MICROWAVE REMEDIATION OF MEDICAL WASTES

• US 20100316526A1
• Filed: 06/12/2009
• Published: 12/16/2010
• Est. Priority Date: 06/12/2009
• Status: Active Grant

• Current Assignee: Ashwin-Ushas Corporation, Inc.
• Original Assignee: Ashwin-Ushas Corporation, Inc.
• Inventors: CHANDRASEKHAR, PRASANNA
• Granted Patent: US 8,318,086 B2
• Time in Patent Office: Days
• US Class Current: 422/21
• CPC Class Codes: A61L 11/00 Methods specially adapted for refuse disintegrating medical waste B02C19/0075; disposal of medical waste B09B3/00
• CPC Class Codes: A61L 2/12 Microwaves

Abstract

Methods, devices, and remediation compositions for the microwave remediation of medical wastes are provided. The remediation compositions include a microwave active fluid including a microwave active liquid, a microwave enhancer, and a viscosity modifying agent. Methods include immersing medical waste in the remediation composition and then irradiating the medical waste and the remediation composition to remediate the medical waste. The devices include a container for the medical waste and the remediation composition, a microwave radiation source and a temperature monitoring device.

Claims

1. A microwave-active fluid composition for medical waste remediation comprising:

(a) a microwave active liquid having a boiling point from about 150°

C. to about 300°

C.;

(b) a microwave enhancer; and

(c) a viscosity modifying agent for modifying the viscosity of the microwave active liquid.

2. The composition of claim 1, wherein the microwave active liquid is water soluble.

3. The composition of claim 1, wherein the microwave active liquid comprises a poly(glycol).

4. The composition of claim 3, wherein the microwave active liquid comprises poly(ethylene glycol), polypropylene glycol), or combinations thereof.

5. The composition of claim 4, wherein the microwave active liquid is poly(ethylene glycol).

6. The composition of claim 5, wherein the poly(ethylene glycol) has an average molecular weight, M_n from about 200 to about 420.

7. The composition of claim 1, wherein the microwave active liquid comprises glycerol monostearate, glycerol lactate, glycerol acid esters, or combinations thereof.

8. The composition of claim 1, wherein the viscosity modifying agent comprises about 0.01 wt. % to about 5 wt. % of the composition.

9. The composition of claim 1, wherein the viscosity modifying agent comprises about 0.1 wt. % to about 1 wt. % of the composition.

10. The composition of claim 8, wherein the viscosity modifying agent is an emulsifier or a stabilizer.

11. The composition of claim 1, wherein the viscosity modifying agent is poly(ethylene oxide) having an average molecular weight, M_n of from about 100,000 to about 8,000,000.

12. The composition of claim 1, wherein the viscosity modifying agent is poly(ethylene oxide) having an average molecular weight, M_n of about 200,000.

13. The composition of claim 1, wherein the viscosity modifying agent is soluble in the microwave active liquid.

14. The composition of claim 1, wherein the microwave enhancer comprises about 0.25 wt. % to about 5 wt. % of the composition.

15. The composition of claim 14, wherein the microwave enhancer comprises activated carbon, SiC, Fe₃O₄, or combinations thereof.

16. The composition of claim 15, wherein the activated carbon is a decolorizing activated charcoal.

17. The composition of claim 1, wherein the microwave active liquid comprises at least about 80 wt. % of the composition, the viscosity modifying agent comprises about 0.01 wt. % to about 5 wt. % of the composition, and the microwave enhancer comprises about 0.25 wt. % to about 5 wt. % of the composition.

18. A method for preparing the microwave active liquid composition from medical waste remediation of claim 1, the method comprising the steps of:

(a) mixing a viscosity modifying agent into a microwave active liquid having a boiling point from about 150°

C. to about 300°

C. to form a solution, while maintaining the temperature of the solution at about 100°

C. to about 150°

C. during mixing to form a solution;

(b) cooling the solution of (a) to less than about 30°

C. to form a gel comprising the microwave active liquid;

(c) adding a microwave enhancer to the microwave active liquid in the gel of (c) under conditions sufficient to form a sol;

(d) cooling the sol of (c) to at least 30°

C. for a time sufficient for any unincorporated microwave enhancer to separate from said sol;

(e) irradiating the cooled sol of (c) under conditions sufficient to heat the sol to at least about 150°

C.;

(f) cooling the irradiated sol of (e) to at least about 100°

C.;

(g) optionally repeating steps (e) and (f) at least one time;

(h) irradiating the cooled sol of (c) under conditions sufficient to heat the sol to at least about 150°

C.;

(i) cooling the irradiated sol of (h) to less than about 30°

C. to form a gel and

(j) isolating the gel formed in (i) to yield the microwave active liquid composition for medical waste remediation.

