Waste treatment with control over biological solids

Abstract

Waste-treatment processes are enhanced through generation and introduction of specific biological populations customized to perform or favor specific tasks either during the main process, or for solids minimization purposes in a post-treatment process. These bacteria may be grown from specialized mixes of activated sludge and waste influent by exposing these materials to controlled environments (e.g., in an off-line treatment area). They may then be added back to the main process to perform certain tasks such as converting particulate cBOD into soluble cBOD for utilization, to reduce high solids yield organisms by supplementing the population with low yield organisms, to improve nitrification/denitrification efficiency, or to disfavor filamentous biology such as Norcardia sp.

What is claimed is: 
     
       1. A method of treating wastewater, the method comprising the steps of:
 conducting wastewater to a treatment vessel for treatment comprising contact with a first biological population having a first-biological population profile to produce a mixed liquor including activated sludge;   separating the activated sludge from the mixed liquor;   drawing off a first portion of the separated activated sludge and returning said first portion to the treatment vessel;   drawing off a second portion of the separated activated sludge and adding that second portion to at least one off-line treatment area;   controlling the off-line treatment area so as to produce, in the off-line treatment area, a second biological population having a second-biological population profile different from the first-biological population profile; and   returning at least a fraction of the produced second biological population to the treatment vessel, wherein the second biological population achieves lower solids levels.   
     
     
       2. The method of  claim 1 , wherein the step of returning at least a fraction of the produced second biological population includes decanting a percentage of the produced second biological population from the off-line treatment area. 
     
     
       3. The method of  claim 1 , wherein the step of returning at least a fraction of the produced second biological population includes removing a percentage of the produced second biological population from the off-line treatment area. 
     
     
       4. The method of  claim 1 , wherein wastewater is combined with the second portion of activated sludge in the off-line treatment area. 
     
     
       5. The method of  claim 1  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and 
 iv. mixing without aeration to achieve anaerobic conditions. 
 
     
     
       6. The method of  claim 1  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; 
 iii. mixing without aeration to achieve anaerobic conditions; 
 iv. allowing settling to produce a decantable volume; and 
 v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       7. The method of  claim 1  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. stopping the mixing for a period of time; 
 iii. mixing; and 
 iv. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       8. The method of  claim 1  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and 
 iii. stopping the aeration but continuing the mixing. 
 
     
     
       9. The method of  claim 1  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; 
 iii. stopping the aeration but continuing the mixing; 
 iv. allowing settling; and 
 v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       10. A method for treating wastewater in a wastewater treatment system including a first treatment vessel for receiving wastewater and for treatment including contact with a first biological population having a first-biological population profile, the method comprising the steps of:
 drawing off a portion of the first biological population and adding said drawn-off portion to an off-line treatment area;   controlling the off-line treatment area to produce a second biological population having a second-biological population profile different from the first-biological population profile, such controlling including sequentially subjecting the off-line treatment area portion to one of aerobic conditions, anoxic conditions and anaerobic conditions followed by subjecting the off-line treatment area to at least one of aerobic conditions, anoxic conditions and anaerobic conditions; and   returning at least a portion of the second biological population to the treatment vessel.   
     
     
       11. The method of  claim 10 , wherein the step of returning at least a fraction of the produced second biological population includes decanting a percentage of the produced second biological population from the off-line treatment area. 
     
     
       12. The method of  claim 10 , wherein the step of returning at least a fraction of the produced second biological population includes removing a percentage of the produced second biological population from the off-line treatment area. 
     
     
       13. The method of  claim 10 , wherein wastewater is combined with the drawn-off portion of the first biological population in the off-line treatment area. 
     
     
       14. The method of  claim 10  wherein controlling the off-line treatment area comprises:
 i. mixing the drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and 
 iv. mixing without aeration to achieve anaerobic conditions. 
 
     
     
       15. The method of  claim 10  wherein controlling the off-line treatment area comprises:
 i. mixing the drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; 
 iii. mixing without aeration to achieve anaerobic conditions; 
 iv. allowing settling to produce a decantable volume; and 
 v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       16. The method of  claim 10  wherein controlling the off-line treatment area comprises:
 i. mixing the drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. stopping the mixing for a period of time; 
 iii. mixing; and 
 iv. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       17. The method of  claim 10  wherein controlling the off-line treatment area comprises:
 i. mixing the drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and 
 iii. stopping the aeration but continuing the mixing. 
 
     
     
       18. The method of  claim 10  wherein controlling the off-line treatment area comprises:
 i. mixing the drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; 
 iii. stopping the aeration but continuing the mixing; 
 iv. allowing settling; and 
 v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       19. A method of treating wastewater, the method comprising the steps of:
 combining wastewater and a first biological population having a first-biological population profile in a treatment vessel;   exposing the wastewater and first biological population in the treatment vessel to at least one of an anaerobic, anoxic and aerobic conditions to form a mixture including sludge;   separating the sludge from the mixture;   drawing off a first portion of the separated sludge and returning said first portion to the treatment vessel;   drawing off a second portion of the separated sludge to an off-line treatment area;   controlling the off-line treatment area so as to produce, in the off-line treatment area, a second biological population having a second-biological population profile different from the first-biological population profile, such that the second-biological population profile is customized to minimize the disposal volume of residual solids produced by the treatment of the wastewater; and   returning at least a fraction of the produced second biological population to the treatment vessel.   
     
