The reverse osmosis (RO) segment will comprise more than 50% of the total. This is the latest finding in the continually updated RO, UF, MF World Market published by the McIlvaine Company.
Cross-flow membrane filtration differs from full low filters in that only a portion of the liquid is filtered. The remainder continues across the membrane and is discharged or recycled. The advantage of the cross-flow technique is its ability to resist plugging. The disadvantage is the loss of product. In the case of desalination, the loss is not significant. However, for juices or pharmaceutical products there is a need to recycle the lost liquid.
There are four efficiency levels depending on the pore size in the membranes. Reverse osmosis is the most efficient. Nanofiltration is next. In the McIlvaine analysis, nanofilration revenues are included with ultrafiltration which is the next most efficient. Microfiltration is least efficient, but still compares well with granular media filters and other non-membrane alternatives.
There is presently a US$1.3 billion market for replacement RO membranes. Most of the market is in desalination of seawater. However the electronics, pharmaceutical and chemical industry are also major purchasers.
Ultrafiltration is utilized as pre-filtration for RO systems but also by itself for many applications. The food industry is using higher temperature resistant ultrafilters on processes where cooking and similar processes are involved.
Microfiltration is also used for pre-filtration with RO systems. Another major use is in municipal drinking water plants. It has proven more efficient than the granular media filters which have been traditionally used.