FR2815276A1 - Method for removal and processing dangerous materials comprises making enclosure around support containing material and projecting high pressure jet on support coating and sucking and storing residues tank - Google Patents

Abstract

A confining enclosure (11) is made around the plaster or paint support (3) containing the dangerous material by covering the ground with an impermeable membrane (11b). A high pressure liquid jet (16') is projected against the support coating. The paste and mud containing a quantity of dangerous materials from the coating residues (17) created by the jet are sucked and stored in a tank (21). The tank is connected to a separator/compactor (35) which dehumidifies the residues and separates them into liquid and solid phases. An Independent claim is included for an installation for removal of dangerous materials.

Description

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 The invention relates to a method for removing, treating and conditioning materials hazardous to health applied as a protective and / or finishing coating on a support, such as a plaster or paint coating, containing lead or asbestos. .

 The hazardous materials concerned are currently subject to regulations for the protection of the environment and specific measures for personnel responsible for their removal. They only include solid elements of a non-radioactive nature.

 The imagined treatment chain relates, in particular, to: - the techniques and materials used for environmental protection (confinement of the operating area in particular), - the removal of coatings or materials covering the support to be treated , by jets of liquid (preferably water) at very high pressure, - recovery of the waste produced and their physical treatment before packaging for shipment to a specialized center.

 To the knowledge of the applicant, there is currently no such processing chain. The techniques and means used are very "handcrafted" and do not meet the requirements of efficiency, profitability, speed, security, sought here.

 A main objective of the invention is therefore to provide a safe, reliable, technically efficient solution, adaptable to various site conditions, easy to implement and sufficiently inexpensive to ensure a commercial future, while being respectful of the environment.

 Thus, the method of the invention provides that: - a confinement enclosure is produced around the support on which we are working, by covering at least the ground with an impermeable membrane of sufficient mechanical strength to keep it waterproof air and a liquid sprayed on it under a high pressure of between 1000 and 2000 bars approximately, i.e. lx 10-2 and 2x 10-2 kg / m2,

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 (minimum 800 bars) for a few seconds to a few tens of seconds, and at a distance of approximately one meter, - a jet of high pressure liquid with a pressure greater than approximately 1000 bars is sprayed against the coating covering the support, ie lx 10-2 kg / m2 (minimum 800 bars), - among the coating residues created by said spraying, those which are pasty or muddy, charged with moisture and containing a certain quantity of said dangerous materials are then sucked up and stored in a reservoir, - not connecting this reservoir to the supply of a separator / compactor device which dries the aspirated residues from this reservoir, separating them between a liquid phase and a solid phase with a water content of less than about 45 %.

 Note now that the percentages provided in this text are to be considered to within 15%, and by weight.

 For a residue density greater than approximately 1.2 (typically 1.3 and above), the suction will typically consist of pumping the residues which will then typically have a dryness of between 35 and 50%. For lower densities, we will use a suction with depression of the tank.

 In addition to this, the invention has in particular endeavored to define the characteristics of the aforementioned resistant membrane of the enclosure, in order to satisfy the cost requirements, ease of installation, cleaning, removal, sealing, mechanical and chemical resistance, and safety. . Also another characteristic of the invention provides that, preferably, at least the strips on the ground are made of polypropylene, with a thickness of between approximately 0.8 mm and 1.6 mm and the corresponding membrane formed at least on the ground comprises such strips welded together continuously, to obtain impermeability, including at the junction between the strips, such

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 membrane rising laterally, at least at the location of peripheral readings.

 On the unsupported parts (typically the rear vertical wall of the enclosure) or on the irregularly supported parts (gravelly soil), the membrane will internally double (enclosure side) a hard and continuous outer wall against which it will be applied, favoring security and conditions of employment.

 Attempts have also been made to control the yield, costs and efficiency of the separator / compactor.

 In this regard, it is thus advised in the invention that the suction step towards the reservoir comprises a reduction in fragments of the coating blocks possibly sucked, by passage through a rotary crushing device, before the residues fall into the tank, where an agitator maintains a substantially homogeneous mixture.

