ABSTRACT
Arsenic (As) is very toxic to human health and its slow poisoning is observed even in the scalp hair samples of affected people (Uddin et al., 2006). A variety of health hazards is observed due to its long term exposure, including several types of cancer, cardio vascular disease, diabetes, neurological disorders (Abernathy et al., 2003; Kapaj et al., 2006). Therefore, considering the toxicity of As, several national and international agencies including the World Health Organization has reduced the guideline value from 50 to 10 µg L−1. However, a few countries still follow the higher maximum contaminant level (MCL) (50 µg L−1) (Nriagu et al., 2007). The MCL of the affected countries varies due to lack of appropriate treatment technologies with respect to different socio-politico-economical conditions (Roy et al., 2008). Therefore, an effective treatment technology seems to be essential in order to reduce the As concentration from drinking water. Various treatment technologies have been used till now, including oxidation, coagulation/flocculation, adsorption and membrane based technologies to mitigate the problem (Mondal et al., 2013). A better understanding of these treatment technologies is essential for further research. In this chapter, an overview on traditional technologies (oxidation, coagulation/ flocculation, and adsorption), including membrane pressure driving processes, together with a more detailed discussion on innovative membrane-based technologies, such as forward osmosis (FO) and membrane contactors (MC), is reported.
