Continuous process and apparatus for the separation of recyclable material from and the disinfection of infectious medical waste

• US 5,173,257 A
• Filed: 05/13/1991
• Issued: 12/22/1992
• Est. Priority Date: 04/03/1991
• Status: Expired due to Fees

• Current Assignee: Erich H. Pearson
• Original Assignee: Erich H. Pearson
• Inventors: Pearson, Erich H.
• Primary Examiner(s): Warden, Robert J.
• Assistant Examiner(s): Thornton, Krisanne M.
• Application Number:
  US07/699,202
• Time in Patent Office: 589 Days
• Field of Search: 422/37, 422/38, 422/3, 422/2, 422/224, 422/26-29, 422/140, 210/749-760, 210/764, 210/173, 210/195.3, 210/252, 210/513, 210/295, 209/3, 209/10, 209/211, 241/152 R, 241/152 A, 241/20, 241/21, 241/24, 241/29, 241/46.17, 241/69, 241/DIG. 38, 261/DIG. 70, 261/DIG. 42
• US Class Current: 422/3
• 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 2/202 Ozone
• 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: Y10S 241/38 Solid waste disposal
• CPC Class Codes: Y10S 241/606 Medical/surgical waste comminution

Abstract

A process and apparatus for continuously treating infectious waste, which comprises: (a) introducing bulk unseparated infectious waste material into a receiving container means, the receiving container means adapted to receive a flow of disinfectant such that the receiving container means remains substantially free of infectious contaminants; (b) shredding the waste material by a primary shredding means; (c) separating the shredded waste material from waste residue in a separation tank means having a predetermined fluid level thereby producing a waste slurry; (d) pumping the waste slurry into a reactor vessel means; (e) contacting the waste slurry with a disinfecting fluid in the reactor vessel means for a sufficient amount of time to disinfect the waste slurry; and (f) dewatering the disinfected waste slurry to recover solid disinfected waste material.

The process and apparatus is also adapted to separate and treat recyclable materials, such as pulpable materials, glass, metal, and the like, found in the incoming waste stream.

Claims

1. A process for the continuous treatment of infectious waste material, which comprises:

(a) introducing bulk unseparated infectious waste material comprising pulpable components and nonpulpable components into a receiving container means, said receiving container means being in communication with a primary shredding means whereby bulk unseparated infectious waste material supplied to said receiving container means is conducted to said primary shredding means;

(b) shredding said bulk unseparated waste material by said primary shredding means;

(c) transferring the shredded waste material from said primary shredding means to a pulping means having a means to provide a predetermined fluid level to said pulping means, said pulping means effective for repulping said pulpable components and creating a pulped slurry therefrom and also effective for creating a nonpulpable slurry from said nonpulpable components and separating said pulped slurry from said nonpulpable slurry;

(d) transferring said pulped slurry from said pulping means to a first reactor vessel means, said first reactor vessel means comprising a first reactor means communicating in series relationship with at least one second reactor means, and transferring said nonpulpable slurry from said pulping means to a separator means to separate and remove from said nonpulpable slurry glass and metal components contained therein and to form a separated nonpulpable slurry and thereafter transferring said separated nonpulpable slurry to a second reactor vessel means, said second reactor vessel means comprising a primary tank means communicating in series relationship with at least one second tank means;

