Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
A DEVICE FOR TREATING AND RECYCLING WATER
Document Type and Number:
WIPO Patent Application WO/2020/244820
Kind Code:
A1
Abstract:
A device (80) for treating and recycling water (83), contaminated with waste, from a waste soil cleaning system, which system is upstream of the device has a settlement tank (11) divided into a first compartment (15) and a second compartment (16) by a partition wall (14), with a channel (40) therebelow. Contaminated water indicated by arrows (81) (solids), (82) (floatable contaminated waste) and (83) (water) enters device (80) by way of the height adjustable inlet basin (17). The contaminated water overflows into the first compartment (15) and the solids (81) drop into base (18), for removal through a solids outlet (18), while the floatable contaminated waste (82) floats to the surface of the water where it is skimmed therefrom by a mechanical skimmer( 84), which pushes the floatable contaminated waste (82) up an inclined plate (not shown) to a waste receptacle (not shown). The water (83) passes through the channel (40) into the second compartment (16) and any remaining floatable contaminated waste (82) will rise to the surface of the water in the second compartment (16), to be removed by skimming and transfer up an additional inclined plate (41) into the first compartment (15) for removal by skimming. Any additional solids (81) in the second compartment (16) will drop into the base (23) for removal through a second solids outlet (24). The clean water (83) exits the second compartment (16) through a treated water outlet (26) for recycling back to the waste soil cleaning system.

Inventors:
DRENNAN NIALL (IE)
Application Number:
PCT/EP2020/056707
Publication Date:
December 10, 2020
Filing Date:
March 12, 2020
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
NIALL DRENNAN ENTERPRISES LTD (IE)
International Classes:
E03F5/16; B01D21/00; B01D21/24
Domestic Patent References:
WO2018225890A12018-12-13
Foreign References:
US20170120165A12017-05-04
KR101957650B12019-03-13
KR101660448B12016-09-28
JPS5867306A1983-04-21
Attorney, Agent or Firm:
RYAN, John (IE)
Download PDF:
Claims:
Claims: -

1. A device for treating and recycling water, contaminated with waste, from a waste soil cleaning system, which system is upstream of the device, and which device comprises a separation tank having a base, walls upstanding therefrom, with the tank being open at the top and having a partition wall mounted therein, which divides the tank into first and second compartments, an inlet, for receipt of the contaminated water, mounted in the first compartment, the first compartment having a base section on which solid waste, with a density greater than water, settles, in use, as the contaminated water circulates within the first compartment, a first solids outlet in the base section for removal of the settled, solid waste, an inclined plate mounted on the top of the first compartment and directed towards the surface of the water therein, in use, which inclined plate is adapted to receive floatable contaminated waste, which is skimmed from the surface of the water, up the inclined plate and into a waste receptacle, a channel below the partition wall, which channel is at a position below the surface of the water, such that relatively clean water circulates through the channel into the second compartment, within which any remaining solid waste, with a density greater than water, is removable through a second solids outlet in the base section of the second compartment, with any remaining floatable contaminated waste being removable from the surface of the water in the second compartment by skimming, and a treated water outlet in the second compartment for removal of the treated water therefrom for recycling back to the waste soil cleaning system.

2. A device according to Claim 1 , wherein a height adjustable inlet basin is located at the inlet and extends across the width of the first compartment, which inlet basin receives contaminated water from the inlet, in use, which contaminated water overflows from the inlet basin into the first compartment.

3. A device according to any one of Claims 1 or 2, wherein the depth to which the partition wall extends in the first compartment and hence the depth of the channel, below the surface of the water, is adjustable. 4. A device according to any one of Claims 1 to 3, wherein the treated water outlet is positioned within the second compartment at the same depth below the surface of the water as the channel.

5. A device according to any preceding claim, wherein formations are mounted on the tank walls in the second compartment, which formations are adapted to receive an additional partition wall, with the second compartment being subdivided by the insertion of the additional partition wall therein, and which additional partition wall has an additional channel therebelow, which additional channel is at the same position below the surface of the water as the channel under the partition wall, such that relatively clean water circulates through the additional channel into a further compartment.