19. The method of claim 18, wherein the irradiated sol in steps (e) and (h) are irradiated under conditions sufficient to heat the sol to between about 150°

C. to about 300°

C.

20. The method of claim 18, wherein the irradiated sol in step (f) is cooled to about 50°

C. to about 100°

C.

21. A method for microwave irradiation of medical waste, the method comprising the steps of:

(a) placing the medical waste in a microwave-transparent container;

(b) adding a remediation composition to the container in a quantity sufficient to immerse the medical waste therein, remediation composition comprising a microwave-active fluid comprising;

(i) a microwave active liquid having a boiling point from about 150°

C. to about 300°

C.;

(ii) a microwave enhancer; and

(iii) a viscosity-modifying agent;

(c) irradiating the container containing the medical waste immersed in the remediation composition in a microwave chamber for a time sufficient to remediate the medical waste.

22. The method of claim 21, further comprising inserting a temperature probe into the remediation composition to monitor the temperature of the remediation composition during the irradiation step.

23. The method of claim 21, further comprising controlling the amount of irradiation in the microwave chamber based on the temperature reading from the temperature probe.

24. The method of claim 21, further comprising the step of interrupting the irradiation step for a time period, and then continuing the irradiation step.

25. The method of claim 21, wherein the irradiation time period ranges from 5 minutes to 60 minutes.

26. A system for medical waste remediation comprising:

(a) a container;

(b) a waste receptacle for holding medical waste, the waste receptacle being sized to fit in the container;

(c) a remediation composition immersing the medical waste, the remediation composition comprising a microwave-active fluid comprising a microwave active liquid having a boiling point from about 150°

C. to about 300°

C., a microwave enhancer, and a viscosity modifying agent;

(d) a container lid;

(e) a temperature probe for measuring the temperature of the remediation composition in the waste receptacle; and

(f) a microwave oven for irradiating the medical waste and the remediation composition.

27. The system of claim 26, wherein the container, the waste receptacle, and the container lid are made from microwave-transparent materials.

28. The system of claim 27, wherein the container, the waste receptacle and the container lid are made from borosilicate glass, polytetrafluoroethylene (“

PTFE”

), poly(imide) or poly(ether imide).

29. The system of claim 26, further comprising a controller for controlling the power level of the microwave oven, the controller in communication with the temperature probe and the microwave oven.

30. The system of claim 26, wherein the waste receptacle is made from metal having perforations about 1 cm in diameter.

31. A device for medical waste remediation utilizing microwave radiation, the device comprising:

a housing including a remediation chamber having an aperture;

a remediation chamber closure for placement on the aperture of the remediation chamber;

a rotatable cutter assembly for cutting waste in the remediation chamber;

a motor driving the cutter assembly;

a means for delivering microwave radiation to the remediation chamber;

a first waste receptacle sized to fit within the remediation chamber;

a reservoir for containing a remediation composition, the reservoir being in fluid communication with the remediation chamber;

a pump in fluid communication with the reservoir and the remediation chamber, said pump adapted for transferring the remediation composition from the reservoir to the remediation chamber; and

a controller for controlling the device, the controller in communication with the motor, the cutter assembly, the magnetron, and the pump.

32. The device of claim 31, wherein the remediation chamber further comprises an adjustable opening for egress of the remediated medical waste.

33. The device of claim 31, wherein the remediation chamber further comprises a mechanism for retaining the first waste receptacle in the remediation chamber.

34. The device of claim 31, wherein the first waste receptacle comprises a plurality of openings.

35. The device of claim 31, further comprising a temperature probe in communication with the first waste receptacle and the controller.

36. The device of claim 31, wherein the motor is in communication with a means to rotate the first waste receptacle.

37. The device of claim 31, further comprising a second motor for driving the cutter assembly.

38. The device of claim 31, wherein the cutter assembly comprises a piston driving cutter blades.

39. The device of claim 31, wherein the cutter assembly extends through the remediation chamber closure.

40. The device of claim 31, further comprising a second waste receptacle adjacent to the first waste receptacle, the first and second waste receptacles are oriented to allow transfer of the medical waste from the first waste receptacle to the second waste receptacle through an adjustable opening in the remediation chamber.

41. The device of claim 31, wherein the means for delivering microwave radiation to the remediation chamber is a magnetron.

42. The device of claim 31, further comprising a filter for the remediation composition, the filter being disposed between the waste container and the reservoir.

43. The device of claim 31, further comprising a liquid sensor for determining the liquid content of the medical waste in the first waste receptacle, the liquid sensor being in communication with the controller.

44. The device of claim 31, wherein the housing further comprises a waveguide to direct the microwave radiation from the magnetron into the remediation chamber.

