An aqueous solution containing an alkali metal compound solute and organic compound contaminants may be treated with ozone to oxidize andor dissolve the organic contaminants. When the indicated time has been reached, the data display control apparatus executes instructions to control the display of the multimedia data. One embodiment of the present invention employs the NAT registers associated with general-purpose registers to distinguish special values, often indicating error conditions, stored in general-purpose registers serving to store the return values of functions and routines. The backing member is coupled with the rear surface of the frame to releasably secure the blocking member within the frame.