A cartridge filter is a great option for whole house sediment removal purposes. They are easy to install, inexpensive to purchase, generate no wastewater and they don’t need electricity to work. The only real disadvantage to a cartridge filter is that the sediment will eventually block the membrane pores. This will cause a pressure drop that will lead to a decline in water pressure throughout your home. This situation can be avoided by replacing the cartridge filters regularly, and this is simple to do. Let’s take a close look at cartridge filter so that you can choose the right one to suit your needs.
A cartridge filter is easy to change, and certain pleated surface cartridges can even be cleaned and then re-used. There are many sizes and types of filter cartridges available on the market for sediment removal. Generally, the choices fall into two broad cartridge filter types; they are depth filter cartridges and surface filter cartridges.
The Depth Filter Cartridge
This type of filter cartridge could have either a wound up a string like or a “melt-blown” internal structure. Both designs work by trapping larger particles on the surface and then holding smaller particles down near the core. This is a good filter design to use when particles in a wide variety of sizes need to be filtered out of the water. A depth filter can remove and hold more sediment before a pressure loss occurs compared to a surface filter cartridge unit.
Dual Grade Depth Filters
If the sediment is very fine, perhaps in the 1-5 micron range, a dual grade filter may be needed. This filter design has a 50 micron rating on the outer surface and a 5 micron rating on the inside. This makes the dual grade depth filter even more effective at filtering a wide variety of differently sized sediment particles. This design could remove as much as 2.3 times more sediment compared to a standard depth filter cartridge.
The Surface Filter Cartridge
The filtration in these filters takes place across the filter membrane surface. Sheets of material, such as Teflon, nylon or polypropylene, are bonded and pleated into shape to make a higher surface filtration area. Any contaminants are trapped on the surface of this sheet, over time a layer is formed that even improves the filtration process for a while. Eventually, a pressure drop will increase, the filter cartridge will need to be thoroughly washed and then it can be reused.
Surface Filtration in Detail
A whole house filter housing will allow the homeowner to experiment with a variety of cartridge filters to find the one they like best. Many experts recommend pleated surface filters between 30-50 microns in size for effective pre-filtering.
A pleated surface filter can act as a course pre-filter in the 30-500 micron range, and it can even be used as a sub-micron filter for finer consistent filtration. In fact, there are pleated surface filter cartridges available at 0.04 microns in size for pharmaceutical and semiconductor water filtering purposes.
A pleated surface filter usually has a far higher filtration area compared to a depth filter. The pleated filter is designed to compensate for a lack of depth; the filtration area could be as high as 11 sq ft in a standard 10”x2.5” filter cartridge.