than 5 min, and thus more than 10 min, at a temperature above 70 ° C is quite effective for Legionella pneumophila bacteria and bacteria. amoebae Naegleria fowleri, even in the encysted form of these amoebae. These results should be supplemented by the fact that an analysis of the condensates collected in test no. 5 revealed the absence of Legionella pneumophila.

Also, it should be noted that the device and the method according to the present invention make it possible to obtain at any point of the waste layer, for the materials which have been the subject of a test, a temperature greater than 70 ° C., and often of the order of 80 to 100 ° C.

For materials with good vapor permeability, ie sandy mud, wet scale, scale of PVC strips and scaled PVC strips, a thickness of 5 to 10 cm allows to obtain rapid temperature rise (of the order of 2 minutes).

For materials with a lower vapor permeability and a heterogeneous structure, for example sludge, forming clumps of various sizes, it is preferable to treat them with steam to a possibly smaller thickness (from 5 to 10 cm , or preferably less than 5 cm) by carrying out a prior homogenization treatment of the structure. Such a homogenization treatment may consist of making a crumbling or grinding, in order to reduce the size of the pieces to be treated. It can be implemented regardless of the type of material treated to ensure homogeneity of treatment throughout the layer of the material forming the waste. This homogenization treatment is however particularly recommended for materials with compact clods.

It has been found, for less permeable materials, the vapor, such as sludge, that a thickness of about 3 cm of the treated layer makes it possible to obtain rapid rise in temperature (of the order of 2 to 5 minutes ).

As is also evident from the results in Table I (Run 17), less vapor permeable materials such as slurry or sludge may, depending on a solution of the homogenization process, be mixed with a material having better vapor permeability. , such as sandy mud and serving as a structuring material. This mixing solution makes it possible to perform an effective treatment by means of a layer having a thickness thus greater, of the order of 5 to 10 cm.

Also, in the case of more liquid sludges which also have a lower vapor permeability, the application of the treatment according to the invention logically results in a higher production of leaching products.

In this case, to avoid a too long treatment time, we will favor a preparation of this material to reduce its moisture content to obtain a semi-solid state. This preparation can consist of a dehydration like that carried out for sludge purification, namely natural or mechanical dewatering, by dewatering, evaporation, thickening, centrifugation, vacuum filtration, various types of pressure filtration, drainage, passage between rollers, flotation in the presence of acids, or any other method , with or without use of heat.

This preparation may also consist of mixing with an absorbent (for example of the sawdust type).

Also, among the advantages of the present invention can be noted; a disinfection installation forming an equipment implementing a method adapted to the treatment of different materials that can be mixed together; sludge, scale, plastics such as PVC, metal ...;

a treatment that can be carried out near the places of production of the waste to be disinfected (for example the cooling towers of the nuclear power plants), which avoids the transport of these wastes before their disinfection treatment;

- since no chemical is used and no combustion occurs, this installation and this disinfection process do not produce chemical residues for treatment or combustion.

Claims (10)

