Upflow ozone contactor for quenching residual ozone

An upward ozone contacting tank is provided to supply raw water from bottom to top in order to remove residual ozone in a water purification process, thereby preventing a loss of water head within a filtering material. An upward ozone contacting tank comprises the following units. An upward contacting chamber(104) is arranged between a reaction chamber(103) and an outlet(110). A porous plate(11) is arranged across the upward contacting chamber. A filtering material(12) which is oxidized with carbon and placed on the porous plate removes residual ozone. One or more gate unit(10) is located in a lower part of a panel. The gate unit controls the flowing rate of raw water which flows into the upward contacting chamber.