Trace contaminant removal with nanofiltration
The occurrence and fate of both organic and inorganic trace contaminants in the aquatic environment has long been recognized as an important issue of public health and environmental concern. A wide range of trace organics, both synthetic and natural, have been detected and identified as important contaminants in sewage and effluent impacted water bodies including surface and groundwater. Trace inorganic contaminants can also occur naturally in groundwater under certain geochemical conditions. Trace contaminants are defined as chemicals of concern to human health and the biotic environment due to a combination of their physicochemical toxicological properties. In the aquatic environment, they are present at trace levels, usually in the μg/L range or less. From a toxicological point of view, low concentrations of trace contaminants in ground and drinking water may not always be harmful to humans (in fact in most cases health effects are unknown at this stage), but they are undesirable in regard to the “precautionary principle” . Although trace contaminant removal is an issue facing various industries, this chapter focuses mostly on the water purification process. The role of nanofiltration (NF) in water and wastewater treatment, occurrence of trace contaminants and their environmental implications, separation processes and a review of current studies are presented in this chapter.