6. A device according to Claim 5, wherein the second compartment and any additional subdivision thereof has an additional inclined plate, which inclined plates are positioned at the top of the respective compartments, such that, in use, any remaining floatable contaminated waste on the surface of the water in a particular

compartment may be manually skimmed therefrom, up the inclined plate and into the preceding compartment and thence to the first compartment, where it will be removed to the waste receptacle.

7. A device according to any one of Claims 1 to 6, wherein the base sections of the first and second compartments have the shape of an inverted cone, with the first and second solids outlets being located at the apex of the respective cone.

8. A device according to any preceding claim, wherein the and each solids outlet is connected to a sludge pump, which pumps any solids to a sludge buffer holding tank.

9. A device according to Claim 8, wherein the operation of the sludge pump is intermittent and is automated.

10. A device according to any preceding claim, wherein a mechanical skimming unit is mounted at the top of the first

compartment, which mechanical skimming unit, in use, skims any floatable contaminated waste from the surface of the water, up the inclined plate and into the waste receptacle.

11. A device according to Claim 10, wherein the mechanical skimming unit has a conveyer belt with a plurality of scrapers attached thereto, with the conveyer belt being orientated in the first compartment to skim floatable contaminated waste from the surface of the water and up the inclined plate, and with the clearance between the and each scraper and the surface of the inclined plate being such that any floatable contaminated waste is conveyed up the inclined plate to the waste receptacle.

12. A device according to Claim 1, for treating and recycling water, contaminated with waste, from a waste soil cleaning system, which system is upstream of the device, substantially as hereinbefore described with particular reference to and as illustrated in Figs. 1-5 and Figs. 6-7 of the accompanying drawings.

Description:
A device for treating and recycling water

Technical Field

This invention relates to a device for treating and recycling water and, in particular, to a device for treating and recycling water

contaminated with waste, from a waste soil cleaning system.

Background Art

Waste soil cleaning processes are used to wash and recycle waste aggregate and soils. The waste water from the soil cleaning process is often dosed with a coagulant, (such as ferric chloride or aluminium sulphate to coagulate the colloidal particles) and/or a flocculant (such as alum, A1 2 (S0 4 ) 3 ยท 14 H2O) to conglomerate the particles into bigger clusters, which results in the settling of the soil/silt from the water. The clean water then overflows and is recycled back to the wash plant. The soil or silt is pumped to another process. When washing and processing/recycling waste soils, these soils can contain cement, concrete, gypsum, petroleum products, including oils and plastics, and organic waste, such as wood. The water, as it leaves the coagulant/flocculant stage, is aerated, which results in soil and floatable materials floating on the surface of the clean water. This causes problems when recycling this water back to the washing process.

A water treatment process known as Dissolved Air Flotation (DAF) is used in some applications to remove suspended matter, such as oil or solids, from wastewater. The removal is achieved by dissolving air in the wastewater under pressure and then releasing the air at atmospheric pressure into a flotation tank basin. The released air forms micron-sized bubbles that attach to the suspended matter causing the suspended matter to float to the surface of the water where it may be removed by a skimming device. The remaining water exits the flotation tank as a clarified effluent and can be recycled.

Whilst the DAF process separates the suspended solids from the water, it does not separate the suspended solids, which are all skimmed off the surface of the water together.

In the oil industry, Dissolved Gas Flotation (DGF) units use nitrogen gas rather than air due to the risk of explosions.

It is an object of the present invention to overcome the

disadvantages of the water treatment processes hereinbefore described. Disclosure of Invention

Thus, the invention provides a device for treating and recycling water, contaminated with waste, from a waste soil cleaning system, which system is upstream of the device, and which device comprises a separation tank having a base, walls upstanding therefrom, with the tank being open at the top and having a partition wall mounted therein, which divides the tank into first and second compartments, an inlet, for receipt of the contaminated water, mounted in the first compartment, the first compartment having a base section on which solid waste, with a density greater than water, settles, in use, as the contaminated water circulates within the first compartment, a first solids outlet in the base section for removal of the settled, solid waste, an inclined plate mounted on the top of the first compartment and directed towards the surface of the water therein, in use, which inclined plate is adapted to receive floatable contaminated waste, which is skimmed from the surface of the water, up the inclined plate and into a waste receptacle, a channel below the partition wall, which channel is at a position below the surface of the water, such that relatively clean water circulates through the channel into the second compartment, within which any remaining solid waste, with a density greater than water, is removable through a second solids outlet in the base section of the second compartment, with any remaining floatable contaminated waste being removable from the surface of the water in the second compartment by skimming, and a treated water outlet in the second compartment for removal of the treated water therefrom for recycling back to the waste soil cleaning process.

