High efficiency reverse osmosis applications

High efficiency reverse osmosis (HERO) is a patented process (US Patent 5925255, Debasish Mukhopadhyay, 1999) originally developed to treat high silica water for the microelectronics industry. Its use has expanded to power and zero liquid discharge applications (see Chapter 15.4.3). Features of the process include ... 

The high efficiency reverse osmosis (HERO ) process is used for enhanced rejection of silica and boron in SWRO and HPW applications [30]. The process is capable of high rejection of silica, TOC and boron with RO. Further, organic cleaning is minimised at high pH levels, akin to operating the RO unit in a continuous cleaning mode. 

Reverse osmosis, like freezing, is a commonly used desalination process 178, 509). The theory and applications have been described (5/0) and reviewed for pollutants 511). The efficiency of separation (which can be as high as 99.5%) increases as the concentration of solute decreases, but decreases as the concentration factor is increased (5/2). The application of reverse osmosis to the preconcentration of inorganic solutes for analytical purposes has been neglected. Some work with organic 513) or biochemical solutes 514) has been reported. Reverse osmosis has been used to concentrate radioactive waste (5/5). The addition of surfactants (2 x 10 M sodium hexadecylsulfate) to aqueous radioactive solutions has increased the separation efficiency from 30-35% to 98% for radioactive isotopes (5/6). 

In the case of high pressure applications such as reverse osmosis, and nanoflltration, a turbine may be utilized to recover part of the energy. A liquid turbine is a device in which the liquid does work on the turbine blades at the expense of its kinetic energy. Hence, the process is expansion of a liquid from high pressure to low pressure in which work is produced. The process is in fact the opposite of compression and the same equation can be derived for the work only the efficiency q is now in the nominatot... 

Another popular method which gives a high-quality water is reverse osmosis (RO), often called ultrafiltration or hyperfiltration. Though often considered too expensive for industrial use, RO has found extensive applications in domestic water supplies. The production of highly efficient osmotic membranes has made RO competitive with distillation for the production of salt-free water. RO does not, however, remove volatile organic compounds (VOC) from the water supply. Treatment with granulated activated carbon (GAC) can be very effective for this purpose (see Chap. 16 and Appendix C). 

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