Methods and apparatuses for removing contaminants. At least one injection well is drilled through the vadose zone to a depth below the water table defining the upper boundary of the aquifer. A plurality of venting wells or venting laterals are established to a depth above the water table sufficient to discourage fouling by contaminated water or condensate, and oxygenated substances are injected under pressure through the injection wells. Additional biochemical cleansing may occur at ground level prior to venting of contaminated air. Microbes natural to the contaminated site may be extracted, analyzed, fermented, and reintroduced to enhance biodegradation, and nutrients, food, or both, may be supplied to the microbial population to sustain high levels of degradation activity. Relatively pure liquid contaminant may be separated from other fluids, such as water. Modes of enhancing the lateral dispersion of injected substances are disclosed, for example, hingedly connected radially extendible injection tubes which expand the radius of injection.