The facility (1A) includes at least two treatment devices (2) each with an exchange chamber (20) intended to contain a liquid bath in the bottom part and at least one injection line (21). An aeraulic means (4), creates by suction or by blowing, simultaneously and in parallel for each treatment device (2), an incoming gas stream (F) originating from outside the exchange chambers (2) and passes through the discharge opening of the injection line (21) by being introduced into the liquid bath contained in the bottom part of the exchange chamber (20), below the surface (S) of said liquid bath. The exchange chambers (20) communicate hydraulically with one another so that when the aeraulic means (4) are shut down, each exchange chamber (20) is suitable for containing or contains, in the bottom part, an initial volume (Vinitial) of liquid, with an initial liquid level (Hinitial) that is identical in all the exchange chambers (2).