Saturday, December 30, 2006

Activated Carbon Treatment

This post is a continuation of the series of articles aimed at providing some degree of in-depth understanding of various water treatment processes that may be considered for recycling applications. The topic this time is activated carbon treatment. Consistent with previous such posts, I have provided a couple of references at the end for those who may be inspired to research the topic further (or check that I’m not making it up as I go along!).

Activated carbon is a form of carbon usually derived from charcoal. The term ‘activated’ refers to the way the carbon has been prepared to enhance its ability to physically ‘adsorb’ chemicals to its surface. Adsorption is the accumulation of a dissolved chemical (solute) onto a solid surface.

Activated carbon

An important property of activated carbon is its extremely high surface area. One gram (about a teaspoon full) of activated carbon can have a surface area of 400-2000 square metres. By comparison, a tennis court is about 260 square metres. A microscopic view of activated carbon reveals a complex web structure intermingled with trapped smaller particles. There are many nooks and crannies, which provide excellent conditions for adsorption of suitable chemicals.

Activated carbon is widely used in drinking water treatment for the removal of certain chemicals. The chemicals for which activated carbon is most effective are those which are relatively non-polar in their chemical structure.

A term commonly applied to describe chemicals is their degree of ‘lipophilicity’. Lipophilic chemicals are generally non-polar chemicals that are accumulated in lipids (fats and oils). The same properties that tend to make chemicals accumulate in lipids also tend to make them well adsorbed to activated carbon. Therefore, lipophilic chemicals are chemicals that are generally well removed from water by activated carbon treatment.

The most common applications of activated carbon for water treatment are known as granular activated carbon (GAC) and powdered activated carbon (PAC). These terms simply refer to the physical form (particle size) in which the activated carbon is applied. Smaller particle sizes (PAC) tend to have higher surface areas while large particle sizes (GAC) tend to be more easily separated from the water subsequent to treatment. PAC is often used by direct addition to water with mixing and then separated by gravity and/or filtration. Alternatively, GAC is more commonly used as filtration media with the water being percolated through it.

PAC and GAC are effective for the removal of a diverse range of lipophilic organic compounds as well as well as some relatively lipophilic inorganic compounds such as nitrogen, sulphides and heavy metals. However, more polar compounds are relatively poorly removed by activated carbon adsorption.

The parameter most commonly used to describe how well a substance can be adsorbed to activated carbon is known as the Freundlich capacity factor. The Freundlich capacity factor is determined experimentally by testing various ratios of chemical concentration and activated carbon surface area in otherwise clean waters under controlled conditions. A high Freundlich capacity factor indicates that the chemical is very effectively adsorbed, while a low Freundlich capacity factor indicates that the chemical is poorly adsorbed.

The range of Freundlich capacity factors for potential water contaminants is extremely wide. For example, polychlorinated biphenyls have Freundlich capacity factors greater than 10,000 while N-nitrosodimethylamine (NDMA) has a Freundlich capacity factor of around 0.0001. Furthermore, specific mixtures of compounds in a raw water source will affect the adsorptive capacity for each compound.

In 2005, a group of researchers from Arizona State University, Northwestern University (Illinois) and Southern Nevada Water Authority published a paper investigating the fate of endocrine-disruptors, pharmaceuticals, and personal care products during simulated water treatment processes [1]. For this research, they collected raw drinking water supplies and artificially spiked in high concentrations of 62 different chemicals. These waters were then treated by a number of laboratory-scale water treatment processes including PAC. Addition of 5 milligrams per litre of PAC with a 4-hour contact time removed different compounds by between 10% to greater than 98%. Higher PAC dosages improved the removal of most compounds. This study confirmed that the removal effectiveness for specific chemicals could be reasonably well predicted based on their lipophilicity.

GAC has also been shown to be effective for the removal for some important organic chemical contaminants in water. For example, a group of researchers in Germany has investigated the removal of selected pharmaceuticals during a range of drinking water treatment processes [2]. This study revealed GAC filtration to be an effective method for removing most of the studied compounds. The image below shows the relative concentrations of some of these compounds that were actually measured in raw drinking water sources (that is, they were not artificially spiked in). It can be seen that GAC treatment, in combination with other conventional treatment processes, significantly removed most of the pharmaceuticals. In a number of cases, remaining concentrations were reported to be below the limit of quantitation (LOQ). This simply means that the concentrations were too low to be reliably measured.

Click to Enlarge

These studies are consistent with the conventional understanding and application of activated carbon treatment processes. Like all water treatment processes, activated carbon is not a silver bullet and is not intended to be so. However, used as a component of a carefully selected suite of treatment processes, activated carbon has an important role to play in water purification.

