Process for digesting solid waste

• US 5,326,477 A
• Filed: 03/11/1992
• Issued: 07/05/1994
• Est. Priority Date: 05/07/1990
• Status: Expired due to Fees

• Current Assignee: Bio-Sep Limited
• Original Assignee: Bio-Sep Limited
• Inventors: Fugua, Clark R., Thomas, Ronald L., Gooding, Charles H.
• Primary Examiner(s): WYSE, THOMAS G
• Application Number:
  US07/849,469
• Time in Patent Office: 846 Days
• Field of Search: 210/606, 210/632, 210/631, 210/612, 210/614, 435/277, 435/816
• US Class Current: 210/632
• CPC Class Codes: B03B 9/061 the refuse being industrial
• CPC Class Codes: B09B 3/00 Destroying solid waste or transforming solid waste into something useful or harmless
• CPC Class Codes: B09B 3/0075 Disposal of medical waste casings for used articles, e.g. sharps A61B50/362; sterilisation of refuse A61L11/00; disposal of used needles or syringes A61M5/3205; disintegrating medical waste B02C19/0075
• CPC Class Codes: C02F 3/342 characterised by the enzymes used
• CPC Class Codes: Y02W 30/52 Mechanical processing of waste for the recovery of materials, e.g. crushing, shredding, separation or disassembly
• CPC Class Codes: Y02W 30/62 Plastics recycling; Rubber recycling
• CPC Class Codes: Y10S 435/816 by solubility

Abstract

A process and apparatus for reducing the volume and mass of solid waste (A) by initially subjecting the solid waste to a digestive enzymatic solution (20) agitated by fluid jets (28) under conditions which convert substrate (12) into a liquid waste which is discharged through a conventional sewage system (30). Non-biodegradable plastic shells (10) may be collected in a strainer basket (24) to be removed for further solid waste treatment such as shredding and the like.

Claims

1. A process for disposing of solid waste such as absorbent pads which include a non-biodegradable plastic shell and an absorbent substantially cellulosic fibrous substrate secured to said plastic shell, wherein said process comprises:

separating said substrate from said plastic shell by agitating said wastes in an enzymatic digestive solution, generally without bacterial fermentation from added microorganisms, for a controlled time period to degrade and convert said substrate into a liquefied waste;

discharging said liquefied waste; and

recovering said non-biodegradable shell as a residual solid waste.

2. The process of claim 1 including discharging said liquefied waste into a conventional sewage system.

3. The process of claim 1, including agitating said solid waste in said enzymatic solution by using fluid agitation.

4. The process of claim 1 including agitating said solid waste in an enzymatic solution containing a cellulase enzyme.

5. The process of claim 4 wherein endoglucanase is included in said enzymatic solution.

6. The process of claim 5 wherein exoglucanase is included in said enzymatic solution.

7. The process of claim 1 including agitating said solid waste in said enzymatic solution containing an enzyme in a range of about 0.01 to 1.0% by weight of the enzymatic solution.

8. The process of claim 1 including agitating said solid waste in an enzymatic solution containing a volume of about 0.20 to 1.0 gallons per pound of waste.

9. The process of claim 1 including agitating said solid during an agitation period in a range of about 0.5 to 6 hours.

10. The process of claim 1 including maintaining the temperature of said enzymatic solution at a temperature in a temperature range of about 32°

to 140°

F.

11. The process of claim 1 including maintaining the pH of said enzymatic solution at a pH in a range of about 3 to 9.

12. The process of claim 1 including agitating said solid waste in said enzymatic solution containing about from 0.05% to about 0.2% enzyme by weight of enzyme and from about 0.25 to about 0.75 gallons of enzymatic solution per pound of waste, during an agitation period from about 0.5 hour to about 2 hours, at a temperature from about 90°

F. to about 120°

F., and a solution pH from about 3 to about 7.

