GB2540678A

GB2540678A - Bioremediation system

Info

Publication number: GB2540678A
Application number: GB1612127.9A
Authority: GB
Inventors: Attwell Moorhead David
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-07-22
Filing date: 2016-07-13
Publication date: 2017-01-25
Anticipated expiration: 2036-07-13
Also published as: GB2603094A; GB201512950D0; GB2603094B; GB202206012D0; GB201612127D0; GB2540678B

Abstract

A system for recovering bioremediation material comprises a series of tanks 40, 30, 20, each with a lip on one edge of the settlement tank, forming weirs 28 for conveying bioremediation material and pollutants from one settlement tank to the next in series. An input 14 is provided to the first settlement tank. The final settlement tank in the series may have a weir or lip 88 to a tank, which can include an adjustable skimmer 50 feeding a funnel and out of the tank. The tanks may be emptied onto inclined ramps 29 on which grit and heavy hydrocarbons are deposited, as material is conveyed from one tank to the next. A further weir may extend upwards from the bottom of the tank over which recovered bioremediation material flows as the first tank fills, to a further tank. The further tank may have a further weir leading to a third tank 40. The bio-remediation method may involve applying a surfactant and a hydrocarbon to a polluted surface such as a car in a carwash, and subsequently applying a bioremediation material before entering input 14.

Description

Bioremediation system

This invention relates to bioremediation systems and more particularly to a separator for separating bioremediation material from pollutants. The separator enables bioremediation material to be separated from pollutants for example when clearing pollution, in waste management or cleaning vehicles or other objects. WO03/104361 (Autoglym) for example describes a bioremediation material used in connection with car washes. When such a material is sprayed or poured onto a hydrocarbon polluted area. These sprayed material and pollutants can be gathered with lighter fractions floating to the surface of the treatment. Heavier fractions and other solid material (such as attached dirt and grime) will remain suspended or go to the bottom of the treatment material. It is desirable to the recover the floating hydrocarbons and separate the remaining treatment material from the other solids for reuse.

According to the present invention a system for recovering bioremediation material from pollutants treated with the bioremediation material comprise a series of settlement tanks with an edge of each of said settlement tanks having a lip forming a weir over which mixture of pollutants and bioremediation material flows from one tank to another.

In one embodiment each settlement tank of the series of tanks is mounted at the top of another larger tank and is demountable from the larger tank, the final tank in the series of tanks has a lip forming a weir over which a mixture of remaining pollutants and bioremediation material flows from the series of tanks to the larger tank.

An adjustable height skimmer may be provided to skim hydrocarbons floating on the surface of the bioremediation and pollutant mixture from the larger tank. In this way light hydrocarbon pollutant can be removed from the surface of the pollutant and bioremediation material which has flowed into the first tank and any remaining grit, dirt and any heavy hydrocarbon fractions fall to the bottom of the larger settlement tank. Where there is light hydrocarbon pollution the skimmer could be omitted, as the bioremediation material will digest the remaining light hydrocarbons in the larger settlement tank(s).

The larger tank may be connected by to one or more further tanks each optional having additional removable smaller settlement tanks into which recovered bioremediation material and remaining pollutant may be initially fed.

The pollutant and bioremediation treatment can be substantially separated from heavier grit and hydrocarbon fraction and captured in the settlement tanks before entering the series of larger tanks. The settlement tanks being removable are easily cleaned.

The each member of the series of settlements tanks can be emptied onto inclined ramps where trapped grit and heavy hydrocarbons are captured on the ramp and liquid run off and returned to the settlement tanks.

In a second embodiment the system comprises a series of two or more tanks, the liquid and pollutant being passed to the first of the settlement tanks, which has a has an adjustable height skimmer, to skim hydrocarbons floating on the surface of the bioremediation and pollutant mixture from the tank and a vertical baffle extending downwards from the top of the tank reaching towards the bottom of the tank forcing liquid passing through the tank to follow a sinuous path enhancing trapping of grit, dirt and heavy hydrocarbons. Trapping can be further improved with further baffle extending up from the bottom of the first tank in front of the downwardly extending baffle in terms of the direction of flow of pollutant and bioremediation material. The tanks are connected to one another by pipes.

In both embodiments, the recovered bioremediation material dwells in the separation tanks for a time to allow settlement, to maintain or enhance the remedial properties of the bioremediation materials the settlement tanks are aerated.

