Not with chemical actuators but by specific magnetic resonance of di-hydrol base cluster into specific temperature plus ionic polarization of permutation to reduce the vapor pressure and promote the selective increasing of the net di-hidrol base doped of water and differentiate of the combination mono-hydrol and gas, then you obtain potable water.
To design a secondary clarifier, you could, for instance, refer to some books : "Waste water Engineering : treatment and ressource recovery (Metcalf & Eddy) is highly advisable.
you just do a mass balance over you're clarifier to calculate your volume. Then you use your hydraulic application rate for your average flowrate to determine the area. After that you can estimate 1 clarifier per aeration lane and calculate your diameter.