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1 significant -'iffcrence between spray aeration and air stripping is that no oacking material is present in the aeration process which may become ;o,:ied and require subsequent replacement The RSI system further enhances the separation of hydrocarbons from water by using vacuum ana heat The pressure is reduced so the temperature at which the hydrocarbons vaporize drops An increase in the temperature from the addition of heat further increases the potential for hydrocarbon ' vaporization. The RSI spray aerator takes advantage of both of these principles oy spraying heated water in a vacuum To ensure sufficient hydrocarbon removal, the water is recirculated through a second set of spray nozzles In geographic areas where benzene becomes a governing factor, carbon canisters for water polishing may be required. ' A vacuum up to 15 inches of mercury may be placed on the tank and the water heated to 100 degrees F There are limits to the level o f ' vacuum on the tank and the water temperature must be monitored carefully to avoid evaporating a large quantity of water along with hydrocarbons. For example, at 110 degrees F and 27 inches of mercury, ' all the water would evaporate and be passed to the engine The soil vacuum extraction system consists of a vacuum pump driven by the internal combustion engine. The vacuum on the extraction well causes the hydrocarbons to volatilize and flow with the air into the well and up to the vacuum pump. The vapors drawn by ' the vacuum are combined with the hydrocarbon vapors which have been stripped from the ground water and are directed to the intake of the engine where they are mixed with the auxiliary fuel (if required) and then burned in the engine through the process of thermal oxidation where temperatures can exceed 5000° F, thus consuming the total hydrocarbon mixture. The engine's air to fuel ratio is adjusted to ' maintain efficient combustion when the vapor from the wells is combined with the fuel from the carburetor, thus resulting in minimum ' emissions from the engine. The exhaust from the engine is passed through an automobile catalytic converter to ensure a maximum destruction of the hydrocarbons. These catalytic converters meet EPA ' requirements and the CARR Executive Order D-193-2 allowing their use in California. The temperature at the catalyst exit ranges between 800 and 1400 degrees Fahrenheit ('F). The system is under a vacuum from the extraction wells to the engine cylinders, so leaks at the seals or connections are into the system, with no loss of hydrocarbons to the atmosohere SAFETY OF OPERATION The engine is the power source for all other equipment so all systems stop operating when the engine stops This eliminates any ' 3