In the second embodiment, and the first embodiments where more than one tank is provided, the tanks are connected by pipes. Low micron filters can be included in the pipes joining each tank; the filters may also have a back wash attachment. A back wash attachment enables any particles trapped by the filter to be flushed by passing water through the filter in a direction opposite that of normal flow. In a further arrangement, the tanks may be arranged in line, one on top of another with the first tank in series at the top and the other tanks below. In a still further variation the tanks are arranged one inside the other with the last in line being the biggest and the outmost tank and the first tank being the innermost. Alternatively each of the settlement tanks has a lip on its edge adjoining an adjacent settlement tank, acting as a weir over which bioremediation material and remaining pollutant flows to the adjacent settlement tank in the series.

In both embodiments, to aid cleaning of the settlement tanks each tank is provided with a drain near the bottom of the tank. In one preferred arrangement the floors of the settlement tanks are inclined towards the said drains.

The system is particularly useful used in connection with a vehicle wash. A surfactant and bioremediation material can applied to a vehicle together, but it has been found advantageous if the surfactant and a hydrocarbon are applied to the surface of a vehicle initially and a bioremediation material applied subsequently.

If a bioremediation is used as a vehicle wash, it can be seen that the system described enables a semi-closed cycle vehicle washing facility.

This is achieved by capturing the bioremediation material after the vehicle has been washed and pumping it to the first tank or first settlement tank if removable settlement tanks are deployed in the first tank. The recovered liquid from the final tank can be reused. This minimises the water input into the wash. Ideally bioremediation material recovered from the bioremediation process is fed to a header tank associated with a vehicle washing facility. The header tank may have a bottom inclined towards its outlet to facilitate cleaning.

The invention has also been used successfully in waste management systems were a surfactant, hydrocarbon and bioremediation material were mixed with waste, polluted with hydrocarbons, the run-off from the waste is then circulated through a system according to the invention and the bioremediation material recovered.

The invention will now be more fully described, by way of example only, with reference to the accompanying drawings, in which

Figure 1 is a perspective view of a series of three tanks forming a bioremediation separation unit according to the invention with their lids closed;

Figure 2 is the same series of tanks with their lids removed;

Figure 3 is a vertical section of the same series of tanks;

Figure 4 is a perspective view of a series of tanks forming a bioremediation unit, similar to that shown in figure 2, but using preliminary separator tanks;

Figures 5A shows a removable used in the system of figure 4; figure 5B shows the schematic arrangement of settlement tanks and settlement tanks of figure 4; figure 5C is a schematic view of an incline for separating grit, heavy hydrocarbons and other heavy pollutants captured in a settlement tank of Figure 5A or 5B; and

Figure 6 is a schematic diagram of a vehicle washing facility employing the present invention.

In figures 1 to 3, one embodiment of a bioremediation separation unit for use with the invention. The unit comprises three tanks 10, 30 and 40 with brims 26 around their perimeters. The first tank 10 has a lid 12 an input 14 and outlet(s) 16.

Recovered liquid comprising the hydrocarbon pollutant, other solid particles and suspended materials, and the bioremediation material is pumped or delivered by tanker from where the bioremediation material is being applied (for example a vehicle wash) into the first tank 10, or if the separation unit is below ground or the below where application of the bioremediation is taking place, the flow could be by gravity. The first tank has a pair of vertical baffles 18 and 20, the first baffle 18 of the pair extending upwards from the bottom of the tank 10 and across the width of the tank but below the normal operating depth of bioremediation material and pollutant in the tank, the second baffle 20 of the pair extending from the of the tank across the width of the tank to below the top of the first of the pair, the first baffle 18 of the pair being closer to the input 14 than the second baffle 20 of the pair. The depth of the second baffle 20 of the pair is substantially greater than the height of the first baffle 18 reaching almost to the bottom of the separation tank 10. The two baffles are close together, the first baffle 18 is of sufficient height to prevent most solid material in the pollutant from going over its top, so trapping it at the bottom of separation tank 10 between input 14 and baffle 18.

Within tank 10, a skimmer 50 is mounted atop a pipe 52 leading to an external outlet 53. The skimmer 50 comprises a funnel 56 mounted by a screw thread 54 to the upper end of the pipe 52. A C-sectioned cross member of the funnel receives a small cross arm 57 of a T-bar 58, to enable the funnel 56 to be turned in relation to the pipe 52 and so to have its height adjusted by turning about screw thread 54. As an alternative to the T-bar, the height adjustment can be undertaken by manually turning the funnel 56 about the screw thread 54. Light hydrocarbons present float to the top of the liquid in the tank 40 and, by adjusting the height of the skimmer 50, can be made to flow down funnel 56 into pipe 52 and out of the tank through an outlet 53 from where they can be collected for recovery

