Henry's Law, one of the gas laws, states:
At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.
Bio-enhancing contaminated groundwater with O2 to raise dissolved oxygen levels is commonly performed to create or enhance a natural aerobic biodegradation of contaminants. At standard ambient temperature and pressure (25ºC, 1bar), the solubility of dissolved oxygen in fresh water is approximately 39 mg/L.
The solubility of oxygen in water is dependent on temperature and pressure:
H = C / P
H = Henry's constant for O2 in water at a given temperature and pressure ( H is different for every gas, temperature, and solvent)
Practical Implications for O2 bio-enhancement remediation techniques:
The solubility of DO in water will increase with depth to contaminated groundwater plume (i.e. depth is proportional to increased pressure and decreased temperature)
Practical implications for use of the Waterloo Emitter:
- Once the O2 has diffused through the Waterloo Emitter tubing into groundwater (see Fick's Law), the solubility of O2 in water will increase with depth to contaminated groundwater plume, as depth is proportional to increased pressure and decreased temperature i.e. typically, the deeper a Waterloo Emitter is installed, the more soluble O2 becomes
- When a gas is applied to the Emitter there is a direct correlation between an increase in applied pressure and an increase in the amount of gas that will diffuse into the groundwater, however, diffusion is the only mechanism that allows the amendment to be added to the groundwater (see Fick's Law).