A multi-media filter
A multi-media filter is primarily used for the removal of turbidity and suspended solids as low as 10-20 microns. Inside a sand-anthracite filter is a layered bed of filter media. The bed is graded from bottom to top as follows:
1st layer=gravel support bed
2nd layer=2mm filter sand
3rd layer=fine filter sand
4th layer=anthracite
Having the filter media graded this way enables the sand anthracite filter to run for longer times before a backwash is necessary. |
 |
| Mpa |
≤0.6 |
(mg/L) |
0.5~3 |
| C |
5~50 |
(L/M2.S) |
|
15~18 |
| m/h |
8~12 |
|
10~12 |
| mg/L |
≤20 |
|
12~16 |
|
An activated carbon filter
An activated carbon filter as it is sometimes called, is primarily used for its absorbent capacities and the removal of dissolved organics.Tastes and Odours: an activated carbon filter will also remove chlorine and other halogens and low-molecular-weight substances (below 100mm).
Activated carbon filters are very prone to infection from bacteria and can become somewhat of a breeding ground. All activated carbon filters must be periodically sterilised to avoid bacterial growth and contamination.
An activated carbon filter is backwashed frequently with a reverse flow wash but will eventually exhaust, unless fitted after a reverse osmosis plant or after ultra-filtration. Activated carbon can be re-activated once completely exhausted but this requires a heat treatment process which cannot always be undertaken on site and, owing to its relatively low cost, is usually just replaced |
 |
| Mpa |
≤0.6 |
mm |
1500~2000 |
| C |
5~50 |
mg/L |
5 |
| m/h |
8~12 |
mg/L |
2 |
| mg/L |
≤5 |
|
|
|
| |
 |
