Rigid filter elements, related apparatus and methods

摘要

Modules for use in forming rigid filter beds by laying a plurality of the modules upon a planar base comprise a bottom grid unit to the top of which is fixed a rigid, porous layer. The grid unit has several intersecting series of strip elements with structured portions to promote drainage of liquid through and away from the porous layer. The grid unit may also include portions to insure interlocking of the top porous layer thereto.