| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a filter medium capable of being directly thrown into the water, selectively positioned at the depth where there are many colonies of microorganisms effective in purifying the water of rivers, lakes, marshes, ponds, etc., and highly stable against the water stream. SOLUTION: A filter medium 7 formed by packing a bisque 2' used as a member having >=1 sp.gr. and a float 3 in a basket-shaped container 1 and a filter medium 6 prepared by packing the bisque in another basket-shaped container are connected through a rope-shaped connecting member 5, and further the filter mediums are connected to a weight 4. The filter medium thus obtained has efficient purifying capacity and high stability against the water stream.</p> |
