Process and apparatus for removing impurities from water used in food processing utilizing a mixture of ozone and air

• US 5,053,140 A
• Filed: 07/26/1989
• Issued: 10/01/1991
• Est. Priority Date: 07/26/1989
• Status: Expired due to Term

• Current Assignee: American Water Purification, Inc.
• Original Assignee: American Water Purification, Inc.
• Inventors: Hurst, William D.
• Primary Examiner(s): Hruskoci, Peter
• Assistant Examiner(s): Popovics, Robert James
• Application Number:
  US07/386,438
• Time in Patent Office: 797 Days
• Field of Search: 210/188, 210/221.1, 210/221.2, 210/750, 210/758, 210/760, 210/703, 210/704, 210/712, 210/718, 210/202, 210/764, 426/312, 426/320, 426/417, 422/28, 422/32, 422/293, 261/DIG. 42
• US Class Current: 210/704
• CPC Class Codes: B01D 36/02 Combinations of filters of different kinds B01D29/50, B01D33/35 take precedence
• CPC Class Codes: B01D 37/00 Processes of filtration processes specially adapted for filtering gases B01D46/00
• CPC Class Codes: C02F 1/24 by flotation C02F1/465 takes precedence
• CPC Class Codes: C02F 1/76 with halogens or compounds of halogens C02F1/4674 takes precedence
• CPC Class Codes: C02F 1/78 with ozone C02F1/4672 takes precedence
• CPC Class Codes: C02F 2103/023 Water in cooling circuits
• CPC Class Codes: C02F 2103/22 from the processing of animals, e.g. poultry, fish, or parts thereof
• CPC Class Codes: C02F 2103/32 from the food or foodstuff industry, e.g. brewery waste waters
• CPC Class Codes: C02F 9/00 Multistage treatment of water, waste water or sewage
• CPC Class Codes: Y10S 261/42 Ozonizers

Abstract

An apparatus and a process for using the apparatus for removing fat, bacteria, solids and other impurities from water used in food processing so that substantially all the water may be reused includes a tower. The water is passed through a coarse filter to remove large pieces and is then introduced into the tower near the top thereof and flows out the tower near the bottom thereof. A mixture of ozone and air is introduced at the bottom of the tower and bubbled up through the tower, counter to the flow of the water. The ozone and water mixture carries impurities, especially the fat, over the top of the tower as a foam. The foam then flows over the tower into a waste drain. The process and apparatus may be varied to include a second tower unit with an alternative intermediate filter unit between the first tower and second tower unit. In this embodiment, large pieces are removed in the coarse filter, fat is mostly removed in the first tower, remaining solid particles are removed in the intermediate filter and additional impurities, including protein, are removed in the second tower unit by a counter-current air and ozone mixture. After the second tower unit, the water is passed through a polish filter, ozones removing device and a chlorinator.

Claims

1. A process for removing fat and other impurities from water, said process comprising the steps of:

(a) introducing wastewater that has previously been used for chilling in a carcass cooling process including water and other impurities and having a substantial quantity of fat therein into a tower having a top and a bottom, the wastewater introduced through an inlet near said tower top;

(b) flowing at least the water portion of the wastewater from near said tower top to near said bottom;

(c) injecting an ozone and air mixture into the wastewater in said tower near said bottom;

(d) flowing said ozone and air mixture upwardly through the wastewater, counter to movement of the wastewater through said tower, thereby forming a foam of said fat and said impurities including substantially all of said fat entering said tower with said wastewater;

said foam rising to the top of said tower;

(e) withdrawing the water from said tower at an outlet near said tower bottom; and

(f) allowing said foam with substantially all of said fat to overflow said top of said tower into a waste drain, wherein said waste drain comprises a shroud surrounding the upper end of said tower.

2. The process of claim 1 including the steps of:

(a) flowing the wastewater through a coarse filter prior to the step of introducing the wastewater into said tower, said coarse filter removing large debris from the wastewater; and

(b) subsequent to passing through the tower, passing the water through a residual ozone remover so as to remove residual ozone from the water.

3. The process of claim 1 including the step of:

(a) adjusting the percentage of ozone in relationship to water within said tower to provide sufficient contact between said ozone and said water to substantially disinfect said water.

4. The process of claim 3 including the step of:

(a) during operation of said process adjusting the percentage of ozone and air mixture in relationship to the residence time of the wastewater in said tower by controlling the flow rate of the ozone and air mixture into said tower to sufficiently remove fat from said water and disinfect said wastewater.

