A contaminant gas is removed from a feed gas in two absorption and stripping circuits operated in tandem. The gas is first passed through a rich gas absorber producing a rich absorption liquor from which contaminant gas is stripped in a rich liquor stripper. A lean gas exiting the rich gas absorber is passed through a lean gas absorber, producing a lean absorption liquor from which contaminant gas is stripper in a lean liquor stripper. Regenerated absorption media exiting the respective strippers are recirculated to the respective absorbers.

In variants, an air treatment module can include a sorption module defining a sorption cavity, an air intake channel, an air exhaust channel, and a target substance exhaust channel. The air treatment module can include a sorbent encapsulated within a sorbent structure (e.g., microencapsulated carbon sorbent) which can sorb carbon dioxide from air passing through the sorption cavity. The air treatment module can desorb carbon dioxide from the air and store the carbon dioxide in long term storage.

A utility vehicle is configured for independently controlling torque at each of the ground-engaging members.