2. Aeration is particularly utilized to supply oxygen in water treatment. a. How do the impurities (pollutants or other ions) in water affect aeration efficiency? b. In a 2 steps cascade aeration, each step increases oxygen concentration from (10+a) % to (30+a) % of saturation c level. If the initial oxygen S concentration is (20+a) % of saturation level and minimum oxygen is required to be 6 mg/L at the end of aeration, is the system efficient or not? Show your calculations. Inlet water temperature is 15 C (Cs = 10.2 mg/L)

2. Aeration is particularly utilized to supply oxygen in water treatment. a. How do the impurities (pollutants or other ions) in water affect aeration efficiency? b. In a 2 steps cascade aeration, each step increases oxygen concentration from (10+a) % to (30+a)% of saturation level. If the initial oxygen concentration is (20+a)% of saturation level and minimum oxygen is required to be 6mg/L at the end of aeration, is the system efficient or not? Show your calculations. Inlet water temperature is 15C(Cs=10.2mg/L)