Hard to swallow
Can drought-prone Australia afford to turn up its nose at recycled water any longer? Selina Mitchell reports
TO some, the idea of drinking recycled sewage is akin to eating cockroach-chip ice cream — unthinkable, even if shown to be safe. Others in positions of power, such as Queensland’s Premier Peter Beattie, are so desperate for a solution to dwindling dam supplies they are willing to risk community disgust and implement the option anyway, using treated effluent to eke out diminishing rainwater reserves.
All protagonists are keen for scientific evidence to back their arguments — and now they feel they have their ammunition.
Australian health and science authorities have issued a draft of the world’s first safety guidelines on recycling sewage for human consumption. Recycling has been taking place in some areas of the world for decades, but national guidelines have never been created in any of the countries doing so.
Details of the draft guidelines, released recently, are being seized on by both water experts and anti-recycling campaigners as fodder for their causes.
On the ‘‘ pro’’ side, the draft guidelines state that it is possible to safely recycle sewage for drinking purposes, as long as strict treatment and management processes are followed.
But the guidelines set the bar so high that they are likely to stop small, parched towns from taking up the controversial option — an assessment anti-recyclers seeing as a win.
The guidelines warn that the process of recycling waste water is highly complex and risky, and requires expensive technology and skills — resources difficult to find among local government or small utilities. Anti-recycling campaigners say that the draft guidelines, as they stand, would have ruled out the failed Toowoomba waste water recycling plan and could scuttle proposals to augment supplies in Canberra and nearby Goulburn.
National Health and Medical Research Council ( NHMRC) Water Quality Advisory Committee member David Cunliffe says the guidelines were not designed as a political tool, but to outline how to strip sewage water of contaminants such as viruses and chemicals so it is safe to drink.
‘‘ It can be done, but it is a challenge,’’ Cunliffe said. ‘‘ It is naive to think incidents won’t occur, but controlled and timely responses will ensure incidents don’t present a health risk.‘‘The expertise required will make it difficult for local governments and small utilities to do — it is not an approach for a small town or utility and it will be a challenge even for the largest utilities or governments.’’
Brisbane will become the first Australian town or city to use recycled sewage for drinking by the end of next year, with recycled water to be pumped to the Wivenhoe Dam through the $1.7 billion western corridor pipeline, the biggest project of its kind in Australia. Despite voting against a recycled water proposal last year, Toowoomba will get recycled water from that pipeline.
The guidelines may be in draft form and open for public comment, but the Queensland, Goulburn and ACT authorities cannot wait until the final version is released: they need to know now how they could safely implement a scheme now. Each of these groups is relying heavily on the draft.
Along with a complicated 12-step system for the safe operation of water recycling facilities, the guidelines provide key principles for recycling. These include that the protection of public health is paramount and should never be compromised, any attempt to augment supplies must have community support, and utilities which take on the task must have the resources to properly meet the challenge and their staff must have appropriate skills and training.
While the draft fails to detail a specific set of technologies which must be used to treat the water, the principles do state that every system must use multiple barriers, such as membrane filtration, reverse osmosis and advanced oxidation, as none is perfect and each has strengths and weaknesses (see table).
Also, industrial waste water must be monitored and managed under separate programs. And each scheme must be subject to regulatory surveillance.
The guidelines all but rule out the direct augmentation of supplies — where recycled water enters the drinking supply system without going through an intermediary receiving body of water, such as a river or reservoir. There is only one case of direct potable reuse in the world, and that scheme — in Namibia — was developed in the 1960s.
The scope for assessing water quality and
Not convinced: Peter Collignon questions the wisdom of turning sewage into drinking water