Process for digesting cellulose containing solid wastes

• US 5,709,796 A
• Filed: 05/21/1996
• Issued: 01/20/1998
• Est. Priority Date: 05/07/1990
• Status: Expired due to Fees

• Current Assignee: Bio-Sep Limited
• Original Assignee: Bio-Sep Limited
• Inventors: Gooding, Charles H., Fuqua, Clark R., Thomas, Ronald L.
• Primary Examiner(s): Wyse, Thomas G.
• Application Number:
  US08/651,667
• Time in Patent Office: 609 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 solid waste digestion 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 solid waste;

separating the resulting liquefied waste from said any residual solidified waste and discharging the resulting liquefied waste.

2. The process of claim 1 including agitating said solid waste in an enzymatic solution during said enzymatic digestive process which contains a cellulase enzyme.

3. The process of claim 2 wherein endoglucanase is included in said enzymatic solution.

4. The process of claim 2 wherein exoglucanase is included in said enzymatic solution.

5. The process of claim 2 including agitating said solid waste in said enzymatic solution by using fluid agitation.

6. The process of claim 1 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;

at a temperature range of about 32°

F. to 120°

F.; and

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

7. The process of claim 6 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.

8. The process of claim 1 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.

9. A solid waste digestion 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

discharge the resulting liquefied waste.

10. The process of claim 9 including agitating said solid waste in an enzymatic solution during said enzymatic digestive process which contains a cellulase enzyme.

11. The process of claim 10 wherein endoglucanase is included in said enzymatic solution.

12. The process of claim 10 wherein exoglucanase is included in said enzymatic solution.

13. The process of claim 9 including agitating said solid waste in said enzymatic solution by using fluid agitation.

14. The process of claim 9 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.

15. The process of claim 14 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 hours 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.

16. The process of claim 10 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.