Decontamination system and process

Abstract

A decontamination system 1 for decontaminating a material comprising a decontamination tank 20 for a mixture of the material and a disinfectant, an agitator 21 for agitating the and an ultrasonic gene

Description

The present application relates to a decontamination system and process. More specifically, the application relates to a decontamination system and process for decontaminating plastics materials. BACKGROUND The use of plastics materials is ubiquitous in the research and healthcare sectors. The benefits of using such materials include low cost, ease of manufacture, longevity and low reactivity. However, due to the difficulty in treating, decontaminating and recycling plastic products at the end of their intended use, particularly when they have come into contact with hazardous materials, such products are often disposed of rather than recycled. This results in a vast amount of plastics material waste being generated by the research and healthcare sectors each year. Research and healthcare facilities tend to have little infrastructure in place to deal with waste sustainably, and waste management companies often lack the know-how and scalable technology to recycle used components generated by research and healthcare facilities. In some cases, this means that the vast majority of used plastics materials generated by laboratories, for example, is sent to landfills or for incineration. It is known to decontaminate plastics materials using autoclave technology. Autoclave decontamination processes utilise high pressure and temperature; however, these conditions are damaging to plastics material such as polyethylene terephthalate (PET) and polystyrene (PS), which are commonly use in laboratory equipment and consumables. Once a material has been autoclaved, it goes through a size-reduction process (for example, shredding) in which it can be turned into flakes or pellets, followed by a washing stage using high-temperature water, before being subjected to a drying process. In addition to being energy-intensive, autoclaving processes have a low material recovery rate in which the value of initially high-grade laboratory materials is lost. The resulting ‘recycled’ plastics are typically grey or dark in colour, with odour and contaminants that present quality concerns, meaning that they can only be down-cycled to be used in products such as furniture. The present invention seeks to ameliorate the disadvantages of the prior art. SUMMARY OF INVENTION According to a first aspect of the invention there is provided a decontamination system for decontaminating a material, the system comprising: a decontamination tank for containing a mixture comprising the material and a disinfectant; an agitator for agitating the mixture in the tank; an ultrasonic generating device for applying ultrasound to the mixture in the tank. In a preferred embodiment, the system is for decontaminating a plastics material. The agitator can comprise a paddle. The ultrasonic generating device can comprise an ultrasonication probe. The ultrasonic generating device can apply to the mixture ultrasound waves with a frequency of 20kHz-100kHz, preferably 40kHz-50kHz. The disinfectant can comprise a disinfectant solution and, optionally, the decontamination tank can comprise a sensor for sensing the level or volume of the disinfectant solution in the decontamination tank. The decontamination system can comprise a shredder for shredding the material, wherein the shredder is arranged upstream of the decontamination tank. The shredder can comprise an applicator for applying a disinfectant to the material in the shredder. The applicator can comprise a nozzle for applying a jet of the disinfectant solution to the material in the shredder. The decontamination system can comprise a sieve, optionally a vibrating sieve, for separating disinfectant from the material, the sieve being arranged downstream of the decontamination tank. The decontamination system can comprise a decontamination tank conduit for conveying the material and disinfectant from the decontamination tank to the sieve. The decontamination system can comprise a disinfectant container for containing disinfectant separated from the material by the sieve, the disinfectant container being located downstream of the sieve and wherein the decontamination system optionally comprises a disinfectant container conduit arranged between the disinfectant container and the decontamination tank for conveying separated disinfectant from the container to the decontamination tank. The decontamination system can comprise a rinsing tank for rinsing disinfectant from the material using a rinsing liquid. The rinsing tank can comprise an agitator for agitating the material and the rinsing liquid in the rinsing tank; and an ultrasonic generating device for applying ultrasound to a mixture of the material and the rinsing liquid in the rinsing tank. The rinsing tank can comprise a sensor for sensing the level or volume of rinsing liquid in the rinsing tank. The rinsing tank can be located downstream of the sieve, and wherein the decontamination system optionally comprises a sieve conduit arranged between the sieve and the rinsing tank for conveying the material from the sieve to the rinsing tank. The decontamination system can comprise a dewatering sieve for separating the rinsing liquid from the material, wherein the dewatering sieve is arranged downstream of the rinsing tank. The decontamination system can comprise a rinsing solution container for containing rinsing liquid. The decontamination system can be controlled by a controller. According to a second aspect there is provided a decontamination process, wherein the process comprises using the disclosed system to decontaminate a material, optionally a plastics material. According to a third aspect of the invention there is provided an automated process