As always, I'd be grateful for your comments...


[1] Westerhoff, P., Yoon, Y., Snyder, S. and Wert, E. (2005) Fate of endocrine-disruptor, pharmaceutical, and personal care product chemicals during simulated drinking water treatment processes. Journal: Environmental Science and Technology, Volume: 39, Issue: 17, Pages: 6649-6663.

[2] Ternes, T. A., Meisenheimer, M., McDowell, D., Sacher, F., Brauch, H.-J., Haist-Gulde, B., Preuss, G., Wilme, U. and Zullei-Seibert, N. (2002) Removal of pharmaceuticals during drinking water treatment. Journal: Environmental Science and Technology, Volume: 36, Issue: 17, Pages: 3855-3863.

Since I stole the nice activated carbon image from another website, I suppose it would be polite to point you to their site as an example of a company that supplies GAC and PAC for a wide range of applications...not just drinking water treatment.

Tuesday, December 19, 2006

LA Health Effects Study 1962-1981

I’ve been crawling around some dark and dusty corners of the UNSW library, tracking down some old reports on health effects studies of recycled water. Brushing aside the cobwebs, I found a paper published in 1984 by Dr. Ralph Frerichs from the UCLA School of Public Health (see bottom of this post for the full reference).

Dr Frerichs’ study was undertaken in eastern Los Angeles County of California, which had been intentionally recharging underground drinking-water supplies with treated effluent since 1962. Although water extracted from the recharged system consistently met current drinking water standards, there was concern that potentially hazardous substances may have been either overlooked or not considered due to low concentrations.

The proportion of recycled water in drinking water supplies was (and is) variable in different parts of LA. In order to monitor the health of the population potentially exposed to unknown water contaminants, four separate study areas were identified. In two of the areas (the northwest and central control areas) drinking water did not contain any recycled water. In the third area (low recycled water area) households received less than 5 per cent recycled water. In the fourth area (high recycled water area) households received 5 per cent or more recycled water. During the course of the study (in the mid-1970s), the proportion of recycled water increased to nearly 16 per cent in the high recycled water area and 6 per cent in the low recycled water area. At the time, around 1.2 million people resided with the combined four study areas.

A study that examines the health statistics of a population in order to try to identify causes of illness is called an epidemiologic study. Such a study was undertaken in the four LA areas, starting with data from 1969 and going through until 1980. This part of the study relied on census health data and a local cancer surveillance program which was established in 1972.

In addition, a household survey was conducted in 1981 among approximately 2500 women living in the central control area and the high recycled water area. This survey was added to pick up information about adverse reproductive outcomes such as miscarriages; general indicators of illness such as bed-ridden days; possible confounding effects such as alcohol consumption and cigarette smoking; patterns of water consumption; and general morbidity (illness).

The health and disease outcomes included in the monitoring program are shown below.

Existing Vital and Health Data

Mortality (deaths)
1. Death due to all causes
2. Diseases of the heart
3. All cancers (malignant neoplasms)
4. Cancer of the stomach
5. Cancer of the colon
6. Cancer of the rectum
7. Cancer of the bladder
8. Death due to all other causes

Morbidity (illnesses)
9. All potential waterborne diseases
10. Hepatitis A
11. Shigellosis

Birth Outcomes
12. Low weight birth (less than 2,500 gms)
13. Very low weight birth (less than 1,500 gms)
14. Neonatal deaths
15. Infant deaths
16. Congenital malformations at birth

Cancer Surveillance System Data

Incident Cases
17. Cancer of the stomach
18. Cancer of the colon
19. Cancer of the rectum
20. Cancer of the bladder

Household Survey of Women

Adverse Reproductive or Gynecological Outcomes
21. Infertility
22. Menstrual problems
23. Congenital defects
24. Spontaneous abortions (stillbirth)

Functional Impairment
25. Restricted activity days
26. Bed-disability days
27. Hospital-bed days

The relative incidences of these health effects were statistically analysed in the four study areas. The effects of several confounding variables were controlled for where appropriate, including age, sex, race, age of mother and birth weight.

If the consumption of recycled water contributed to excess disease or death, we would expect the relative incidences to be greatest in the high recycled water area, intermediate in the low recycled water area, and similar to the remainder of LA County in the two control areas. Furthermore, we would expect this dose-response relationship to be more amplified in the later years of the study since the concentration of recycled water gradually increased.

Some minor statistical differences were observed between the study areas, including deaths due to all cancers, cases of shigellosis, very low births, and neonatal mortality. However, for none of these factors, were the differences in a direction that would support the hypothesis that increased concentrations of recycled water contributed to excess disease.

