Saturday, August 11, 2007

Hard to swallow

An interesting article from The Australian this morning. A number of familiar names appearing and even brief cameo from yours truly, -if you make it that far. It’s good to see the draft water recycling guidelines generating some interest and receiving some analysis in the media.

As for ‘cockroach chip ice-cream’, could it really be so bad? I’m sure there must be a market for it out there somewhere…


Hard to swallow

Selina Mitchel
The Australian
August 11, 2007

Can drought-prone Australia afford to turn up its nose at recycled water any longer?

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 intervening before substandard water is supplied to consumers is limited," the draft says. Community acceptance of such schemes would be difficult and any successful implementation would be exceedingly expensive, it adds.

The draft guidelines -- developed by experts in public health, toxicology and drinking water management -- are based on the best available scientific evidence from around the world.

But the evidence on some health aspects of wastewater recycling -- such as the potential impact on allergy sufferers -- is still scant, the authors of the draft guidelines admit.

A group of government, science and legal experts met in Canberra earlier this month to discuss the draft, and similar public consultation workshops will take place in other capital cities over the next four weeks.

Queensland's chief health officer Jeannette Young and ANU infectious diseases expert Peter Collignon raise concerns about the lack of mention of potential effects on allergy sufferers in the draft.

"I am going to have every allergy group in the state asking if their child will be safe (drinking recycled water)," Young says.

Cunliffe says the issue of allergies will be considered before the final guidelines are released. "We know some pharmaceuticals have allergic outcomes for some people, but it is very difficult to assess. We will see if there is a way of dealing with it."

The authors of the guidelines do not doubt the technology. Their concerns centre on institutional capability and operator capacity -- the human element.

Technical director of the Water Services Association of Australia Peter Donlon says there are vast differences in the capabilities of water providers across the country, and most small operators are simply not equipped to recycle wastewater.

"If you are not big enough, don't bother," says Donlon. The WSAA is the representative of city water suppliers.

Donlon says there is already only very patchy implementation of guidelines for the treatment of drinking water from traditional sources, and that regulatory bodies need to ensure new (and old) guidelines are followed.

The capacity issue is not just one for local government, but for state government as well, Mark Batty from the WA Local Government Association says. He says the West Australian Government is currently investigating its capability to provide safe water to the public.

NHMRC Water Quality Advisory Committee chair Don Bursill likened novices running the recycling treatment process to a janitor flying a jumbo. "These are complex technologies. If people don't understand these things, they shouldn't be in the game.

Bursill says the main tenet of the draft guidelines is that domestic waste water can be recycled for drinking, but all other options must be ruled out first. "We do recognise that it has to be done sometimes," he says.

University of NSW water recycling expert Greg Leslie says many of the treatment and management systems and processes used in traditional drinking water supply systems could be used in recycled waste water systems just as effectively.

Collignon, who has raised concerns about the safety of a proposed recycling scheme for Canberra, welcomes the new guidelines. But he thinks they need to be improved, and should state recycling must only be considered as a last resort.

Toowoomba councillor and anti-recycling campaigner Snow Manners claims the NHMRC and other organisations that have endorsed the "flawed" guidelines are "flying blind", asserting there is not enough evidence to show recycling is safe.

Manners likens drinking recycled water to eating cockroach-chip ice-cream. "It is probably very nutritious and safe, but people don't like the idea of it," he says.



Karin Leder, from Monash University's Infectious Disease Epidemiology Unit, says she supports the guidelines. "We are not saying there is no risk -- we are saying there is acceptable risk."

Stuart Khan, program leader at the Centre for Water and Waste Technology, says more work is required on the guidelines. He says it will never be possible to check recycled water for every potential contamination, so it will be better to develop a list of surrogate chemicals which could indicate the overall quality of the treated water.

Over the next four weeks the draft guidelines will be taken to every capital city across the country for consultation. Overseas bodies have also grabbed the opportunity to assess the guidelines. So far, it seems they have only gone so far in clearing the public's mind over what is proving a very murky issue.

9 comments:

Annette said...

Snow's quote: "It is probably very nutritious and safe, but people don't like the idea of it", seems to me like a fairly straight-forward acknowledgement of the "yuck factor". Funny then, that people so opposed to water recycling get so upset when it is suggested to them that they may be responding to this very same yuck factor.

Snow Manners said...

Annette. I think it is totally rational human behaviour to be reluctant about drinking water sourced from the back end of a sewage treatment plant. It is also totally rational behaviour, for the same reason, to be reluctant to eat icecream with cockroach bits in it.

The reason is that from a young age most people have been taught to resile from those sources of food and water.

It really has nothing to do with any 'yuck factor' although that term describes the phenomenom well because 'yuk' is the very word we use to teach small children what is safe to put in their mouth and what is not.

