4. (20 marks)The laboratory trickling filter data in the following table were obtained at 20C : (a) Using the data to find k and n in the Eckenfelder (or Schultz-Germain) model for this waste and medium. (b) The lowest expected temperature is 10C. For a depth of 5.5m and recirculation ratio of 2.0 , what is the design filter diameter for an influent flow of 4000m3/d with BOD 5 concentration of 220mg/L ? The desired BOD5 removal is 90%. Assume the temperature correction factor () is 1.030