5. The process of claim 1 including the step of:

(a) adjusting the percentage of ozone in relationship to the air within said ozone and air mixture to be within approximately a range of one-tenth of one percent (0.1%) to four percent (4%) by weight.

6. The process of claim 5 including the step of:

(a) adding between 0.01 and 1 gram of ozone to the water in said tower for each gallon of water.

7. A process for removing impurities including a substantial amount of fat, microorganisms, and other solids from wastewater having water therein that had been used in cooling food products being processed containing such fat in a food processing environment so that a substantial portion of the water may be returned to the food processing area for reuse, said process comprising the steps of:

(a) introducing the wastewater with said fat therein into a first tower having a top and a bottom, the wastewater being introduced through an inlet near said first tower top;

(b) flowing the wastewater from near said top of said first tower to near said bottom;

(c) injecting a first ozone and air mixture into the wastewater in said first tower near said bottom;

(d) flowing said first ozone and air mixture upwardly through the wastewater, counter to movement of the wastewater through said first tower, thereby forming a first foam near said top of said first tower, said first foam including substantially all of said fat in said wastewater and said ozone and air mixture;

(e) flowing said first foam with said fat therein over said tower into first waste drain means comprising a first shroud surrounding the upper end of said first tower;

(f) subsequently introducing the wasterwater stream less the portion thereof removed in said first tower into a second tower having a top and a bottom with the wastewater being introduced through an inlet near said second tower top;

(g) flowing the wastewater in the second tower from near said top of said second tower to near said bottom thereof;

(h) injecting a second ozone and air mixture into the wastewater in said second tower near said bottom thereof;

(i) flowing said second ozone and air mixture upwardly through the wastewater in said second tower, counter to movement of the wastewater through said second tower, thereby forming a second foam near said top of said second tower, said second foam including impurities from the wastewater; and

(j) flowing said second foam over said top of said second tower into second waste drain means comprising a second shroud surrounding the upper end of said second tower.

8. The process of claim 7 including the steps of:

(a) flowing the wastewater through a coarse first filter prior to the step of introducing the wastewater into said first tower, said coarse filter removing large debris from the wastewater;

(b) subsequent to said wastewater exiting said first tower and prior to entering said second tower, passing said wastewater through a fine second filter;

(c) subsequent to said wastewater exiting said second tower, passing the waste through a third filter; and

(d) passing the wastewater through an ozone remover, said ozone remover removing residual ozone from the wastewater.

9. The process of claim 7 including the step of:

(a) adjusting the amount of said ozone and air mixture introduced into said first tower in relationship to the water to remove substantially all fat from the water in said first foam overflowing said first tower.

10. The process of claim 7 including the step of:

(a) adjusting the percentage of ozone in relationship to the water in said first and second towers to substantially kill microorganisms in the water during passage through the towers.

11. The process of claim 7 including the step of:

(a) adjusting the percentage of said ozone and air mixture relative to the water introduced into said second tower to substantially remove any remaining impurities from the water, to oxidize oxidizable materials in the water and to kill microorganisms remaining in the water.

12. The process of claim 11 including the step of:

(a) adjusting the percentage of ozone in relationship to the water in said second tower to substantially kill all remaining microorganisms in the water.

13. The process of claim 7 including the step of:

(a) adjusting the percentage of ozone in relationship to the air within said ozone and air mixture to be within approximately a range of one-tenth of one percent (0.1%) to four percent (4%) by weight of the mixture.

14. The process of claim 7 including the step of:

(a) adjusting the ozone added to said first tower such that between 0.01 and 1 gram of ozone is added to the water in said first tower for each gallon of water.

15. A process for removing impurities including fat, microorganisms, and other solids from wastewater subsequent to use of water in the wastewater for chilling food products being processed in a food processing environment so that a substantial portion of the wastewater may be returned to the food processing area for reuse, said process comprising the steps of:

(a) introducing the wastewater with the fat therein into a first tower having a top and a bottom with the wastewater being introduced through an inlet near said first tower top;

(b) flowing the wastewater from near said top of said first tower to near said bottom thereof;

(c) injecting a first ozone and air mixture into the wastewater in said first tower near said bottom thereof;

(d) flowing said first ozone and air mixture upwardly through the wastewater, counter to movement of the wastewater through said first tower, thereby forming a first foam near said top of said first tower, said first foam including a substantial portion of the fat and said ozone and air mixture;

