Nitrification is a biological process for removing NH 3 from wastewater as NH4+:
NH4+ + 2 O 2 ⟶ NO3− + 2 H+ + H2O
The first-order rate constant is given as
k1 = 0.47e0.095(T − 15˚C)
where k1 is in day −1 and T is in ˚C. If the initial concentration of NH 3 is 3.0 mol/m3, how long will it take to reduce the concentration to 0.35 mol/m3 in the winter (T = 10˚C)?