1) Water treatment 
[water treatment] Filters are employed to remove particles from liquids. Water treatment filters that can be backwashed include rapid sand filters, pressure filters and granular activated carbon (GAC) filters. Diatomaceous earth filters are backwashed according to the proprietary arrangement of pumps, valves and filters associated with the ...
the process of cleaning a rapid sand or mechanical filter by reversing the flow of water.
the process of cleaning a rapid sand or mechanical filter by reversing the flow of water.
The washing of dyed or undyed wool sliver before or after gilling and/or combing.
Reversing the flow of water back through the filter media to remove entrapped solids.