In the household survey, no significant differences were observed between the two groups of women in restricted-activity days, bed-disability days, hospital bed-days, or recent contacts with a health professional. Nor were differences observed in the rate of spontaneous abortions, congenital malformations, menstrual problems, or problems of fertility.

The authors of the study summarised their conclusions as follows:

While we can never ensure the complete safety, it is reasonable to assume that the disease risk attributed to the consumption of reclaimed water has been minimal for persons residing in the high and low recycled water areas in eastern Los Angeles County. This does not mean that there is no risk. Nor does it mean that there will be no risk in the future. Rather, available epidemiologic evidence provides no indication that the reuse of water has had a noticeable harmful effect. If findings in the on-going water characterization study are also negative, the combined investigations should provide strong evidence to both the public and to the responsible governmental officials as to the relative safety of water reuse.

All studies of this type have their limitations (people moving into and out of areas, unidentified confounding factors, limited sensitivity to detect extremely low risks, etc). I know that 1984 -when the paper was published- was a long time ago, but I still think this is a nice piece of epidemiology.

What do you reckon?


Source: R.R. Frerichs “Epidemiologic Monitoring of Possible Health Reactions of Wastewater Reuse”. Journal: The Science of the Total Environment. Vol: 32, Year: 1984, Pages: 353-363.

Wednesday, December 06, 2006

A more appropriate argument

An argument is brewing over recycled water in Texas, USA.

The situation is a bit like Toowoomba in some ways: An inland city (in this case Dallas) has witnessed water resources being depleted over the last few years, while populations continue to rise. The city sits towards the top of an important river system (The Trinity River) and currently discharges treated effluent into that river. A plan has been developed to reduce that discharge and recycle the water for Dallas to use again.

There is growing disagreement about whether it is acceptable to recycle the water in Dallas or if it should be left to flow downstream as it currently does. However, this is where the comparisons with Toowoomba end. You see, downstream towns and cities on the Trinity River consider the “unplanned” recycled water that they receive to be a valuable resource. While some Australians refer to such schemes as “bad practice” [which, I notice has recently evolved to “bad science”], Texans are prepared to fight for it.

The city of Dallas operates two sewage treatment plants, -Central WWTP and South Side WWTP. Since 2003, Dallas Water Utilities has been developing a plan to upgrade the effluents from these plants and convey these back to city’s main storage reservoirs, Lewisville Lake and Lake Ray Hubbard.

The figure below was presented by Dallas Water Utilities personnel at a conference that I attended in 2005. It is not currently a formal plan of the agency, but shows in concept the types of ideas that are under consideration. Click for a larger image.


Dallas Assistant City Manager, Ramon Miguez, says that in the long term Dallas intends to supplement its supply with 60 million gallons of recycled water per day. However, there is now concern that newly developing legislation will prevent the city from keeping the water for its own use. Under this expected new legislation, the State of Texas could require the city to apply for a special permit to recycle the water instead of allowing it to flow downstream. In other words, the State could overrule any plans from Dallas that may reduce the volume of recycled water available for downstream communities.

The Trinity River supplies water to a number of very dry cities as it makes its way down to the Gulf of Mexico. Towards the bottom, the State’s largest city, Houston imports part of its supplies from the river to supplement its own diminishing groundwater supplies.

A lobbyist hired to represent Dallas’ interests was quoted this week as saying [be sure to read this with a Texan accent!] “if a powerful lobby of parched cities across Texas demands that Dallas send more water down the river, North Texas could see decades of deliberate planning flushed away”.

State Representative, Robert Puente, says the legislation will be based on science, not politics [-yes, I know its an unorthodox idea, but I can’t help thinking that it might have some merit]. He said “we need to make sure there’s enough water in our lakes and rivers to get all the way down to the Gulf of Mexico”. That seems like a very fair argument and I am certainly not suggesting that it is not an extremely important consideration.

There’s an argument brewing, to be sure. However, its strangely refreshing to see cities arguing for their right to practice (planned or “unplanned”) indirect potable water recycling. A truly bad practice –or bad science- is the failure to recognise a valuable resource when we see it. Perhaps we’ll work it out one day...

Friday, December 01, 2006

Has Toowoomba already voted NO?

As most readers would be aware, South East Queensland will vote in March on the question of whether to supplement drinking water sources with recycled water. Or as Premier Beattie put it today:

"This (question) basically is: 'Are you or are you not in favour of drinking purified recycled water to a standard that's accepted by health officials around the world'"

Nineteen Shires are to vote, including Toowoomba since that city is considering the possibility of extracting future supplies from Wivenhoe Dam. But ‘hold on’, you say! Didn’t Toowoomba vote no to the same question only five months ago?