1. Disinfection installation (10; 110; 210; 310) of cooling tower waste for the destruction of possible pathogens, comprising: - a sealed enclosure (12; 112; 212; 312) containing support means (14; 114; 214; 314) permeable to vapor and on which the waste is capable of being layered (100); steam generating means and steam injection means (16; 116; 216; 316) for supplying steam into the chamber (12; 112; 212; 312), and - temperature measuring means (18; 118; 218; 318) adapted to detect the temperature of the waste (100) disposed on said support means (14; 114; 214; 314). 2. Installation according to claim 1, characterized in that said support means (14; 114; 214; 314) come into contact with the wall of the enclosure (12; 112; 212; 312) over their entire periphery so that defining in the enclosure (12; 112; 212; 312), on either side of said support means (14; 114; 214; 314), a lower space in which the steam is injected and an upper space in which the steam reaches after passing through said support means (14; 114; 214; 314). 3. Installation (10) according to claim 1 or 2, characterized in that said support means comprise at least one floor (14) permeable to steam. 4. Installation (110; 210) according to claim 1 or 2, characterized in that said support means comprise at least one endless belt (114; 214) disposed at least partially in the enclosure (112; 212) and associated driving means (115; 215) for continuously advancing the endless belt (114; 214), and control means for said driving means (115; 215). 5. Installation (310) according to any one of claims 1 to 4, characterized in that the support means comprise at least one carriage (314) movable, in that said enclosure comprises at least one movable panel (312a, 312b) for the entry and / or exit of the carriage (314) relative to the enclosure (312), and in that said installation further comprises positioning and guiding means enabling the carriage (314) to traverse the installation (310) and to be placed in a treatment position in the enclosure (312). 6. Installation (10; 110; 210; 310) according to any one of claims 1 to 5, characterized in that it further comprises means (20; 120; 220; 320) programming the duration and the processing temperature, connected to said temperature measuring means (18; 118; 218; 318). 7. Installation (10; 110; 210; 310) according to any one of claims 1 to 6, characterized in that it further comprises waste feed means (30; 130; 230; 330) allowing disposing the waste to be treated (102) on said support means (14; 114; 214; 314) and means for discharging (140; 240; 340) the disinfected waste (104) for emptying the disinfected waste out of the enclosure (12; 112; 212; 312). 8. Installation (10; 110; 210; 310) according to any one of claims 1 to 7, characterized in that it further comprises means for draining the condensate (22, 24; 122, 124; 222, 224). 322, 324) which forms in the enclosure (12; 112; 212; 312). 9. Installation (10; 110; 210; 310) according to claim 8, characterized in that it further comprises, upstream of the waste feed means (30; 130; 230; 330), processing means waste, in particular means for raking, crushing, dehydrating the waste, or mixing with other waste and / or with a structuring material. 10. Installation (210; 310) according to any one of claims 1 to 9, characterized in that said enclosure comprises at least two disinfection chambers (312c and 312d) adapted to contain each of the support means (214; 314) for the simultaneous treatment of several layers of waste (100). 11. A method of disinfecting waste cooling towers that may contain pathogenic elements, wherein: the layered waste is previously disposed on vapor-permeable support means (14; 114; 214; 314) contained in an enclosure (12; 112; 212; 312); said waste (100) is subjected to steam so that it has a minimum temperature of 60 ° C. for a minimum duration of 5 min, whereby a disinfection is achieved which destroys any presence of Legionella pneumophila type bacteria; and amoebae of the Naegleria fowleri type. 12. Disinfection process according to claim 11, characterized in that the minimum temperature of the waste is 70 ° C. 13. Disinfection process according to claim 11 or 12, characterized in that the minimum duration during which the waste is subjected to steam is 10 min. 14. Disinfection process according to any one of claims 11 to 13, characterized in that the temperature of the waste is measured in several locations. 15. The disinfection method as claimed in claim 11, wherein said support means (14; 312) over their entire periphery so as to delimit in the enclosure (12; 112; 212; 312), on either side of said support means (14; 114; 214; 314), a lower space in which the steam is injected and an upper space in which the steam reaches after passing through said support means (14; 114; 214; 314), and in that the steam is injected under said support means (14; 114; 214; 314). 16. Disinfection method according to any one of claims 11 to 14, characterized in that it is further used waste feed means (30; 130; 230; 330) for disposing the waste on said means. support (14; 114; 214; 314) and means for discharging (140; 240; 340) disinfected waste for emptying the disinfected waste from the enclosure (12; 112; 212; 312). 17. Disinfection method according to any one of claims 11 to 16, characterized in that it further comprises the following step: it performs an initial treatment of the waste, before subjecting them to steam, especially a crawling , grinding, dehydration or mixing with other waste and / or with a structuring material. 18. A method of disinfection according to any one of claims 11 to 17, characterized in that it further comprises the following step: at least one chemical adjuvant, in particular an oxidizing or biocidal adjuvant, is combined with the vapor or the waste before sending said vapor to the waste (100). 19. Disinfection method according to any one of claims 11 to 18, characterized in that it is carried out continuously by means of at least one endless belt (114; 214) forming the support means, disposed at least partially in the enclosure (112; 212) and associated with drive means (115; 215) for continuously advancing the endless belt (114; 214), and control means of said drive means . 20. Disinfection method according to any one of claims 11 to 18, characterized in that it is produced by batches of waste by means of at least one movable carriage (314) forming the support means, adapted to come into the enclosure (312) and associated with guiding and positioning means for the carriage (314), via at least one movable wall (312a, 312b) of the enclosure (312), to enter and exit the enclosure. enclosure (312) respectively before and after the disinfection step. 21. Disinfection process according to any one of claims 11 to 20, characterized in that the waste (100) belong to the group of materials formed of sludge, scale, plastic, metal or a mixture of between them. 22. Disinfection process according to any one of claims 11 to 21, characterized in that the waste is disposed in layer (100) to a thickness of between about 3 and 80 centimeters.