 Regarding the reduction in fragments, we recommend using rotary knives located in the upper part of the tank, at the point of entry through which the "muddy or pasty residue from the coating" is sucked into the tank and falls into its bath .

 It will further be noted that, preferably in combination with such a reduction of the largest debris at the inlet of the tank, with advantageously stirring of the mixture in the tank, the invention also promotes direct vitrification, in a specialized unit, of the solid phase from this separator / compactor, after having adapted the water content of this solid phase during the drying step, so that said vitrification can take place without any other drying treatment of the solid phase created.

 In this regard, it has been found that obtaining such a solid phase having a dryness of between 60 and 70% is particularly suitable and meets the cost-performance-efficiency requirements of the installation.

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overall, the final vitrification allowing the remainder to meet the desired requirements of effective environmental protection
In particular, in order to finally eliminate the product, it is also advisable to use, as a separator / compactor, one of a band filter and a press filter.

 It will also be noted that the above recommendations are particularly valid for the removal, treatment and conditioning of coatings and other materials containing asbestos applied on hard supports, such as steel or concrete.

 Lead paints on such supports are also affected.

 Still for questions of respect for the environment and safety, it is further advised in the invention that at the end of the separation / compaction phase, and before any subsequent recovery, for in particular a vitrification or a storage in a technical landfill, the solid phase is transported to the recovery center concerned in an air and water tight drum, inside a hermetically sealed flexible envelope.

 An even more detailed description of the invention will now be given with reference to the accompanying drawings in which: - Figure 1 schematically shows the general principle of the invention, in the case of the use of a filter press , - Figure 2 schematically shows a barrel for storing the dried up final product, - Figure 3 shows the replacement of the vacuum cleaner of Figure 1 by a pump discharging into the intermediate storage tank, - Figure 4 shows an alternative of embodiment in which the filter press is replaced by a band filter,

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 - And Figure 5 schematically shows the transport in barrels of residues at the end of the separation / compacting step, before they are taken care of in the selected specialized center.

 In Figure 1, we schematically see an intervention site.

The dangerous materials in question, such as asbestos, lead paint, etc., whatever the process used, release a certain proportion of dangerous elements when they are removed.
In this case, it was assumed the presence of an asbestos flock constituting a coating 1 on a "hard" support constituted by the concrete reinforcement 3 forming a part of the roof 5 and of a parking wall 7 underground.

 As can be seen, the covering 1 extends over the whole of the represented part of the roof, on the lower surface thereof, as well as over most of the interior surface of the wall 7, without however reaching the ground 9.

 To contain the air and water in the treatment zone, an enclosure 11 has been created.

 The walls include a flexible membrane that can be easily applied and removed, in particular made of plastic. Polypropylene is recommended, possibly polyvinyl chloride (PVC).

 In this case, the enclosure 11 was built with polypropylene strips with a thickness of about 1 mm, in width from 3 to 6 m (type "HYDRONAP @, from the French company SIPLAST).

latérale et arrière (seule la paroi arrière lla a été repérée sur la figure), ainsi que pour le sol llb et pour la partie basse du mur 7 (paroi avant lle). These bands were used on three sides of the vertical walls,

lateral and rear (only the rear wall 11a has been identified in the figure), as well as for the floor 11b and for the lower part of the wall 7 (front wall 11).

 Whatever the configuration of the site, at least the soil llb will be covered with such a resistant membrane (that is to say having the characteristics of mechanical resistance presented at the beginning of the description) and this soil membrane will rise very advantageously at least at the location of the peripheral readings. Above, a membrane

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 less resistant could be used, at least if the safety conditions are considered sufficient by the site manager.

 In vertical (rear wall), the membrane 11a constitutes an interior coating of a continuous hard wall 12, along which it extends and against which it can be pressed. The wall 12 is therefore generally smooth, that is to say essentially devoid of asperities capable of tearing or damaging the liga membrane.

