Water Journal : Water Journal February 2014
FEBRUARY 2014 WATER Recently, the results of our own Deloitte-AWA yearly survey of water industry professionals were released. The survey explored attitudes to three different water sources for differing uses -- recycled water, stormwater and desalinated water for potable and non- potable use. The report said "responses to the survey showed that just 9% considered recycled water suitable for potable use, 10% considered stormwater as suitable and 60% considered desalinated water as a viable option". The press responded with stories reporting "strong concern in the water industry about using recycled water for drinking, with just 9 per cent of the industry thinking it was suitable for potable use". In fact, a more careful perusal of the results shows that a further 39% of respondents replied that recycled water was suitable for both potable and non-potable use, bringing the total of industry respondents supporting recycled water for drinking to 48%. But that is still less than half of the industry's participants. Have we no faith in our own capabilities? No wonder our politicians do not feel con dent to take potable recycling forward to the community if industry professionals aren't comfortable with the idea. PUTTING PRECAUTIONS IN PLACE So let's look at our approach to potable recycling. The aim is to ensure we have validated secure protection mechanisms, including hazard and critical control point risk assessment regimes and realtime monitoring that allow water to be withheld from entering the supply system if it is off-speci cation at any of those points, and the ability to take quick action to isolate such water before it reaches the consumer. One of the nal aspects has been to have an "environmental buffer" into which recycled water is added, thereby diluting it with "natural" catchment water, giving comfort to the consumer. But we all know that recycled water, usually produced by micro ltration, reverse osmosis and advanced oxidation, is almost always better in biological and chemical characteristics than the environmental buffer into which it is being added. We are, in essence, spending a lot of energy moving water to an environmental buffer to achieve a reduction in its quality. Although it might provide some short-term political comfort, is this sensible in either health, environmental or economic terms? The issue has been ushed out twice within Australia in recent months. The rst occasion was the report Drinking Water Through Recycling, commissioned by the Australian Water Recycling Centre of Excellence from the eminent and independent Australian Academy of Technological Sciences and Engineering (ATSE), which is comprised of the top 800 applied scientists and engineers in the nation. Authored by Dr Stuart Khan, the report came out squarely in suggesting that direct potable recycling should be considered among the range of available water supply options for Australian cities and towns. An appendix by consultant GHD established potentially lower capital and long-run operating costs for direct potable recycling compared with indirect potable, third pipe or desalination systems. The report's conclusions parallelled a 2011 National Research Council of the US National Academy of Sciences report that also suggested that if US coastal communities added advanced water treatment procedures to the treated wastewater that is now discharged to ocean, they could increase the amount of municipal water available by as much as 27 per cent. More locally speci c was the joint submission from AWA, the Water Services Association of Australia (WSAA) and the Australian Water Recycling Centre of Excellence (AWRCoE) to the Queensland State Development, Infrastructure and Industry Committee in regard to its inquiry into the issues contained in the Queensland Audit Of ce Report to Parliament 14 for 2012--13: Maintenance of Water Infrastructure Assets. The joint submission suggested building a short pipeline directly from the Bundamba Advanced Water Treatment Plant to the Mount Crosby Water Filtration Plant to supply direct potable recycled water to Brisbane. It also suggested developing the capability to reverse the ow of the Bundamba-Wivenhoe pipeline to bring water from upper Lake Wivenhoe to Brisbane during oods when water from the Brisbane River was too turbid or otherwise too polluted to use. Increased Wivenhoe water could be allocated for economic development of irrigation by Lockyer Valley farmers, the water so consumed being offset by direct potable supplies from the Western Corridor Scheme advanced water treatment plants. This may sound a little fanciful in the light of current community attitudes to recycled water for drinking, although the Water Corporation in Perth has shown that attitudes can be moved in a favourable direction in a relatively short time. 9 My Point of View Seeing the process and tasting is believing! Becky Mudd, tour coordinator at Orange County Water District, at the end of a recycled water tour shows three water streams. Left to right: nal product water for tasting; MF water in uent to RO; and third-pass RO brine.
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