| 摘要 |
<p>A filtration apparatus comprising: a filtration column having a perforated hollow member mounted inside it to define a filtrate zone therein and a filtering zone in the volume of said filtration column external to said hollow perforated member, wherein a portion of said filtering zone is filled with filtering grains up to a level sufficient for entirely covering said hollow perforated member, and wherein said filtrate zone is adapted to receive a filtrate obtained from passage of a stream of raw-water introduced via the upper portion of the filtration column and passed through the filtering grains and the perforations of the hollow perforated member.</p> |