of decontaminating material, the process comprising the steps of: passing the material to be decontaminated into a decontamination tank for containing a mixture comprising the material and a disinfectant; adding disinfectant to the decontamination tank; activating an agitator to agitate the mixture in the tank; and activating an ultrasonic generating device to apply ultrasound to the mixture in the tank. The process can further comprise the steps of: activating a shredder to shred the material; activating an applicator to apply a disinfectant to the material in the shredder; and conveying the shredded material from the shredder to a decontamination tank, wherein the shredder is arranged upstream of the decontamination tank. The process can further comprise the steps of: conveying the mixture from the decontamination tank to a sieve, optionally a vibrating sieve, for separating the disinfectant from the material, the sieve being arranged downstream of the decontamination tank and the mixture being conveyed via a decontamination tank conduit; and optionally, activating the sieve to vibrate. The process can further comprise the steps of: conveying the material from the sieve to a rinsing tank for rinsing the disinfectant from the material using a rinsing liquid via a sieve conduit, the rinsing tank being located downstream of the sieve; adding rinsing liquid to the rinsing tank; activating an agitator to agitate the mixture and the rinsing liquid in the rinsing tank; and activating an ultrasonic generating device to apply ultrasound to the mixture and the rinsing liquid in the rinsing tank. The process can further comprise the steps of: conveying the material and the rinsing liquid to a dewatering sieve, optionally a vibrating dewatering sieve, for separating rinsing liquid from the material, wherein the dewatering sieve is arranged downstream of the rinsing tank; and optionally, activating the sieve to vibrate. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a front view of a decontamination system. Figure 2 is a side view of the decontamination system of Figure 1 showing a shredder and a decontamination tank. DETAILED DESCRIPTION Figures 1 to 2 show a decontamination system 1 according to an embodiment of the invention. The decontamination system comprises a shredder 10, a decontamination tank 20, a sieve 30, a disinfectant container 40, a rinsing tank 50, a dewatering sieve 60 and a rinsing solution container 70. The shredder 10 comprises a shredder hopper 11, into which is introduced the contaminated material. The shredder 10 has a shredding mechanism 12 for shredding or reducing the size of contaminated material in the shredder to produce, for example, flakes or pellets of contaminated material. A jet (not illustrated) can be used to apply a disinfectant solution to the material as it passes through the shredder 10. A controller such as a control panel 100 can be used to control the shredding mechanism 12 and the disinfectant jet. Once the material has been reduced in size by the shredder 10, it can be flushed into or conveyed to the decontamination tank 20, for example by pumping via a conduit. The decontamination tank 20 is arranged to contain the shredded material and a disinfectant, which is added to the tank from the disinfectant container 40 (as described below). Suitable disinfectants include solutions such as hydrogen peroxide, peroxygenic acid solutions such as Virkon (RTM), Chemgene (RTM), ozonated water, sodium hypochlorite solutions, lactic acid solutions, acetic acid solutions and chlorine solutions. The decontamination tank 20 comprises an agitator 21 for agitating the mixture of the material and disinfectant in the tank, and a ultrasonicator 22 (i.e. an ultrasonic generating device or transducer) for applying low frequency ultrasound to the mixture. In the illustrated embodiment, the agitator 21 is a paddle and the ultrasonicator 22 is an ultrasonication probe. In a preferred embodiment, the decontamination tank 20 also comprises a sensor (not shown) for sensing the level or volume of a disinfectant solution in the decontamination tank 20. The level or volume of the disinfectant in the decontamination tank 20 may be used to activate various process steps, for example activating the agitator or ultrasonicator. The ultrasonicator can apply to the material ultrasound waves with a frequency of 20kHz-400kHz, preferably 20kHz-100kHz and more preferably 40kHz-50kHz. The decontamination tank 20 further comprises a pump 23, which can be a venturi eductor, for conveying the mixture of material and disinfectant to the sieve 30, which in the illustrated embodiment is a vibrating sieve. The mixture is conveyed to the sieve 30 via a decontamination tank conduit 24. A valve 25, which can be automated, can control the flow of liquid from the decontamination tank 20 and into the conduit 24. The control panel can control the agitator 21, the ultrasonicator 22, the pump 23, the valve 25 and the sieve 30. The sieve 30 is used to separate the material from the disinfectant, the material being held in the sieve and the separated disinfectant being conveyed into the disinfectant container 40 via a conduit. The disinfectant solution may be returned from the disinfectant container 40 to the decontamination tank 20 via a disinfectant container conduit 41. This allows the disinfectant to be reused, with the number of times a disinfectant can be reused in a cycle being determined by the type of disinfectant. If ozonated water is used as the disinfectant, an ozone generator (not illustrated) is provided. The generated ozone is then dissolved in water or other appropriate solutions. The ozone generator may be installed on the disinfectant container 40. Once the disinfectant has been separated from the material by the sieve 30, the separated material can be conveyed to the rinsing tank 50 via a sieve conduit 31. This is aided by vibration of the