NOVELTY - A wastewater treatment apparatus comprises denitrification reactor and bubble tower. The denitrification reactor (10) in which carrier (a) (25) is filled in state that sulfur-oxidizing bacteria are immobilized, and removes nitrate in raw water at anaerobic conditions. The bubble tower reactor (50) into which treated water (c) flows after denitrified in denitrification reactor, and carrier (b) (65) is filled in state that sulfur-oxidizing bacteria are immobilized to remove hydrogen sulfide generated from denitrification reactor.    USE - Wastewater treatment apparatus is used for sewage water.    ADVANTAGE - The Wastewater treatment apparatus removes nitrate in wastewater and hydrogen sulfide generated in nitrate removal process by using heterotrophic sulfur-oxidizing bacteria. The method effectively treats wastewater and has high efficiency.    DETAILED DESCRIPTION - A wastewater treatment apparatus comprises denitrification reactor and bubble tower. The denitrification reactor (10) in which carrier (a) (25) is filled in state that sulfur-oxidizing bacteria are immobilized, and removes nitrate in raw water at anaerobic conditions. The bubble tower reactor (50) into which treated water (c) flows after denitrified in denitrification reactor, and carrier (b) (65) is filled in state that sulfur-oxidizing bacteria are immobilized to remove hydrogen sulfide generated from denitrification reactor. The denitrification reactor comprises a component (d) (11), porous panel (e) (13) having several through holes and reaction portion (f) (20) which is divided by porous panel, and in which carrier (a) is filled. The porous panel comprises upper porous panel (13a), intermediate porous panel (13b) and lower porous panel (13c). The reaction portion includes upper reaction portion (20a) and lower reaction portion (20b). The bubble tower reactor includes a component (g) (51), porous panel (h) (53) having several through holes, reaction portion (i) (60) which is divided by porous panel (h) , and in which carrier (b) is filled, and air supply unit connected to bottom portion of component (g) to generate bubbles in first treated water flown into component (g). An INDEPENDENT CLAIM is included for treating wastewater which includes flowing raw water into denitrification reactor filled with carrier (a) is fixes sulfur-oxidizing microorganism, and removes nitrate in the raw water at anaerobic condition. Then hydrogen sulfide is removed from the processing water in bubble tower reactor. A pearlite (in weight parts) (50-70), sulfur (in parts per 100 parts of resin), water (200-400) and calcium hydroxide (30-50) are mixed to obtain carrier (a), and calcium hydroxide (80-120), water (200-400) pearlite (in parts per 100 parts of resin) to obtain carrier (b). The obtained carriers (a,b) are added to bubble tower reactor and then sulfur-oxidizing microorganism is mixed during processing water is denitrified in denitrification.    DESCRIPTION OF DRAWING(S) - The drawing shows water treatment apparatus.    Denitrification reaction tank (10)    Component (11,51)    Porous panels (13,53)    Upper porous panel (13a)    Intermediate porous panel (13b)    Lower porous panel (13c)    Reaction portion (20,60)    Upper reaction portion (20a)    Lower reaction portion (20b)    Carriers (25,65)    Bubble tower reactor (50)