I don’t believe they did. I watched that debate fairly closely and was assured by many of the ‘No’ campaigners that there were specific issues associated with the Toowoomba proposal that motivated them to vote no. Here’s how Cr Snow Manners put it three days after the poll:

Posted by Snow Manners of Toowoomba on Tue 01 Aug 06 at 03:58pm
"The Toowoomba debate was not about drinking recycled water. It was about a community considering it options, dam water, bore water, rainwater or sewage water. Sewage water was not the preferred option (apparently). The other options are now being more closely examined. People of Toowoomba also expressed concern that they were never given the opportunity to provide inputs to Council about their preferred options. Toowoomba has a very high proportion of tertiary educated people in the community by virtue of being a city of 100,000 people with a major University and a host of highly respected private schools serving western Queensland and also by virtue of having major corporate offices and government headquarters serving that huge region as well as being a centre for medical specialists serving the region. Other trade professionals and ordinary folk are not ill informed either. As a chosen retirement destination for farmers and graziers there are a lot of practical people in the city. Toowoomba’s choice was an educated and intelligent decision about options not a potable reuse debate."

Another “No” campaigner, “John C” left variations of the following two messages on numerous websites and blogs in the days following following the poll:

John C Says: August 20th, 2006 at 2:17 pm
"The problem with the recycled sewage plant proposed for Toowoomba is that it just would not work. It is not possible to produce 11,000 ML of recycled water from 8,000 ML of sewage. Toowoomba City Council also had nowhere for the RO waste stream to go. Acland Coal did not want it. Singapore pumps its RO waste stream into the sea. The plant could never have been built for $68 million - closer to $150-200 million would be more accurate when you take into account the hundreds of acres of evaporation ponds required which were not included in the budget. Regardless of your view on recycled water use, the No vote in Toowoomba was correct because the proposal was a dud".

John c says: July 31st, 2006 at 11:06 pm
"Many people in Toowoomba voted No, not because of any scare tactics, but because they had read the Council’s NWC funding application that Mayor Thorley tried to keep secret. This document showed the project as being fundamentally flawed. The Water Futures project was never a solution - where was the RO waste stream going to go. Where was Thorley going to hide it? Acland Coal didn’t want it. Without their involvement, the project’s cost doubled. How high would rates be then? You will be surprised at how quickly other water source options are now adopted for Toowoomba".

In addition to the issues raised by Cr Manners and “John C”, many people expressed concern about the loss of the water that currently flows from the Wetalla Sewage Treatment Plant, eventually into Oakey Creek and the Condamine River. This water is a recognised valuable resource to irrigators in the region and the loss of that water may have caused considerable hardship in these times of severe drought. Finally, there was widespread concern that the Toowoomba scheme would not solve current water shortages since it would not be online for a number of years.

Of course, all of these people will realise that any proposal involving recycled water from Luggage Point to Wivenhoe Dam will be quite a different proposal. Only those who voted according to some ideological opposition or support for (planned) potable recycling would suggest that their vote for Toowoomba is automatically transferable to the proposed South East Queensland Scheme.

People would not have raised the above issues if these did not significantly contribute to the decisions that they ultimately made.

Don’t you reckon?

Sunday, November 26, 2006

Today RO, tomorrow FO?

Here’s a challenge for any budding scientists/inventors out there. It’s a promising concept for advanced water treatment. However, it is currently very much more a ‘concept’ than it is a ‘reality’ for large scale implementation.

Australians have been actively talking about municipal water recycling and desalination for a couple of years now. Many people have been interested enough to find out about one of the most touted technologies for these processes, being reverse osmosis (RO). For a very quick refresher on the general principal of RO you might like to skim through my previous post on seawater desalination.

RO has the potential to clean almost any water to practically any quality we may desire. However, there are two major limitations to RO. The first is considerable energy requirement to force saline water through a semi-permeable membrane against an osmotic pressure pushing in the opposite direction. The second is the production of large volumes of concentrated brine which must somehow be disposed of.

Researchers at Yale University (USA) are working on a novel potential answer to these limitations. Rather than working against the osmotic pressures of RO, Prof Menachem Elimelech proposes a concept that makes the osmotic pressure his ally. The process is called forward osmosis (FO).

Unlike RO, the driving force for FO separation is osmotic pressure, not hydraulic pressure. By using a concentrated solution of high osmotic pressure called the “draw solution”, water can be induced to flow from contaminated or saline water across a semipermeable membrane, leaving the dissolved contaminants behind. The (now diluted) draw solution can then be reconcentrated, yielding purified water and a “draw solute” ready to be recycled in a closed loop.