sieve 30. The rinsing tank 50 comprises an agitator (not illustrated) and a ultrasonicator (not illustrated). An appropriate rinsing solution or liquid, preferably water, is introduced into the rinsing tank 50 such that any remaining disinfectant can be rinsed from the material. The rinsing tank 50 also comprises a sensor (not shown) for sensing the level or volume of rinsing solution in the rinsing tank 50. The level or volume of the rinsing solution in the rinsing tank 50 may be used to control or activate various process steps, for example activation the agitator or ultrasonicator in the rinsing tank 50. The mixture of the material and rinsing liquid in the rinsing tank 50 can be conveyed to a second sieve (or dewatering sieve) 60 via a rinsing tank conduit 51. A pump (not illustrated) may be used to convey the liquid to the dewatering sieve. The dewatering sieve 60 is used to separate the rinsing solution from the material. Separated rinsing solution falls through the sieve 60, and a pump (not shown) is used to convey the separated rinsing solution to the rinsing solution container 70, via a rinsing solution conduit 61. The water that is contained in the rinsing solution container 70 may be returned to the rinsing tank for reuse, which can lower water consumption. The separated material may be conveyed to a dryer (not illustrated) so that the material may be dried. The dryer can be arranged adjacent the dewatering sieve. Once the drying step has been completed, the end product of flakes or pellets of processed material is safe to handle and transport for recycling. A controller such as a control panel 200 controls the agitator and ultrasonicator in the rinsing tank 50, a valve 52 which control the flow of the rinsing solution from the rinsing tank and into the rinsing tank conduit 51, and the sieve 60. An example process of using the system 1 according to an embodiment of the invention will now be described. The steps of the process are as follows: - Load contaminated plastics material into the hopper 11 of the shredder 10, and activate the shredding mechanism 12 for approximately 5 minutes to reduce the size of the material as a jet of disinfecting solution is applied to the material. During this time, disinfectant solution is conveyed from the disinfectant container 40 to the decontamination tank 20; the supply of disinfectant solution is stopped when the decontamination tank sensor detects that the correct level or volume of solution is present in the decontamination tank 20. The shredder 10 can be stopped when the decontamination tank 20 has been filled to the correct level or volume. - Flush or convey the shredded plastics material into the decontamination tank 20. - Start the decontamination cycle: the mixer paddle is activated for approximately 10 seconds, and the ultrasonication probe is activated for approximately 5 minutes. This step is repeated several times, and preferably four times. - Activate the pump 23 and the vibrating sieve 30. - Open a valve at the bottom of the decontamination tank 20 so that the mixture of material and disinfecting solution is conveyed to the vibrating sieve 30. - Close the valve when the decontamination tank 20 is empty (and flow is therefore zero). - Once the disinfectant solution has been separated from the material in the sieve 30 and the material has been conveyed to the rinsing tank 50 by vibration of the sieve 30, deactivate the pump 23 and the sieve 30. - Convey the rinsing solution from the rinsing solution container 70 to the rinsing tank 50, and activate the agitator and ultrasonicator (not shown) of the rinsing tank 50. - Convey the mixture of material and rinsing solution to the dewatering sieve 60 to separate the material and rinsing solution. - Activate vibration of the dewatering sieve 60 to cause the material held in the sieve to be conveyed to the dryer (not illustrated). - Apply a drying process to the material. - Return the rinsing solution to the rinsing solution container 70 via the rinsing solution conduit 61. Some of these steps may be omitted depending on the features of the system. In a preferred embodiment, once the decontamination tank 20 is emptied of the mixture of material and disinfecting solution, the shredder 10 can be activated to allow a second decontamination process to begin before the first decontamination process has been completed. In a preferred embodiment, once the starting material has been loaded into the shredder, the process is automated and controlled by a computer running appropriate control software. The system and process of the invention provides a viable solution for recycling high-grade laboratory plastics, utilising a combination of mechanical and chemical decontamination with low energy consumption and high material recovery rate. An example of the end product of the process is high-grade recycled plastics material pellets or flakes which are suitable for laboratory consumable manufacturing. This has the potential to create a circular laboratory plastics material supply chain. The ultrasonication steps accelerate chemical disinfection and improve the cleanliness of the processed material compared to conventional rotary washers, which use friction. The agitators increase mixing of the plastics and ensure sufficient surface contact between the processed material and the solution. The system and process provide efficient decontamination without using an autoclave, leading to lower energy consumption. Furthermore, the material is not exposed to the high temperature and pressure conditions of autoclave processing, both of which can lead to a reduction in quality of the material. The system diverts materials such as used laboratory plastics from landfills and incineration, and can result in a material recovery rate of over 95%. The disclosed system can be integrated into shipping containers and used as a mobile and / or modular decontamination unit.