By a waste soil cleaning process in this context is meant a process for washing and recycling oil contaminated soil, hazardous soil waste, Construction and Demolition (C&D) waste, Trommel Waste fines, or road sweeper waste.

An advantage of the device in accordance with the invention is that the circulation of the water in the first and second compartments separates the water into three layers, an upper layer to which the floatable contaminated waste migrates, a middle layer of relatively clean water, and a lower layer containing solid waste, with a density greater than water. The floatable contaminated waste is skimmed off the surface of the water, the solid waste, with a density greater than water will drop to the base of each compartment to be removed through the solid waste outlets and the relatively clean water will flow through the channel and thence to the treated water outlet. This separation of waste from water is achieved by allowing the contaminated water to slowly circulate within the first and second compartments and does not require any other treatment such as the addition of pressurised gas.

Preferably, a height adjustable inlet basin is located at the inlet and extends across the width of the first compartment, which inlet basin receives contaminated water from the inlet, in use, which contaminated water overflows from the inlet basin into the first compartment.

An advantage of this aspect of the invention is that the velocity of the contaminated water flow is slowed down as it enters the first compartment from the inlet basin, and this slowing down of the water flow encourages the separation of the solid waste from the floatable waste.

Further, preferably, the depth to which the partition wall extends in the first compartment and hence the depth of the channel, below the surface of the water, is adjustable.

An advantage of this aspect of the invention is that the position of the channels can be adjusted to suit the characteristics of the

contaminated water entering the separation tank. Suitably, the treated water outlet is positioned within the second compartment at the same depth below the surface of the water as the channel.

An advantage of this aspect of the invention is that it minimises the likelihood of contaminated waste being recycled back to the waste soil cleaning process.

In one embodiment in accordance with the invention formations are mounted on the tank walls in the second compartment, which formations are adapted to receive an additional partition wall, with the second compartment being subdivided by the insertion of the additional partition wall therein, and which additional partition wall has an additional channel therebelow, which additional channel is at the same position below the surface of the water as the channel under the partition wall, such that relatively clean water circulates through the additional channel into a further compartment.

An advantage of this aspect of the invention is that the flow profile of the water in the separation tank can be tailored for a specific

application.

Preferably, the second compartment and any additional

subdivision thereof has an additional inclined plate, which inclined plates are positioned at the top of the respective compartments, such that, in use, any remaining floatable contaminated waste on the surface of the water in a particular compartment may be manually skimmed therefrom, up the inclined plate and into the preceding compartment and thence to the first compartment, where it will be removed to the waste receptacle.

An advantage of this aspect of the invention is that any waste material that manages to pass through the channel between the first and second compartments will be removed in the second compartment and any additional subdivision thereof.

Suitably, the base sections of the first and second compartments have the shape of an inverted cone, with the first and second solids outlets being located at the apex of the respective cone. An advantage of this aspect of the invention is that the cone shape encourages the concentration of the solid waste at the solid waste outlet in the particular compartment.

In a further embodiment in accordance with the invention, the and each solids outlet is connected to a sludge pump, which pumps any solids to a sludge buffer holding tank.

An advantage of this aspect of the invention is that the solid waste is removeable to a central holding tank. Thus, excess build-up of solid waste in the base of each compartment is avoided.

Preferably, the operation of the sludge pump is intermittent and is automated. An advantage of this aspect of the invention is that the sludge pump and associated pipe work can be flushed out at regular intervals to avoid failure of the pump.

In a further embodiment in accordance with the invention, a mechanical skimming unit is mounted at the top of the first

compartment, which mechanical skimming unit, in use, skims any floatable contaminated waste from the surface of the water, up the inclined plate and into the waste receptacle.

