Monday, April 16, 2007

A Message From The CSIRO

Dr Simon Toze is a Principal Research Scientist at CSIRO Land and Water. He wrote the following opinion piece that was published in today's Canberra Times. I think its a well written contribution to the current public discussion. What do you think?

Research Guides Way Forward
Simon Toze
The Canberra Times
16 April 2007

AS WE ALL know, Australia is waking up to the variability in water supply across the continent and experiencing documentable climate change. The eastern seaboard is still in the grip of the worst drought in living memory. Water levels in dams over much of the country are at critically low levels. Water is no longer taken for granted, but is now widely acknowledged as a precious resource that we need to manage.

The recycling of waste water is seriously being considered by most water utilities as one of several ways to increase their water resources and to provide a buffer against drought. Using water just once and then discarding it is now viewed as wasteful and unsustainable. Reusing water reduces the strain on our existing freshwater resources and is better for the environment.

Technology is now so advanced that waste water can be treated to a level that is better than the water coming out of our taps. But there are other options, so why recycle water? Why expose ourselves to the risks? Waste water has the advantage over other sources such as storm water in that it is available in plentiful amounts, irrespective of climatic conditions. It also has the advantage that it tends to be of a consistent quality, not necessarily a good quality, but consistent. This makes treatment easier than for a water of variable quality such as storm water. The treatment of waste water is less energy intensive than desalination as it contains about 35 times less salt than seawater.

There is a downside. Waste water can contain contaminants that could be harmful to our health. This can include all the wastes and contaminants discarded from our households, ranging from faecal matter containing bacteria and viruses through to medications excreted in our urine. Then there are the cleaning products and other chemicals used in households.

What are the real risks from these contaminants and how effective are the treatment processes? How sure are we that the water utilities can consistently provide us with a safe product? CSIRO, water utilities, universities and government departments have been undertaking research for a number of years to begin to predict the actual risk from many of these contaminants and understand the effectiveness of treatments to remove them from water. Research has also shown that conventional treatment barriers can effectively remove germs that cause illness. Similarly, the removal of heavy metals and nutrients are well documented.

A group of contaminants that has recently come to the forefront of public awareness is trace organics. These chemicals include the sex hormones oestrogen and testosterone as well as chemicals which mimic the activity of these hormones. Other trace organics receiving attention are pharmaceuticals and personal-care products such as shampoo and body cleansers. Less is known about the presence of these chemicals in waste water and the effectiveness of treatment processes to remove them. These chemicals are usually present in such low concentrations that detection is very difficult. For other chemicals it has been difficult to distinguish them from the large number of other organic compounds, some of which are naturally found in tap water. In other cases, such as newly developed medications, they have only been in use for the past few years and detection methods are yet to be developed. Conventional treatment removes many of these chemicals from waste water or reduces them to levels at the limit of detection. In fact, many researchers are now coming to the opinion that their very low concentrations in treated waste water do not pose a human health hazard.

In order to better understand the environmental risks of these compounds, research is being undertaken to assemble better data on the effect of these compounds on native animals in our water ways. The ability of advanced treatment systems to completely strip these trace organics from recycled water is also being closely examined to ensure that humans and the environment are protected. This is especially important as Australian governments and cities move toward the concept of treating recycled water for drinking purposes.

Research efforts to date have also led to the development of new guidelines for recycling water. The new Australian Guidelines for Water Recycling use an internationally accepted risk-management approach, and are currently being extended to address recycling for drinking water. The guidelines recommend that in the design of water reuse schemes there are a number of fail-safe barriers which ensure treatment effectiveness. This means that if one treatment barrier fails, another is able to cope. Control points which alert if a failure occurs are also required, and in many cases are able to shut down delivery immediately a failure is detected in the plant.

