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Activated Sludge Workshop Techniques and Tools that Improve Clarifier Performance

Activated Sludge Workshop Techniques and Tools that Improve Clarifier Performance. Mike Beattie Operations and Reliability. Topics Today. Troubleshooting: Provide some simple things to assist Can you run your plant using only a settleometer? Diagnostics

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Activated Sludge Workshop Techniques and Tools that Improve Clarifier Performance

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  1. Activated Sludge WorkshopTechniques and Tools that Improve Clarifier Performance Mike Beattie Operations and Reliability

  2. Topics Today • Troubleshooting: • Provide some simple things to assist • Can you run your plant using only a settleometer? • Diagnostics • Fundamental biology vs. Operating adjustments • Develop a Robust Operational Scheme • Limit Standard Deviation • Limit changes on other areas • Avoid CTRL-ALT-DEL Brown and Caldwell

  3. My History 1992 Administrative Order • Reduce overflows • No more convenience pressure relief • Treat more/bypass less • Would a clarifier that could only treat 3 MGD be of any use? Brown and Caldwell

  4. Seen it All • Foaming, Scum • Bulking • Solids Washout • Rising Sludge • Ashing • Straggler Floc • Plant could only handle 3 MGD • Anything > = MASSIVE WASHOUT • 16 X 120 Clarifiers Brown and Caldwell

  5. Questions and Quest for Knowledge (The Grail) • What causes all of these things to happen? • What where the commonalities? • The end result had to be a simple decision making tool • Operators had to Understand Original Design Intent (train, train, train, 21 conversations) • SOR, Weir Overflow Rate, Solids Loading Rate, Solids Under-loading Rate Nuances of settled sludge • Too much or too little food results in poor sludge quality Brown and Caldwell

  6. Needed to Understand Original Design Intent and Changes • Drawings • Influent Distribution • Baffles • Pump Capacities • Flow Meters • Calibration Brown and Caldwell

  7. Drawing Review • Found that the tanks were built in 1956 • Original Primary Clarifiers • Original operating depth was 7 feet • Institutional knowledge was “ever since (1972) we got that aeration basin and those new primary clarifiers these final clarifiers have been nothing but a problem” 1972 Grit Removal Primary Clarifiers Aeration Basin series/and parallel Gas Storage Digester Retrofit old primary clarifiers to finals Disinfection Brown and Caldwell

  8. 1978 Upgrade Added Three Ponds (did I mention our collection system 240 MGD) Brown and Caldwell

  9. Final Clarifiers-I (used to) Have Baffles • Drawings Said Yes • Tank Inspection=NO! • Most taken out during collector upgrade but not replaced • $3,000 fix Brown and Caldwell

  10. Influent Distribution • Inspecting for debris is very helpful • Sampling the entire water column? • Could a sludge judge, some buckets and a little laboratory work tell you anything? • Proper Sludge Judge Use (ITA Study) • Dye testing can be helpful • CFD modeling can be helpful Brown and Caldwell

  11. Additional Efforts • Quieted the entry of the aeration basin effluent (no waterfalls into clarifier) mid-depth entry is was best • Adjusted influent gates to even flow • Leveled and set effluent the weirs • Bucket tests of the RAS pumps Brown and Caldwell

  12. Design Issues Vetted-Next Step-Operate • Identify all parameters where someone could make a decision, adjustment, equipment on and off • Calculate standard deviation for the parameters • Found out RAS Flow standard deviation was 200% • MLSS standard deviation was 1500 mg/L • WAS Concentration similar Brown and Caldwell

  13. How does the tail wag the dog here? • Can the operator directly influence RAS TSS? • Can the operator directly influence MLSS TSS? • Can the operator directly influence WAS parameters? • How ?? • How ?? • How ?? Brown and Caldwell

  14. The influences did not matter unless I understood the goal: Quality sludge to get the most out of our clarifiers! What is Quality Sludge? Activated sludge that: • Flocculates • Settles and filters • Compacts Brown and Caldwell

  15. Learn the Blues Before You Learn How to Rock and Roll • Recommends Using the Settleometer • Recommends that RAS Flow Control is Very Important • Discusses the concept of different settling sludges exist that can do the same thing Brown and Caldwell

  16. What is SVI Really? Does SVI allow you to measure- • Flocculation? • Settling? • Compaction? • What does Sludge Volume Index have to do with any of these? • When is it done flocculating, settling, compacting? Brown and Caldwell

  17. Rate of Settling • Sludge can settle at a rapid rate • Sludge can settle at a normal rate • Sludge can settle at a slow rate • All three types of sludge can flocculate, settle and compact • All three can remove enough BOD to meet permit • All three can perform well in a clarifier Brown and Caldwell

  18. How Does RAS Concentration respond to Changes in RAS Flow? Brown and Caldwell

  19. How does MLSS respond to changes in RAS Flow? Brown and Caldwell

  20. How Do Solids Filter and Compact in the Settleometer? Brown and Caldwell

  21. Recommendations from Al’s Work • Collect more data during settle test • 5, 10, 15, 20, 25, 30, 60, 120, 180, 240 minutes • 5 minute-measures settling • 15 minute-filters • 30 minute-compaction Brown and Caldwell

  22. Use 5 minute reading on MLSS to Type Less than 500  500-900 900 or higher  I have a Rapid Settling Sludge I have a Normal Settling Sludge I have a Slow Settling Sludge Brown and Caldwell

  23. Al Says - How do I know when its time to send the bugs back to the aeration tank? • The goal is to determine when is the RAS sludge done settling, filtering and compacting in the final clarifier • Spending the correct amount of time in the final clarifier allows much better process control • RAS Settleometer Test • Collect Data at: • 30 Minute • 60 Minute • 120 Minute Brown and Caldwell

  24. Use 5 minute reading on MLSS to Decide RAS Test <500  Rapid  RAS at 30 Min 500-900  Normal  RAS at 60 Min 900 or higher  Slow  RAS at 60 Min Brown and Caldwell

  25. What Now? • What kind of sludge • Use appropriate RAS Reading (30, 60 or 120 min) • When RAS is at 900 its done • Is reading above or below 900? • If above 900 RAS turn RAS rate up 5-10% • If below 900 turn RAS rate down 5-10% Brown and Caldwell

  26. Remember My Plant? Before • No more than 3 MGD • Massive solids loss during storm events • Permit Anxiety • Flow diverted to other facilities • Extreme STD DEV After • 13 MGD • Highest effluents out of plant were 50 ppm • Reduced flow diversion by 85% • MLSS STD DEV 300 mg/L • RAS STD DEV 25% Brown and Caldwell

  27. If you can master this simple settleometer technique • Unlock hidden capacity without adding any concrete • Reduce energy usage • Nutrient removal • UV disinfection Your ready to rock and roll! Brown and Caldwell

  28. Questions?? Mike Beattie Brown & Caldwell Operations/Reliability mbeattie@brwncald.com 952-240-0341 Brown and Caldwell

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