This disclosure describes a passive system that keeps stored water oxygenated and in continuous slow motion using nothing but capillary action and gravity — no pump, no electricity, and no moving parts in the wetted path. A porous hydrophilic matrix is partially submerged in a storage or collection tank. Capillary suction continuously lifts water a very short distance (typically 0.1–0.5 m) to an overflow edge; the overflowing water then descends through a passive cascade or Venturi feature that entrains atmospheric air, and the re-oxygenated water is returned to the body of stored water, completing a circulation loop. The central engineering insight, developed and quantified herein, is that restricting the design to small lift heights permits coarse, inexpensive capillary media and yields very high volumetric throughput per unit cross-sectional area, making the approach economically practical for water-quality maintenance even though the same mechanism is uneconomic for high-volume pumping against large heads. The disclosure is intended to be enabling at the level of a person skilled in fluid transport and water treatment, and to cover the broad family of embodiments enumerated in Section 6, including integration into buried geothermal-buffered tanks and into the collection/storage reservoirs of separate water-harvesting systems.
Lius et al. (2026) studied this question.