This then leads us to the ultimate question. Is it safe for Australians to drink recycled water? The short answer is that with appropriate treatment and safeguards the water is as safe as our current water supplies. Any researcher working on water recycling will admit there is much still to learn. We do know already that the risks are very low, and are probably less than those associated with drinking water already flowing from our taps. Other places such as California, Belgium, Singapore and Namibia are already recycling water for drinking and despite extensive epidemiological studies no detrimental health impacts have been detected. The Australian public can be reassured that government agencies, researchers from CSIRO and universities, and water utilities are not blindly leaping into recycling for drinking purposes but are taking measured, educated steps using sound research to guide developments and the next course of action.

And do researchers like me put our money where our mouth is? Indeed. I have drunk recycled water, and given it to my five year old, and felt perfectly confident in doing so.

Dr Toze is principal research scientist at CSIRO Land and Water.


Water boy said...

Agree - good article. But so was the Dwyer article on why Canberra shouldn't drnk recycled water.

Stuart Khan said...

G’day Water boy,

Yes, indeed all perspectives are worth considering. Dr Terry Dwyer is a visiting fellow at the Australian National University's Crawford School of Economics and Government. He published an opinion piece this week in the Canberra Times, which can be accessed from here.

Dwyer’s apparent dismissal of the importance of environmental flows in Australia’s rivers is a bit of a concern (at least to me). However, I accept the point that natural flow regimes in Australia do clearly involve periods of extreme wet and extreme dry. I don’t claim to be an ecologist by any stretch of the credentials (and neither would I assume Dr Dwyer to so). But I expect that natural variability plays an important role in the overall riverine ecosystem.

Furthermore, I tend to agree that (well treated) effluent already has a legitimate role in supplementing environmental flows in inland towns and cities. I have always acknowledged this (see many earlier comments on this blog regarding Toowoomba). The benefits and costs of any recycling scheme (potable or non-potable) in such towns or cities should be assessed in this context.

I note that some members of the Canberra community have suggested that any water saved by recycling would have to be replaced by increased releases from potable water storages. I’d like to know more about this and will continue to investigate. If this suggestion is accurate in such simplistic terms, it would indeed seem like a strange endeavour. If anyone can provide me with any information, I would be most grateful.

Mark said...

Hi Stuart,

Here’s my comments for Dr Toze.

Singapore, as I have commented previously, actually recycle far more via storm water than via wastewater. So hopefully Dr Toze will have an open mind to storm water recycling as well as other alternatives. Also, I'm surprised by his statement that effluent is of consistent quality - I have read elsewhere that pathogen concentrations in effluent can fluctuate a lot.

It has become accepted wisdom that one must be either for or against potable recycling. Meanwhile, a third position is staring everyone in the face: lets go and pilot-test the technology and then make up our minds. Each of the examples given by Dr Toze (California, Wulpen in Belgium, Windhoek and Singapore) pilot tested extensively before full-scale production. By doing so, they ironed out problems without any risk to anyone including optimizing the process. They were also able to design their larger scale process with more confidence and to demonstrate the process to whoever cared.

So instead of scientists standing up and coming to one "opinion" or another and trying to sell them, they would be doing what they are best at: collecting and interpreting real data. As we know, each recycling case is unique. So let’s deal with the uncertainties by spending a few million dipping our toes a little deeper into recycled water before diving straight into it with a cool billion or so.

I don't know what it is about this country, but we seem to think we are too tough to do pilot-testing. Take the case of the West-Australian nickel laterite processes of the late 90's - Bulong, Cawse and Murrin Murrin. Each became huge financial disasters when technical problems had to be solved on a large scale. Urgency and bravado lead to rapid scale-up from bench-scale to the full-production scale. The risks with the water recycling business are more acute than for minerals where mostly only money was lost. As Dr Toze's colleague from the CSIRO, Dr John Radcliffe stated, the water recycling industry "must ensure that recycling and drinking water supplies are managed to the highest possible standards so that there is no risk of the hard-earned community trust being lost by a single incident that will be long remembered and not readily forgiven".


Anonymous said...

Hi Mark
The proposal in Western Australia is to do a 3 year trial of groundwater replenishment using reverse osmosis treated wastewater. For more information go to

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