     
       20. The method of  claim 19 , wherein the step of returning at least a fraction of the produced second biological population includes decanting a percentage of the produced second biological population from the off-line treatment area. 
     
     
       21. The method of  claim 19 , wherein the step of returning at least a fraction of the produced second biological population includes removing a percentage of the produced second biological population from the off-line treatment area. 
     
     
       22. The method of  claim 19 , wherein wastewater is combined with the second portion of separated sludge in the off-line treatment area. 
     
     
       23. The method of  claim 19  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and 
 iv. mixing without aeration to achieve anaerobic conditions. 
 
     
     
       24. The method of  claim 19  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; 
 iii. mixing without aeration to achieve anaerobic conditions; 
 iv. allowing settling to produce a decantable volume; and 
 v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       25. The method of  claim 19  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. stopping the mixing for a period of time; 
 iii. mixing; and 
 iv. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       26. A The method of  claim 19  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and 
 iii. stopping the aeration but continuing the mixing. 
 
     
     
       27. A The method of  claim 19  wherein controlling the off-line treatment area comprises:
 i. mixing the second drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation; 
 ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; 
 iii. stopping the aeration but continuing the mixing; 
 iv. allowing settling; and 
 v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes. 
 
     
     
       28. A method for treating wastewater in a wastewater treatment system including a first treatment vessel for receiving wastewater and for treatment including contact with a first biological population having a first-biological population profile, the method comprising the steps of:
 drawing off a portion of the first biological population and adding said drawn-off portion to an off-line treatment tank;   controlling an ORP level in the off-line treatment tank to produce a second biological population having a second-biological population profile different from the first-biological population profile, such controlling including sequentially subjecting the off-line treatment tank to one of aerobic conditions, anoxic conditions and anaerobic conditions followed by subjecting the off-line treatment tank to at least one of aerobic conditions, anoxic conditions and anaerobic conditions; and   returning at least a portion of the produced second biological population to the treatment vessel, wherein the returned portion of the second biological population contains a higher level of soluble cBOD, nitrate or biological nutrients than the wastewater.   
     
     
       29. The method of claim 28, wherein the step of returning at least a portion of the produced second biological population includes decanting a percentage of the produced second biological population from the off-line treatment tank. 
     
     
       30. The method of claim 28, wherein the step of returning at least a portion of the produced second biological population includes removing a percentage of the produced second biological population from the off-line treatment tank. 
     
     
       31. The method of claim 28, wherein wastewater is combined with the drawn-off portion of the first biological population in the off-line treatment tank. 
     
     
       32. The method of claim 28 wherein controlling the off-line treatment tank comprises:
 i. mixing the drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation;   ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and   iii. mixing without aeration to achieve anaerobic conditions.   
     
     
       33. The method of claim 28 wherein controlling the off-line treatment tank comprises:
 i. mixing the drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation;   ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes;   iii. mixing without aeration to achieve anaerobic conditions;   iv. allowing settling to produce a decantable volume; and   v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes.   
     
     
       34. The method of claim 28 wherein controlling the off-line treatment tank comprises:
 i. mixing the drawn-off portion without aeration to achieve anaerobic conditions without substantial sulfide generation;   ii. stopping the mixing for a period of time;   iii. mixing; and   iv. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes.   
     
     
       35. The method of claim 28 wherein controlling the off-line treatment tank comprises:
 i. mixing the drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation;   ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes; and   iii. stopping the aeration but continuing the mixing.   
     
     
       36. The method of claim 28 wherein controlling the off-line treatment tank comprises:
 i. mixing the drawn-off portion of wastewater without aeration to achieve anaerobic conditions without substantial sulfide generation;   ii. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes;   iii. stopping the aeration but continuing the mixing;   iv. allowing settling; and   v. mixing with aeration to achieve biological growth conditions without substantial production of obligate aerobes.   
     
     
       37. The method of claim 28, wherein the second biological population includes a lower proportion of filamentous biology than the first biological population. 
     
     
       38. The method of claim 28, wherein controlling an ORP level of the off-line treatment tank comprises a step of aerating until the ORP level is greater than 100 mV. 
     
     
       39. The method of claim 28, wherein controlling an ORP level of the off-line treatment tank comprises a step of aerating until the ORP level is greater than 150 mV. 
     
     
       40. The method of claim 28, wherein controlling an ORP level of the off-line treatment tank comprises a step of aerating until the ORP level is greater than 200 mV.