13. A process for reducing the volume and mass of solid wastes which includes a non-biodegradable shell and an absorbent substantially-cellulosic substrate secured to said shell wherein said process comprises:

(a) separating said substrate from said shell by agitating said solid wastes in an enzymatic digestive solution in the absence of bacterial fermentation from added microorganisms, to degrade and convert said substrate into a liquefied waste;

(b) agitating said solid waste in said enzymatic solution containing an enzyme in a range of about 0.01 to 1.0% by weight of the enzymatic solution and a volume of enzymatic solution of about 0.20 to 1.0 gallons per pound of waste;

(c) agitating said waste during an agitation period in a range of about 0.5 to 6 hours, and at a temperature in a temperature range of about 32°

to 140°

C.;

(d) discharging said liquefied waste; and

(e) recovering said non-biodegradable shell as a residual solid waste.

14. The process of claim 13 including agitating said solid waste in an enzymatic solution containing a cellulase enzyme.

15. The process of claim 14 wherein endoglucanase is included in said enzymatic solution.

16. The process of claim 14 wherein exoglucanase is included in said enzymatic solution.

17. The process of claim 13 including maintaining the pH of said enzymatic solution at a pH in the range of about 3 to 9.

18. The process of claim 13 including agitating said solid waste in said enzymatic solution by using fluid agitation.

19. The process of claim 13 including agitating said solid waste in said enzymatic solution containing about from 0.05% to about 0.2% by weight of enzyme and from about 0.25 to about 0.75 gallons of enzymatic solution per pound of waste, during an agitation period from about 0.5 hour to about 2 hours, at a temperature from about 90°

F. to about 120°

F., and a solution pH from about 3 to about 7.

20. A solid waste disposal process comprising reducing the mass and volume of substantially untreated solid waste having cellulose as its major component by subjecting the solid waste to a preliminary enzymatic digestive process, in the presence of an enzymatic solution at a controlled temperature without appreciable bacterial fermentation from added microorganisms, to convert the solid waste into a liquefied waste and any residual non-cellulose solid waste;

separating the resulting liquefied waste from said any residual non-cellulose solid waste; and

discharging the resulting liquefied waste through a conventional sewage system.

21. The process of claim 20 including agitating said solid waste in an enzymatic solution during said enzymatic digestive process which contains a cellulase enzyme.

22. The process of claim 21 wherein endoglucanase is included in said enzymatic solution.

23. The process of claim 21 wherein exoglucanase is included in said enzymatic solution.

24. The process of claim 20 including agitating said solid waste in said enzymatic solution by using fluid agitation.

25. The process of claim 20 including agitating said solid waste in said enzyme solution containing an enzyme in a range of about 0.01 to 1.0% by weight of the enzymatic solution and a volume of enzymatic solution of about 0.20 to 1.0 gallons per pound of waste;

agitating said solid waste during an agitation period in a range of about 0.5 to 6 hours; and

at a temperature range of about 32°

to 120°

F.; and

maintaining the pH of said enzymatic solution at a pH in a range of about 3 to 9.

26. The process of claim 25 including agitating said solid waste in said enzymatic solution containing from about 0.05% to about 0.2% of enzyme by weight and from about 0.25 to about 0.75 gallons of enzymatic solution per pound of waste, during an agitation period from about 0.5 hour to about 2 hours, at a temperature from about 90°

F. to about 120°

F., and a solution pH from about 3 to about 7.

27. The process of claim 20 wherein said untreated solid waste having cellulose as its major component is selected from the group consisting of throw-away diapers, underpants, paper, and food products.

28. A solid waste disposal process for reducing the mass and volume of substantially untreated solid waste having cellulose as its major component, the process consisting essentially of:

subjecting solid waste having cellulose as its major component to a preliminary enzymatic digestive process, in the presence of an enzymatic solution at a controlled temperature, to convert the solid waste into a liquefied waste and any residual non-cellulose solid waste;

separating the resulting liquefied waste from said any residual non-cellulose solid waste; and

discharging the resulting liquefied waste through a conventional sewage system.

29. The process of claim 28 including agitating said solid waste in an enzymatic solution during said enzymatic digestive process which contains a cellulase enzyme.

