Sunday, May 28, 2006

What's driving opposition in Toowoomba?

From reports of yesterdays’ community meeting, there is clearly a groundswell of opposition to the current water recycling proposal in Toowoomba. I think it is useful to identify the key issues that have people so wound up.

As I have written previously, I don’t consider it appropriate for me to stick my nose into the local political situation. Since some of the major issues are plainly ‘political’, I have decided not to offer criticism or pass judgement on any of the seven identified issues, but simply to list them as I see them. As an ‘outsider’, I have the advantage of not being influenced by any personal gripes against any local identities. However, if you think I have got it wrong, I’d be very grateful for your comments.

A number of the high-profile opponents apparently have a very good grasp of the scientific or technological aspects of the proposed scheme. However, it is my opinion that these actually have very little to do with most peoples’ concerns. On the contrary, it is fairly evident to me that the principal opposition is much more emotional. Consider the following expression of discontent that was recently posted to the WaterFutures blog:

If the people of Toowoomba vote YES to this plan, the will be civil unrest. The NO voters will want blood, and it will be the YES voters blood, not the TCC. Thorley know this and is using this as a tatic to gain support. Thorley and the State Gov. can not force this on such a large community, I have filed a formal complaint with The Prime Ministers Cabinet and my report have been noted and forwarded to Jon Howard and The Health Commnision for investigation. I can only hope that Howard has more of these reports to do something about a Mayor out of control.. I will want blood if the YES vote wins, it's that simple. Its' time Thorley woke up and see that recycled sewage will not save the city from drying up, only New Water from a stable supply will do that. Does Thorley have an import license to buy bottled water from singapore, no she doesn't, so why isn't customs on her back, or is the water taste test another lie.

Presumably such comments are driven by something more than a perceived deficiency in local water resources planning. Having taken a close interest in such blogs and associated comments, communicated privately with a number of Toowoomba citizens and politicians, and also listened to Toowoomba City Council’s perspective at a recent conference, I propose the following as the seven primary ‘drivers of dissent’:

1. A feeling that the planning for the scheme was undertaken in secrecy to prevent opportunities for community opposition.
2. A feeling that this preconceived plan was then attempted to be forced on the community without any real opportunity to comment, to offer alternative solutions, or to reject it.
3. A feeling that worldwide experience with water recycling was intentionally misrepresented to the community.
4. An on-going feeling that the proponents of the scheme are unwilling to provide answers to the communities questions.
5. A suspicion that someone is secretly trying to take advantage of the Toowoomba community (eg. state government, local government, scientists (for experimentation), water treatment companies, bottled water companies and/or other private interests).
6. General discomfort with the ‘concept’ of potable water recycling (regardless of actual water quality).
7. Concern that potential visitors or future residents of the city may share that discomfort and thus be dissuaded, resulting in decreased tourism and property prices.

It may appear that I have forgotten the ones about ‘endocrine disrupting chemicals’, ‘waterborne pathogens’, 'protecting unborn babys' and other ‘unresolved health issues’. However, it is my opinion that these are not serious concerns, but simply used as attempts to sway the opinion of others. None of those arguments stand up when people are prepared to seriously consider the massive worldwide scale of (unplanned) potable reuse (with much lower levels of treatment and stringency of management). Furthermore, they do not stand up against serious consideration of relative exposure to many hazards from recycled water compared to more significant sources. I have found that inviting people to engage in such considerations is a sure way to have them change the topic (or delete my comments from their blog!).

Anyhow, I offer you the “comments” section below to tell me whether you think I am close to the mark or have completely misunderstood where the community are coming from. Don’t hold back.


Thursday, May 25, 2006

Exposure to Phthalates from Water Insignificant

News and opinion articles in the Australian media continue to suggest links between genital abnormalities and water supplies. This week its a group of chemicals called 'phthalates' towards which the finger is pointed. Lets take a closer look at the issue.

Phthalates are man-made chemicals that have been shown to have hormonal-type effects on some animals exposed to high doses in laboratory experiments. These effects include improperly formed reproductive organs, reduced sperm counts and a general decrease in mating, pregnancy and fertility.

Scientists reasonably suspect that similar effects may be possible for humans exposed to sufficient doses. However, very little is currently known about human health effects. Direct links between the effects observed in animals and a decline in human reproductive health have so-far been unable to be established.

These concerns make it very important for the issue to be carefully investigated and monitored. The first questions we should ask are how much are we exposed to phthalates? And what are the significant sources of exposure?

Last year an international group of experts met at a Workshop on Environment, Reproductive Health and Fertility in Copenhagen, to discuss current issues in human fertility and reproduction trends. The papers from this meeting were published in the International Journal of Andrology (Vol 29, No. 1). Phthalates were an important topic on the agenda. A number of the papers presented described the likely major sources of exposure to people.

