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Sewage Treatment Eye Openers - Dr. Ananth Kodavasal

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An assessment of various technologies

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Sewage Treatment Eye Openers - Dr. Ananth Kodavasal

  1. 1. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986www.ecotech-india.com PIONEERS & LEADERS IN WASTEWATER TREATMENT Dr. Ananth S Kodavasal Director Sewage Treatment Eye Openers www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 An assessment of various technologies March 2019Presented for ADDA Water Workshop
  2. 2. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 THREE CARDINAL LAWS FOR A GOOD STP PROPER DESIGN PROPER ENGINEERING PROPER OPERATION & MAINTENANCE
  3. 3. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 THE ZEROTH LAW SELECTION OF THE APPROPRIATE TREATMENT TECHNOLOGY
  4. 4. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 wrong technology 2500 STPs IN BANGALORE 350 MLD SEWAGE 80% STPS ARE DEFUNCT incorrect design poor engineering huge operation & maintenance
  5. 5. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 wrong technology 600 STPs IN PUNE 100 MLD SEWAGE 80% STPS ARE DEFUNCT incorrect design poor engineering huge operation & maintenance
  6. 6. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Bangalore suffers from SBR itis Pune suffers from MBBR itis STP diseases – the Dr.’s diagnosis
  7. 7. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 typical naïve STP tender from architect “The vendor may select any process as per their area of expertise and proprietary design…”
  8. 8. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 typical naïve STP tender from architect “…acceptable technologies include Extended Aeration, SBR, FAB, SAFF, FBBR, RBC, MBR…”
  9. 9. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 typical naïve STP tender from architect “…anaerobic systems like UASB, Septic tank…physical/chemical like enzyme activated …electrolysis…”
  10. 10. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 An Experienced Consultant must : Specify the most appropriate technology, and not the one the vendor is “comfortable” with
  11. 11. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 huge fresh water savings potential over Rs. 1600 crore in STP assets in Bangalore 20-25% investment enough to revamp 2000 defunct STPs protect waterbodies
  12. 12. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 COMMUNITIES CAN BE 60% SELF-SUFFICIENT IN WATER BEYOND 100 KLD, STP MAKES MONEY PAYBACK PERIOD IS MONTHS
  13. 13. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Classic EAAS Anaerobic CAACO EADOX SBR MBBR/Fixed MBR STP TECHNOLOGIES PREVALENT IN BANGALORE
  14. 14. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 CLASSIC, CONVENTIONAL EXTENDED AERATION ACTIVATED SLUDGE IS BEST
  15. 15. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 1 | Extended Aeration Activated Sludge (EAAS)
  16. 16. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 sludge recirculation 1. bar screen 2. grease trap 3. equalisation tank (aerated) 4. aeration tank 5. settling tank filtratio n treated water excess sludge Stages 3 & 4 allow for extended aeration sludge recirculation – activated sludge EAAS SYSTEM
  17. 17. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS WITHIN 72 HOURS
  18. 18. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 2 | Moving Bed Biofilm Reactor (MBBR)
  19. 19. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MOVING BED BIOREACTOR (MBBR) PRIMARY SEDIMENTATION ISSUES SLUDGE HANDLING ISSUES POORLY DESIGNED & ENGINEERED NOT APPROPRIATE FOR SMALL STPS PLASTIC MEDIA TO INCREASE SURFACE AREA
  20. 20. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 PROF. HALLVARD ODEGAARD OF NORWAY INVENTED MBBR IN LATE ‘80S (NOT NEW TECH) PROPER PRIMARY SEDIMENTATION IS A MUST UNDER ALL CIRCUMSTANCES THE MBBRS WE HAVE INSPECTED SKIP THIS AND JUST END UP TANKERING OUT THE SLUDGE (BAD !)
