1. (Learning objective #12) Penn State uses two 1-stage stone trickling filter for biological treatment of 50% of its wastewater (25% goes to each = 0.5 MGD to each). The BOD entering the plant is 285 pprn. Assume that 35% of the BOD is removed by the primary clarifier.
a. Using a BOD loading requirement of 35 lb/1000 ft'-day and a filter depth of 6ft, determine the diameter of the filter. (68.4')
b. Calculate the hydraulic loading if the recirculation ratio is 1 (0.19 gpm/sf)
c. Calculate the efficiency if the recirculation ratio is 1. (79.5%)
d. Who is the concentration of BOD leaving the trickling filter if the recirculation ratio is 17 (38 PPm)
e. What is the concentration of BOD leaving the trickling filter if the recirculation ratio is 2? (35 PPm)