(e) flowing said first foam with substantially all of said fat therein over the top of said tower into first waste drain means comprising a first shroud surrounding the upper end of said first tower;

(f) flowing said wastewater from said first tower;

(g) introducing the wastewater subsequent to said first tower into an initial tower of a multi-tower unit, said multi-tower unit having a plurality of successive towers, each tower in said unit having a top and a bottom, the wastewater being introduced through an inlet near said top of said initial tower;

(h) flowing the wastewater from near said top of said initial tower to near said bottom thereof;

(i) flowing the wastewater from said initial tower at an outlet near the bottom of said initial tower;

(j) subsequently introducing the wastewater into a successive tower of said multi-tower unit through an inlet near the top of said successive tower;

(k) flowing the wastewater from near the top of said successive tower to near the bottom thereof;

(l) flowing the wastewater from said successive tower from an outlet near the bottom of said successive tower;

(m) passing the wastewater through each of said towers of said multi-tower unit in the same manner as described in steps (j) through (l);

(n) injecting a second ozone and air mixture into the wastewater in each of said towers of said multi-tower unit near the bottom of each of said towers, said second ozone and air mixture flowing upwardly through the wastewater, counter to the movement of the wastewater, thereby oxidizing oxidizable material within the wastewater and forming a second foam near the top of each of said towers, said second foam including impurities and said ozone and air mixture; and

(o) flowing said second foam over the top of each of said towers of said multi-tower unit into second waste drain means comprising a second shroud surrounding the upper end of said multi-tower unit.

16. The process of claim 15 including the steps of:

(a) flowing the wastewater through a coarse first filter prior to the step of introducing the wastewater into said first tower, said coarse filter removing large debris from the wastewater;

(b) subsequent to said first tower and prior to said initial tower of said multi-tower unit, flowing the wastewater through a second filter;

said second filter being a fine filter relative to said first filter to remove solid debris from said wastewater;

(c) subsequent to said wastewater exiting said multi-tower unit, passing the wastewater through a third filter; and

(d) subsequently passing the wastewater through an ozone remover, said ozone remover removing residual ozone from the water.

17. The process of claim 15 including the step of:

(a) adjusting the percentage of ozone and air mixture in relationship to the water introduced into said first tower to remove a substantial amount of the fat from the water.

18. The process of claim 17 including the step of:

(a) adjusting the percentage of ozone in relationship to the water in all of said towers to substantially kill all microorganisms in the water during passage through said towers.

19. The process of claim 15 including the step of:

(a) adjusting the percentage of the ozone and air mixture in relationship to the water introduced into each of said towers of said multi-tower unit to remove substantially any floatable impurities remaining in the water subsequent to said first tower.

20. The process of claim 15 including the step of:

(a) during operation of said process adjusting the percentage of ozone in relationship to the wastewater in each of said towers to provide sufficient ozone relative to each gallon of water to satisfy a preselected disinfecting of the water related to quantity of ozone per gallon and residence time of the wastewater adjusted by controlling the flow rate of the ozone and air mixture into said first tower in contact with the ozone.

21. The process of claim 15 including the step of:

(a) adjusting the percentage of ozone in relationship to the air within said first and second ozone and air mixtures to be within approximately a range of one-tenth of one percent (0.1%) to four percent (4%) by weight.

22. The process of claim 15 including the step of:

(a) adding between 0.01 and 1 gram of ozone to the water in said first tower for each gallon of water.

23. An apparatus for removing impurities including fat from wastewater used for chilling food products being processed in a food processing environment, said apparatus comprising:

(a) a first tower for receiving the wastewater with the fat therein, said first tower having an upper portion and a lower portion;

(b) said first tower upper portion having a top and an inlet near said top thereof for introducing the wastewater into said first tower;

(c) said first tower top adapted to connect to a first waste drain by overflow means comprising a first shroud surrounding the upper end of said first tower;

(d) said lower portion of said first tower having a bottom and an outlet near said bottom for removing the wastewater from said first tower;

(e) said bottom of said first tower communicating with a source of an ozone and air mixture;

(f) said first tower having a flow directing means such that the wastewater flows generally downward and said ozone and air mixture flows generally upward, counter to movement of the wastewater so that said ozone and air mixture mixes with the water and forms a foam that floats to the top of said first tower so as to generally remove fat from the wastewater;

said flow direction means operably maintaining the upper level of the water in said first tower below but in close proximity to said overflow means such that the foam overflows the first tower into said first waste drain;