 If in particular the ground 9 and the wall 7 are sufficiently "clean" (devoid of said edges, protruding pebbles, etc.), the membrane can be placed directly against them, on its part llb, 1lc.

 An airlock 13 located at the rear of the confined enclosure allows entry and exit.

 For the desired seal, the aforementioned bands constituting the enclosure are hermetically bonded to each other. For this, they are welded two by two continuously. Such waterproof junctions meet current safety regulations.

 Note that the surface condition of the polypropylene allows efficient cleaning and therefore subsequent recycling. In the thicknesses indicated, it is also typically packaged in strips and can therefore be easily implemented.

 Maintaining such assembled strips in the vertical position can be carried out by any known means (hanging on the wall, etc.).

 Correctly protected, two men 15a, 15b, were represented as working inside the enclosure.

 The person closest to the covering 1 to be removed is equipped with a lance 16 ejecting a jet 16 of liquid (in particular water) at very high pressure in the direction of the covering covering the walls to be treated.

 In this regard, provision may be made in particular for using very high pressure equipment of the "WOMA ECOMASTER (g)" type, equipped

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d'un groupe fournissant une pression de service de 2000 à 2500 bars (soit 2x 10-2 à 2, 5 X 10-2 kg/m2) et des débits de 20 litres/mn à 15 litres/mn.

a group supplying an operating pressure from 2000 to 2500 bars (i.e. 2x 10-2 to 2.5, 10 X 10-2 kg / m2) and flow rates from 20 liters / min to 15 liters / min.

 Under the pressure of the jet, moisture-laden residues (water) are created.

 Typically, part of them can consist of large blocks which can be removed with a shovel (and which we will not talk about here), another part being in a pasty or muddy form which we have schematized in 17 in FIG. 1, on the ground.

 Of course, this waste is loaded with hazardous material.

un retrait des déchets 17 en créant une dépression à l'intérieur d'une cuve ou réservoir 21. In Figure 1, the waste is assumed to be low enough viscosity to be recovered on the floor covering llb using a waste vacuum cleaner identified as a whole 19 whose object is to ensure

removal of the waste 17 by creating a vacuum inside a tank or tank 21.

 For this, the tank 21 (closed, typically made of metal, waterproof and airtight) has an inlet 23 connected to the suction nozzle 25 of the vacuum cleaner, by a hose 27, the suction motor. 29 being in turn connected at 31 in the upper part of the tank, above the maximum level 31 of filling of the latter. H can be a vacuum cleaner with a power of approximately 7 to 10 kW, capable of creating a maximum vacuum of approximately 4200 mm WC, with a maximum air flow of 12 to 151 / min.

 As illustrated, the tank 21 and the suction motor 29 are located outside the confinement enclosure 11, the rear wall 11a of which is crossed by the hose 27, without breaking the seal.

 As soon as the interior of the tank 21 is in depression with respect to the ambient pressure in the enclosure 11, the waste 17 will be sucked through the hose towards the tank in which they will fall, after having passed through the inlet 23, until a sufficient filling level is reached to ensure efficient supply of the separator / compactor device generally identified 33 in FIG. 1.

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 To ensure relative homogeneity in the highly liquid mixture (typically having a dryness of between 20 and 50%) contained in the tank 21, an eccentric agitator 35 is provided and set in motion within the debris which has been sucked therein.

 In addition, the upper bell 37 of the tank where the inlet 23 is situated advantageously contains a rotary crushing device shown diagrammatically at 39 which will reduce into fragments (break) any blocks of coating which are too large and which would therefore risk altering uniformity. overall of the "bath" 21a of the tank.

 Typically, it will be one or more knives rotated by a motor located at the top of the bell.

 As for the separator / compactor 33, it is connected by a pipe 41 to an outlet 43 located in the lower part of the tank. A pump 45 feeds the unit 33.

 As shown, this is a plate filter called "filter press".

 Such equipment will in particular make it possible to treat sludge containing a high proportion of gypsum (greater than 60%) bound to asbestos (5 to 15%) or to lead, where dry matter concentrations of approximately 500 g / l lead to materials with tyxotropic properties of a permanent nature.

