Removal of Emerging Trace Organic Chemicals by Forward Osmosis

Abstract

Occurrence of emerging trace organic chemicals in sewage, secondary treated effluent and sewage impacted water bodies is a major human and environmental health concern. The full extent of the impact of these emerging trace organic chemicals on human health is still a subject of intense scientific debate. However, some of these chemicals have already been shown to cause serious adverse effects on a range of organisms at environmentally relevant concentrations (Snyder et al. 2003; Carballa et al. 2004; Schwarzenbach et al. 2006; Basile et al. 2011). Forward osmosis (FO) can potentially provide a new perspective to the removal of these emerging trace organic chemicals. In FO, a water-permeable and salt-rejecting membrane is placed between a feed solution and a concentrated draw solution with high osmotic pressure. Extraction of water is driven by the osmotic pressure difference and at the same time, it couples the rejection of the salt and contaminants in the feed solution by the FO membrane. To produce freshwater, FO is usually combined with pressure driven membrane processes, such as NF and RO (Hoover et al. 2011; Yangali-Quintanilla et al. 2011; Shaffer et al. 2012), or thermal processes, such as conventional column distillation (McCutcheon et al. 2005; McGinnis and Elimelech 2007) and membrane distillation (MD) (Cath et al. 2005; Martinetti et al. 2009). As a result, elucidating transport mechanisms of these emerging organic chemicals through an FO membrane is fundamental and critical for the further development and deployment of FO. In this chapter, we provide a comprehensive review on the current state of knowledge on the rejection of emerging trace organic chemicals by FO processes. The review begins with a brief introduction of the occurrence of emerging trace