GB2368839A

GB2368839A - Removal of contaminants from waste water

Info

Publication number: GB2368839A
Application number: GB0119999A
Authority: GB
Inventors: Paul Dixon
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-08-18
Filing date: 2001-08-16
Publication date: 2002-05-15
Anticipated expiration: 2021-08-16
Also published as: GB0119999D0; GB0020362D0; GB2368839B

Abstract

The apparatus comprises a container 1 having input means 2 and output means 4, 5. The container holds a porous particulate material 6 supporting plants 8. The container has an anaerobic zone 11 which is devoid of the particulate material and plants. The plants may be common reeds. The apparatus is used to treat waste water containing contaminants from the servicing and repair of motor vehicles.

Description

VEHICLE WASTE TREATMENT APPARATUS AND METHOD

The present invention relates to an apparatus and method for the treatment of waste fluids produced by motor vehicles. In particular, the method and apparatus allows for the removal of various contaminants from such fluids and is especially useful for the treatment of aqueous based liquids providing a treated aqueous liquor substantially free from contaminants, which may be safely discharged to the drain.

The disposal of contaminated waste liquors generated by motor vehicles has long been a problem for the motor industry. Most particularly, difficulties have been encountered by small garage proprietors and by vehicle disposal experts in safely disposing of the fluids generated during vehicle servicing and repair procedures, and vehicle dismantling and disposal procedures, respectively. Such fluids typically include, for example, engine oil residues, engine coolants, wash liquors from windscreen cleaning reservoirs, clutch fluids and brake fluids. The advent of more rigorous environmental regulations has necessitated the development of safe disposal procedures, with the likelihood of more stringent requirements being imposed in the future.

Previously, smaller dealers have been required to store certain waste and arrange for its subsequent collection and safe disposal by experts in the field. Less toxic waste has been run off to the drains. However, the latter procedures are gradually being phased out due to legal requirements, with the consequence that such dealers will be required to dispose of all waste via disposal experts, a procedure that is unduly financially burdensome.

Clearly, therefore, there is a need for a simple, efficient and economical procedure which may be employed by motor dealers in order to remove contaminants from, and safely dispose of, such waste fluids without the necessity to employ disposal experts for the purpose. It is therefore, an object of the present invention to provide an apparatus and method whereby such a procedure may be carried out by the motor

dealer at his own premises, allowing for the removal of contaminants from the waste fluids, and the subsequent disposal of the treated aqueous liquids to the drains.

Several methods are described in the prior art for the removal of pollutants from water, principally in the treatment of sewage. For example, US Patent 3770623 proposes a method of removing suspended and dissolved pollutants from water by first passing the water through a settling tank and then, successively, through one or more filtration beds and one or more elimination beds. The filtration beds consist of a bottom layer of coarse porous material and a top layer of a fine porous material having rooted and growing therein plants having nodes, e. g. the common reed (phragmites communis). Water from the settling tank is introduced into the filtration bed above the surface of the porous layers of the bed and the level is maintained thereabove so that the suspended matter and slime will settle on top of the bed as the water filters therethrough. The plants root and grow in the slime which is converted to top soil or humus. The water being filtered passes through the filtration bed and is removed near the bottom to be passed into the elimination bed having a layer of porous material such as sand or glass fibres therein in which plants selected for the removal of particular dissolved pollutants known to be present are growing.

US Patent 3770623 indicates that, in general, the filtration and elimination beds will be in the form of trenches dug in the soil.

In addition, GB Patent 2247233 discloses a filtration system for polluted water, comprising at least one layer of porous particulate material capable of supporting suitable plants such as the common reed, and an outlet at or adjacent the bottom of the filter bed, wherein the or each filter bed is provided in a portable open topped tank, wherein the suitable plants are grown in the porous particulate material before transportation to the site of use of the filtration system, and wherein a plurality of air inlets are provided for introducing air into the filter bed.