That is why a long term community engagement process is an essential part of any plan to introduce potable reuse.

The same long term would also provide time for longitudinal studies on the possible intergenerational effects of minute combinations of chemicals that show up in water after it has been subjected to the 'purifying' process.

I sincerely feel that because of the desperate water supply situation brought about through a lack of long term infrastructure planning and an unusually harsh drought, recycling is being prematurely introduced before it has been properly studied.

Anonymous said...

What's the picture supposed to be?

rwindsor said...

Dear Stuart
I find it ironic that we seem so concerned about the possible contaminants of recycled water while we willingly add a toxic industrial waste product to our drinking water in the name of dental health.
I am unable to find any current published evidence on risk analysis of adding crude fluoride compounds to domestic water supplies despite concerns over the possible contamination by heavy metals and good evidence of direct fluoride toxicity.

Stuart Khan said...

Hello Anonymous,

Yes, I know it’s a pretty lame ‘cockroach-chip ice cream’. I did have a more creative idea that I tried to assemble today. However, believe it or not, even in Sydney cockroaches are fairly hard to come by at this time of year…

Hello RWindsor,

I don’t really feel that I have the capacity (or expertise) to engage in a serious discussion about drinking-water fluoridation (and I know a can of worms when I see one!). However, I think it would be fair for me to say that if you have been unable to find any published risk analysis studies, you have not been looking in the right places. Numerous studies have been published and you can find a reasonably comprehensive review of many of them by McDonagh et al, published in the British Medical Journal. I have pasted the reference and abstract below for your interest.


McDonagh MS, Whiting PF, Wilson PM, et al.
Systematic review of water fluoridation
BRITISH MEDICAL JOURNAL 321 (7265): 855-859 OCT 7 2000

Objective: To review the safety and efficacy of fluoridation of drinking water.

Design: Search of 25 electronic databases and world wide web. Relevant journals hand searched; further information requested from authors. Inclusion criteria were a predefined hierarchy of evidence and objectives. Study validity was assessed with checklists. Two reviewers independently screened sources, extracted data, and assessed validity.

Main outcome measures: Decayed, missing, and filled primary/permanent teeth. Proportion of children without caries. Measure of effect was the difference in change in prevalence of caries from baseline to final examination in fluoridated compared with control areas. For potential adverse effects, all outcomes reported were used.

Results: 214 studies were included. The quality of studies was low to moderate. Water fluoridation was associated with an increased proportion of children without caries and a reduction in the number of teeth affected by caries. The range (median) of mean differences in the proportion of children without caries was -5.0% to 64% (14.6%). The range (median) of mean change in decayed, missing, and filled primary/permanent teeth was 0.5 to 4.4 (2.25) teeth. A dose-dependent increase in dental fluorosis was found. At a fluoride level of 1 ppm an estimated 12.5% (95% confidence interval 7.0% to 21.5%) of exposed people would have fluorosis that they would find aesthetically concerning.

Conclusions: The evidence of a beneficial reduction in caries should be considered together with the increased prevalence of dental fluorosis. There was no clear evidence of other potential adverse effects.

Ken said...

What about the issue of people with allergies?

If there are unknowns about the effect of recycled water on people with allergies, why is this proceeding?

Isn't there some risk of a portion of our population being adversely affected?

Stuart Khan said...

Hi Ken,

The issue of allergies came up during discussions of how ‘safe levels’ of contaminants were determined. The point being –of course- that unless you take into account the allergic responses that some people may have to specific chemicals, then the ‘safe’ level that you identify may not be sufficiently low to fully protect such people.

This issue applies equally to our current drinking water guidelines and all other situations where safe levels of chemicals are determined for anything (food, fruit juice, furniture, carpets, air quality, etc). It is by no means an issue that is particular to recycled water.

However, it is important not to mistake the levels of chemicals identified as ‘safe’ in the draft guidelines as being anything like the actual levels in recycled water. In most cases, the actual levels will be thousands or millions (or more) times lower. In the case of most pharmaceuticals, even the highest concentrations that have ever been reported in secondary treated effluent anywhere in the world are generally above the identified safe levels. The fact that advanced water treatment then lowers concentrations further means that final concentrations will be numerous orders of magnitude below the ‘safe levels’.

I think it is important to keep some perspective on this issue. Water which has been treated by advanced treatment processes including reverse osmosis and advanced oxidation will be the cleanest drinking water source supplied to any town or city in the country. The issue is more to do with the identifying the most comprehensive and scientifically rigorous approach to actually demonstrating safety.

Anonymous said...

Annette you are an idiot as always. The Toowoomba people understand recycled water better than anyone else since we have thoroughly studied it for more than 2 years now. Its not a yuk factor but real risks and we are supported by many mdeical experts around Australia. Get over it!!

Annette said...

Thanks "anonymous". Keep up the good work.

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