  21. 21. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Original Genuine MBBR ▪ Originally developed by Norwegian University of Science & Technology with M/S Anox Kaldnes of Norway (Now Veolia) ▪ Every treatment flowsheet requires primary solids removal – Crux of an MBBR System
  22. 22. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Typical issues with MBBRs in India ▪ No primary sedimentation ▪ Primary sewage solids (faeces) cannot be digested in small MBBRs in less time ▪ Generic plastic carrier media used (Density, Roughness, Surface Area - not tailor made ) ▪ Cannot transfer more Oxygen in less time using Coarse Bubble Diffusers
  23. 23. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MBBR issues (cont’d) ▪ Fine Bubble Diffuser cannot be used due to media interference (have to use less efficient coarse bubble diffuser) ▪ Shallow MBBR tanks – less efficient oxygen transfer ▪ Primary solids (faeces) slip out of MBBR tank ▪ Dead microbes slough off from MBBR tank
  24. 24. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MBBR issues (cont’d) ▪ Plate/tube settler cannot be used for Biomass settling ( This is WTP legacy for chemical sludge) ▪ Sludge/solids adhere to plate/tubes and then become septic and escape out ▪ Thin slurry from plate settler difficult to dewater ▪ Sludge requires thickening, digestion, conditioning before dewatering
  25. 25. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Plastic Carrier Media for MBBR developed by Anox Kaldness
  26. 26. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Fig. 1 – What is actually used in MBBRs in India Fig. 2 – What should be used: Anox Kaldness MBBR media with microbial coating
  27. 27. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
  28. 28. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 The Big Question then? Question #1 If dead or dying microbes along with some living microbes on the outside can float out of any MBBR tank, why can they not do the same in the settling tank? MBBR Tank Cross Section is much larger!
  29. 29. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 The Big Question then? Question #2 If microbes can attach to plastic media under turbulent conditions in the MBBR tank, why will they not attach to the plastic tube/plate in the secondary settler under calm, quiescent conditions?
  30. 30. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MBBR sludge difficult to handle ▪ Without primary settling, human faeces slip out of MBBR tank ▪ Solids slipping out of MBBR tank are inherently difficult to settle, fluffy, light, do not dewater ▪ Need thickening, digestion, conditioning
  31. 31. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MBBRs we have seen in recent times ▪ No primary sedimentation ▪ Less than 50% treatment ▪ Filter press never used ▪ Sludge tankered out (ILLEGAL!)
  32. 32. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MBBRs we have seen in recent times ▪ Not one MBBR STP working per design ▪ Have converted many MBBRs to EAAS ▪ In Pune-Hinjewadi 220 KLD, and 435 KLD in Kharadi
  33. 33. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS versus MBBR
  34. 34. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Lifecycle of microbes
  35. 35. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 A genuine, well-engineered MBBR
  36. 36. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 A genuine, well-engineered EAAS
  37. 37. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS : SUSPENDED GROWTH REGIME SLUDGE RECIRCULATION MBBR : ATTACHED GROWTH REGIME PRIMARY SEDIMENTATION NO SLUDGE RECIRCULATION Key differences EAAS vs MBBR
  38. 38. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 3 | Sequencing Batch Reactor (SBR)
  39. 39. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 1 fill wastewater 2 react 3 settle 4 decant 5 idle waste sludge treated water aeration aeration NO ISSUES WITH TECHNOLOGY AIMS TO SAVE SPACE & ENERGY SEQUENCING BATCH REACTOR (SBR)
  40. 40. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MOTORISED DECANTERS NEEDED SLUDGE ENTERS DECANT WATER BUT RUDIMENTARY DECANTERS USED FOULS TERTIARY FILTERS & OPERATOR WILL JUST BYPASS DECANT TANK WITH SLUDGE GOES SEPTIC
  41. 41. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Motorised Decanter required for proper treatment, but never used
  42. 42. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 DECANT VELOCITY 3000 TIMES SETTLING VELOCITY DECANT ISSUES
  43. 43. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 AREA AND POWER MYTHS OVERSIZED COLLECTION TANK FOR SMALL STPS TO DEAL WITH 8 HOURS OF EFFLUENT POWER SAVINGS ONLY WITH TWO SETS OF AIR BLOWERS AREA & POWER BENEFITS ONLY FOR LARGE PLANTS BEYOND 10 MLD
  44. 44. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 INAPPROPRIATE FOR SMALL STPS – RESIDENTIAL, COMMERCIAL DISTINCT PEAK FLOWS REQUIRE LARGER EQUALISATION TANK DECANT ONLY 33% OF AT VOLUME →LARGER AERATION TANK NEEDED ODOUR NUISANCE, MORE ENERGY, LARGER FOOTPRINT, MORE EQPTS
