Water. Desalination + reuse
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TECHNOLOGY | 26 | Desalination & Water Reuse | February-March 2016 likely that the FO field will be characterized by a diverse portfolio of application niches for some time to come, and it is unlikely that there will be a dominant offering as in RO. However, the niches could individually be very attractive and ideal for specialized business units with unique intellectual property tailored to exploit the opportunity. PaTENTs It is interesting to see some of the players that hold significant intellectual property positions as reflected in the numbers of patents, relating to FO. Figure 1. Annual number of forward osmosis research papers published. Source: BlueTech IP Watch. The figures indicate clearly that there has been a steady increase in the number of published research papers in the area of FO over the past five years, with a 60% increase between 2012 and 2013 (Figure 1). It is clear also that the number of FO patents granted has been increasing consistently year on year between 2009 and 2014 (Figure 2). The patents are coming from a diverse range of sources including Oasys (7%), Yale University (7%), National University of Singapore (7%) and University of Reno Nevada. This is certainly an indication that there is potential for intellectual property generation in this area, and that universities and private companies see value in building intellectual property positions in FO. PrOmisiNG siGNs FO is a promising technology but presents a difficult set of technical hurdles and has so far failed to make a significant commercial impact. However, recent interest has grown sharply both from academia and several specialized companies, and there has been good progress in addressing the challenges. Several attractive application niches are now developing which could present an ideal opportunity for diverse product offerings from specialized suppliers. leaders in RO membranes, are visibly absent from the FO world. BlueTech was keen to explore the reason for this. What was the perspective of the major players on FO: did they view it as a curiosity or a technology with real potential? The incumbents in any industry, and this is also true of RO, are generally focused on sustaining innovation that improves on the established technology. Discontinuous or disruptive innovation tends to come from new entrants. BlueTech aimed to delve into what was the current situation in FO technology, asking: for which applications might FO make sense? And will it remain a niche technology or eventually affect the mainstream market? EarLY sTaGE There are many variants of FO depending on the objective of the separation. The osmotic driving force can be augmented with pressure as in pressure-assisted osmosis, which has been considered to boost the competitiveness of seawater desalination, and pressure retarded osmosis, in which the energy of the osmotic gradient is harvested. Despite years of development, the technology has only recently been considered seriously for commercial development and uptake is still in its infancy. Examples of the technology that have progressed from the research phase are largely still at the pilot or demonstration scale stage. And, in terms of market adoption, FO is the domain of innovators. However, a review of recent conference papers shows that interest in FO is acute, with many papers from academic researchers and newly formed membrane and system suppliers providing multiple sessions on this technology. So what are the challenges faced by FO as it strives towards commercialization? FO has been considered for the full suite of applications in water and wastewater in which dissolved components need to be separated from the bulk liquid. However, a general concern in most applications considered is the problem of reverse salt diffusion. This leads to a loss of the osmotic agent and a potentially unwelcome contamination of the feed/product stream. Potential embodiments for FO have included large-scale systems and, at the other end of the spectrum, point-of-use devices. Despite many years of research and considerable ingenuity in the development of both products and processes, a straightforward broad-based implementation of FO still remains a distant goal. This is partly due to the difficult technical challenges of FO, but also due to the process complexity and cost inherent to many FO schemes. However, FO has been found to be cost-effective at the margins of the application envelope where feeds are too challenging for RO. The current market baseline is therefore small and erratic, and it is not possible to predict future growth prospects confidently in general terms. However, high growth potential is possible for some promising niches. FO tends to be used for more difficult applications, or as a hybrid process in tandem with RO. At the margins, RO may not be able to perform effectively. An example would be brine concentration, for which pressures in RO would exceed the membrane tolerance. FO is ideally suited for these feeds and the highly concentrated challenge provides strong driving forces. An example of a successful hybrid would be to use seawater as a draw solution for FO working with a wastewater feed. RO would then treat the diluted seawater to allow the draw solution to be recycled. The range of FO applications has meant that very different commercial products have been developed to handle them. It is Figure 2. Annual number of forward osmosis patents granted. Source: BlueTech IP Watch.