 Note that no pre-treatment, for example using flocculants or thickeners is necessary in the context of gypsum loaded with asbestos.

 Note also that the number and size of the filter trays will be a direct function of the desired treatment capacity, the nature of the canvas of the trays being likewise adapted to the hazardous products to be treated. In the case of plaster loaded with asbestos, one can use a mixed mono-multifilament fabric.

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 Thus, with sludge 17 having a dryness of between 20% and 50%, one can hope to obtain "cakes" from pressing having a dryness of between 60% and 70%.

These dried "cakes" will be, at the outlet of the apparatus 33, packaged in barrels 47, a belt conveyor 49 which can be used for this purpose
As shown in Figure 2, the "cakes" 51 from the device 33 are advantageously placed in drums 47 airtight and water tight, lined internally with a plastic envelope 53 approved for the transport of hazardous material concerned. In Figure 2, this inner envelope was closed with an adhesive material, after filling.

Then the lid of the keg itself was closed and blocked. It may in particular be UN approved drums for the transport of dangerous products - Oasse il and m-with a maximum capacity of 2251.

In FIG. 3, the vacuum cleaner 19 is replaced by a pump 20 which pumps from the enclosure towards the tank 22 (which is no longer under vacuum) waste 17 ′ more viscous than the previous ones (having a density typically between 1.25 and 1.45, a dryness of around 35% to 55% and a concentration of hazardous materials which can be around 500 g / l to 700 g / 1). Preferably, before the pump discharges into the tank 22, a crushing system 39 crumbles the largest waste (replacing the system 39 in Figure 1). At the outlet, the pipe 41 always directs the residue bath towards the separator / compactor.

In FIG. 4, this separator / compactor has been identified as a whole 55. It is a band filter (which replaces the filter press 33). Its power supply 57, connected to the outlet 43 of the tank, through a motor 59, brings the mud between the two bands 61, 63, from the filter where the material is dried, before falling in this case on a conveyor 65 which directs the dried material to a barrel 47 already presented.

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 The choice of a band filter can be stopped to obtain a continuous flow when the material allows it, and in particular for fibrous flocking (asbestos + other materials such as glass wool, rock wool, ... ) linked by a small proportion of plaster.

 It will also be noted that the "liquid phase" which has not been mentioned above in terms of product recovered at the outlet of the separation / compacting apparatus (33 or 55) -that is to say the water from filtrate will be treated appropriately before being rejected, namely filtration (in the case of asbestos) possibly combined with physico-chemical treatment with regard to, for example, heavy metals.

 Returning to the barrels, Figure 4 shows that they will be transported for example by truck (such as 67) to an appropriate recovery center: in particular technical landfill center or vitrification plant 69.

 Advantageously, the vitrification solution will be retained, if the water content of the solid phase (dried residues such as 51 leaving the separator / compactor) is appropriate and is in particular less than 40% (typically between 30 and 40%) .

paroi de soutien 12'. Dans cette hypothèse, la partie lla de membrane et la paroi 12 seraient de préférence retirées.Optionally, the containment could contain the tank, or even the separator / compactor, as well as the barrel 47 when it was filled. Figure 1 also schematizes this possibility, in phantom: we see that the soil membrane ll'b can extend under the aforementioned means, beyond the barrel 47, and go up in ll'a along the

support wall 12 '. In this case, the membrane part 11a and the wall 12 would preferably be removed.

Claims (12)