US scientist, Dr Ted Schettler from the Science and Environmental Health Network identified a long list of consumer products which contain phthalates. These included “building materials, household furnishings, clothing, cosmetics, pharmaceuticals, nutritional supplements, medical devices, dentures, children’s toys, glow sticks, modelling clay, food packaging, automobiles, lubricants, waxes, cleaning materials and insecticides”. He did not identify drinking water among the significant sources.

A team of German scientists from the Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, University of Erlangen-Nuremberg, also identified an extensive list of products containing phthalates. These were flooring, carpeting, roofing, vinyl wall covering, upholstery, wire and cable sheathing, clothing, packaging, toys, detergents, industrial solvents, wetting agents or lubricating oils, e.g. for lacquers, colours or adhesives. Again, drinking water supplies were not identified as a significant source.

Dr Schettlers paper states “Historically, the diet has been considered the major source of phthalate exposure in the general population, but all sources, pathways, and their relative contributions to human exposures are not well understood. Medical devices containing di-(2-ethylhexyl) phthalate are a source of significant exposure in a susceptible subpopulation of individuals. Cosmetics, personal care products, pharmaceuticals, nutritional supplements, herbal remedies and insecticides, may result in significant but poorly quantified human exposures to dibutyl phthalate, diethyl phthalate, or dimethyl phthalate”.

Since phthalates are known to leach from plastics, it may reasonably be assumed that bottled water (and anything consumed from a plastic container) may be a source worth investigating. However, having now reviewed all of the papers presented at this meeting, I have been unable to find any justification to reasonably assume Australian tap-water supplies to be a significant exposure source.

I have searched, but have not been able to find any data showing any Australian drinking water to contain concentrations of phthalates that could come within a bull’s roar of the much higher doses that we are exposed to from practically everything else we come into contact with.

Accordingly, current calls, by a few doctors, to revise Australian drinking water guidelines on the basis of phthalate exposure seem to me to be unfounded and alarmist. To link Sydney's drinking water supplies to a reported increase in genital abnormalities in New South Wales is utterly unscientific. Nonetheless, I am always willing to consider any alternate evidence that anyone would like to provide me with.

If a need to more carefully control phthalate exposure from drinking water is established, major drinking water recycling schemes offer a unique opportunity to do this. Only advanced treatment processes such as reverse osmosis and advanced oxidation are able to significantly remove these compounds. It is unrealistic to expect that these expensive and energy-intensive processes will be routinely employed for conventional drinking water sources. However, planned drinking-water recycling schemes provide a strong justification for their use.

Promoting fear about chemical exposures from recycled water seems to be an increasingly popular pastime in Australia. However, perhaps it makes more sense to see water recycling as an opportunity to actually decrease our exposure to hazardous chemicals.

Tell me what you think.


Saturday, May 20, 2006

Dihydrogen Monoxide (DHMO) – The truly dangerous chemical in recycled water

Recycled water does contain one chemical that is undeniably dangerous – dihydrogen monoxide (DHMO). The United States Environmental Assessment Centre describes DHMO as “a colorless and odorless chemical compound, also referred to by some as Dihydrogen Oxide, Hydrogen Hydroxide, Hydronium Hydroxide, or simply Hydric acid”.

DHMO is reported to have been used in death camps in Nazi Germany, and remains in use in prisons in Turkey, Serbia, Croatia, Libya, Iraq and Iran. Astonishingly, it is also widely used in Australia in abortion clinics and other medical practices. Even worse, it is a major component of some major-brand tick and flea formulations promoted in Australia for use on household pets. Similarly, DHMO is used in the production of pesticides used in the Australian cotton industry.

DHMO contamination is widespread in Australia and has been physiologically associated with high blood pressure and urinary tract infections. Alarmingly, DHMO has also been identified in biopsies of pre-cancerous tumors and lesions. DHMO is now ubiquitous in human tissue throughout the world and significant concentrations have even been reported in Antarctic ice caps.

A fact widely known amongst doctors, but less widely discussed, is that semen with abnormally low numbers of viable sperm regualrly contains high concentrations of DHMO.

While precise figures are not available, it is estimated that during the last decade alone, hundreds of thousands of people died as a result of acute accidental overexposure to DHMO.

Chapter 4 of the Australian draft National Guidelines for Water Recycling include this substance in its list of “Constituents potentially found in recycled water, which could pose a risk to the environment”. This is of particular concern since advanced water treatment technologies are unable to completely remove DHMO. Reverse osmosis is partially effective (typically only 10-20% is retained by the membranes). Subsequent processes such as advanced oxidation with UV radiation have been shown to be completely ineffectual.

