| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a filter medium which can be used for the formation of an anaerobic filter bed and an aerobic filter bed, can be manufactured at a low price, can surely retain an anaerobic area inside even when used under an aerobic environment, and can efficiently carry out a denitrification action. <P>SOLUTION: In the filter medium for fixed bed in a sewage treatment tank where tabular filter media are parallelly disposed in the sewage tank using microorganisms so as to leave a space of 40 mm to 100 mm between them for carrying out both or either of removal of organic substances in sewage and denitrification, the tabular filter medium is made of an open-cell foam having a thickness of 10 mm to 100 mm, and the number of bubbles in the open-cell foam is 10-40 per inch. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