  45. 45. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS versus SBR (qualitative) Sl. Existing SBR Proposed EAAS Remarks 1 Inappropriate Technology for res. complexes Most suitable for Mini, Small STP* See PPT* 2 Large Footprint Smaller footprint 3 High energy Less energy 4 Unscientific decant system* N.A See PPT* 5 Very thin sludge Thick Sludge * Easy to dewater * 6 High Solids carryover * Clear water Filters Stressed * 7 Frequent Backwash filters Less Frequent Operators will bypass 8 Large Collection tank Smaller collection tank Collection tank receiving raw sewage generates max. odour 9 Very High failure rate Almost NIL if designed well * Robust performance 24/7 for decades * 10 3 Nos. Air blower 400 Derate to 275cmh each * Less noise, less vibration * 11 Membrane life Short* Membrane life longer Cyclic air flux rates * 12 Long stabilisation period after upset Short recovery period * Less downtime * Loss Minimised 13 Does not deliver quality water 24/7 for in sustained manner Our first EAAS for ITC – Frazer town still delivering after 30 years Least life cycle cost 14 N.A. Converted Several SBR to EAAS with 100 % success* - Latest 500 KLD Phoenix market City Yet to see a good SBR working to 100 % design capacity*
  46. 46. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS versus SBR (quantitative) Sl. Item Existing Proposed SBR Larger by Remarks SBR EAAS 1 Footprint, Sqm 315 250 0.26 Could have been less if designed from scratch 2 Tank constructed volume, cum 1200 770 56% (140 % if EAAS designed from scratch) Could have been less at 500 cum if designed from scratch 3 Connected load 43 KW 42 KW -- Could have been less @ 35 KW if designed from scratch 4 Energy Used, Units 526 338 0.56 Energy can be reduced further with new 1.5 HP pump 5 No. of equipment 10 9 0.11 Could have been less if designed from Scratch 6 Filters size 1.3m Dia 1.3 m Dia 1.3 dia is undersized for SBR since filtration hours must be shorter
  47. 47. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 SLUDGE HANDLING ISSUES FLAT BOTTOM SBR THIN EXCESS SLUDGE CONVENTIONAL EAAS THICK EXCESS SLUDGE
  48. 48. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS IN ACTION TREATED WATER SAMPLE FROM BANGALORE’S BIGGEST MALL AFTER HEAVY SATURDAY NIGHT RUSH SBR STP UPGRADED TO EAAS BY US IN OCT 2017. ECOTECH HAS BEEN PERFORMING O&M OF THIS STP SINCE THEN
  49. 49. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 4 | Anaerobic Treatment
  50. 50. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 not suitable for urban residential & commercial buildingsanaerobic treatment unfit for urban reuse foul odour black colouration black solid particles 3 STPs modified by us 200 KLD, 350 KLD, 500 KLD
  51. 51. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 6 | Anaerobic Bio-Reactor (ANBR) for micro STPs
  52. 52. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986
  53. 53. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 DEWATS of Ludwig Sasse
  54. 54. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 50 KLD ANBR HDFC SCHOOL HADAPSAR
  55. 55. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 60 KLD ANBR KUNDALAHALLI BANGALORE
  56. 56. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 7 | Electrocoagulation (EADOX)
  57. 57. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 similar to chemical coagulation EADOX electrocoagulation removes only solids and colloids six STPs studied by us – all defunct does not remove dissolved organics unsustainable electrode costs tertiary filters overload costs
  58. 58. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 6 | Membrane Bio-Reactor (MBR)
  59. 59. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 NO PROBLEM WITH TECHNOLOGY MEMBRANE BIOREACTOR (MBR) GOOD FUTURE PROSPECTS RELIABILITY & COST ISSUES: NOT MATURE FOR SMALL STPS
  60. 60. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 MBR Flowsheet
  61. 61. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Typical Membrane Cassettes
  62. 62. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 Key Takeaways ▪ From a long-term perspective, EAAS is still the best available, practicable, and most appropriate technology ▪ Anaerobic, CAACO, EADOX are unsuitable ▪ SBR, MBBR inappropriate for micro & mini STPs ▪ MBR is for the future but only when all current issues are resolved
  63. 63. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 But isn’t Modern Technology always better?
  64. 64. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 METRO (CONVENTIONAL TECHNOLOGY) MOST APPROPRIATE FOR WITHIN TOKYO BULLET TRAIN (MODERN TECHNOLOGY) GREAT FOR TOKYO TO OSAKA (INTER-CITY)
  65. 65. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986 EAAS is the best technology for mini and small STPs 10-80 KLD Micro 100 – 1000 KLD Mini 1000 – 5000 KLD Small
  66. 66. www.ecotech-india.com EXCELLENCE AND INTEGRITY, SINCE 1986www.ecotech-india.com THANK YOU for patiently listening Dr. Ananth S Kodavasal, Ecotech

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