DHMO does not break down in the environment and is expected to survive in some places for many thousands of years. If DHMO is used in your community, it is extremely likely to end up in any recycled water scheme.

There are allegations that suggest that the United States Environmental Protection Agency (EPA) may be conspiring to cover up the whole DHMO issue. Don’t let this happen in Australia!

Information available on the internet states “Research conducted by award-winning U.S. scientist Nathan Zohner concluded that roughly 86 percent of the population supports a ban on dihydrogen monoxide. Although his results are preliminary, Zohner believes people need to pay closer attention to the information presented to them regarding Dihydrogen Monoxide. He adds that if more people knew the truth about DHMO then studies like the one he conducted would not be necessary.

A similar study conducted by
U.S. researchers Patrick K. McCluskey and Matthew Kulick also found that nearly 90 percent of the citizens participating in their study were willing to sign a petition to support an outright ban on the use of Dihydrogen Monoxide in the United States.

The Truth About DHMO: Okay, so by now I am sure that most readers have realised that dihydrogen monoxide is just another description for H2O, -plain old water.

So what is this all about? A sick joke? Well, no there is a serious point here. I hope this post provides some insight into just how easy it is for people with their own agenda to spread fear and hysteria by compiling a few unrelated facts and citing a few dodgy websites.

There are a couple of blog sites* available in Australia (I wont point to them), whose sole aim is to do exactly that. Just as it is true that DHMO can be associated with all sorts of terrible things, so too can any other chemical we choose to name. But are we really all prepared to leap in and sign the US researchers petition mentioned above, or do we ask for evidence and details first?

Phthalates, human hormones, RU486 abortion pills… yes they are all powerful chemicals and all have the potential to cause harm. But we need to consider how we (and the environment) are exposed to these things. To suggest that advanced-treated recycled water is a significant exposure route is simply not plausible. It’s a scare tactic used by people who think you will fall for it.

*note: I am not referring to Water Futures or 4350Water, both of which I consider to be valuable discussions of issues relating to the Toowoomba Water Futures project.

Comments encouraged.

Friday, May 19, 2006

Perception, Trust and Credibility

Instead of boring everyone to death with another technical post (I’ll get back to UV disinfection later), I decided to address some of the comments that I have received about perception, trust and credibility.

I have no interest in commenting on local social or political environments in Toowoomba, Goulburn or anywhere else (except perhaps Sydney, which I think I am more entitled to comment on!). Therefore, none of the below should be interpreted as an analysis of any specific organisation, but as general observations from an impartial perspective.

A number of proposed water recycling projects around the world have failed as a direct result of a lack of community confidence. They include schemes in Europe, Australia and the USA. In each case, community misgivings could be attributed, in part, to a lack of trust towards the organisation responsible for the proposed water recycling scheme.

Community views of water recycling have been a topic of interest to social scientists since the early 1970s. Since then, water treatment technologies have undergone considerable development and improvement. However, during that time, community support for many forms of water recycling has not significantly increased. As such, there appears to be no strong correlation between the quality of reclaimed water and community acceptance of its use for specific applications.

To fully understand community attitudes to water recycling, it is necessary to consider instinctive and emotional responses that people have to the issue. It has been shown that many people trust their own impressions of water quality (often based on cloudiness or colour of the water) more than they trust medical and scientific evidence. In other words, perceptions of water quality are not simple and not always entirely rational.

Some researchers have suggested that once water has been in contact with contaminants, it can be psychologically very difficult for people to accept that it has been purified. These factors can create mental barriers to the acceptance of recycled water as a source of pure water.

Despite these challenges, a recent review of studies undertaken in the USA has revealed highly positive insights to community perceptions and attitudes towards water recycling. I suspect many would also apply in Australia:

  • The community is interested in being meaningfully involved in water reuse decisions.
  • The community is interested in finding ways to ensure independent and secure water supplies for their communities.
  • While the community is not well versed in the water cycle, they are generally aware that there are water supply problems in many parts of the country.
  • The community believes that some form of potable reuse is inevitable, given growth and water supply constraints.
  • Information sharing, educational activities and opportunities for reflection upon the concepts of water recycling can increase support.

Ultimately, success of water recycling projects will largely depend on the credibility of the supplier of information. The credibility of the water recycling organisation and its senior personnel are as important to the success of the project as the quality of the project itself. A recent study by Anna Hurlimann (University of South Australia) demonstrated that the degree of trust that an individual had for a water authority was proportionate to the individual’s level of confidence that a planned recycled water supply would not pose unacceptable risks to their health. Dr June Marks (Flinders University, Adelaide) has further reported that institutional frameworks that inform and involve the community are required factors for the generation of trust.

