摘要 |
A biological treatment technique in which waste water or other liquid to be processed is conducted downwardly through a bed of carrier particles to which biological material is attached. In a system for carrying out this technique, the bed (13) is suspended within a vertical reactor (10) by the liquid, the carrier particles having a specific gravity that is less than that of the liquid. The liquid is introduced into the upper end of the bed (12) to pass through the particles and exits through the bottom of the reactor (21). Excess biological material found on the particles is removed therefrom (16L). |