The removal of sediment and other suspended particles is critical to the clean operation of any system. Even cooling water should be filtered to remove sediment and avoid fouling piping or heat exchangers. Of course, removing sediment and small particulates is key to the efficient, cost effective operation of any purified water treatment system. Performed using depth filtration media, this clarification and prefiltration processes preserve system performance and can reduce operating costs.
Many water treatment systems involve water passing through resin beds (either softening or deionization). Resin can break down over time and particulate can escape resin vessels, so filters are used to trap the particles and prevent their contamination of downstream processes. Again, depth filtration is most often used for this function.
After primary treatment, water may be stored in a tank system for distribution. That tank may be part of a distribution loop that continuously circulates the flow or just a surge tank to feed intermittent uses. In either case, filtration acts as a critical contamination control step for protecting your water from particle contamination from particles ranging in size from dust to particles as small as 0.03 microns.
Filtration in Distribution Loops
To assure that the water in the distribution loop remains pure, filters are used to remove contaminants that might enter the system or particles that are shed by system components. These filters may be used for bioburden reduction, for sterilizing filtration or for ultrafine particle removal. Membrane filters with pore sizes of 0.22 μm, 0.10 μm, or 0.03 μm are usually used for these applications. Filter membranes with a positive charge may be chosen because of their ability to remove charged particles and molecules, including pyrogens that are smaller than the pore size of the membrane.
Point-of-Use Filters (POU)
As with the filters in distribution loops, membrane filters with pore sizes of 0.22 μm, 0.10 μm, or 0.03 μm are usually used for POU applications for bioburden reduction, for sterilizing filtration or for ultrafine particle removal. Water temperature has an effect on the choice of filter configurations. Polyethersulfone and nylon 6,6 membranes are effective in temperatures when water is a liquid, even if the temperature is slightly above the boiling point. However, standard filter configurations only operate continuously at temperatures up to 80°C. The standard filter "hardware", the polypropylene cage, core and supporting structures around the membrane, can be affected by temperatures over 80°C. Critical Process Filtration has enhanced hardware that will remain integral at temperatures up to 95°C.
Contact Critical Process Filtration to learn how we can help you find cost effective filtration solutions for your system.