APPARATUS FOR DOWN-WELL OXYGEN-TRANSFER INTO CONTAMINATED AQUIFERS

In-situ methanotrophic bioremediation of ground water contaminated wit h petroleum hydrocarbons and chlorinated aliphatic hydrocarbons (CAHs) often require the addition of O-2 for compound oxidation. The purpose of this research was to test the feasibility of a down-well gas-trans fer apparatus for adding O-2 directly into recirculating ground water. At times it may be desirable to add other gases as well, such as meth ane for CAH cometabolism. A high downward velocity of water through th e inlet tube of an inverted cone prevented upward movement of injected O-2 bubbles. The addition of gas-liquid mixing cones within the trans fer section of the inverted cone increased the turbulence below the in let. Complete dissolution of gases is possible. The relationships betw een O-2 transfer rate and system variables such as pressure loss, wate r flow rate, and N-2 content in the influent water were evaluated. A s ignificant factor affecting O-2 mass transfer was the total dissolved gas content in the water entering the transfer device. From the result s of this study, a design for practical conditions of operation was de veloped.