Apparatus for enhanced bioremediation of underground contaminants

An apparatus for use in biodegrading a contaminant in groundwater within a subsurface region of earth, the apparatus comprising:

• an injection well having a lower end disposed in the subsurface region;
• means disposed at the lower end of the injection well for permitting flow of groundwater from the injection well into the subsurface region;
• a recovery well having a lower end disposed in the subsurface region;
• means disposed at the lower end of the recovery well for permitting entry of groundwater into the recovery well from the subsurface region;
• means for recycling groundwater from the recovery well to the injection well;
• means disposed between the injection and recovery wells for introducing under pressure molecular oxygen into the groundwater as a dispersion of molecules and at a rate such that oxygen is present in the groundwater flowing from the injection well approximately at a maximum solubility level for oxygen in the groundwater;
• means for maintaining oxygen within the introducing means at the pressure;
• and
• means for inhibiting biofouling of the apparatus.

A method for biodegrading a contaminant in groundwater within a subsurface region of earth, the method comprising the steps of:

• providing a first well having a lower end disposed in the subsurface region;
• providing a second well having a lower end disposed in the subsurface region a distance from the lower end of the first well;
• introducing groundwater from the lower end of the first well into the subsurface region;
• introducing under pressure an oxidizing agent into the groundwater introduced by the first well, the oxidizing agent being introduced into the groundwater as a dispersion of molecules and at a rate such that the oxidizing agent is present in the groundwater within the subsurface region approximately at a maximum solubility level for the oxidizing agent in the groundwater;
• recovering the groundwater from the subsurface region in the lower end of the second well;
• recycling groundwater from the second well to the first well;
• and
• inhibiting biofouling of the apparatus.

An apparatus for use in biodegrading a contaminant in groundwater within a subsurface region of earth, the apparatus comprising:

• a well casing adapted to permit passage of groundwater into a subsurface region;
• a screen surrounding at least a portion of the well casing;
• a diffusion tube surrounding the screen and well casing, the diffusion tube being adapted to introduce under pressure an oxidizing agent into the groundwater as a dispersion of molecules;
• and
• means for regulating the introduction of the oxidizing agent into the groundwater at a rate at which that the oxidizing agent is present in the groundwater approximately at a soluble level for the oxidizing agent in the groundwater.