Identifying suitable draw solutions is currently the largest obstacle to the successful large-scale implementation of FO water treatment. Ideally, draw solutes should be those that can be easily chemically or thermally precipitated from solution for removal. Some researchers have proposed the use of dissolved gases that can be removed by thermal means, or the use of larger molecular weight solutes that can be separated by physical means.

An ideal draw solute would have a high solubility, a low molecular weight, and a way of easily being removed from the water. High solubility coupled with low molecular weight allows for the generation of large osmotic pressures which lead to high product water transport across the membrane and high purified water recoveries (ie. minimal brine volumes). The ability to be easily removed from the water is crucial since the overwhelming majority of the energy used in the FO process is for draw solute recovery.

Ideas for using FO for water purification processes have been around for some time and a small number of studies have been published since the mid-1970s. Furthermore, a number of patents have been awarded, but none of these have really matured or proven practical for implementation. Interestingly, the US space agency NASA is currently investigating FO for direct potable reuse of wastewater in advanced life support systems for space applications.

One draw solution currently being investigated is composed of ammonium salts which are formed when ammonia and carbon dioxide gases are mixed in water. Once the concentrated draw solution is used to effect separation of water from the feed source, the subsequently diluted draw solution may be treated thermally to remove the ammonium solutes, producing purified water as the primary product.

This thermal separation of draw solutes is based on the useful characteristic of these ammonium salts to decompose back into ammonia and carbon dioxide gases when the solution is heated. If the process is done under vacuum, the necessary applied temperature can be as low as 40°C, meaning that low grade “waste heat” from other industrial processes may be a viable energy source.

However, current methods for fully recovering the ammonia and carbon dioxide gases from the product water are still relatively inefficient and still render the overall process relatively energy-intensive. Therefore, further improvements are required for draw-solute recovery to improve the overall viability of FO for large-scale implementation.

Any good ideas?

Tuesday, November 21, 2006

Politics of IPR in Queensland

I don’t want to get too caught up in politics, but this has been an interesting week for water recycling in Queensland (and its only Tuesday!). I thought it would be useful to provide an update on where the major political players stand in that State. The issue, of course, is indirect potable water recycling (IPR)…involving using highly treated effluent to (intentionally and openly) supplement dwindling supplies in Brisbane’s Wivenhoe Dam.

QLD Premier Beattie has proposed a community poll on the issue, originally slated for 2008. However, Beattie now suggests a South East Queensland poll may be required as soon as next year.

QLD Liberal Leader Dr Bruce Flegg says forget the poll and get on with water recycling as a matter of urgency.

Labor and Liberal members of Brisbane City Council voted today to support any poll, but Liberal Councillor Jane Prentice agrees with Dr Flegg that such a referendum is a waste of time and Beattie should just bight the bullet.

Brisbane (Liberal) Lord Mayor Campbell Newman is a strong supporter of IPR and was prepared to say so long before most.

The State Nationals Leader Jeff Seeney says it is “the Coalition’s vision to ensure all of Queensland’s waste water was recycled to put an end to ocean outfalls”. However, Seeney’s support is for a pipeline to carry recycled water for industry and agricultural use. He has stopped short of supporting IPR except as a “a worst-case scenario”. He says “there would be no decision on whether to support the recycled water referendum until the question's wording was revealed”.

Democrat Senator Andrew Bartlett has been a tireless campaigner for water recycling as an alternative to building new dams in Queensland.

The Queensland Greens have a formal policy supporting IPR as a component of overall urban water management.

So there you have it. In South East Queensland at least, the political differences appear largely to have moved on from support or opposition to IPR. Of course, not everyone supports it but the main differences now seem to revolve around details like whether a poll is appropriate or an unnecessary delay, and just how urgent things need to get before action should be taken.

Friday, November 17, 2006

Ask a stoopid question...

In June last year Toowoomba City Council (TCC) submitted a proposal to the Commonwealth Government for co-funding of a planned indirect potable recycling scheme to supplement that city’s dwindling water supply.

The Commonwealth Government would provide one third of the scheme costs through the National Water Commission (NWC). The Queensland State Government would also contribute one third on the basis that the NWC funding was forthcoming. TCC would be responsible for funding the remaining third. Early indications were that the NWC would support the proposal and even the local member of Federal Parliament (Ian MacFarlane) publicly expressed support.

A month later, Mr MacFarlane received a community petition opposing the co-funding of TCC’s proposal. The petition carried the weight of around 7000 signatures and MacFarlane quickly changed his tune. He claimed to have been misled about the details of the proposal and the established safety of (planned) potable water recycling.