An advantage of this aspect of the invention is that the floatable contaminated waste is being continuously removed from the surface of the water in an efficient manner and without human intervention.

Preferably, the mechanical skimming unit has a conveyer belt with a plurality of scrapers attached thereto, with the conveyer belt being orientated in the first compartment to skim floatable contaminated waste from the surface of the water and up the inclined plate, and with the clearance between the and each scraper and the surface of the inclined plate being such that any floatable contaminated waste is conveyed up the inclined plate to the waste receptacle.

An advantage of this aspect of the invention is that the conveyer belt with a plurality of scrapers is unlikely to fail as the force required to remove the floatable contaminated waste is spread across a number of scrapers at a particular instant. The invention will be further illustrated by the following description of embodiments thereof, given by way of example only with reference to the accompanying drawings in which:

Brief Description of Drawings Fig. 1 is a plan view of a device, in accordance with the invention, for treating and recycling water, contaminated with waste, from a waste soil cleaning system, which system is upstream of the device;

Fig. 2 is a front elevation of the device of Fig. 1;

Fig. 3 is a section view on line III - III of Fig. 1; Fig. 4 is a rear elevation of the device of Fig. 1;

Fig. 5 is an end view of the device of Fig. 1;

Fig. 6 is a schematic representation of the water flow through a further embodiment of the device in accordance with the invention; and Fig. 7 is a perspective view of the embodiment of Fig. 6.

Best Mode for Carrying out the Invention

Referring to Fig. 1, there is illustrated generally at 10, a device for treating and recycling water, contaminated with waste, from a waste soil cleaning system, which system is upstream of the device 10. Device 10 has a separation tank 11 having a base 12, and walls 13 upstanding therefrom, with the tank 11 being open at the top and having a partition wall 14 mounted therein, which divides the tank 11 into a first

compartment 15 and second compartment 16. An inlet 17, for receipt of the contaminated water, is mounted in the first compartment 15. Inlet 17 is a height adjustable inlet basin which extends across the width of the first compartment 15, which inlet basin 17 receives contaminated water which overflows from the inlet basin into the first compartment 15. The first compartment 15 has a base section 18 on which solid waste, with a density greater than water, settles, in use, as the

contaminated water circulates within the first compartment 15, and a first solids outlet 19 in the base section 18 for removal of the settled, solid waste. An inclined plate 20 is mounted on the top 21 of the first compartment 15 and is directed towards the surface of the water therein, in use, which inclined plate 20 is adapted to receive floatable

contaminated waste, which is skimmed from the surface of the water in the first compartment 15, up the inclined plate 20 and into a waste receptacle 22.

The second compartment 16 has a base section 23 on which any remaining solid waste, with a density greater than water, settles, in use, as the contaminated water circulates within the second compartment 16, and a second solids outlet 24 in the base section 23 for removal of the settled, solid waste.

A platform 25 is mounted along the side 13 of the separation tank 11, which platform 25 provides access along the length of the separation tank 11.

A treated water outlet 26 is mounted in the second compartment 16 at position 27 on the wall 13.

Referring to Fig. 2, a front elevation of the device 10 is illustrated. Device 10 is supported by an open framework, shown generally at 30. The base section 18 of first compartment 15, and the base section 23 of the second compartment 16, have the shape of inverted cones 31 and 32 respectively, with the first and second solids outlets 19 and 24, respectively being located at the apices 33 and 34 of the base sections 18 and 23, respectively. Referring to Fig. 3 a sectional view of the device 10, on line III -

III of Fig. 1, is shown. As previously described, the partition wall 14 divides the separation tank 11 into a first compartment 15 and second compartment 16. The partition wall 14 has a channel 40 therebelow, which channel 40 is at a position below the surface of the water, such that relatively clean water circulates through the channel 40 into the second compartment 16, within which any remaining solids waste, with a density greater than water, is removeable through the second solids outlet 34 in the base section 23 of the second compartment 16. Any remaining floatable contaminated waste is removed from the surface of the water in the second compartment 16 by skimming the surface of the water. An additional inclined plate 41 is mounted on the top 42 of partition wall 14 and the remaining floatable contaminated waste is pushed up the additional inclined plate 41 and into the first compartment 15, where it will be removed to the waste receptacle (not shown).

