摘要 |
<p>An effluent collector (1) precedes the mechanical purification stage. The mechanical purification stage possesses a preliminary purification contrivance (2) such as a rake, a sand-trap tank (3) with aeration equipment (4), and subsequent intermediate clarifier equipment (5) with a sludge offtake (6). Before erection of the subsequent biological purification stage (8) it can be independently operated by itself as a basic constructional stage, and after erection of the subsequent biological purification stage it can be operated in combination with the latter. <IMAGE></p> |