Water. Desalination + reuse
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TECHNOLOGY | 30 | Desalination & Water Reuse | August-September 2015 plants developed by PWN and Metawater (>100,000 m 3 /d) becoming operational in 2014. Growing applications of ceramic membranes include drinking water treatment, metal/radium removal from groundwater, oil/water separation in industrial processes, and pool water recirculation. Historically the primary barrier to ceramic membrane utilization is the much higher capital cost compared with polymerics with ceramics requiring two-to-three times greater outlay. The process advantages of ceramic membranes over polymerics, which include greater pH resistance, higher flux rates, and longer membrane service life, have enabled suppliers to carve out a few niche markets. Among these growth areas, drinking water treatment, produced water treatment, oil/water separation in industrial processes, commercial pool water recirculation, and radium removal from groundwater stand out (table 1). DriNkiNG waTEr TrEaTmENT The robustness of ceramics compared with polymerics has led to many suppliers targeting industrial and difficult-to-treat waters, however the largest market by volume of sales is drinking water treatment. In North America and Europe, UF membranes – primarily polymeric membranes – have found considerable market success in drinking water treatment because the membrane is a physical barrier for microorganisms such as cryptosporidium. Outbreaks of cryptosporidium contamination in the early 1990s in Nevada and Wisconsin made removal of disinfection-resistant microbes a critical priority for municipalities. Recent large-scale drinking water installations completed by PWN (Metawater/ NGK) indicate that ceramics are beginning to show life-cycle cost competitiveness with polymeric membranes. A principal challenge when evaluating ceramic life-cycle cost to date was validating suppliers' 15-20 years service life claims for the membranes. Commercial installations by companies including Purifics have now been active since the early 1990s, many of which are still using the original membrane module. The validation of this claim, combined with Metawater's decreasing module capital cost which it estimates at US$ 100/m 2 , and the market's growing familiarity with the technology, indicate strong potential for future growth in drinking water treatment. A recent project tender for an upgrade to the 26,500 m 3 /d Butte-Silver Bow Public Works Department's Basin Creek water treatment plant revealed that the proposed Metawater ceramic monolith system showed a better 20-year life-cycle cost than the three competing UF system proposals. Two of the proposals were disqualified on the grounds of compliance failures in the scope, but the other accepted bid was more than US$ 0.9 million more than Metawater's US$ 8.7 million tender. The inclusion of a specific request of the project owners for a warranty for the system may have contributed to Metawater's cost advantage. Recently completed large-scale drinking water projects include a 171,000 m 3 /d plant in Coahoma, Japan; the 120,000 m 3 /d Andijk Markets for ceramic membranes Application frequency Suppliers active Drinking water treatment Majority of installations and installed capacity (>50%) of ceramic membranes Metawater (PWN), Purifics, ItN Nanovation, Liqtech, Likuid Groundwater treatment Few installations Purifics, ItN Nanovation, Meidensha industrial process water/wastewater treatment Many installations (>30), much smaller in size (100- 1000 m 3 /d) compared with drinking water Tami, Atech, Liqtech, Likuid Commercial pool water treatment Few installations, mainly in northern Europe Liqtech Produced water treatment Minimal installations (<10) Veolia, Liqtech, Cerahelix Table 1. Applications for ceramic membranes to date. III plant in the Netherlands, and a 37,000 m 3 /d plant in Colorado. In late 2014, a 90,000 m 3 /d project was tendered in Plymouth, UK. OiL aND PrODuCED waTEr The added fouling resistance and ease of cleaning ceramic modules has fueled strong speculation that produced water treatment and oil/grease removal represented a strong market opportunity for ceramics. Yet installations in the oil and gas industry have been few, with Veolia (CeraMem) the most active company in this area. Veolia claims to date, to have completed three installations in the capacity range 300-400m 3 /d after seven years of aggressively targeting the market. Liqtech has also been active in this market, with an installation for a North Sea offshore oil platform and has recently won a contract to supply ceramic membranes for enhanced oil recovery. Given the challenges encountered when commercializing new water technologies in the oil and gas sector, this can be viewed as a minor success. However the recent decline in oil prices has placed great strain on Canadian oil sands and US shale oil market segments which are targets for ceramic membrane companies. So while growth potential in the oil and gas sector appears limited it will continue to be a target for ceramics. muNiCiPaL wasTEwaTEr Ceramic membranes have made little penetration to date in the municipal wastewater treatment market. But two notable installations – one in Australia and the other in Singapore – sustain the lower lifetime cost promise of ceramics compared to polymerics and offer further indicators of ceramics' potential in wastewater treatment. The 2013 PWN reuse pilot project in Melbourne, Australia, combines ozone treatment and ceramic membranes. Preliminary results for the project indicate reduced lifecycle costs for the ceramic system as compared to polymerics due to the increased flux rate (150-200 lmh). A pilot project in Singapore by Japan's Meidensha in collaboration with Singapore PUB utilizes a ceramic anaerobic (USAB) membrane bioreactor (MBR) to reclaim wastewater for reuse. Following a year of piloting at the 4,546m 3 /d facility, Meidensha was awarded a contract to construct a 18,184m 3 /d ceramic MBR at Singapore PUB's Changi Water Reclamation Plant. The larger scale facility being constructed by Meidensha adds strength to the case for the effectiveness of ceramics for