The credibility of an organisation planning water recycling will be judged on a number of factors, which may include perceptions of the organisation’s:

  • commitment to the welfare of the community
  • performance record based on previous initiatives
  • knowledge of the issues, as demonstrated by spokespersons
  • impartiality regarding the subject matter

Surveys undertaken by June Marks indicate that water and sewerage authorities often receive the lowest degrees of community trust. The medical profession commands the greatest degree of community trust, followed by public health authorities, reputable research institutions, environmental protection agencies and non-government environmental groups.

In instances where the community associates a high level of risk with a water recycling project, trust has shown to be maximised when the following conditions are met:

  • Dialog is sustained
  • The community has independent sources of information, not linked to the sponsoring agency
  • The community can ask questions
  • The community is involved early
  • Information is available to everyone
  • Behaviour is non coercive. It is considered a reasoned and fair way to make a decision
  • Everyone’s opinion matters, and there is a willingness to listen to all views and expand the discussion if necessary
  • Citizens have some level of control in the process (such as by contributing to the agenda or ground rules)

I would argue that it is the responsibility of the organisation promoting water recycling to generate this trust over time. However, I would also argue that well-placed trust in the organisation is very much in the communities’ interest. The water management problems faced by Australians are real and serious. We need to implement sustainable solutions as a matter of urgency.

It is clear to me that communities can over-come their natural trepidation and place their trust in responsible organisations when they see clearly that it is in their interest to do so. Every time we get on train or bus we depend on the relevant authority or owner to have employed suitably trained drivers who will get us to our destinations safely. When we eat in a restaurant, we trust the chef not to poison us. When we drink bottled water, we trust the bottling company to have properly treated and managed the water. We even trust hospitals and doctors to cut us open to make repairs, -all because we have determined that the benefits far outweigh the risks. The same can and should apply to a well planned and carefully managed water recycling scheme.

As always, send your feedback, praise or personal abuse by clicking the “comments” link below.

Thursday, May 18, 2006

Membrane Biofouling

My thanks to ‘Greg’ for really rasing the bar on the level of discussion here. Greg’s comment is a little too long to reproduce, but you’ll find it below my previous post. It’s the comment starting “The Achilles heel of reverse osmosis (RO) membranes is biofouling…”.

“Biofouling” refers to the growth of biological organisms (bacteria, algae, slime, etc) on a moist surface. Sounds pretty gross, but the same types of “biofilms” currently line the insides of all our drinking water pipes. If we were to allow biofilms to grow on membranes unchecked, they would soon clog up the membrane. For some types of membranes, biofouling could also potentially damage the membrane as suggested by Greg. However, we have three very effective ways of preventing biofouling from becoming a problem:

1. Pretreat the feedwater prior to reaching the RO membranes.
This is the most important means of biofouling control. In almost all water treatment plants, RO treatment would be preceded by another membrane process with larger pores (usually either microfiltration or ultrafiltration). This removes the suspended solids and colloidal material before they reach the RO membrane, significantly reducing the biological organisms that can reach the RO membrane. If further removal of biological organisms is required, this can be achieved by “disinfecting” the feedwater to the RO. Common methods for disinfection include the use of chlorine, ozone or ultraviolet radiation (all the same disinfecting processes that are currently used for drinking water). Chlorine disinfection is the most common and the two most common forms of chlorine disinfection are chlorine gas and chlorine dioxide (some membranes are sensitive to chlorine and thus monochloramine is also commonly used). Yes, both are quite toxic substances (which, actually is the whole point!). However, they are both used very safely in all reticulated drinking water supplies in Australia. In most cases, this chlorine will be largely removed from recycled water, either by “dechlorination” immediately prior to RO or by the RO process itself.

These "pretreatment" methods of preventing biofilms from growing in the first place are a much more reliable approach than the one described by Greg (letting the biofilms grow and then hitting them with a strong dose of chlorine dioxide).

2. Select membranes made of materials that bacteria cannot degrade.
Membranes are available made from a variety of materials to be suited for a variety of applications (not just drinking water treatment). The most common materials include polypropylene, cellulose acetate, aromatic polyamides and thin-film composite membranes. Most of these are quite resistant to bacterial degradation, but cellulose acetate membranes may be expected to be more susceptible than the others. Aromatic polyamides are very resistant.

3. Regularly replace membranes.
Just like anything else, membranes have a life-span. This is normally caused by the pores eventually clogging up with the various components that they remove from the water. As this occurs, the pressure needed to force the water through the membrane gradually increases. The treatment plant operators would monitor this pressure and when it reaches a certain level, the membrane module would be taken off-line and a new one installed. Well managed modern RO membranes typically need to be replaced every couple of years.

