Hollow Fiber Cross Section
Sand filters and media filtration have been around since the 1800s. However, as with most conventional filtration methods, they require consistent raw water quality to deliver quality effluent, which is not always possible. They also don't provide an absolute barrier. Traditional media filters typically remove particles to down to about 0.5 microns.
Ultrafiltration (UF), however, does not suffer from those limitations. This technology uses a membrane barrier to exclude particles as small as 0.01 microns, including bacteria, viruses and colloids, meeting increasingly stringent water quality standards around the world providing a stable, reliable and consistent water quality.
- High and consistent product quality measured by turbidity (NTU), silt density index (SDI) or log removal value (LRV).
- Tolerance to feed water quality upsets.
- No use of pretreatment chemicals (polymer, coagulant, pH adjustment) and associated costs for sludge disposal.
- Small footprint and less weight than media filters.
When used as a pre-treatment for reverse osmosis (RO), UF also helps reduce fouling of RO membranes, which can lead to:
- Reduced chemical cleaning frequency and consequently, lower operating costs and downtime.
- The potential to operate RO at higher flux, with fewer membranes and vessels – leading to lower capital cost for the RO system.