A method for removing contaminants such as oil and solids from water by feeding a mixture of water containing the contaminants and carbon dioxide to a cyclone; separating water from the mixture; separating a second mixture of oil, carbon dioxide and water from the mixture and feeding the second mixture to a separator wherein oil, carbon dioxide and water are recovered from the separator. A three dimensional phantom is custom formed for a desired imaging space of a given imaging system. The battery clip also includes a top portion spaced from the printed circuit board with a tab extending from the top portion in a downward direction toward the printed circuit board. The display unit has a first state before the display unit is expanded, and a second state after the display unit is expanded.