Outlets 16 connect to pipes 22 and the inputs 38 of the second tank 30, which has a lid 32. A vertical baffle 28 extending downwards from the top of the tanks towards the floor causes liquid passing through the tank 30 to follow a sinuous path. Further finer particles settle in tank 30, and liquid which, by now comprises almost solely bioremediation material and light hydrocarbons, flows on through outlets 34 and further pipes 36 through the inlets 44 of a third tank 40. This tank 40, too, has a lid 42. A further vertical baffle 28 extending downwards from the top of tank 40 towards the floor causes liquid passing through the tank to follow a sinuous path. Tank 40 has an outlet 46, set towards the lower part of the tank, from which the bioremediation material can be drained for recovery, or in a closed loop system, say in a washing plant, pumped around for reuse in the washing cycle. A skimmer 50 is mounted atop a pipe 52 leading to an external outlet 53. The skimmer 50 comprises a funnel 56 mounted by a screw thread 54 to the upper end of the pipe 52. A C-sectioned cross member of the funnel receives a small cross arm 57 of a T-bar 58, to enable the funnel 56 to be turned in relation to the pipe 52 and so to have its height adjusted by turning about screw thread 54. As an alternative to the T-bar, the height adjustment can be undertaken by manually turning the funnel 56 about the screw thread 54. Light hydrocarbons present float to the top of the liquid in the tank 40 and, by adjusting the height of the skimmer 50, can be made to flow down funnel 56 into pipe 52 and out of the tank through an outlet 53 from where they can be collected for recovery. The remaining liquid can be removed from the tank 40 through outlet 46 and out of the tank. This remaining liquid will be substantially the bioremediation material recovered

To allow flushing of the tanks 10, 30 and 40 of any sediment on the bottoms of the tanks 10, 30 and 40, small drain cocks 11,31 and 41 are provided at the bottom of each tank 10, 30, and 40. In the case of tank 10 the drain cock is between the second baffle 20 and the wall below outlet 16.

More substantial course material is collected between the input 14 of the first separation tank 10 and the first baffles 18, this tank will need to be cleaned out regularly.

To remove any suspended particles in the liquid, conventional low micron filters are included in the pipes from the outlet of each tank; the filters may also have a back wash attachment to enable cleaning of the filters. Although shown as aligned the tanks may be arranged in some other way, for example one above the other with the first tank at the top and liquid flowing from one to another under gravity.

Each of the tanks has one or more connections 24 to enable compressed air to be passed into the tank to aerate the liquid in the tank; this maintains and to an extent regenerates the bioremediation material in the tanks.

The first tank, especially, in the system as illustrated in figures 1 to 3 requires frequent cleaning. In order to ease the cleaning requirements, a modified system as illustrated in figure 4 has been developed.

In figure 4, the baffles 18 and 20 are omitted, and a series of small removable rectangular settlement tanks 81,82, 83 on inlet side of a first larger tank 10. A cross member 80 parallel to the end of first tank 10 is provided to aid support of the settlement tanks 81,82, 83. Settlement tank 81, has a wide brim on three sides 85, 86, and 87, (see figure 5A) to rest on the brim 26 of larger tank 10 and cross member 80, the fourth side has a lip 88 which extend over the side of settlement tank 82 forming a weir between settlement tank 81 and settlement tank 82. The edges 85, 86, and 87 have each have a raised portions or beading 89 to prevent overflowing on these sides. Similarly settlement tank 82 has wide brims on two sides to overlap the brim 26 of tank 10 cross member 80 for support, and a lip on the opposed side to that overlapped by lip 88 of settlement tank 81, the lip on settlement tank 82 overlaps settlement tank 83, which in turn has a lip to form a weir over which liquid may flow into larger tank 10. The sides of settlement tank 83 not overlapped by the lip on settlement tank 82 or having a lip, have brims which rest on the brim 26 of tank 10, the lip of settlement tank 83 passes over cross-member 80. The brims have raised or beaded portions preventing overflowing.

Figure 5B shows the general flow arrangements. Pollutant and bioremediation mix into the first settlement tank 81 from a duct 15. The liquid overflows from settlement tank 81 over lip 88 to settlement tank 82, in figure 5B two intermediate settlement tanks 82 are shown, whereas in figure 4 one is shown, the liquid and any remaining pollutant flower into settlement tank 83 and over its lip to tank 10, where light hydrocarbons are skimmed and removed. From tank 10 it flows on to tank 30 and tank 40. Most of the grit and heavy hydrocarbons arriving duct15 will be trapped in settlement tank 81, or in the subsequent settlement tanks 82 and 83. The settlement tanks are mounted to be easily removable, whereas the larger tanks 10, 30 and 40 are less easily lifted. The settlement tanks 81,82, 83 can be lifted on a daily basis, cleaned and replaced. The tanks 10, 30 and 40 where light dust and other sediment will settle need to be cleaned less frequently, weekly or even less.

