Reverse-osmosis concentration organic compounds

In terms of organic rejections, PEC-1000 membrane shows the highest values among all commercial reverse osmosis membranes. Table 5.6 lists rejection data for a variety of organic compounds. In most cases, these were measured at solute concentrations of 4 to 5%, which represents a severe test protocol. Organic solute rejections determined for other commercial membranes were typi-... 

Processes available for the extraction of natural organics from waters include vacuum distillation, freeze-drying, freeze concentration, co-precipitation, ultrafiltration, reverse osmosis (RO), solvent extraction, sorption, anion exchange, and non-ionic macroporous sorbents (Aiken (1985)). Many of these methods include chemical treatment that may alter the HS characteristics. In this section, the most common methods for the processing of large samples will be described. An important issue in NOM extraction is the recovety of organics. Minimising the loss of certain fractions, such as small compounds which are difficult to treat, is also important. 

Leachate can be treated by a variety of physical processes. In some cases, simple density separation and sedimentation can be used to remove water-immiscible liquids and solids. Filtration is frequently required and flotation can be useful. Leachate solutes can be concentrated by evaporation, distillation, and membrane processes, including reverse osmosis, hyperfiltration, and ultrafiltration. Organic constituents can be removed from leachate by solvent extraction, air stripping, or steam stripping. In the case of volatile organic compounds in leachate (VOCs), care must be exercised to prevent excessive escape to the atmosphere, thus creating an air pollution problem as the result of leachate treatment. 

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