Water Journal : Water Journal June 2013
WATER JUNE 2013 112 Water Business CHANGING THINKING ON WASTEWATER RECYCLING There are major challenges in converting wastewater to water that can be bene cially reused. The treatment that has been generally accepted to date is a combination of multiple treatment technologies. In most cases, this has included membrane micro ltration and reverse osmosis followed by oxidation. This multiple barrier approach is costly when treatment of most surface water can be achieved with membrane ltration alone. Recognising the delicate balance between the high cost and potential bene ts of ceramic membranes for water treatment applications, PWN Technologies, the R&D offshoot of PWN (the water utility of North Holland), decided to focus research on developing a cost-effective con guration for ceramic membranes. The resulting CeraMac® ceramic membrane treatment system has reduced the cost of the equipment and offers more treatment capacity in a smaller space. In 2010 the company set up an Asia Paci c of ce in Singapore and, following an 18-month demonstration of CeraMac®, PUB -- Singapore's national water agency -- is now exploring whether ceramic membrane ltration can be included as an option as part of the upgrading works at Choa Chu Kang Waterworks (CCKWW). In Australia, an international team of experts led by Victoria University, and funded primarily by the Australian Water Recycling Centre of Excellence (an Australian Commonwealth Government initiative) with contributions from project partners PWN Technologies, Melbourne Water, South East Water, Black & Veatch and Water Quality Research Australia, is currently undertaking research on a trial plant to determine if wastewater recycling can be more affordable and sustainable. The Singapore demonstration, which was completed with positive results in March this year, con rmed the potential for the installation of a sustainable and durable ceramic membrane ltration system. The results of the 18-month demonstration showed that the CeraMac® system performed well as a membrane ltration system for clari ed water with or without ozone. However, PUB is interested in optimising the available options and harnessing as much water treatment capacity as possible from the available space. The use of pre-ozone improved the operation, with a stable trans-membrane pressure (TMP) and minimal down-time for cleaning. The operational synergy between ozone and ceramic membranes appears to mitigate fouling issues, which have been problematic for membrane systems, and achieve a steady state of ltration that has never been shown before. The data from this demonstration-scale study at CCKWW bring to light a long quest for better stability of membrane ltration. The demonstration plant consisted of an ozone generator, a side-stream venturi injection system, contactor vessels, a CeraMac®-19 vessel (containing 19 full- scale sized ceramic membrane elements), a backwash supply tank, and a backwash receiving tank. With a 19-element vessel, a range of uxes from 100 --315 litres per square meter per hour (lmh) produces 1140 to 3591 cubic metres per day (m3/d) of ltered water. The Australian trial combines the treatment into a single step using the CeraMac® system. Ozone can be applied directly onto the membrane. This has a catalytic reaction on the membrane, which keeps the membrane clean. The end result is that the system can work at a very high rate ( ux) maintaining high water production and reduced waste byproducts. AWA Victorian Branch is organising a workshop to showcase the trial of the PWN Technologies' CeraMac® ozone and ceramic membrane process to treat secondary ef uent, operating at the Eastern Treatment Plant in Melbourne, on 5 July 2013. For more information go to: www.awa.asn.au/VIC.aspx codesafe.com.au Key safety and installation instruction on demand AIRVAC 27 Aquatec-Maxcon 25 Aurecon 21 AWMA 108 Bintech 18 Brown Brothers Engineers 110 CH2M HILL 65 Codesafe 112 Comdain 9 Degremont 11 Hach Paci c 7 IDE OBC James Cummings 107 JCB Generators Australia 26 McBerns 70 Nacap 36 Nov Mono Pumps 19 Oda Tech 57 Odour Control Systems 111 Pentair IFC Proco Products 111 Projex 110 Quantum Filtration Medium 109 RPC Technologies 23 Sydney Water 16 Tenix 2&3 TRILITY 12 UGL -- United Group Infrastructure 38 Water Infrastructure Group 20 Weidmuller 13 Xylem 17 Xylem Water Solutions Australia 29 Zetco Advertisers Index CeraMac-19® vessel (right) and backwash tank (left) being installed into an existing empty sand lter bed at CCKWW, Singapore.
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