In summary, I strongly agree with Greg’s comments that it is very important to control biofouling for reverse osmosis membranes. However, this can be quite easily and very effectively achieved. Greg’s further comment that “it relies on us trusting those operating the technology” is irrefutable. Just as we currently rely on those responsible for delivering our safe drinking water supplies (and so many other things in life), we will need to have confidence that people responsible for operating the system are well trained and following well established protocols.

Comments, corrections or criticism encouraged,


Wednesday, May 17, 2006

The Mechanisms of Chemical Removal by Reverse Osmosis

A number of people have expressed doubt regarding my earlier description of how reverse osmosis membranes work to remove other chemicals from water. Here's my description:

"Trying to squeeze larger chemicals such as human hormones through a reverse osmosis membrane is like trying to push a golf ball through a tea strainer. Reverse osmosis is so effective that some important ions such as carbonate need to be re-added to stabilise the over-purified water."

Two of the comments received were:

“NOT TRUE. I’m not quite sure where you have got your information from about RO membrane technology, perhaps it was Toowoomba City Councils Water Futures booklet. You will need to address this issue more scientifically if you wish to evoke any sort of intelligent conversation about the technology and the process which IMO is seriously flawed.”


“...The problem with your synopsis Stuart is that most of us now have researched this membrane technique a little more deeper then water recycling companies would have liked us to and the whole squeezing large things through small holes is a childish misconception of the whole process..."

My response to these comments is that they are partially correct and partially misinformed. The fact is that size-exclusion is a very important mechanism for rejecting the passage of large molecules through membranes. However, the correspondents are quite correct in identifying that size-exclusion is not the only mechanism. Other important mechanisms that assist in preventing molecules from passing through the membrane include hydrophobic adsorption and, in some cases, electrostatic repulsion.

Some of my colleagues at UNSW published an important paper on this topic in 2003:

Title: Removal of Natural Hormone Estrone from Aqueous Solutions using Nanofiltration and Reverse Osmosis.
Authors: AI Schaefer, LD Nghiem and TD Waite.
Source: Environmental Science and Technology, Vol 37 (2003), pages 182-188.

The abstract from that paper reads:

“The ability of a variety of nanofiltration and reverse osmosis membranes to retain the natural hormone estrone are examined here as a function of solution conditions. While size exclusion dominates retention with the tighter membranes, both size exclusion and adsorptive effects appear to be instrumental in maintaining high retention on nanofiltration membranes that otherwise exhibit relatively low ion retentions. These adsorptive effects may be driven by hydrogen bonding between estrone and the membrane. Electrostatic attraction appears to aid retention with an apparent slight decrease in retention at high NaCl concentrations. Deprotonation of estrone leads to a significant decrease in retention, most likely as a result of the effect of strong electrostatic repulsive forces decreasing the proximity of the negatively charged estrone to the negatively charged membrane surface and thus lowering the potential for adsorptive retention. This deprotonation effect is absent for tight RO membranes. The results reported here indicate that while open nanofiltration membranes may be effective in retaining estrone under some conditions, the extent of retention may be very susceptible to maintenance of adsorptive capacity at the membrane surface and depend on solution chemistry.”

To paraphrase the findings of that paper, it means that reverse osmosis membranes (which have very small pores…also known as “tighter membranes”) rely very much on size exclusion. Accordingly, I do maintain that my golf-ball in a tea strainer analogy is entirely appropriate.

However, if we consider membranes with larger pores (which is somewhat irrelevant in the case of Toowoomba) such as nanofiltration, we find that even in cases where we would not expect size-exclusion to sufficiently retain chemicals, we actually do get some removal. That removal is caused by adsorption of the chemical onto the membrane and is highly dependant on solution chemistry.

The same phenomena were recently confirmed in a study involving 52 different endocrine disrupting compounds (EDCs), pharmaceuticals and personal care products. This study looked only at nanofiltration and ultrafiltration. It did not include reverse osmosis (which has significantly smaller pores and thus significantly greater size-exclusion):

Title: Nanofiltration and Ultrafiltration of Endocrine Disrupting Compounds, Pharmaceuticals and Personal Care Products.
Authors: Y. Yoon, P. Westerhoff, S. Snyder, E. Wert.
Source: Journal of Membrane Science, vol 270 (2006), pages 88-100.


