Filtration Water then flows into the filter beds where layers of anthracite (coal), sand and gravel remove any remaining impurities in the water.
(Filtration Water; flows; into the filter beds; T:then) (sand and gravel; remove; any remaining impurities in the water; L:the filter beds)
Filtration Water sand and gravel
flows remove
into the filter beds T:then
any remaining impurities in the water L:the filter beds