Modeling TF Performance: The LTF Model

Trickling filter programs can be obtained at: www.engr.psu.edu/ce/enve What is needed to promote nitrifying biofilms in fixed-film systems? P Low concentration of BOD (<20 mg/L) to eliminate biofilm competition (space and oxygen) P Conditions that promote high oxygen transfer rates P Conditions that permit a thick biofilm to be maintained High Concentrations of BOD reduce nitrification rates Figure 4 from Parker et al. (1998) Oxygen transport rates in cross-flow (XF) and vertical-flow (VF) media Figure 5 from: Logan (1993) Different approaches used to maintain thick biofilms- Biofilm control through flooding- Alkaline washing to remove predators- Two filters in series, with alternating units receiving influent flow OBJECTIVES Remove sBOD to < 12 mg/L- Predict sBOD removal using LTF- Add solids Contact if necessary Nitrifying Trickling Filter (NTF) model- Key is oxygen transport- Calculate oxygen transfer using NTF NTF Design approach Solving operational problems of NTF