Claims

1. A decontamination system for decontaminating a material, the system comprising:a decontamination tank for containing a mixture comprising the material and a disinfectant;an agitator for agitating the mixture in the tank;an ultrasonic generating device for applying ultrasound to the mixture in the tank.

2. A decontamination system according to claim 1 for decontaminating a plastics material.

3. A decontamination system according to any preceding claim wherein the agitator comprises a paddle.

4. A decontamination system according to any preceding claim wherein the ultrasonic generating device comprises an ultrasonication probe.

5. A decontamination system according to claim 3 or claim 4 wherein the ultrasonic generating device applies to the mixture ultrasound waves with a frequency of 20kHz-100kHz, preferably 40kHz-50kHz.

6. A decontamination system according to any preceding claim wherein the disinfectant comprises a disinfectant solution and, optionally,wherein the decontamination tank comprises a sensor for sensing the level or volume of the disinfectant solution in the decontamination tank.

7. A decontamination system according to any preceding claim comprising a shredder for shredding the material, wherein the shredder is arranged upstream of the decontamination tank.

8. A decontamination system according to claim 7 wherein the shredder comprises an applicator for applying a disinfectant to the material in the shredder.

9. A decontamination system according to claim 8 when claim 7 is dependent on claim 6, wherein the applicator comprises a nozzle for applying a jet of the disinfectant solution to the material in the shredder.

10. A decontamination system according to any preceding claim comprising a sieve, optionally a vibrating sieve, for separating disinfectant from the material, the sieve being arranged downstream of the decontamination tank.

11. A decontamination system according to claim 10 comprising a decontamination tank conduit for conveying the material and disinfectant from the decontamination tank to the sieve.

12. A decontamination system according to claim 10 or claim 11 comprising a disinfectant container for containing disinfectant separated from the material by the sieve, the disinfectant container being located downstream of the sieve and wherein the decontamination system optionally comprises a disinfectant container conduit arranged between the disinfectant container and the decontamination tank for conveying separated disinfectant from the container to the decontamination tank.

13. A decontamination system according to any preceding claim comprising a rinsing tank for rinsing disinfectant from the material using a rinsing liquid.

14. A decontamination system according to claim 13 wherein the rinsing tank comprises an agitator for agitating the material and the rinsing liquid in the rinsing tank; and an ultrasonic generating device for applying ultrasound to a mixture of the material and the rinsing liquid in the rinsing tank.

15. A decontamination system according to claim 13 or 14 wherein the rinsing tank comprises a sensor for sensing the level or volume of rinsing liquid in the rinsing tank.

16. A decontamination system according to any of claims 13-15 when dependent on any of claims 10-12 wherein the rinsing tank is located downstream of the sieve, and wherein the decontamination system optionally comprises a sieve conduit arranged between the sieve and the rinsing tank for conveying the material from the sieve to the rinsing tank.

17. A decontamination system according to any of claims 13-16 comprising a dewatering sieve for separating rinsing liquid from the material, wherein the dewatering sieve is arranged downstream of the rinsing tank.

18. A decontamination system according to any of claims 13-17 comprising a rinsing solution container for containing rinsing liquid.

19. A decontamination system according to any preceding claim comprising at least one controller for controlling the system.

20. A decontamination process, wherein the process comprises using the system of any of claims 1-19 to decontaminate a material, optionally a plastics material.

21. An automated process of decontaminating material, the process comprising the steps of:passing the material to be decontaminated into a decontamination tank for containing a mixture comprising the material and a disinfectant;adding disinfectant to the decontamination tank;activating an agitator to agitate the mixture in the tank; andactivating an ultrasonic generating device to apply ultrasound to the mixture in the tank.

