Optimizing Air Scouring Energy for Sustainable Membrane Bioreactor Operation

Optimizing Air Scouring Energy for Sustainable Membrane Bioreactor Operation by Characterizing the Combination of Factors Leading to Limiting Condition Changyoon Jun, March 06, 2024, 16:45 – 17:15 Beyond Trivial Solutions 30~60%1 of MBR system Pre-determined COMPLEX Setpoint MLSS characteristic, fouling condition, configuration, etc. e.g., Specific Air Demand STOCHASTIC Temporal and Spatial Variation in Random 1Barillon et al. 2012 Introduction Theory Method Results Take Away A Relationship Should Exist Between Energy Input to Solids Flux / Removal lavomeR vs K VALUE “GOOD” QUANTIFIES vs Deposition “BAD” vs IN SPECIFIC CONDITION “ALSO BAD” Introduction Theory Method Results Take Away Air Optimization Must Adapt to Various Limiting Conditions Objective 1 : Testing and Validating the K Value Metric Using a Data-Driven Approach Objective 2 : Estimate Reducible Air Scouring Energy High Flux High Local Flux Due to Fouling Introduction Theory Method Results Take Away Eq. P : power dissipated in a volume (V) μ : absolute viscosity of the fluid abs  Larger total resistance (R ) increase hydraulic barrier, increasing Local Solid Flux T MLSS: Mixed Liquor Suspended Solid Concentration [g/l] Eq. Q : permeate flow [m3/hour] P A: membrane surface [m2] Solid Flux R : Total Resistance [m-1] T Introduction Theory Method Results Take Away Limiting K Value Quantifies Shear Force Required for Maximum Sustainable Deposition Rate Solid Removal should be higher than its Deposition Eq. K : critical coefficient Lim is estimated with data-driven analysis Eq. 4 : packing density (A/V) 𝛼𝑠 = K value at specific permeate cycle Introduction Theory Method Results Take Away MBR Configuration and Features for Plants Evaluated Hollow-fiber + flat-sheet Vertical ML flow path incorporating air, influent, Channels aligned Horizontally and return activated sludge (RAS) flow Higher packing density Introduction Theory Method Results Take Away Datasets are Collected from Plant A and Plant B CATEGORY PLANT A PLANT B Number of Trains 2 Surface Area per Train [ft2] 126,000 91, Mean Permeate Flux [LMH] 9.2 7. Mean SAD [m3/m2/h] 134.08 146.73 m Mean SAD [-] 15.0 20.6 p MLSS [mg/L] 3,700 ~ 7,000 5,000 ~ 8, RAS Q [-] 5 SRT [day] 15 ~ 25 SAD : Specific Air Demand to Membrane Surface Area m SAD : Specific Air Demand to Permeate Flow p Introduction Theory Method Results Take Away TAKE AWAY K Indicates the Threshold Boundary Lim Substantial Energy Savings Possible by Adjusting Air Scouring Flowrate to Given Operational Condition. This Method is Undergoing Validation Through Pilot MBR Test.