45. A method for medical waste remediation, the method comprising the steps of:

(a) loading medical waste into a first waste receptacle;

(b) loading the first waste receptacle into a remediation chamber of a housing through an aperture of the remediation chamber, the housing comprising;

(i) the remediation chamber;

(ii) a remediation chamber closure adapted for closing the aperture of the remediation chamber;

(iii) a rotatable cutter assembly for cutting the medical waste;

(iv) a motor driving the cutter and piston assembly; and

(v) a means for delivering microwave radiation to the remediation chamber;

(c) immersing the medical waste in the first waste receptacle in a remediation composition;

(d) delivering microwave radiation from the means for delivering microwave radiation to the medical waste and the remediation composition for a time sufficient to remediate the medical waste to form irradiated medical waste;

(e) draining the remediation composition from the waste receptacle and the remediation chamber;

(f) transferring remediated medical waste from the first waste receptacle to a second waste receptacle for disposal

wherein said method further comprises after step (b) and before step (f) reducing the size of the medical waste.

46. The method of claim 45, wherein the size of the medical waste in the first waste receptacle is reduced before immersing the medical waste in the remediation composition.

47. The method of claim 45, wherein the size of medical waste is reduced after immersing the medical waste in the first waste receptacle in a remediation composition and before delivering microwave radiation.

48. The method of claim 45, wherein the remediation composition is dispensed from a reservoir for immersing the medical waste.

49. The method of claim 45, wherein after remediation the remediation composition is drained into the reservoir and optionally filtered during draining to remove any of the treated medical waste.

50. The method of claim 45, wherein the size of the irradiated medical waste is reduced by shredding and grinding and optionally cutting and/or compacting the irradiated medical waste.

51. The method of claim 45, wherein the means for directing microwave irradiation into the remediation chamber is a magnetron and said method further comprising directing the microwave radiation from the magnetron into the remediation chamber with a waveguide.

52. A device for medical waste remediation utilizing microwave radiation, the device comprising:

a first chamber comprising a means for introducing medical waste and at least one grinder for grinding the medical waste;

a remediation chamber in fluid communication with the first chamber, the remediation chamber optionally comprising a drain for draining a microwave active fluid for remediating the medical waste;

at least one means for delivering microwave radiation to at least the remediation chamber;

at least one motor for driving the grinder; and

a fluid reservoir for housing the microwave active fluid, the fluid reservoir in fluid communication with at least the remediation chamber.

53. The device of claim 52, wherein the first chamber and the remediation chamber are separated by a fluid-permeable layer.

54. The device of claim 52, wherein the fluid-permeable layer comprises a valve.

55. The device of claim 52, wherein the first chamber further comprises a piston for directing the medical waste to the at least one grinder.

56. The device of claim 52, wherein the first chamber further comprises an angled sub floor for directing the medical waste to the remediation chamber.

57. The device of claim 52, wherein the remediation chamber further comprises a means for rotating the medical waste.

58. The device of claim 52, wherein the remediation chamber further comprises a waste receptacle.

59. The device of claim 52, wherein the waste receptacle comprises walls with a plurality of openings.

60. The device of claim 52, further comprising a finish chamber for receiving remediated medical waste from the remediation chamber.

61. The device of claim 60, wherein the remediated medical waste is received into the finish chamber through a valve of the remediation chamber.

62. The device of claim 60, wherein the finish chamber comprises a waste container for receiving the remediated medical waste.

63. The device of claim 60, wherein the finish chamber comprises an opening for removing the remediated medical waste.

64. The device according to claim 52, wherein said means for introducing medical waste into said first chamber is an opening in said chamber.

65. The device of claim 52, wherein said first chamber comprises two grinders.

66. A device for medical waste remediation utilizing microwave radiation, the device comprising:

(a) a first chamber comprising a means for introducing medical waste, at least one rotatable cutter assemblies for cutting medical waste in said first chamber, a means for directing said medical waste to said rotatable cutter assembly and floor for directing said medical waste to a remediation chamber;

(b) a remediation chamber which is in fluid communication with said first chamber, said remediation chamber comprising a waste receptacle and a cooling supply for cooling fluid in said remediation chamber;

(c) a fluid permeable layer separating the first chamber from the second chamber;

(d) a reservoir in fluid communication with the remediation chamber, said remediation chamber comprising a drain for draining a microwave active fluid for remediating medical waste;

(e) at least one motor driving the rotatable cutter assembly;

(f) at least one means for delivering microwave radiation to at least the remediation chamber and

(g) at least one motor driving the cooling supply for cooling fluid in said remediation chamber.

67. The device of claim 66, wherein said first chamber comprises two rotatable cutter assemblies.