22. An automated process according to claim 21, wherein the process further comprises the steps of:activating a shredder to shred the material;activating an applicator to apply a disinfectant to the material in the shredder; andconveying the shredded material from the shredder to a decontamination tank, wherein the shredder is arranged upstream of the decontamination tank.

23. An automated process according to claim 21 or 22, wherein the process further comprises the steps of:conveying the mixture from the decontamination tank to a sieve, optionally a vibrating sieve, for separating the disinfectant from the material, the sieve being arranged downstream of the decontamination tank and the mixture being conveyed via a decontamination tank conduit; andoptionally, activating the sieve to vibrate.

24. An automated process according to claim 22, wherein the process further comprising the steps of:conveying the material from the sieve to a rinsing tank for rinsing the disinfectant from the material using a rinsing liquid, via a sieve conduit, the rinsing tank being located downstream of the sieve;adding rinsing liquid to the rinsing tank;activating an agitator to agitate the mixture and the rinsing liquid in the rinsing tank; andactivating an ultrasonic generating device to apply ultrasound to the mixture and the rinsing liquid in the rinsing tank.

25. An automated process according to claim 23, wherein the process further comprises the steps of:conveying the material and the rinsing liquid to a dewatering sieve, optionally a vibrating dewatering sieve, for separating rinsing liquid fromthe material, wherein the dewatering sieve is arranged downstream of the rinsing tank; andoptionally, activating the sieve to vibrate.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS15CLAIMS21 10 241. A decontamination system for decontaminating a material, the system comprising:5 a decontamination tank for containing a mixture comprising thematerial and a disinfectant;an agitator for agitating the mixture in the tank;an ultrasonic generating device for applying ultrasound to the mixture in the tank, andio a shredder for shredding the material, wherein the shredder isarranged upstream of the decontamination tank,wherein the system further comprises:a sieve for separating disinfectant from the material, the sieve being arranged downstream of the decontamination tank, and15 a disinfectant container for containing disinfectant separated from thematerial by the sieve, the disinfectant container being located downstream of the sieve and wherein the decontamination system comprises a disinfectant container conduit arranged between the disinfectant container and the decontamination tank for conveying separated disinfectant from the container20 to the decontamination tank.

2. A decontamination system according to claim 1 for decontaminating a plastics material.25 3. A decontamination system according to any preceding claim wherein theagitator comprises a paddle.

4. A decontamination system according to any preceding claim wherein the ultrasonic generating device comprises an ultrasonication probe.

305. A decontamination system according to claim 3 or claim 4 wherein the ultrasonic generating device applies to the mixture ultrasound waves with a frequency of 20kHz-100kHz, preferably 40kHz-50kHz.

6. A decontamination system according to any preceding claim wherein the disinfectant comprises a disinfectant solution, and wherein the decontamination tank comprises a sensor for sensing the level or volume of the disinfectant solution in the decontamination tank.

7. A decontamination system according to claim 1, wherein the shredder comprises an applicator for applying a disinfectant to the material in the shredder.

8. A decontamination system according to claim 6 and 7, wherein the applicator comprises a nozzle for applying a jet of the disinfectant solution to the material in the shredder.

9. A decontamination system according to claim 1 comprising a decontamination tank conduit for conveying the material and disinfectant from the decontamination tank to the sieve.

10. A decontamination system according to any preceding claim comprising a rinsing tank for rinsing disinfectant from the material using a rinsing liquid.

11. A decontamination system according to claim 10 wherein the rinsing tank comprises an agitator for agitating the material and the rinsing liquid in the rinsing tank; and an ultrasonic generating device for applying ultrasound to a mixture of the material and the rinsing liquid in the rinsing tank.

12. A decontamination system according to claim 10 or 11 wherein the rinsing tank comprises a sensor for sensing the level or volume of rinsing liquid in the rinsing tank.

13. A decontamination system according to any of claims 10-12 wherein the rinsing tank is located downstream of the sieve, and wherein the decontamination system optionally comprises a sieve conduit arrangedbetween the sieve and the rinsing tank for conveying the material from the sieve to the rinsing tank.

14. A decontamination system according to any of claims 10-13 comprising a 5 dewatering sieve for separating rinsing liquid from the material, wherein thedewatering sieve is arranged downstream of the rinsing tank.

15. A decontamination system according to any of claims 10-14 comprising a rinsing solution container for containing rinsing liquid.io16. A decontamination system according to any preceding claim comprising at least one controller for controlling the system.

17. A decontamination process, wherein the process comprises using the system 15 of any of claims 1-16 to decontaminate a material, optionally a plasticsmaterial.21 10 24

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