“Reports of endocrine disrupting compounds (EDCs) and pharmaceuticals and personal care products (PPCPs) have raised substantial concern among important potable drinking water and reclaimed wastewater quality issues. Our study investigates the removal of EDC/PPCPs of 52 compounds having different physico-chemical properties (e.g., size, hydrophobicity, and polarity) by nanofiltration (NF) and ultrafiltration (UF) membranes using a dead-end stirred-cell filtration system. EDC/PPCPs were applied to the membrane in one modelwater and three natural waters. Experiments were performed at environmentally relevant initial EDC/PPCP concentrations ranging typically from 2 to 250 ng/L. EDC/PPCP retention was quantified by liquid and gas chromatography with mass spectroscopy–mass spectroscopy. A general separation trend due to hydrophobic adsorption as a function of octanol–water partition coefficient was observed between the hydrophobic compounds and porous hydrophobic membrane during the membrane filtration in unequilibrium conditions. The results showed that the NF membrane retained many EDC/PPCPs due to both hydrophobic adsorption and size exclusion, while the UF membrane retained typically hydrophobic EDC/PPCPs due mainly to hydrophobic adsorption. However, the transport phenomenon associated with adsorption may depend on water chemistry conditions and membrane material.”

I realise that there is alot of technical jargon in this post, but the degree of detail seemed to be what was being requested. I will try to keep explanations simpler in the future!

I hope that this information will be helpful in providing a more detailed understanding of how membranes work to remove chemicals from water. I would be grateful to receive any comments.


Response to a great email from Lyle Shelton

I received an excellent email from Lyle Shelton, Toowoomba City Councillor and National Party candidate for Toowoomba North for the next Queensland State election. Lyle’s email is reproduced (with permission) in full below.

It is clear that there are numerous local issues involved in Toowoomba and certainly, living 2000 kilometres away, I do not presume to be qualified to comment or pass judgement on those. Accordingly, these are presented without criticism and are accepted by myself as legitimate local points of view. However, I also accept that others may hold different (equally legitimate) points of view.

On the other hand, I do believe that I can offer some constructive response to the more technical issues that Lyle has raised. These include the relevance of existing "precedents" and the safety of drinking-water recycling. Discussion is provided below Lyle’s email. Comments (dissenting or supporting), are as always, encouraged.

From: "Lyle Shelton"
To: Stuart Khan
Subject: Re: Water Recycling blog
Date: Tue, 16 May 2006

Hi Stuart,

Thanks for your e-mail. I read your article in today's Courier Mail. I am on the public record here in Toowoomba as saying I am 80-90 per cent convinced that the technology you speak of to clean water is available. I am not a flat earth Luddite and I am more than open to science.

However, I withdrew my support from the Toowoomba Water Futures project after it became apparent to me that we were trying to sell a controversial project to a community based on false propositions. I am very upset that I was misled as a Councillor about the world-wide experience with urban recycling waste water for drinking.

False propositions included:

1. What Toowoomba is proposing is routinely done around the world. I have since discovered that there is only one plant on the planet like the one Toowoomba proposes and that is Singapore where just 1pc of their drinking water is sourced from recycled sewage. Originally, the Council did not wish to disclose to the people of Toowoomba that the percentage in Singapore was so low.

I am aware that unplanned potable reuse occurs everywhere and that this is generally seen as bad practice. A meeting of residents was told last Saturday by Council that the President of the US drinks up to 90 per cent recycled sewage water at the White House from Fairfax County’s Upper North Occoquan reservoir. If that were true, I'm sure the debate about drinking recycled sewage water would be far more advanced than it is and that George Bush and Bill Clinton would have joined hands by now to promote indirect drinking-water recycling as the solution to the world's water crises.

2. We were told there were no other options for Toowoomba. There are many viable, cost effective options that would provide arguably a much longer sustainable water supply than Water Futures (WF is based on 5000Ml of recycled water and 5000-7000Ml of water sourced from over-allocated aquifers). And I don't like being lied to about options. Peter Beattie told Malcolm Turnbull there were no other options then he turns around and says Dams located less than 40km from our dams will be secure for the long term after he builds the Mary River Dam. (Whether Beattie's plan is realistic or not is not my problem. I and the public have every right to take him at his word and he said he would have an abundance of water available by 2011. He took out a full page ad in our local paper to tell us about all this new water which we are not allowed to drink).

3. We are constantly told recycled sewage water is completely safe for drinking. Morris Iemma doesn't think so, Peter Beattie doesn't and Alan Carpenter is testing it for 10 years with the CSIRO. I'm more interested in what politicians do, not what they say. Our community has every right to question the safety of this new technology rather than be labelled as flat earth and anti-science for having reservations.

If the Council had been honest with the people of Toowoomba about this, had properly researched the other options without presenting a take it or leave it plan that vilifies anyone with a different view, I might have been persuaded to champion recycling for drinking. I probably wouldn't have become a champion though, because there are other options and I agree with the American Waterworks Association which says IPU should be an option of last resort.

Also, if the water is so pure as we are constantly told, why is it that no one in the water industry seriously advocates direct potable reuse? I can only suppose that there are unresolved issues. A large quantity of expensive, "pure" water is to be lost to evaporation. If the water industry and the science community want to convince the public about IPU for the future, they are going about it the wrong way by backing a Toowoomba scheme sold to the public on false propositions.

