Abstract: Disclosed are methods for continuous production of ozone strong water, the methods comprising the steps of injecting an acidification agent into a pressurized feed water to maintain a pH value of the pressurized feed water below 7, diffusing a two-phase mixture of O2-O3 gas and recirculated water into a body of acidic pressurized water to dissolve ozone into the acidic pressurized water. The disclosed methods include simultaneously maintaining a start-up mode in an upper portion of the dissolution column that favors high efficiency of ozone mass transfer into the acidic pressurized water and a steady state mode in a lower portion of the dissolution column that favors a high concentration of dissolved ozone in the acidic pressurized water coexistent in the body of the acidic pressurized water, wherein an ozone concentration gradient is formed along a height of the body of the acidic pressurized water.