(e) contacting, in said first reactor vessel means, said pulped slurry with a disinfecting fluid comprising ozone in gas phase and in aqueous solution, said contacting being achieved by flowing said pulped slurry and said disinfecting fluid through a mixer of said fist reactor means for mixing said pulped slurry with said disinfecting fluid and flowing the resulting mixture into said first reactor means of said first reactor vessel means, retaining the resulting mixture in said first reactor means for sufficient time to achieve at least partial disinfection of said pulped slurry and further discharging from said first reactor means undissolved gas which emits from the resulting mixture, said contacting being further achieved by additionally mixing said pulped slurry from said first reactor means with disinfecting fluid in a mixer of said at least one second reactor means and flowing the resulting mixture into said at least one second reactor means of said first reactor vessel means, retaining the resulting mixture in said at least one second reactor means for sufficient time to achieve substantially complete disinfection of said pulped slurry and further discharging from said at least one second reactor means undissolved gas which emits from the resulting mixture, and contacting, in said second reactor vessel means, said separated nonpulpable slurry from said separator means with said disinfecting fluid, said contacting being achieved by flowing said separated nonpulpable slurry and said disinfecting fluid through a mixer of said primary tank means for mixing said separated nonpulpable slurry with said disinfecting fluid and flowing the resulting mixture into said primary tank means of said second reactor vessel means, retaining the resulting mixture in said primary tank means for sufficient time to achieve at least partial disinfection of said separated nonpulpable slurry and further discharging from said primary tank means undissolved gas which emits from the resulting mixture, said contacting being further achieved by additionally mixing said separated nonpulpable slurry from said primary tank means with said disinfecting fluid in a mixer of said at least one second tank means of said second reactor vessel means and flowing the resulting mixture into said at least one second tank means, retaining the resulting mixture in said at least one second tank means for sufficient time to achieve substantially complete disinfection of said separated nonpulpable slurry and further discharging from said at least one second tank means undissolved gas which emits from the resulting mixture; and

(f) transferring said disinfected pulped slurry from said at least one second reactor means and transferring said disinfected separated nonpulpable slurry from said at least one second tank means to dewatering means to remove liquid therefrom and to recover solid disinfected waste material.

2. The process of claim 1, wherein said infectious waste comprises an infectious medical waste.

3. The process of claim 1, wherein said primary shredding means is a rotary shear shredder, said primary shredding means being in communication with said receiving container means.

4. The process of claim 1, wherein said separated nonpulpable slurry is further shredded by a secondary shredding means to reduce the size of particles in said separated nonpulpable slurry prior to transferring said separated nonpulpable slurry into said second rector vessel means.

5. The process of claim 4, wherein said secondary shredding means is a rotary shear shredder, said secondary shredding means being in communication with said separator means.

6. The process of claim 5, wherein said separated nonpulpable slurry is further shredded by a tertiary shredding means to reduce the size of particles in said separated nonpulpable slurry, prior to transferring said separated nonpulpable slurry into said second reactor vessel means.

7. The process of claim 6, wherein said tertiary shredding means is a rotary shear shredder, said tertiary shredding means being in communication with said secondary shredding means.

8. The process of claim 1, wherein collectively said pulped and nonpulpable slurry comprises from about 1% to about 16% by weight shredded solids.

9. The process of claim 1, wherein said at least one second reactor means comprises from 1 to about 10 reactor vessels communicating in series relationship and said at least one second tank means comprises from 1 to about 10 reactor vessels communicating in series relationship.

10. The process of claim 1, wherein said disinfecting fluid of step (e) comprises ozone gas diluted in air.

11. The process of claim 1, wherein said ozone gas is present in a concentration of from about 0.5% to about 10% by weight of said disinfecting fluid.

12. The process of claim 1, wherein each of said pulped slurry and separated nonpulpable slurry is flowed through said first and second reactor vessel means, respectively, in a direction opposite to the buoyancy of ozone gas bubbles in contact with said pulped slurry and said separated nonpulpable slurry.

13. The process of claim 12, wherein each of said pulped slurry and said separated nonpulpable slurry is flowed downward through, respectively, said first and said second reactor vessel means at a nominal rate of about 1.1 meters per second.

14. The process of claim 1, wherein each of said pulped slurry and separated nonpulpable slurry is contacted with said disinfecting fluid for a period of from about 5 to about 45 minutes.

15. The process of claim 1, wherein the concentration of said ozone is continuously monitored by an analyzing means communicating with each of said first and second reactor vessel means, said analyzing means effective for monitoring and controlling the amount of disinfecting fluid introduced from a source thereof to said first and said second reactor vessel means and for monitoring the amount of disinfecting fluid utilized in said first and said second reactor vessel means.

16. The process of claim 1, further including the step of introducing said disinfecting fluid into said receiving container means to disinfect surfaces of said receiving container means.

