Apparatuses for removal of volatile organic compounds in a soil formation include a microporous diffuser for injecting air and gaseous ozone as bubbles into water in the soil formation. The gaseous ozone is present at concentrations to effect removal of volatile organic compounds by the gaseous ozone reacting with the volatile organic compound(s). Injection of air and gaseous ozone is controlled by a timer to allow separation of bubbles by size. In various embodiments, a plurality of microporous diffusers may be controlled by a single timer or each of the plurality of microporous diffusers may be controlled by one of a plurality of timers.