| 摘要 |
<p>The tank is of the type in which the water is agitated by an aerator, e.g. a rotary impeller, The aerator is surrounded by a partition enclosing an inner zone of liq. and an annular outer zone of liq. is held between the partition and the outer wall of the tank. A passage is formed through the partition at or near surface level and another passage at or near tank base level. The aerator creates a flow of liq. through a passage from the inner zone to the outer zone. The transferred liq. circulates around the outer zone before finding its way back to the inner zone via a different passage. The passages are pref. formed and positioned and related to the direction of rotation of the aerator so that flow is outwards from the inner zone via upper passages and inwards from the outer zone via lower passages. The tank is pref. of vertical cylindrical form with a coaxial, vertical cylindrical partition around a central aerator. The treated effluent can be equal to that delivered from the conventional 3-stage process, i.e. free of ammonia and probably nitrates too. For such effective treatment the new plant is very compact and inexpensive.</p> |
