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Ppt on fab mbbr


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Ppt on fab mbbr

  1. 1. Introduction andprocess description ofFAB/MBBRByKETAN WADODKAR12418000416/06/131
  2. 2. Content MBBR (Moving Bed BiofilmReactor) Introduction Process Description Design Consideration Advantages16/06/132
  3. 3. MBBR (Moving bed biofilmreactor) Small cylindrical shaped polyethylene carrieradded in aerated or non aerated basin tosupport biofilm growth. Biomass grows primarily on protected surface onthe inside of the carriers. Air agitation or mixers are used to continuouslycirculate carriers. Perforated plates at the outlet of the tanks keepsbiofilm carrier inside the tank. MBBR can be a single reactor or configured asseveral reactors-in-series.16/06/133
  4. 4. 16/06/134Fig: Moving Bed Biofilm Reactor (MBBR)
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  8. 8.  Retention of the carrier withinthe reactor encouragesselection and enrichment fororganisms that are bestadapted to the nutrientconditions that prevail in thatreactor at steady state. Carriers occupy 25-70% oftank volume. The specific surface area ofcarrier is about 500m2/m3. The carriers are slightlybuoyant and have a specificgravity between 0.94 and 0.96g/cm3. Media carrier life is around 15-20 years.16/06/138
  9. 9. Various types of bio carriersused16/06/139
  10. 10.  treatment capacity is a function of the specific surfacearea (SSA) of the reactor. The SSA for a reactor = the quotient of the total surfacearea on the carrier that is available for biofilmestablishment and the reactor volume.TABLE: SSA of attached growth media (Source: Metcalf&eddy, 2003)16/06/1310
  11. 11. Design Consideration Adequate preliminary treatment: to prevent plastic biofilm carrier retention screen blinding To prevent the accumulation of inert material in MBBRtank Well designed aeration system: Promote the rolling water circulation pattern thatuniformly distributes plastic biofilm carriers throughout theMBBR. diffused aeration is used for aerobic MBBR tank (Coursebubble diffusion) Typical oxygen transfer rates are 2.5 – 3.5 % per meter ofwater submergence. Typical air flow rate = 6 to 8 m3/m2.h. Properly specified/designed mechanical mixers fordenitrification tank 16/06/1311
  12. 12. Fig: Influence of organic load and reactor DO concentration onTAN removal in a Kaldnes MBBR, at 15 C and with TAN in excess (2.5mg N/L). (Hem et al. 1994). 16/06/1312
  13. 13.  Media carrier retention screens: Scum must be removed from the system Typical screen design allows for a maximum 50 to150mm head loss Effective liquid–solid separation system: The general SS in MBBR effluent found out to be 150-250mg/L, when treating medium to high strengthwastewaters. MBBR are low HRT biofilm reactors According to Ahl et al. (2006), the particle sizedistribution shifts towards larger particle size withincrease in HRT. As biomass accumulation is settling independent, MBBRis flexible in choice of settler used. (Coagulation &flocculation. Tube settler, MF/UF etc.)16/06/1313
  14. 14.  Length-to-width ratio (L:W) in the range 0.5:1 to 1.5:1. Ratio more than above results in non uniformdistribution of bio carriers. Biofilm thickness is controlled by air flow ormechanical mixing energy. Low-rate MBBRs promote nitrification. Medium-rate MBBRs typically are designed for anOLR in the range 5 to 10 g BOD5/m2.d (at 10uC). Higher-rate systems require chemically enhancedliquid–solids separation and/or flotation. OLR = 45-60g BOD5/m2d @25 oC. (Ødegaard, 2006). MBBR support SNDN which is dependant on type ofcarrier selected. It do no require any return activated sludge orbackwashing.16/06/1314
  15. 15. Advantages: High-efficiency cBOD removal and nitrification(even in low temperature environments) Retention of slow-growing and temperature-sensitive bacterial populations (i.e., autotrophicnitrifiers and methanol-degrading heterotrophs,respectively) low HRT high biomass concentration low solids loading on liquid–solids separation unitprocesses Reduced sludge production compared withactivated sludge16/06/1315
  16. 16.  No problems with odours,snails or red-worms as in airphase fixed films. Non clogging design. Is a continuous system andbiofilm thickness is maintainedby the aeration-mixingprocess. Smaller foot prints. MBBR Provides Five times theBiofilm Surface Area in lessthan ¼ Reactor Volume asTrickling Filter Can be operated at varyinginfluent load Can be easily retrofitted.16/06/1316
  17. 17. References McQuarrie J. P., Boltz J. P. (2011) Moving Bed Biofilm ReactorTechnology: Process Applications, Design, and Performance;Water Environment Research, London, United Kingdom, 83 (6),page no. 560-575. Ødegaard, H. (2006) Innovations in Wastewater Treatment: TheMoving Bed Biofilm Process. Water Sci. Technol., 53 (9), 7–33. Hem, L.J., Rusten, B., Ødegaard, H., 1994. Nitrification in amoving bed biofilm reactor. Water Res. 28 (6), 1425–1433. Metcalf and Eddy (2003), Wastewater Engineering: Treatmentand Reuse, 4thEdition, TATA McGraw-Hill, New Delhi.16/06/1317