| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent the involution of oxygen and to hold dissolved oxygen to a low level while preventing the lowering of treatment capacity. SOLUTION: A water treatment apparatus has a first sedimentation tank (pretreatment tank) 1, a denitrification tank (carrier packed tank) 2 and an air lift pump tank (pump tank) 3. The denitrification tank 2 and the air lift pump tank 3 are partitioned by a screen, mesh or wedge wire not permitting a carrier to pass and a backwashing device 5 is provided to the lower part of the denitrification tank 2. By this constitution, the water sent into the bottom part of the denitrification tank 2 from the first sedimentation tank 1 is returned to the first sedimentation tank 1 along with a suspended substance after backwashing.</p> |
