| 摘要 |
<p>1,206,601. Treating sewage. N. WADDLETON (Dorr-Oliver Inc.). 2 Oct., 1967, No. 44688/67. Heading C1C. The effective biological aeration of sewage to remove phosphorus is preceded by a chemical precipitation of a calculated amount of phosphorus to leave only that phosphorus which can be efficiently dealt with by the biological process.</p> |