MacFarlane responded by asking Malcolm Turnbull to make any NWC approval of co-funding conditional on a positive outcome of a community poll. MacFarlane’s request was approved and the City of Toowoomba went to the polling booths on 29th of July 2006. The question posed was simply:

“Do you support the addition of purified recycled water to Toowoomba’s water supply via Cooby Dam as proposed by the Water Futures Toowoomba Project?”.

The answer was a resounding “No” (62% of formal votes). The only other option provided was “Yes” and the whole process provided no viable solution.

As far as I am aware, Toowoomba is the only city on Earth to have been given the opportunity to vote (directly) on its potable water supply source. But MacFarlane and Turnbull appear to have set a precedent. Queensland Premier Peter Beattie has since indicated that he intends to call a similar planned potable water recycling poll for Brisbane in 2008. A few individuals are now demanding a poll in Goulburn (NSW). But is this an effective approach for addressing imbalances in a city’s water supply and demand?

Even Toowoomba’s prominent “No” campaigners expressed dissatisfaction in the limited options provided for in the “Yes” or “No” poll. (Almost) all members of the Toowoomba community appear to agree that new water management strategies are required, but no opportunity was provided to properly evaluate, compare or express preferences for alternative strategies. What’s the point in rejecting one option without identifying an alternative? Ironically, Malcolm Turnbull should be as aware as anyone of the perils of an inadequate referendum question.

Planned potable water recycling has much to recommend it, but it makes little sense when considered in isolation. All water supply options come with costs (economic, social and environmental). Once a specific proposal was announced, seawater desalination became extremely contentious in Sydney and similar community sentiments are now unfolding on the NSW Central Coast. Peter Beattie’s recent announcement of plans to build a new dam to supply Brisbane was met with community outrage. Historical plans for a new dam for Sydney (on the Shoalhaven River) have been shelved after extensive investigations have revealed significant environmental, social and economic costs, coupled with the long term inadequacy of such a dam.

I suggest that communities forget about “Yes or No” polls and consider alternative forms of effective participation in decision making. It is thoroughly inadequate to vote on a question that allows for the possibility of no viable solution to be the preferred outcome.

A better approach is to provide a choice between a range of fully evaluated options. Allow the community to identify the options and provide a clear indication of the social, environmental and economic consequences of each one. Its likely that none of the options will attract an outright majority of the vote, so a preferential voting system will be essential.

If the issues involved are highly complex (which in many cases they will be), an effective approach may be to engage the services of a ‘stakeholder jury’ (or ‘citizen’s jury’).

A stakeholder jury process replicates a court-room procedure. Stakeholder juries typically comprise 10-15 representative stakeholders who consider a particular issue and decide for or against a proposal. Alternatively, juries may be tasked to identify the most favourable of a defined list of proposals. The community should be given the opportunity to nominate jury members (or even elect them).

The jury hears or reads evidence from expert witnesses and jury members are able to question the witnesses directly. The process may last several weeks until the jury reaches an informed decision. The jury may then prepare a short report summarising the debate leading to the decision reached.

A major benefit of stakeholder juries is that they allow participants to select and pursue their own lines of enquiry. They support detailed consideration of key issues or sticking points and may help identify relative levels of concern about specific issues. Members of the public may be invited to make detailed submissions for the jury to consider before making their decision.

There are many options for effective community participation in identifying solutions to Australia’s current water woes. Not only is such participation appropriate, it has the potential to deliver the optimum solutions to what is becoming an exceedingly difficult problem with long-term repercussions. Has the jury reached a verdict?

Friday, November 10, 2006

A closer look at UV treatment

I have been catching up on some recent research about the use of UV radiation for water treatment and thought I would share some of it with interested readers.

Most of this research comes from Associate Professor Karl Linden and his research group at Duke University in North Carolina. I have made an effort to cut out some of the technical jargon without over-simplifying the findings. I hope you will find it readable and worthwhile. For those who are interested in the detail of the studies, I have included a number of references at the end. These are generally not freely available on the internet, but if you ask me politely (okay…even if you choose to abuse me), I’ll try to get you a copy of the papers that you are interested in. You’ll find my email address by clicking on my profile, above. Okay, here goes…

Ultraviolet (UV) radiation is an effective disinfectant in water and is used widely for this purpose in many developed countries including Australia. The disinfecting properties of UV radiation are due to the ability of certain wavelengths to penetrate the cell walls of microorganisms and be absorbed by the nucleic acids (components on DNA and RNA). The effect may be to either cause the death of the cell or to prevent it from replicating. The portion of the UV radiation band that is most effective for inactivating microorganisms is between about 220 and 320 nm. This is known at the ‘germicidal band’.

