| Abstract: |
Reverse osmosis (RO) has become a common deionization (DI) technique widely used in treating make-up water for the microelectronics, pharmaceutical, and power industries. While the make-up water treatment process is different for each of these industries, RO is the primary DI step in a multi-step treatment train designed to produce very high-purity water.
As with any water treatment technique, successful application of RO depends on several factors that can roughly be defined as mechanically- or membrane-based. Mechanical issues can be traced to deficiencies in hardware, such as valves and instrumentation. Membrane-based issues include fouling, scaling, and degradation of the membranes themselves.
Membrane fouling, scaling, and degradation can be complex issues that temporarily or permanently alter the condition of the membrane, which, in turn, affects performance of the RO system and ultimately, the entire make-up water treatment system. Membrane fouling and scaling can result in high operating pressure for the RO system. If left untreated, these conditions can lead to a decrease in productivity by the RO system. Membrane scaling and degradation can bring about a decrease in the quality of water produced by the RO system. Furthermore, membranes that are fouled, or scaled require more frequent membrane cleanings resulting in more downtime and in increased operating costs. Fouled, scaled, or degraded membranes need more frequent replacement, further adding to the operating costs for the system. |