Abstract: A permanent underground compost aeration system enables forward and reverse circulation of air through a compost pile by a single non-reversible blower and air pipe dampering arrangement. Adequate oxygenization of an entire compost pile is assured. Outside air in varying amounts can be introduced into the aeration system during its operation to provide fine control of oxygenation. A complete underground moisture drainage arrangement for the aeration system is provided to prevent flooding of the system. The aeration system is compatible with computer controls for air volume, temperature and moisture content. A pair of parallel elongated main header pipes are connected with two groups of smaller apertured air distribution pipes extending in opposite directions at right angles to the header pipes. All pipes of the aeration system have bottom moisture drain openings.