UV disinfection is generally more effective than chlorine for inactivation of most viruses, spores and cysts. However effective inactivation some of these organisms require higher UV doses than is used for some disinfection systems aimed primarily at bacterial organisms.

UV lamps for water treatment come in two main types known as ‘Low Pressure’ and ‘Medium Pressure’. Low pressure UV lamps generate radiation at mainly a single wavelength (254 nm), which is close to the most effective germicidal range. Medium-pressure lamps generate radiation at numerous wavelengths within the germicidal band. Only about 7 to 15 per cent of the output is near 254 nm, however the total germicidal output can typically be 50 to 100 times that of low pressure lamps.


In addition to microbial disinfection, UV radiation can also be used (directly) to break down organic chemicals in water [1; 2]. Organic chemicals are affected by UV radiation at various wavelengths in the 200-300 nm range, with degradation generally dependant on the presence of aromatic rings or double bonds or triple bonds.

In 2000, The Orange County Water District in California detected small concentrations (nanogram per litre) of the carcinogenic chemical nitrosodimethylamine (NDMA) in their Water Factory 21 scheme. The problem was quickly resolved by the addition of a UV treatment process, which rapidly destroys NDMA.

However, for the purpose of breaking down chemicals, UV radiation is more commonly used to promote the initial formation of hydroxyl radicals (HO.). Hydroxyl radicals are about the most powerful oxidising agents known and are much more effective at breaking down chemicals than direct UV radiation. Processes that promote the formation of hydroxyl radicals are known as Advanced Oxidation Processes (AOPs).

UV-AOPs can be achieved by a number of methods including ‘photocatalysis’ with titanium dioxide (TiO2). However the most common method is by reaction of hydrogen peroxide (H2O2) [3-5] by the following reaction:

H2O2 + UV (200-280 nm) → 2HO.

Oxidation of organic chemicals by hydroxyl radicals is very non-specific and all organic chemicals are ultimately susceptible if sufficient dose is applied [6]. Because of this considerably broader oxidation potential, AOPs can be used to degrade trace amounts of recalcitrant organic chemicals in highly treated effluents.

Once generated, hydroxyl radicals can attack organic molecules by a number of mechanisms. Under suitable conditions, the reaction of hydroxyl radicals with organic compounds may proceed to complete oxidation to produce final products of water, carbon dioxide and salts. This process is known as mineralisation.

The overall extent of oxidation for any AOP is dependant on the contact time and the concentration of ‘scavengers’ in the water (ie non-target oxidisable species). Typically, dissolved organic carbon (DOC) and carbonate/bicarbonate are the most important scavengers in drinking waters or recycled waters. However, pre-treatment processes such as granular activated carbon (GAC) or reverse osmosis significantly reduce DOC concentrations, thus enhancing oxidation efficiency.

In 2004, Linden’s research group published a paper investigating the degradation of some endocrine disrupting chemicals (bisphenol A, ethinyl estradiol, and estradiol) by direct UV photolysis and UV-AOPs [3]. This study included both low pressure UV lamps and medium pressure UV lamps. It revealed that without enhanced hydroxyl radical formation, medium pressure lamps are required for the degradation of these contaminants. However, regardless of which type of lamp was used, the EDCs were much more effectively degraded using UV/H2O2 advanced oxidation. The chemical degradation rate constants for the AOP process were on the order of 10,000,000,000 /M/sec. This means that given suitable initial water quality (achieved by pre-treatment) and sufficient UV/H2O2 dose, these AOP processes can be an extremely effective barrier for these chemicals in water recycling schemes. Some results from the study are shown below (click for a larger image).


[1] Rosenfeldt, E. J., Melcher, B. and Linden, K. G. (2005) UV and UV/H2O2 treatment of methylisoborneol (MIB) and geosmin in water. Journal of Water Supply Research and Technology-Aqua, 54(7), 423-434.
[2] Shemer, H., Sharpless, C. M. and Linden, K. G. (2005) Photodegradation of 3,5,6-trichloro-2-pyridinol in aqueous solution. Water Air Soil Poll., 168(1-4), 145-155.
[3] Rosenfeldt, E. J. and Linden, K. G. (2004) Degradation of endocrine disrupting chemicals bisphenol A, ethinyl estradiol, and estradiol during UV photolysis and advanced oxidation processes. Environ. Sci. Technol., 38(20), 5476-5483.
[4] Shemer, H. and Linden, K. G. (2006) Degradation and by-product formation of diazinon in water during UV and UV/H2O2 treatment. J. Haz. Mat., 136(3), 553-559.
[5] Shemer, H., Kunukcu, Y. K. and Linden, K. G. (2006) Degradation of the pharmaceutical Metronidazole via UV, Fenton and photo-Fenton processes. Chemosphere, 63(2), 269-276.
[6] Shemer, H., Sharpless, C. M., Elovitz, M. S. and Linden, K. G. (2006) Relative rate constants of contaminant candidate list pesticides with hydroxyl radicals. Environ. Sci. Technol., 40(14), 4460-4466.

