OST FAQs

Oxygen is generated by a very safe process called pressure swing adsorption. Compressed air is passed through a media bed that absorbs nitrogen under pressure, producing 90% nominal purity oxygen.

Oxygen is added to the water body from discharging the oxygen-enriched water from the OST unit, which in turn, through natural dispersion, spreads throughout the water body relative to the temperature of the oxygen-enriched water discharged.

Even though the oxygen-enriched water is discharged from a small header relative to the rest of the water body, the oxygen is spread through natural dispersion and advection when the wind blows, causing the water body to seiche (slosh back and forth). Think of slowly pouring cream into coffee and then gently swirling the cup.

The OST unit is placed on the bottom of a lake or pond to promote the circulation of the colder water on the bottom. As the cold water is pumped through the OST unit, the oxygen-enriched water, when discharged, stays blanketed over the bottom, promoting an oxygen blanket over the sediments.

This varies from project to project; however, it is not uncommon to see a 6 – 8-inch reduction in muck following the first year of oxygenation, which was reported for a small pond in Wisconsin.

OST has not had any observed or reported negative effect on lake biota when used to increase and maintain oxygen levels.

Maintaining stratification promotes better health for cold-water fisheries. Mixing homogenizes temperature, which favors fewer species of fish. Also, maintaining a cooler environment slows the sediment’s metabolic rate of organic decomposition. Less mixing means less sediment resuspension, which results in lower oxygen demands to satisfy.

Traditional aeration systems can add about 4 kg-O2 / acre while maintaining 5 mg/L in the bulk water, and they have been observed to add more. However, these results are often biased by algal activity. Although DO levels are observed higher during the photosynthesis process during the day, they drop to 1 to 3 mg/L at night when algae are undergoing respiration and consuming oxygen.

We recommend two oxygen thresholds: a stratified range and a mixed range. For stratified water bodies, we recommend 15 – 20 mg/L in the bottom waters to promote deeper penetration into the sediments. For mixed water bodies, we recommend 80 – 100% saturation at temperature, which is typically 8 – 12 mg/L. We highly recommend a maximum DO level of 25 mg/L. Greater than 25 mg/L places undue stress on fish.

The common electrical cost is $5/acre-day during peak summer operation but may vary depending on regional electrical costs. Operational/maintenance costs range from $500 – $1,000 per year.

Yes, the pump and corresponding motor are in the water. The electrical components use the same protection as a typical fountain.

The off-the-shelf units can fit under a decorative rock or equivalent size structure that measures approximately 48” x 60” x 60” for the larger units and 36” x 48” x 48: for the smaller units.

The two off-the-shelf sizes are three ft2 base and 7ft tall and 4 ft2 base and 8 ft tall.