This proven Pearth™ gas mixing system, from the PFT® line of products, provides an effective method of digester mixing for greatly increased efficiency at higher solids loadings. The full capacity of the compressor is sequentially directed to the individual discharge points, maintaining uniform temperatures and solids concentrations through the entire active tank volume. Gas is withdrawn directly from the gas dome by the compressor and discharged into the digester to a predetermined depth through a series of vertical lances.