(g) intermediate first filtration means operably flow located subsequent to said first tower;

(h) subsequent to said first filtration means, a second tower flow connected and subsequent to said first tower;

said second tower having an upper portion and a lower portion;

(i) said upper portion of said second tower having a top and an inlet near said top for introducing wastewater into said second tower;

said inlet flow connected to said first tower;

(j) said top of said second tower adapted to connect to a second waste drain by overflow means comprising a second shroud surrounding the upper end of said second tower;

(k) said lower portion of said second tower having a bottom and an outlet near said bottom for removing water from said second tower;

(l) said bottom of said second tower communicating with a source of an ozone and air mixture;

(m) said second tower having a flow directing means such that the wastewater flows generally downward and said ozone and air mixture flows generally upward, counter to movement of the wastewater so that said ozone and air mixture mixes with the wastewater and forms a foam that floats to the top of the second tower and overflows into said overflow means so as to remove a substantial portion of remaining impurities from the wastewater.

24. The apparatus according to claim 23 including:

(a) second filtration means connected to receive the water subsequent to said outlet of said second tower; and

(b) a residual ozone remover flow connected to receive said water subsequent to said second tower.

25. An apparatus for removing impurities including fat from wastewater for chilling food products being processed used in a food processing environment, said apparatus comprising:

(a) a coarse filter, said coarse filter connected to a source of the wastewater;

(b) a first tower flow connected to said coarse filter, said first tower having an upper portion and a lower portion;

(c) said first tower upper portion having a top and an inlet near said top thereof for introducing the wastewater with the fat therein into said first tower;

(d) said first tower top having overflow means connected to first waste drain means comprising a first shroud surrounding the upper end of said first tower;

(e) said lower portion of said first tower having a bottom and an outlet near said bottom for removing the wastewater from said first tower;

(f) the bottom portion of said first tower having a gas dispersion nozzle connected to a source of an ozone and air mixture;

(g) intermediate first filtration means operably flow located subsequent to said first tower;

(h) subsequent to said filtration means, a multi-tower unit having a plurality of successive towers, each of said towers having an upper portion and a lower portion;

(i) said multi-tower unit including an initial tower and a final tower;

(j) said upper portion of each of said towers in said multi-tower unit having a top and an inlet near said top for introducing wastewater into each of said towers;

said inlet of said initial tower being flow connected to said intermediate filtration means;

(k) said top of each of said towers in said multi-tower unit each including overflow means connected to second waste drain means comprising a second shroud surrounding said multi-tower unit;

(l) said lower portion of each of said towers in said multi-tower unit having a bottom and an outlet near said bottom for removing the wastewater from each of said towers;

(m) said outlet of each of said towers in said multi-tower unit connecting to said inlet of each successive tower in said multi-tower unit;

(n) the bottom portion of each of said towers in said multi-tower unit having a gas dispersion nozzle connected to a source of an ozone and air mixture; and

(o) each of said towers in said multi-tower unit having a flow directing means, said flow directing means directing the wastewater to flow substantially downward and said ozone and air mixture to flow substantially upward, counter to movement of and in mixing relationship with the wastewater so that said ozone and air mixture forms a foam with the impurities in the wastewater that rises to the top of a respective tower and overflows into the overflow means so as to remove a substantial amount of the impurities from the wastewater.

26. The apparatus according to claim 25 including:

(a) final filtration means flow connected to the outlet of said final tower; and

(b) a residual ozone remover flow connected to the outlet of said final tower.

27. In a process for treating cooled wastewater containing substantial amounts of fat wherein the wastewater has been used in food processing for chilling animal carcasses with a countercurrent flow of an air and ozone mixture;

the improvement comprising;

(a) flowing the wastewater with substantially all of the fat therewith into a tower wherein the wastewater is subjected to the countercurrent flow of air and ozone mixture;

(b) forming a foam at the top of the tower containing substantially all of said fat and thereafter overflowing said foam from remaining wastewater into waste drain means comprising a shroud surrounding the upper end of said tower so as to thereby separate the fat from the remaining wastewater; and

thereafter;

(c) flowing the remaining wastewater substantially free of fats from said tower.

28. The process according to claim 27 wherein:

(a) said water exits said process at a temperature only slightly raised above the temperature of the water just prior to entering the process.