GB2024285A - Process and apparatus for the treatment of sludges and muds in order to solidify them - Google Patents

Abstract

A process for treating muds and sludges includes the steps of extracting the sludges from a swamp or the like, then immediately subjecting them, in their condition after extraction, to a first, pugging, without any additional substance, in order to give them some homogeneity, then filtering them, in order to retain to the maximum the materials of large grain size which they could contain, this operation being followed by transferring under pressure the filtered sludges to a site, near to the extraction locality, where they are subjected to an intensified pugging with a predetermined addition of a reactive substance until the pugged material resulting from the mixing has the desired consistency, this material then being removed under pressure or by being transported, following its pugging, to the locality where it is to be used. Apparatus for carrying out the process is also described.

Description

SPECIFICATION Process for the treatment of sludges and muds in order to solidify them, and apparatus for putting said process into practice The present invention is concerned with a process for the treatment of sludges and muds, by pugging with a reactive substance, in order to solidify them. It is also concerned with an apparatus adapted to put this process into practice, at a site relatively close to, but nevertheless outside, the area where the sludges and muds to be treated are extracted.

Certain types of sludges are impossible to solidify bydrainage or any otherdrying process. It has thus been sought to solidify them by causing them to react with a petrifying substance so that they obtain a homogeneity and a consistency suitable for the foundations of roads and buildings.

Consequently the present invention has for its object to provide a process and apparatus for putting it into practice, enabling the solidification of sludges and muds to be achieved, following their pugging with a reactive substance, this pugging operation being carried out in the vicinity of their site, such as a swamp, a collecting or settling basin or the like, in order to facilitate the transporting thereof after treatment or their utilisation in situ. Numerous economic advantages thus arise, by providing construction materials, the more direct laying out of roads, or even the acquisition of new plots of land suitable for the construction of buildings and giving rise to interest because of their location or their low cost of acquisition.

In accordance with the invention such a process for the treatment of sludges and muds in order to solidify them by pugging them with a reactive substance is distinguished by the fact that it consists of extracting the sludges, then immediately subjecting them, in their condition after extraction, to a first pugging, without any additional substance, in order to give them a certain homogeneity, then filtering them, in order to retain to the maximum the materials of large grain size which they could contain, this operation being followed by transferring under pressure the filtered sludges to a site, near to the extraction locality, where they are subjected to an intensified pugging with a predetermined addition of a reactive substance until the pugged material resulting from the mixing has the desired consistency, this material then being removed under pressure or by being transported, following its pugging, to the locality where it is to be used.

It should be noted that this process enables the extraction of sludges to be started in the locality considered most favourable of the swamp or basin to be worked and then to advance the extraction equipment over the surface of the latter, whether the sludges have been removed, or whether they have been put back in a partially solidifed state. Furthermore, this process enables extracted sludges to be treated in advance in a basin and enables the part of the latter already emptied to be filled up with the treated mixture in the course of setting, thus providing a continuous pugging operation. Moreover, this process is adapted for treating sludges extracted from a basin during emptying and for transporting the treated sludges continuously into another, previously emptied basin, the treatment operation thus taking place in an area of firmer land situated between the two basins.

The apparatus for carrying out this process for the treatment of sludges, and constituting also the subject of the present invention, is distinguished in that it comprises a movable apparatus for extracting sludges adapted to discharge the extracted sludges into a hopper provided at the bottom of an extractor designed to pug the sludges and to give them some homogeneity prior to filtering them, using a vibrating filter arranged at the outlet of the extractor, this filter being arranged so as to remove the materials of large grain size which could be found in the extracted sludges and to fee with filtered sludges the feed chute of a pump which is adapted to supply the sludges under pressure through piping to a pugging apparatus supplied moreover with a reactive substance supplied by a reservoir, this apparatus being located near the extraction locality and designed to discharge the pugged mixture of pre-determined consistency into any transporting means or directly into position with a view to its utilisation.

It should be noted that by means of this apparatus, it is possible to position the movable apparatus for extracting sludges, followed by the filtering apparatus and means for propelling them, at any locality of a basin or swamp, and that the pugging apparatus, which can be constituted by a mixer of the continuous type used for the treatment of heavy cements, can be installed, as can also the reservoir(s) containing the reactive substance, on the bank where the firmness of the land allows access to transport vehicles for carrying away the homogenised mixture during setting or for replenishing the supply of reactive substance.

In a preferred embodiment of the apparatus in accordance with the invention the apparatus for extracting sludges is constituted by a mechanical scoop, of the self-propelled scoop type, to which is secured a carrier truck on which are mounted a pump, of the type of those which serve to pump ready-mixed concrete, and also a hopper adapted to receive the sludges discharged from the bucket of the scoop and comsprising, at its lower part, an extractor screw designed to render the sludges homogeneous and to draw them towards a vibrating filter mounted above a feed chute of the pump, which comprises, furthermore, fixed at its outlet, piping, of the flexible tube type or of articulated lengths of pipe, connecting it to the pugging apparatus.

Other features of the apparatus putting the process in accordance with the invention into practice will appearfrom the following description, which is to be read with reference to the accompanying drawing showing schematically in plan two types of installation of this apparatus, selected by way of example only and not by way of limitation.