 1. Method for removing, treating and conditioning materials hazardous to health applied as a protective and / or finishing coating on a support (3,7, 9), such as a plastered coating or a paint containing lead or asbestos, in which process: - a containment enclosure (11) is produced around the support on which we are working, by covering at least the ground with a waterproof membrane (llb) of sufficient mechanical strength to keep it waterproof air and a liquid sprayed on it under a high pressure of between lx 10-2 and 2x 10-2 kg / rn2 approximately, for a few seconds to a few tens of seconds, and at a distance of approximately one meter, - a jet (16 ') of high pressure liquid with a pressure higher than about lx 10-2 kg / m2 is sprayed against the coating covering the support, - among the coating residues (17,17') created by said projection , we then vacuum those, pasty or muddy, charged in humidity and containing a certain quantity of said dangerous materials, and they are stored in a tank (21, 22), - this tank is connected to the supply of a separator / compactor device (33,55) which dries the sucked residues from this reservoir, separating them between a liquid phase and a solid phase with a water content of less than about 45%.  2. Method according to claim 1, characterized in that the suction step towards the reservoir (21,22) comprises a reduction in fragments of the coating blocks possibly sucked, by passage through a rotary crushing device (39,39 '), before the residues fall into the tank where an agitator (35) maintains a substantially homogeneous mixture. <Desc / Clms Page number 12>  3. Method according to claim 1 or claim 2, characterized in that the suction step comprises a step of pumping the waste having a density greater than about 1.2, which waste is then returned to the tank, by the pump (20).  4. Method according to claim 1 or claim 2, characterized in that the suction step comprises a depression of the tank (21) relative to the pressure prevailing in the enclosure and a suction of waste in a pipe suction (27) connected to this tank.  5. Method according to any one of the preceding claims, characterized in that vitrification directly, in a specialized unit (69), the solid phase from the separator / compactor, after having adapted the water content of this solid phase during the drying step, so that said vitrification can take place without further drying treatment of said solid phase.  6. Method according to any one of the preceding claims, characterized in that the separator / compactor device (33,55) is adjusted to obtain a dryness of the solid phase of between approximately 60 and 70%.  7. Method according to any one of the preceding claims, characterized in that at the end of the separation / compacting phase, and before any subsequent recovery, in particular for vitrification or storage in a technical landfill , the solid phase is transported to the recovery center concerned in drums (47) airtight and water tight, inside a hermetically sealed flexible envelope (53).  8. Installation for removing, treating and conditioning materials hazardous to health applied as a protective and / or finishing coating on a support, such as coatings containing asbestos or lead paints, the installation comprising: - an apparatus (16) for projecting a high jet of liquid <Desc / Clms Page number 13>  - a closed tank (21, 22), airtight and watertight, - pumping means (19,20) for sucking up moisture-laden residues resulting from the disintegration of the coating following the projection onto it of the high pressure liquid jet, and store them in the tank, and - a separator / compactor (33,55) connected to an outlet (43) of the tank to dry the residues from this tank, separating them between a liquid phase and a solid phase with a water content of less than about 45%.

 pressure, of a pressure greater than lx 10-2 kg / m2, - a waterproof membrane (lla, llb, llc) in strips, the strips being linked together to form a containment enclosure (11) around the coated support, including included on the ground, the membrane having, at least for the strips on the ground, a sufficient mechanical strength to maintain its impermeability in the face of a jet of high pressure liquid between lx 10-2 kg / m2 and 2x 10 kg / m, applied to it for at least a few seconds, at a distance of about a meter,

 9. Installation according to claim 8, characterized in that the pumping means comprise a vacuum cleaner (19) for industrial waste suitable for vacuuming said residues, creating a depression in the tank, the vacuum cleaner comprising a hose provided with a nozzle squeegee (25) connected to an inlet to the tank to suck up residues.  10. Installation according to claim 8 or claim 9, characterized in that it comprises a crusher with rotary knives (39,39 ') for breaking the blocks possibly contained in the residues, so that the residues contained in the tank are calibrated.  11. Installation according to any one of claims 8 to 10, characterized in that the membrane (lla, llb, llc) double, on the side of the containment, a hard, continuous external support (7,9, 12 ), essentially devoid of roughness. <Desc / Clms Page number 14>  12. Installation according to one of claims 8 to 11, characterized in that at least the strips on the ground (llb) are made of polypropylene, with a thickness of between approximately 0.8 mm and 1.6 mm, and the corresponding membrane formed at least on the ground comprises such bands welded together continuously to obtain waterproof junctions, such a membrane rising laterally, at least at the location of peripheral surveys.