Such techniques are, however, clearly designed for the large scale treatment of bulk volumes of polluted water and, as such, are unsuitable for present requirements, and

there is a need for a small scale procedure which can address the situations hereinbefore described. According to a first aspect of the present invention, there is provided apparatus for the removal of contaminants from aqueous-based waste fluids produced by motor vehicles said apparatus comprising a container, input means and output means, said container containing plants suitable for the removal of said contaminants and porous particulate material capable of supporting said plants, said container including partition means at least partially defining within the container an anaerobic region free from said plants and said porous particulate material, said input means being capable of delivering said waste fluids into said porous particulate material at low pressure and incorporating means for achieving substantially uniform distribution of said waste liquid in said porous particulate material, and said output means being located adjacent the top of said container and comprising an output channel exiting said container, said output channel being attached to collection means having an inlet portion located below the surface of said porous particulate material.

Typically, said input means comprises a hollow cylindrical tube whose lower portion includes a multiple of apertures which are wholly submerged beneath the surface of said porous particulate material, whilst the upper portion projects above the surface of said material. A suitable arrangement would, for example, see the tube inserted to a level whereby approximately, 75% of its length would be submerged beneath the surface of the porous particulate material, with roughly the lower 50% of said submerged portion containing apertures. The inner part of said submerged section of said tube should be free from said porous particulate material.

Said waste fluids may conveniently be introduced into said input means by means of, for example, a tube, pipe or hose placed in the top of said input means. Said fluids are introduced at low pressure, to assist with efficient distribution through the porous particulate material. Preferably, said tube pipe or hose is positioned so as to introduce the fluid at the level of the surface of the bulk liquid in the container and

thereby allow the fluid to sweep round the inner surfaces of the input means, thus creating a swirl chamber effect which, again, assists with achieving uniform distribution through the porous particulate material, thereby ensuring that the fluid is distributed throughout the aerobic and anaerobic regions in the container and, hence, facilitating the different processes which take place including, for example, anoxicanaerobic fermentation, aerobic oxidation, nitrification, denitrification, plant nutrients uptake, nitrogen assimilation, and the like. It is found that the introduction of the fluids into the apparatus in this way leads to a reduction in the degree of foaming which is produced, and allows water immiscible organic fluids and oils having a lower specific gravity than water to percolate efficiently to the surface of the fluids in the apparatus, rather than being forced downwards into the body of the porous particulate material. Thus, easier separation of said water immiscible materials is facilitated; water-immiscible materials having a higher specific gravity than water separate out and settle to the bottom of the container away from the location of the output means.

In the case of aqueous-based waste fluids containing significant quantities of water immiscible organic fluids and oils, however, it is preferred that means should be provided, prior to introduction of the waste fluid into the input means, for the removal of excessive quantities of said water immiscible fluids and oils which may, otherwise, have a deleterious effect on the overall performance of the apparatus. Typically, said means may comprise an interceptor tank. Thus, the waste fluid to be treated would initially pass through the interceptor tank, or equivalent means, before being conveyed, via the input means, into the container which contains the plants, thereby facilitating the removal of excess quantities of said water immiscible materials prior to the entry of said waste fluid into said container.

Suitable output means could comprise an output channel comprising a tube exiting the side of said container at a point adjacent the top of said container, said tube being attached to a collection means comprising a chamber, which may typically extend substantially perpendicularly from said tube, said chamber being open at both ends,

the lower end forming an inlet and being located at a sufficient distance below the surface of said porous particulate material to ensure that separating water-immiscible organic materials are not allowed to enter therein. Thus, in practice the lower end of said chamber should be at a sufficient depth to be below the bottom level of a separating layer of said organic materials, floating on the surface of the aqueousbased bulk liquid. Generally, it is found that a distance of at least 100 mm, preferably 150 mm, below the surface of the porous particulate material is necessary for this purpose when using a tank of 100 cm total depth. A suitable arrangement would envisage the collection chamber being located such that approximately 60% of its length is submerged below the surface of the porous particulate material, with the output tube being attached to the side of said chamber at the level of the surface of said porous particulate material. Typically, said collection chamber comprises a cylindrical chamber. The inner part of the submerged section of said chamber should be free from porous particulate material.

The container, input means and output means provided in said apparatus may be constructed of any suitable material, for example a metal, such as steel, or a plastics material. The partition means may typically comprise an impervious sheet, mounted on supports, said impervious sheet being spaced apart from, and essentially parallel to, the base of said container. Said impervious sheet and supports are generally constructed of a similar material to said container, input means and output means.