The first tank 10 has s skimmer 50 is mounted atop a pipe 52 leading to an external outlet 53. The skimmer 50 comprises a funnel 56 mounted by a screw thread 54 to the upper end of the pipe 52. A C-sectioned cross member of the funnel receives a small cross arm 57 of a T-bar 58, to enable the funnel 56 to be turned in relation to the pipe 52 and so to have its height adjusted by turning about screw thread 54. As an alternative to the T-bar, the height adjustment can be undertaken by manually turning the funnel 56 about the screw thread 54. Light hydrocarbons present float to the top of the liquid in the tank 40 and, by adjusting the height of the skimmer 50, can be made to flow down funnel 56 into pipe 52 and out of the tank 10 through an outlet 53 from where they can be collected for recovery.

Tank 10 has outlet(s) 16 to pipes 22 connected to the inlets 38 of the second tank 30. A vertical baffle 28 extending downwards from the top of the tank 30 towards the floor causes liquid passing through tank 30 to follow a sinuous path.

Some further finer particles may settle in tank 30, and liquid which, by now comprises almost solely bioremediation material and light hydrocarbons, flows on through outlets 34 and further pipes 36 through the inlets 44 of a third tank 40. A vertical baffle 28 extending downwards from the top of the tank 40 towards its floor causes liquid passing through tank 40 to follow a sinuous path. Tank 40 has an outlet 46, set towards the lower part of the tank, from which the remaining liquid can be drained for recovery, or in a closed loop system, say in a washing plant, pumped around for reuse in the washing cycle. This remaining liquid will be substantially bioremediation material.

To allow flushing of the tanks 10, 30 and 40 of any sediment on the bottoms of the tanks 10, 30 and 40, small drain cocks 11,31 and 41 are provided at the bottom of each tank 10, 30, and 40. In the case of tank 40 the drain cock is on the rear wall below outlet 46. To further facilitate cleaning further, the floors 13, 33, 43 of each of the tanks 10, 30 40 are inclined downwards towards the drain cocks. The bottoms of baffles 28 are shaped to ensure clearance of about 16cm above the inclined floors 33 and 43.

The settlement tanks 81,82 83 are emptied onto a gentle incline 90, seen in figure 5C, having a slightly rough surface, liquid runs to the bottom of the incline to a gutter 92 from where it is pumped back by a submersible pump 94, once the liquid has accumulated at the bottom of the incline to a present depth to the first settlement tank for the bioremediation unit shown in figure 4. The captured pollutant, grit and dust material 96 captured on the incline allowed to dry under cover over a period of up to 30 days, exposed to continuing action from bioremediation material still in the material, after that time it is safe to send to a land fill site.

In a simple system to deal with light pollution the second and third tanks 30 and 40 of figure 4 can be omitted with the output taken from the first tank 10.

In figure 6, a bioremediation separation unit 64 of the kind described above is part of a vehicle washing facility 60, having a spay booth 63. A vehicle is initially sprayed with water containing a biodegradable anionic surfactant up to 15% by weight inclusive and a source of hydrocarbons comprising 0.3% by volume. The vehicle V is then sprayed with bioremediation material 70, which may have been recycled, from spray booth 60. Mud, grit and hydrocarbons on the vehicle drop to the floor of the wash, here the heavier solids tend to congregate, the liquid and lighter solid run in channels 62 to a pipe or gully above the first settlement tank 81 of a bioremediation system 64 as described in figure 4. It has been found that bioremediation material enhances the degradation of the mud. The solids collected on the floor 61 are swept up. The final outlet of the bioremediation system is connected to a pipe 66 and pump 67 which pumps the recycled bioremediation material to a header tank 68 of the vehicle washing facility 60. From the header tank it is pumped by pump 69 though the outlet 72 of header tank 68 to the spray booth 63 forming a spray 70. The header tank 68 has a floor 71 which slopes towards outlet 72 to ease cleaning problems. The floor 71 of tank 68 may preferably be slightly rough to hold any dust particles remaining in the recycled bioremediation material which have settled on floor 71 rather them being dragged into the spray 70. A baffle similar to those shown as 28 in figures 1 to 5 may be included in the header tank, in such a case of clearance of about 10cm above the floor is desirable.