17. An apparatus for the continuous treatment of infectious waste material, which comprises:

(a) a receiving container means for receiving bulk unseparated infectious waste material comprising pulpable components and nonpulpable components;

(b) a primary shredding means in communication with said receiving container means for reducing the particle size of said bulk unseparated infectious waste material and forming a shredded waste material;

(c) a pulping means in communication with said primary shredding means, said pulping means having a fluid filling means for providing a predetermined fluid level in said pulping means, for repulping said pulpable components and creating a pulped slurry therefrom and also effective for creating a nonpulpable slurry from said nonpulpable components and separating said pulped slurry from said nonpulpable slurry;

(d) a separator in communication with said pulping means for receiving said nonpulpable slurry from said pulping means and separating and removing therefrom glass and metal components contained therein thereby forming a separated nonpulpable slurry;

(e) a reaction zone for disinfecting said pulped slurry and said separated nonpulpable slurry, said reaction zone comprising;

(i) a first reactor vessel means communicating with said pulping means for receiving said pulped slurry, said first reactor vessel means comprising a first reactor means communicating in series relationship with at least one second reactor means for disinfecting said pulped slurry;

(ii) a second reactor vessel means communicating with said separator for receiving said separated nonpulpable slurry, said second reactor vessel means comprising a primary tank means communicating in series relationship with at least one second tank means for disinfecting said separated nonpulpable slurry;

(iii) a disinfecting fluid generating means communicating with each of said first reactor vessel means and said second rector vessel means for continuously introducing a disinfecting fluid, comprising ozone in gas phase and in aqueous solution, into said first and second reactor vessel means, said first reactor means being provided with a mixer to mix said disinfecting fluid, comprising ozone in gas phase and in aqueous solution, into said first and second reactor vessel means, said first reactor means being provided with a mixer to mix said disinfecting fluid with said pulped slurry received from said pulping means, said at least one second reactor means being provided with a mixer to mix said disinfecting fluid with said pulped slurry received from said first reactor means, said primary tank means being provided with a mixer to mix said disinfecting fluid with said nonpulpable slurry received from said separator, said at least one second tank means being provided with a mixer to mix said disinfecting fluid with said nonpulpable slurry received from said primary tank means, each of said first reactor means and said at least one second reactor means being further provided with a discharge vent to discharge undissolved gas from said pulped slurry and each of said primary tank means and said at least one second tank means being further provided with a discharge vent to discharge undissolved gas from said nonpulpable slurry; and

(f) dewatering means communicating with said first and second reactor vessel means, for receiving and recovering solid, disinfected waste material from the disinfected slurry.

18. The apparatus of claim 17, wherein said primary shredding means is a rotary shear shredder.

19. The apparatus of claim 17, further comprising a secondary shredding means in communication with said separator, for reducing the size of particles in said separated nonpulpable slurry prior to transferring said separated nonpulpable slurry into said second reactor vessel means.

20. The apparatus of claim 19, wherein said secondary shredding means is a rotary shear shredder.

21. The apparatus of claim 19, further comprising a tertiary shredding means in communication with said secondary shredding means, for further reducing the size of particles in said separated nonpulpable slurry prior to transferring said separated nonpulpable slurry into said second reactor vessel means.

22. The apparatus of claim 21, wherein said tertiary shredding means is a rotary shear shredder.

23. The apparatus of claim 17, wherein said at least one second reactor means comprises from 1 to about 9 second reactor means connected in series and said at least one second tank means comprises from 1 to about 9 second tank means connected in series.

24. The apparatus of claim 17, wherein each of said first reactor means, said at least one second reactor means, said primary tank means, and said at least one second tank means includes a reactor tube extending longitudinally from the top thereof, where said reactor tube is in connecting relation with a recirculation port, to a point proximate the bottom thereof.

25. The apparatus of claim 17, wherein said disinfecting fluid generating means comprises an ozone generator.

26. The apparatus of claim 17, further including a means communicating with said disinfecting fluid generating means and said receiving container means for flowing said disinfecting fluid to said receiving container means for disinfecting the surfaces thereof.

27. The apparatus of claim 17, further including an analyzing means communicating with said first and said second reactor vessel means and said generating means, for continuously monitoring and controlling the amount of disinfecting fluid introduced by said disinfecting fluid generating means and monitoring the amount of disinfecting fluid utilized in said first and second reactor vessel means.