The section of the tank below said partition means is free from the porous particulate material and from the plants suitable for the removal of contaminants and their roots. Consequently, the area defines a region of the apparatus wherein anaerobic conditions exist. When said partition means comprises a supported impervious sheet, seepage of fluids into this area does occur despite the nature of the partition; such seepage is highly advantageous in promoting the anaerobic degradation processes by means of which certain contaminants are removed.

Said porous particulate material may be any material suitable for the purpose, typically sand, gravel, grit or the like.

Said plants suitable for the removal of contaminants comprise, typically, the common reed. Preferably, nitrogen and phosphorus-based nutrients are added to the contents of said apparatus to assist in the biological processes which result in the removal of said contaminants.

According to the second aspect of the present invention, there is provided a method for the removal of contaminants from aqueous-based waste fluids produced by motor vehicles, said method comprising providing an apparatus as hereinbefore described, introducing an aqueous-based waste fluid into said apparatus via said input means, allowing said contaminants to separate from said waste fluids and removing purified aqueous liquor from said apparatus via said output means.

The method of the second aspect of the invention is most satisfactorily carried out as a batchwise procedure wherein said waste fluid is introduced into said apparatus to a level wherein the surface of the liquid in the apparatus substantially coincides with the surface of the porous particulate material. The charged apparatus may then be allowed to stand for a period of up to several hours to ensure efficient contaminant removal, whereupon further fluid may be introduced, leading to the simultaneous removal of the purified liquor from the apparatus. Most conveniently, solid contaminants may be removed by any well-known techniques, such as filtration or settling, prior to treatment of waste fluids by the method of the present invention.

Said purified aqueous liquor may be subjected to testing following removal from said apparatus to ensure that the content of contaminants has been reduced to a satisfactorily low level. In the event that this has been achieved, the liquor may be run off to the drain but, should the contaminant content be unsatisfactorily high, the liquor may be recycled through the apparatus.

It will be apparent to the skilled person that two or more of said apparatus may be connected together as a series of modules to allow for a more rigorous treatment process. Typically, said modules may be mounted on supports such as wooden, metal or plastic pallets.

The porous particulate material and plants may be removed from the apparatus and disposed of on an occasional basis, being replaced by fresh materials at that time.

The apparatus and method of the present invention provides a convenient, efficient and economical means whereby waste fluids from motor vehicles may be purified and disposed of by dealers on site whilst maintaining high ecological standards.

The invention will now be illustrated, though without limitation, by reference to the embodiment illustrated in the accompanying drawings, in which Figure 1 is a side elevation of an apparatus according to the present invention.

Figure 2 shows a plan view of three modules according to the present invention, connected together in series Figure 3 (a) shows a side elevation view of means for the introduction of waste fluid into the input means; and Figure 3 (b) shows a plan view of said means.

Considering firstly Figure 1, there is provided an apparatus comprising a container (1) including input means comprising a hollow cylindrical tube (2) including apertures (3), and output means comprising an exit pipe (4) connected to a collection chamber comprising a hollow cylinder (5). The lower portions of both input means and output means are submerged below the surface of the porous particulate material comprising gravel (6) which fills the container to the water level (7) and supports

plants suitable for the removal of contaminants, said plants comprising the common reed (8). The interior sections of the input means and the output means are free from gravel. The container includes an impervious sheet (9) of steel or plastic mounted on supports (10) and defining an anaerobic area (11). The apparatus may be mounted on a pallet (12). The waste fluid is introduced into the top of the input means and is removed via the exit pipe.

Measurements shown in Figure 1 are in millimetres. It will be appreciated that such measurements are in no way limiting and the apparatus may be produced at any scale suitable for a given purpose, although the relative values of the measurements are indicative of those found to provide the most satisfactory implementation of the invention.

Turning to Figure 2, there is provided a series of containers (1), each comprising input means comprising a cylindrical tube (2) and output means comprising a collection chamber (5) and exit pipe (4). The first apparatus is fed by a pipe (13), with subsequent feeds being via the exit pipe of one apparatus to the input means of the next. Finally, the exit pipe of the third apparatus takes the processed liquid to a testing tank (14) from which fluid which satisfies the analytical criteria may be passed onwards for re-use, whilst fluid which fails to satisfy these criteria is returned to the input means for a second pass through the apparatus.