Spraying aerates the bioremediation liquid making it more effective; it may also be warmed general to around 20° to 40°C further enhancing the performance.

The spraying in figure 5 is shown as emanating from a mechanically operated spray booth 63, however this can be replaced by hand sprays, two in practice, one connected to a source of the water containing a biodegradable anionic surfactant up to 15% by weight inclusive and a source of hydrocarbons comprising 0.3% by volume, the other to a header tank 68 and providing bioremediation material comprising bacilli in water suspension. If there is no bacilli in the header tank, say, if the system is new or has been unused for time, then the second sprayer or spray booth would have to be connected to an external source of bacilli.

The surfactant typically is alcohol ethoxylate, others include a range of products sold under the trade mark TERGITOL™ L Series, or Linear Alkyl Benzene Sulfonate. There are many suitable naturally occurring solvents and surfactants that can be used with this invention, examples include Eco-friendly solvents used in recent times include solvents that are derived from alcohols and esters of soy, corn, rice, palm, cottonseed, linseed, safflower sunflower, Jojoba soil, Jatropha, mustard, walnut and almond oils which are all readily biodegradable and non-toxic. A suitable supply of a bioremediation material for use in this invention is product GS231160190259 obtainable form Green Sword Environmental Ltd 372 Tempo Road, Enniskillen, Fermanagh BT943DS. United Kingdom.

Claims

1. A system for recovering bioremediation material from pollutants treated with the bioremediation material comprising a series of tanks with an edge of each of said tanks having a lip forming a weir over which mixture of pollutants and bioremediation material flows from one tank to another.

2. A system according to claim 1, in which the tank has height adjustable skimmer, to skim hydrocarbons floating on the surface of the bioremediation and pollutant mixture from the tank.

3. A system according to claim 1 or 2 comprising a plurality of removable settlement tanks, mounted in a larger tank, the settlement tanks being rectangular with an edge of each of the settlement tanks having a lip to form weirs over which mixture of pollutants and bioremediation material flows from one settlement tank to another or to the larger tank.

4. A system according to claim 3 in which the settlement tanks are emptied onto inclined ramps, the grit and heavy hydrocarbons being captured on the ramp and liquid run off and returned to the settlement tanks.

5. A system according to claim 3 or 4 in which the tank is connected to one or plurality of further tanks comprising additional settlement tanks.

6. A system according to claim 5 in which one or more of the further tanks has a vertical baffle extending downwards towards the bottom of the tank(s).

7. A system according to claim 1 in which the liquid and pollutant is passed to the first of the tanks, which has a has an adjustable height skimmer and a vertical baffle extending downwards from the top of the tank reaching towards the bottom of the tank forcing liquid passing through the tank to follow a sinuous path.

8. A system according to claim 7 in which a further baffle extending up from the bottom of the first tank in front of the downwardly extending baffle in terms of the direction of flow of pollutant and bioremediation material.

9. A system according to claim 7 or 8 in which one or more of the further tanks in addition to the first tank has a vertical baffle extending downwards towards the bottom of the tank(s).

10. A system according to any one of claims 5 to 9 in which the tanks are connected by pipes containing low micron filters.

11. A system according to claim 10 in which the filters each have a back wash attachment.

12. A system according to any preceding claim in which each tank has a drain near the bottom of the tank.

13. A system according to claim 12 in which the floors of the tanks are inclined towards the said drains.

14. A system according to any preceding claim including the step of aerating one or more of the tanks.

15. A system according to any preceding claim in which the settlement tanks have drains.

16. A bioremediation method employing a system according to any preceding claim the method including the steps of applying a surfactant and a hydrocarbon are applied to a polluted material of surface and subsequently applying a bioremediation material.

17. A bioremediation method employing a system according to any one of claims 1 to 15 in which the bioremediation material recycled for reuse after passing through the tank(s).

18. A bioremediation method according to claim 17 in which recycled bioremediation material is pumped to a header tank the header tank having an outlet to a spray.

19. A bioremediation method according to claim 18 in which the floor of the header tank slopes towards the outlet.

20. A bioremediation method according to claim 19 in which the floor of the header tank is rough

21. A bioremediation method according to claim 20 in which the bioremediation material is heated prior to spraying.

22. A bioremediation method according to claim 21 in which the bioremediation liquid is heated to 20°C to 80°C prior to spraying.

23. A system for recovering bioremediation material hereinbefore described with reference to the accompanying drawings.

24. A bioremediation method substantially as hereinbefore described with reference to the accompanying drawings.