Tell the truth and start again, I say. Trial it somewhere so people can see it. Earn their confidence, don't ram it down their throats. This debate has ripped our community apart, it has divided friends. If it had been conducted with more openness and honesty, it may not have had to have been so acrimonious. Politicians like Beattie and Turnbull have made it worse.

Anyway, I hope the above gives you an insight in to where I'm coming from. I will be more than happy to scan your blog from time to time.




Lyle's email raises some important points.

Lyle’s first point regards the existence of precedents for drinking water recycling schemes that are relevant to the mooted plants of Toowoomba City. It is clearly true that there is no existing scheme that can be claimed to be identical to the proposed scheme. But is there an existing city that can claim to be identical to Toowoomba? Singapore may be considered to be comparable primarily in terms of two aspects only:

1) The very high degree of advanced water treatment technology involved, and

2) The very openly planned and intentional approach to drinking water recycling.

However, there are many many precedents all over the world when we get to considering actual degree of drinking-water reuse. To take a single one, consider the Mississippi River. The Mississippi originates from snow-melt in Canada and then flows north-to-south through the USA. In the north, cities such as Minneapolis withdraw drinking water, use it, and discharge downstream back into the Mississippi. As the water flows south, every other city (eg Memphis) does the same. The city of New Orleans is at the end of the line. The drinking water treatment plants and wastewater treatment plants are conventional plants similar to those common in Australia. There is no reverse osmosis, UV disinfection is relatively rare and nobody really acknowledges that this is clear-and-simple drinking-water reuse. The primary differences with Toowoomba are the lower degree of treatment, the lack of careful planning and the lack of acknowledgement.

In 2001, I was fortunate enough to undertake a research study in Berlin. There I worked with Dr Thomas Heberer at the Technical University of Berlin (Dr Heberer was amongst the first scientists in the world to identify the issue of pharmaceutical residuals in the environment). A similar situation to the Mississippi exists with the Spree River in Berlin, which in dry weather has been shown to be comprised of up to 70% treated effluent.

This type of “unplanned” drinking-water recycling is admittedly much less frequent in Australia. However, this has more to do with geography than with public health concerns. Most major Australian cities are along the coast. Thus they are at the hydrological bottom of their catchments. In other words, there are no major populations up-stream to add treated effluent to down-stream catchments. Nonetheless, there are numerous smaller examples of unplanned (or unacknowledged!) drinking-water reuse in Australia. Consider the Richmond (Western Sydney) drinking water plant that is directly downstream of treated effluent discharged from Penrith Sewage Treatment Plant. While I don’t have the figures at hand (and Sydney Water may be reluctant to release them!), it is clear to any water scientist in this city that (in dry weather) the proportion of water extracted at Richmond that is derived from treated effluent is comparable to the proportion proposed for Toowoomba.

The next point that I can address regards the difference between “direct drinking-water recycling” and “indirect drinking-water recycling”. I am very grateful for an opportunity to address this since it has clearly not been adequately (and honestly) discussed in Australia until now. There are two reasons for the preference for “indirect drinking-water recycling”:

1) By far the most significant reason has been public perception. It has been assumed (and, in fact, scientifically established) that communities are more easily able to accept the concept of indirect recycling. There is a sense of security to be gained by the idea that water returns to the environment before being extracted again for reuse. This “psychological” sense of security exists regardless of any real bearing on real advantages of the practice. However, in most circumstances, it has been politically convenient to work with it rather than against it. Singaporean authorities will not be happy with me saying so, but honestly, what is so “indirect” about that scheme? The recycled water is pumped directly into the drinking water reservoir. Unless the rate of water use can be perfectly matched (24 hours per day) with the rate of clean water production, some sort of storage reservoir is an engineering necessity.

2) Well managed water recycling requires “multiple barrier” protection. Many and diverse barriers are available. These may include numerous treatment processes with an in-built degree of redundancy (or, if you prefer, “surety”). Examples include more than a single-pass reverse osmosis system or subsequent processes such as ultraviolet treatment. “Indirect recycling” offers additional options for multiple barriers since environmental residence can act as such a barrier since any pathogens can be further removed by either underground residence (adsorption to soils and exclusion from light) or residence in surface waters (exposure to disinfecting sunlight).

I am personally prepared to stand by the contention that direct drinking-water recycling can be equally as safe as indirect drinking-water recycling. It all comes down to comprehensive risk assessment and risk management. However, since no Australian schemes are currently advocating “direct” drinking-water recycling, there is no need to convince anyone about this!

As for concerns expressed by Morris Iemma and Peter Beattie, permit me the opportunity to observe that these guys are politicians, not scientists. They respond to their own research regarding “public perceptions”. If their “concerns” can be properly enunciated, I would be most happy to respond to them.

