Small waste water treatment plants, comprising one or more chambers

摘要

Waste water treatment plants (I), particularly small ones, have one or more chambers and device (2) for retaining sand and flotsam,. The device (2) is connected to adjacent chamber(s) (11, 12, 13) via perforated plate wall (3) and an underflow weir (4). (I) have one or more biological reaction chambers (11, 12, 13) aerated by screw aerators (21, 22, 23) and a post-treatment device (5), which may be equipped with pumps. The operating water level of the pump lies above that of the biological reaction chambers. (I) also comprise a device for removing and collecting excess sludge (14), in conjunction with a directing and underflow weir (10) for retention of scum, if necessary. Also claimed is a process for clarifying waste waters in which, after being subjected to flotsam and sand retention, the latter passes into one or more aerated chambers and is then pumped to the post-treatment stage. The water level of the post treatment stage is higher than that of the aerated chambers.