Figures 3 (a) and 3 (b) show different views of the means by which the waste liquor is introduced, at low pressure, by means of a pipe (13) into the cylindrical tube (3) of the input means at the level of the surface of the bulk liquid in the container in such a way as to give a swirl chamber effect, thereby preventing foaming and avoiding oily materials being forced downwards into the body of the bulk liquid.

Claims

CLAIMS 1. Apparatus for the removal of contaminants from aqueous-based waste fluids produced by motor vehicles said apparatus comprising a container, input means and output means, said container containing plants suitable for the removal of said contaminants and porous particulate material capable of supporting said plants, said container including partition means at least partially defining within the container an anaerobic region free from said plants and said porous particulate material, said input means being capable of delivering said waste fluids into said porous particulate material at low pressure and incorporating means for achieving substantially uniform distribution of said waste liquid in said porous particulate material, and said output means being located adjacent the top of said container and comprising an output channel exiting said container, said output channel being attached to collection means having an inlet portion located below the surface of said porous particulate material.
2. Apparatus as claimed in claim 1 wherein said input means comprises a hollow cylindrical tube whose lower portion includes a multitude of apertures which are wholly submerged beneath the surface of said porous particulate material and whose upper portion projects above the surface of said material.
3. Apparatus as claimed in claim 2 wherein said hollow cylindrical tube is located such that approximately 75% of its length is below the surface of the porous particulate material.
4. Apparatus as claimed in claim 3 wherein approximately 50% of said submerged length includes apertures.
5. Apparatus as claimed in any of claims 1 to 4 which includes means for the removal of quantities of water immiscible fluids and oils from said aqueous based waste fluid prior to the introduction of said fluid into said input means.
6. Apparatus as claimed in claim 5 wherein said means for the removal of quantities of water immiscible fluids and oils from said aqueous-based waste fluid comprises an interceptor tank.
7. Apparatus as claimed in any of claims 1 to 6 wherein said output means comprises an output channel comprising a tube exiting the side of said container at a point adjacent the top of said container, said tube being attached to a collection means comprising a chamber, open at both ends, the lower end being located at a sufficient distance below the surface of said porous particulate material to ensure that separating water-immiscible organic materials are not allowed to enter therein.
8. Apparatus as claimed in claim 7 wherein the lower end of said collection chamber is located at a distance at least 100 mm below the surface of said porous particulate material.
9. Apparatus as claimed in claim 7 or 8 wherein said collection chamber is located such that approximately 60% of its length is below the surface of the porous particulate material.
10. Apparatus as claimed in any of claims 7 to 9 wherein said tube extends substantially perpendicularly from said collection means.
11. Apparatus as claimed in any preceding claim wherein said partition means comprises an impervious sheet, mounted on supports, said impervious sheet being spaced apart from, and essentially parallel to, the base of said container.
12. Apparatus as claimed in any preceding claim wherein said container, partition means and supports comprise a metal or a plastics material.
13. Apparatus as claimed in any preceding claim wherein said porous particulate material comprises sand, gravel or grit.
14. Apparatus as claimed in any preceding claim wherein said plants suitable for the removal of contaminants comprise the common reed.
15. Apparatus as claimed in any preceding claim wherein nitrogen and phosphorous-based nutrients are added to the contents of the apparatus.
16. A method for the removal of contaminants from aqueous-based waste fluids produced by motor vehicles, said method comprising providing an apparatus as hereinbefore described, introducing an aqueous-based waste fluid into said apparatus via said input means, allowing said contaminants to separate from said waste fluids and removing purified aqueous liquor from said apparatus via said output means.
17. A method as claimed in claim 16 wherein at least two of said apparatus are connected together as a series of modules.
18. A method as claimed in claim 16 or 17 which comprises a batchwise procedure.
19. Apparatus as claimed in claim 1, substantially as hereinbefore described with reference to the accompanying drawings.
20. A method as claimed in claim 14, substantially as hereinbefore described with reference to the accompanying drawings.