New underdrain design for rapid gravity filters

摘要

The LP Block~TM a low-profile underdrain for rapid gravity filters,is the latest offering from Severn Trent Services.LP Blocks are made from high density poly-ethylene (HDPE),with a porous top plate 25 mm thick constructed of HDPE beads.This is in contrast to the deep layers of gravel normally seen on a header and lateral type system.