Equipment for controlling contaminants in a gas flow, which comprises a main duct (2) for transporting a main flow (F) of contaminated gas and a by-pass circuit (4) equipped with an inlet opening (5) and an outlet opening (6) in connection with the main duct (2) for the extraction and the re-introduction of a secondary gas flow (Fb) from/into the main duct (2) respectively through the inlet opening (5) and the outlet opening (6). The outlet opening (6) is arranged downstream of the inlet opening (5) with respect to the direction of advancement (X) of the main flow (F) of contaminated gas in the main duct. The equipment further comprises circulation means (7) for making the secondary gas (Fb) flow from the inlet opening (5) to the outlet opening (6), means for generating oxidising chemical species (3) arranged to intercept the by-pass circuit (4) and adapted to generate in the secondary flow (Fb) the oxidising chemical species in an excess amount with respect to the amount required to oxidise the contaminant chemical species contained in the secondary flow (Fb), a first base amount of the oxidising chemical species being adapted to react with the contaminant chemical species contained in the secondary flow (Fb) and a second excess amount of the oxidising chemical species being adapted to be transported by the secondary flow (Fb) in the main flow (F). First mixing means (8) are arranged in the main duct (2) downstream of the outlet opening (6) in order to mix the secondary flow (Fb), containing the second excess amount of the oxidising chemical species, with the main flow (F).
