both used to remove
particles such as sand or small gravels; not effective
in removing silt, clay or algae. Secondary screen or
mesh filters are used after media filters to collect any
particles of sand washed from them.
Mesh and
Screen
Multi
Media/Sand filters
consist of layers
of coarse to fine material such as gravel and sand, or
crushed granite, silica or sand. They are used to trap
finer material in suspension, like silt and clay.