As shown in the drawing, on the edge of a swamp 1 containing partially liquid sludge, in the first type of installation, is located an extraction apparatus 2, of the self-propelled scoop type, followed by a carrier truck 3 on which is mounted a pump, of the type of those which serve to pump ready-mixed concrete, surmounted by a hopper for receiving the extracted sludge, this hopper being provided with an extractor adapted for pugging and discharging the sludge on to a vibrating filter placed above the feed chute of the pump. The outlet of the pump is connected by piping 4, in the form of tubing having a certain flexibility or made up of articulated lengths of pipe, to a mixer 5 which is red by an inlet 6 with a reactive substance from at least one supply reservoir 7, constituted e.g. by a moveable silo.

In the second type of installation, as shown schematically in the drawing, a scoop 12 is moved into the swamp 1, accompanied by the carrier truck 13, identical with that referenced 3, and supporting a pump surmounted by an extractor hooper and vibrating filter above its feed chute. This pump pumps the filtered sludge, through the piping 14, similar to the piping 4 but constituted by several articulated lengths of pipe, into the mixer 5. An outlet opening 19 of the mixer allows the homogeneous mixture of treated sludges, which have begun to set, to be removed, for discharge via conveyor belt or hopper (not shown) into a skip or mixer of a transporting vehicle (not shown).The homogeneous mixture may also be, as shown, discharged into a feed chute of a pump 13' which pumps it, via piping 23 supported on one or more supports 24, into another part of the land, possibly an old swamp which has been emptied or an empty basin 25.

These two types of installation just described put into effect the various operations in accordance with the process for the treatment of sludges which is the subject of the present invention. Indeed the scoops 2 and 12 extract the sludges and, by means of their bucket, discharge them into the hopper mounted respectively on the carrier trucks 3 and 13. In each hopper the sludges are pugged a first time by the screw extractor thereof, which renders them reasonably homogeneous, then feeds them via the filter to the feed chute of the pump mounted on each carrier truck. The filtered sludges are then pumped by each pump, via the piping 4 and 14 respectively, into the mixer 5, which is preferably continuously operating, where they are pugged and mixed with a reactive substance from the supply reservoir 7.It should be noted that the reactive substance may be e.g. that known under the name "Petrifix". When the mixture is sufficiently homogeneous it is removed from the mixer and discharged either into the skip of a transport vehicle (not shown), or into the feed chute of the pump 13', which pumps it via the piping 23 into the emptied swamp or empty basin 25.

It should be appreciated that, by means of these installations, putting into practice the process for the sludges, it is possible to locate the mixer 5 on a firm part of the ground, with the supply reservoir(s) for the reactive substance nearby. It is thus possible for the transport vehicles to reach that locality in order to bring the reactive substance or to take away, if desired, the homogeneous mixture as it is setting, when it is to be used some distance away. It is also clear that the piping 23 can be arranged so as to pump the homogeneous mixture, as it is setting, into the part of the swamp 1 which has been emptied of the sludges.

Claims (6)

1. Process for the treatment of sludges and muds in orderto solidify them, by pugging them with a reactive substance, comprising extracting the sludges, then immediately subjecting them, in their condition after extraction, to a first pugging, without any additional substance, in order to give them some homogeneity, then filtering them in orderto retain to the maximum the materials of large grain size which they could contain, this operation being followed by transferring under pressure the filtered sludges to a site, near to the extraction locality, where they are subjected to an intensified pugging with a pre-determined addition of a reactive substance until the pugged material resulting from the mixing has the desired consistency, this material then being removed under pressure or by being transported, following its pugging, to the locality where it is to be used.

2. Apparatus for carrying out the process for the treatment of sludges and muds according to Claim 1, comprising a joveable apparatus for extracting sludges adapted to discharge the extracted sludges into a hopper provided at the bottom of an extractor designed to pug the sludges and to give them a certain homogeneity prior to filtering them, using a vibrating filter arranged at the outlet of the extractor, this filter being arranged so as to remove the materials of large grain size which could be found in the extracted sludges and to feed with filtered sludges the feed chute of a pump which is adapted to supply the sludges under pressure through piping to a pugging apparatus supplied moreover with a reactive substance supplied from a reservoir, this apparatus being located near the extraction locality and designed to discharge the pugged mixture of fixed consistency into any transporting means or directly into position with a view to its utilisation.

3. Apparatus according to Claim 2 wherein the apparatus for extracting sludges is constituted by a mechanical scoop, of the self-propelled scoop type, to which is secured a carrier truck on which are mounted a pump, of the type of whose which serve to pump ready-mixed concrete, and also a hopper s adapted to receive the sludges discharged from the bucket of the scoop and comprising, as its lower part, an extractor screw designed to render the # sludges homogeneous and to draw them towards a vibrating filter mounted above a feed chute of the pump, which comprises, furthermore, fixed at its outlet, piping, of the flexible tube type or of articulated lengths of pipe, connecting it to the pugging apparatus.

4. Apparatus according to either one of claims 2 and 3 wherein, when installed on a gantry, the moveable apparatus for extracting sludges, followed by the filtering apparatus and means for propelling them, can be positioned at any locality of a basin or swamp, and the pugging apparatus, which can be constituted by a mixer of the continuous type used for the treatment of heavy cements, can be installed, as can also the reservoir)s), of the silo type, containing the reactive substance, on the bank at a locality where transport vehicles can reach.

5. Process for the treatment of sludges and muds in order to solidify them, substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

6. Apparatus for carrying out the process of claim 5, arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the accompanying drawing.