Effective Oxygen Delivery

Oxygen is most effectively delivered to ground water by the recirculation of oxygenated water.  The only way to ensure that oxygen is not lost to off-gassing from solution is to not exceed the 40 to 60 mg/L oxygen saturation concentration for shallow ground water.  Water injected at greater depth can hold more oxygen. The equivalent water head of 24.7 feet has a DO saturation of 81.5 mg/L for 90% oxygen gas.  Some off-gassing may occur even at DO concentrations as low as 40 to 50 mg/L if the supply water contains significant dissolved nitrogen.  Nevertheless, DO concentrations of 30 to 45 mg/L are stable with little or no loss in the subsurface, especially if injected at a significant depth below the water table.