Presented is a liquid filtering apparatus and method that overcomes the
disadvantages encountered with prior bed filtration systems by providing
a filtering apparatus that incorporates a super-buoyant filter medium
having a specific gravity very substantially lower than that of the
process liquid being filtered. This feature enables a majority of the
medium to float on top of the process liquid. Due to the significant
differences in specific gravity between the media and the process liquid,
super-buoyant media produce a highly advantageous means of naturally,
gravimetrically separating both clean and contaminated filter media and
process liquid into separate "phases". Under normal filtering operation,
the filter media is contained within a filter housing by a bed support
near the top of the filter housing, and particulate material is filtered
from a process liquid that passes through the housing. To regenerate the
filter media, the housing is drained and a nozzle creates a backwash
spray that washes the particulate material from the filter media. During
the backwash process, the filter media rises past the nozzle as the level
of the backwash liquid in the housing rises, so that the entire filter
media is regenerated.