Solids outlet 33 in first compartment 15 and solids outlet 34 in second compartment 16 and both are connected, through pipes 44 and 45, respectively, to a sludge pump 43, which pumps any solids to a sludge buffer holding tank (not shown). The operation of the sludge pump 43 is intermittent and is automated, including automated opening and closing of the solids outlets 33 and 34. A connector 46 mounted in pipe 44 and a corresponding connector 47, in pipe 45, are adapted to receive a supply of high-pressure water for intermittently cleaning out pipes 44 and 45 and the sludge pump 43.

Clean water enters the treated water outlet 26 through a height adjustable exit chute 48. An exit opening 49 at end 50 of the exit chute 48 is positioned in the second compartment 16 at the same depth below the surface of the water as the channel 40.

Formations 51, 52 are mounted on the walls 13 of the second compartment 16, which formations 51, 52 are adapted to receive additional partition walls (not shown), with the second compartment 16 being subdivided by the insertion of these additional partition walls and have additional channels (not shown) therebelow. These additional channels are at the same position below the surface of the water as channel 40 under the partition wall 14, such that relatively clean water circulates through into a further compartment. Referring to Fig. 4 a rear elevation of device 10 is shown. The waste receptacle 22 consists of a funnel 60 connected to a downpipe 61 through which the floating contaminate waste is delivered to an exterior holding tank (not shown).

Access stairs 62 provide access to the platform 25. Referring to Fig. 5 the construction of the support frame 30 can be seen. The settlement tank 11 is supported on the top beam 70 at end 71 of the frame 30. A pair of legs 72, 73, support the top beam 70. A similar arrangement of legs and beams are to be found at the opposite end (not shown) of frame 30. The ends of frame 30 are connected by longitudinal beams (not shown). Frame 30 supports the settlement tank at a height that is sufficient to accommodate the base section (not shown) of the first compartment (not shown) and the base section 23 of the second compartment 16.

The downpipe 61 extends vertically from funnel 60. Referring to Fig. 6, the water flow through a further embodiment of a device, shown generally at 80, in accordance with the invention, is illustrated. As the construction of the device 80 is similar to the device 10, illustrated in Figs, 1 to 5, like features will be indicated by the same reference numerals. Device 80 has a settlement tank 11 divided into a first compartment 15 and a second compartment 16 by a partition wall 14, with a channel 40 therebelow.

Contaminated water indicated by arrows 81 (solids), 82 (floatable contaminated waste) and 83 (water) enters device 80 by way of the height adjustable inlet basin 17. The contaminated water overflows into the first compartment 15 and the solids 81 drop into base 18, for removal through solids outlet 19, while the floatable contaminated waste 82 floats to the surface of the water where it is skimmed therefrom by a

mechanical skimmer 84, which pushes the floatable contaminated waste 82 up an inclined plate (not shown).

The water 81 passes through the channel 40 into the second compartment 16 and any remaining floatable contaminated waste 82 will rise to the surface of the water in the second compartment 16, to be remove by skimming and transfer up an additional inclined plate 41 into the first compartment 15 for removal be skimming.

Any additional solids 81 in the second compartment 16 will drop into base 23 for removal through the second solids outlet 24.

The clean water 83 exits the second compartment 16 through end 49 of exit chute 48 and out through the treated water outlet for recycling back to the waste soil cleaning system. End 49 is at the same depth as channel 40 and the water 83, circulating at this depth has been cleaned. Referring to Fig. 7, device 80 is illustrated in perspective. The mechanical skimmer 84 consists of a conveyer belt 85 with a plurality of scrapers 86 attached thereto. The conveyer belt 85 is orientated in the first compartment 15 to skim floatable contaminated waste from the surface of the water up the inclined plate 20, and with the clearance between the and each scraper 86 and the surface of the inclined plate 20 being such that any floatable contaminated waste will be conveyed up the inclined plate 20 and into the waste receptacle 22.

Any floatable contaminated waste on the surface of the water in the second compartment 16 can be manually skimmed therefrom, up the additional inclined plate 41 to the first compartment 15, where it will be removed by mechanical skimmer 84.