30. The process of claim 29 wherein endoglucanase is included in said enzymatic solution.

31. The process of claim 29 wherein exoglucanase is included in said enzymatic solution.

32. The process of claim 28 including agitating said solid waste in said enzymatic solution by using fluid agitation.

33. The process of claim 28 including agitating said solid waste in said enzyme solution containing an enzyme in a range of about 0.01 to 1.0% by weight of the enzymatic solution and a volume of enzymatic solution of about 0.20 to 1.0 gallons per pound of waste;

agitating said solid waste during an agitation period in a range of about 0.5 to 6 hours; and

at a temperature range of about 32°

to 120°

F.; and

maintaining the pH of said enzymatic solution at a pH in a range of about 3 to 9.

34. The process of claim 33 including agitating said solid waste in said enzymatic solution containing from about 0.05% to about 0.2% of enzyme by weight and from about 0.25 to about 0.75 gallons of enzymatic solution per pound of waste, during an agitation period from about 0.5 hour to about 2 hours, at a temperature from about 90°

F. to about 120°

F., and a solution pH from about 3 to about 7.

35. The process of claim 28 wherein said untreated solid waste having cellulose as its major component is selected from the group consisting of throw-away diapers, underpants, paper, and food products.

36. A process for disposing of solid wastes such as absorbent pads which include a non-biodegradable plastic shell and an absorbent fibrous substrate secured to said plastic shell, wherein said process comprises:

separating said substrate from said plastic shell by agitating wastes in an enzymatic digestive solution for a controlled period of time to degrade and convert said substrate into a liquefied waste;

discharging said liquefied waste; and

recovering said non-biodegradable shell as a residual solid waste.

37. The process of claim 36 including discharging said liquefied waste into a conventional sewage system.

38. The process of claim 36 including agitating said solid waste in said enzymatic solution by using fluid agitation.

39. The process of claim 36 including agitating said solid waste in an enzymatic solution containing a cellulase enzyme.

40. The process of claim 39 wherein endoglucanase is included in said enzymatic solution.

41. The process of claim 40 wherein said exoglucanase is included in said enzymatic solution.

42. The process of claim 36 including agitating said solid waste in said enzymatic solution containing an enzyme in a range of about 0.01 to 1.0% weight by volume.

43. The process of claim 36 including agitating said solid waste in an enzymatic solution containing a volume of treatment water of about 0.20 to 1.0 gallons per pound of waste.

44. The process of claim 36 including agitating said waste during an agitation period in a range of about 0.5 to 6 hours.

45. The process of claim 36 including maintaining the temperature of said enzymatic solution at a temperature in a temperature range of about 32 to 140 degrees F.

46. The process of claim 36 including maintaining the pH of said enzymatic solution at a pH in a range of about 3 to 9.

47. The process of claim 36 including agitating said solid waste in said enzymatic solution containing about 0.1% enzyme by volume and about 0.5 gallons of treatment water per pound of waste, during an agitation period of about 1 hour, at a temperature of about 100 degrees F., and a solution pH of about 6.5.

48. A process for reducing the volume and mass of solid wastes which includes a non-biodegradable shell and an absorbent substantially cellulosic substrate secured to said shell wherein said process comprises:

(a) separating said substrate from said shell by agitating and digesting said solid wastes in an enzymatic digestive solution to degrade and convert said substrate into a liquefied waste;

(b) agitating said solid waste in said enzymatic solution containing an enzyme in a range of about 0.01 to 1.0% weight by volume and a volume of treatment water of about 0.20 to 1.0 gallons per pound of waste;

(c) agitating said waste during an agitation period in a range of about 0.5 to 6 hours, and at a temperature in a temperature range of about 32 to 140 degrees F.;

(d) discharging said liquefied waste; and

(e) recovering said non-biodegradable shell as a residual solid waste.

49. The process of claim 48 including agitation said solid waste in an enzymatic solution containing a cellulase enzyme.

50. The process of claim 49 wherein endoglucanase is included in said enzymatic solution.

51. The process of claim 49 wherein exoglucanase is included in said enzymatic solution.

52. The process of claim 48 including maintaining the pH of said enzymatic solution at a pH in a range of about 3 to 9.

53. The process of claim 48 including agitating said solid waste in said enzymatic solution by using fluid agitation.

54. The process of claim 48 including agitation said solid waste in said enzymatic solution containing about 0.1% enzyme by volume and about 0.5 gallons of treatment water per pound of waste, during an agitation period of about 1 hour, at a temperature of about 100 degrees F., and a solution pH of about 6.5.