Question 5: Trickling filter

Consider a domestic sewage treatment plant in a tropical region (average temperature 28°C) treating 6,000 m³/day of influent, with the following composition:
1400 mg COD/l; 600 mg BOD/l; 750 mg SS/l; 60 mg NH₄-N/l, 20 mg PO₄-P/l

a. Why could the BOD/COD ratio differ between warm and cold climates?

The water is treated in a trickling filter with the dimensions: diameter = 36 m, height = 3 m.

b. Calculate the loading rate of the trickling filter.

c. Is the system well designed? Explain why, what will happen in the trickling filters during this conditions and how could you solve it.