An industrial wastewater flowing at a rate of 37,000 m3 /day is contaminated by
ID: 942584 • Letter: A
Question
An industrial wastewater flowing at a rate of 37,000 m3 /day is contaminated by 187 mg/L of propanol – CH3CH2CH2OH. As an environmental consultant, you propose to treat the water in an activated sludge process in which propanol is oxidized by oxygen into carbon dioxide – CO2. The reaction is highly favorable and assumed to be complete.
a) Equilibrate the half-reactions and overall reaction that are expected to occur during the treatment process.
b) Determine the theoretical quantity of oxygen (in mol/day) required for the complete oxidation of propanol
c)Determine the volume of pressurized air (2 atm, 15°C) to be provided (in m3 /day) for the complete oxidation of propanol. The partial pressure of O2 in air is 0.2095 atm and the efficiency of oxygen transfer is estimated to be 15%.
Explanation / Answer
a) CH2CHOHCH3 + O2 --> CH3COCH3 {half-reaction}
CH2CHOCH3 +O2 --> CH3COCH3 +O2 --> CH3CH2COOH + O2 --> CO2+H2O {overall reaction}
b) As per the above reaction 1..07 mole of oxygen is required for 1 mole of propanol so totally 187 mole of oxygen is required.
c) (PV)air/(PV)oxygen = Tair/Toxygen
(2) V/(0.2015)(0.15) = 15/25
V is 9.06 cu.m