I should point out that it is not my ambition to coerce the citizens of Toowoomba (or Goulburn, or any other city) into accepting any proposed scheme. However, water recycling is an important national issue and I would like to think that if any scheme (or the broader concept of drinking-water recycling) falls foul of public favour it will not be the result of widespread public lack of knowledge or acceptance of good science. I believe I have something constructive to offer in this arena and that the scientific community in general has a responsibility to help inform the debate.

Just as Lyle is (clearly) not a "flat earth Luddite", I can assure readers that I am equally not a one-eyed "recycling-at-all-costs" obsessive.

Lets talk.


Tuesday, May 16, 2006

Fears won't wash: We have to learn to trust recycled water

To kick off the discussion, below is an opinion piece that I prepared and the Courier Mail were kind enough to print today. Any feedback welcome.,20797,19152290-5003427,00.html

Fears Won't Wash

We have to learn to trust recycled water, writes Stuart Khan

May 16, 2006

HERE'S a fact that should shock nobody: Drinking raw sewage is bad for you. It will make you sick and soon enough it will kill you. There are many thousands of toxic chemicals in this world and most of them can find their way into sewage by one route or another.

But the most important and irrefutable fact is that dirty water can be cleaned.

Dirty water is constantly being cleaned by nature. If it were not, there wouldn't be a drop on Earth left to drink.

In the 21st century we are fortunate that we can also clean dirty water with technology. Reverse osmosis is a process by which dirty water is filtered clean of almost all dissolved chemicals. By applying a very high pressure, H2O molecules are selectively forced through nanoscopic pores of a synthetic membrane, leaving other chemicals behind.

Trying to squeeze larger chemicals such as human hormones through a reverse osmosis membrane is like trying to push a golf ball through a tea strainer. Reverse osmosis is so effective that some important ions such as carbonate need to be re-added to stabilise the over-purified water.

It is now well acknowledged among scientists that the major hurdle left to overcome for water recycling is not a technical challenge but one of public acceptance. The very concept of recycling treated effluent for drinking invokes a multitude of emotional responses.

Humans are naturally repulsed by the idea of drinking water we perceive to have been contaminated. Thousands of years of evolution have brought a survival disadvantage to individuals who have not shared this repulsion. However, that evolution has been in the absence of modern water treatment technology. The inclination remains as relevant as ever but it is now in our interest to trust good science coupled with excellent risk management practices.

We should not blindly accept that any technology is infallible. When dealing with water recycling we can and must demand that there be measures in place that stringently manage and control potential risks to public health. We make such demands in relation to our traditional drinking water supplies and must demand the same high standards regardless of the source.

Australian drinking water guidelines require thorough risk assessment and management. This involves identifying potential chemical hazards, implementing more than a single barrier to protect us from these hazards, and comprehensive monitoring to ensure that this protection is successful. Exactly the same approach can be successfully applied to any drinking water source including recycled water.

National guidelines are currently being developed for water recycling. However, they do not yet include replenishing drinking water supplies as a use for recycled water. Given the growing interest in such practice, Australian governments must now urgently address this shortcoming.

Australians considering major water recycling projects are entitled to expect properly developed risk-management guidelines. However, once appropriate guidelines are in place, we should be confident that public health will be wholly protected by complying water recycling schemes.

The single lingering impediment to recycled water may be our reluctance to overcome our deep-set fears.

This will require a degree of trust from the community towards scientists, regulators and public officials.

Trust is something that cannot be purchased, but must be earned. The means to earning trust involve honesty, transparency and a sincere opportunity to take part in decision-making.

Australians must now work together to focus on these social dimensions of water recycling to benefit from the significant advantages of sustainable 21st-century water supply systems.

Dr Stuart Khan, Centre for Water and Waste Technology, University of New South Wales

Hello and welcome to the Water Recycling in Australia blog.

I intend to use this space for a rational facts-based discussion of issues associated with proposed and existing water recycling schemes in Australia.

In particular, I hope this will soon be a useful resource for communities concerned about public health and environmental risks associated with water recycling.

Anybody with an interest in these issues is very welcome to participate in the discussion and I will do my best address specific issues as they arise.

I very much accept that emotional factors are relevant and legitimate concerns requiring significant consideration. However, my one request is that people wishing to post comments on this blog try to refrain from emotional outbursts. I propose that it is possible for adults to discuss their concerns in a calm and rational manner as long as all parties agree to take the concerns of others seriously.

I expect that there will commonly be instances where I do not agree with opinions expressed by some participants. However, I hereby pledge not to ridicule or belittle such opinions, but to do my best to provide scientifically robust explanations as to why I consider an alternative point of view to be justified.

I hope this blog will be a useful, informative and entertaining experience for you!