6) The plant adds a dewatering centrifuge after the digester to save money on residuals disposal. The centrate is high i

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6 The Plant Adds A Dewatering Centrifuge After The Digester To Save Money On Residuals Disposal The Centrate Is High I 1 (59.06 KiB) Viewed 50 times

6) The plant adds a dewatering centrifuge after the digester to save money on residuals disposal. The centrate is high in ammonia and the plant wishes to add a side stream recirculating planted gravel filter to nitrify the ammonia so it doesn't exert additional oxygen demand on the main plant process. The following assumptions are given: • Filter sized for peak flows of 40,000 gpd • Filter sized to remove 150 mg/L of ammonia from the digestate • Oxygen transfer rate of 22 g 02/m².day, per meter of single pass 3-8 mm media • Design depth of 4 feet • Max hydraulic loading rate of 3.33 gal/ft2.day • Oxygen demand of 4.3 lb O2 per lb NH4-N converted • Organic loading rate limit does not apply • The filter will be sized for two passes A. What is the required minimum footprint for nitrification? (SF) (5) B. What is the required footprint to meet the max Hydraulic Loading Rate of the filter (SF) (1) C. Should filter sizing be based on nitrification or HLR? (1) D. What should the plant consider when choosing whether or not to plant the filter? (1)