Wednesday, October 25, 2006

The New Sewage Marketplace

Since 1999 a private organisation called Services Sydney has petitioned the NSW Government with a proposal to provide an alternative sewage service in Sydney. This would involve treating a large proportion of Sydney’s sewage and then piping it west where it would be used in agriculture and to supplement environmental river flows. Services Sydney would make its money by offering customers an alternative sewage service, selling the reclaimed water and participating in water trading markets.

During the 1990s, the Commonwealth Government established means for private organisations to seek access to publicly owned infrastructure under reasonable terms and conditions. We have seen some results of this in the form of private participation in telecommunications and electricity supply. However, little use has so-far been made of these provisions in areas of water supply and management.

Services Sydney’s proposal originally met with considerable resistance from the NSW Government who argued that critical public interests were at stake. While this may be a reasonable argument, I think its fairly self evident that protection of future dividends from the two state-owned water utilities - Sydney Water and Hunter Water - must also have been an important consideration. Services Sydney eventually took their case to the Australian Competition Tribunal. The Tribunal ruled last year that the NSW Government had no case to withhold access to state-owned water infrastructure.

As a result, the Water Industry Competition Bill was introduced to the NSW Parliament this week. This bill provides a means of third-party access to certain components of Sydney Water and Hunter Water infrastructure.

Participating private organisations will not be subject to price regulation, except where they are monopoly providers. Monopoly providers will have their prices set by the Independent Pricing and Regulatory Tribunal, as it currently does for Sydney Water and Hunter Water. The NSW Government has indicated that “Sydney Water and Hunter Water will become ‘suppliers of last resort’; ready to step in to provide essential water and sewerage services if business fails”.

NSW Minister for Water Utilities David Campbell has said that the bill "will open the floodgates for private industry recycling projects while providing safeguards for consumers". This week The Australian reported John van der Merwe, from Services Sydney, observing that the legislation recognised the fact Sydney’s three largest ocean outfalls (North Head, Bondi and Malabar) are now open for competition.

In the meantime, Sydney Water seems to have gazumped some of Services Sydney’s ambitions with recent plans for expanded agricultural use of recycled water in Western Sydney and river-flow supplementation in the Hawkesbury-Nepean River. So if nothing else, Services Sydney’s efforts appear to have already had a positive effect in expanding the recycling of treated effluents in Sydney.

However, the effluents from Sydney’s three major ocean outfalls remain largely unutilised, so further opportunities involving huge volumes of recyclable water still exist. The ball now seems firmly in the court of interested private organisations and it will be most interesting to see how the next set plays out.

Where will it go from here? Will we see rapid beneficial expansion of water recycling in Sydney and the Hunter? How will increased competition affect efficiency? Will services improve for customers? What about the impact on water prices? Will we see the type of disputes that we have witnessed between companies like Telstra and Optus? What do you reckon?

Saturday, September 30, 2006

The Norwin Noose

Nuwater is the name of a lobby group of Queensland irrigators with a keen interest in recycled water. The front page of their website promotes them as "the peak group lobbying for sustainable water use and new water for Darling Downs agriculture".

Nuwater have an impressive list of sponsors, but to give you an idea of where they are coming from, these include Cotton Australia, Queensland Cotton, Central Downs Irrigators Ltd, Namoi Cotton, Darling Downs Cotton Growers Inc, and Cotton Seed Distributors.

Nuwater’s central cause is to have recycled water from Brisbane pumped to the Darling Downs for irrigation. This would involve a pipeline connecting seven sewage treatment plants from Luggage Point STP (Brisbane) to Wetalla STP (Toowoomba) and then out to the Darling Downs Irrigation Area.

The concept seems quite sensible and has a number of obvious benefits. These would include decreased sewage discharge to Moreton Bay, a sure supply of water for Darling Downs irrigators and (hopefully) decreased extraction of natural water sources from the Darling Downs region. However, the major obstacle is the need to pump the water up over the Great Dividing Range. This implies significant energy requirements and considerable costs.

A task force was set up by the Queensland Government during 2001-2003 to examine four variations on this scheme focusing on the Darling Downs and Lockyer Valley. The key outcomes of the task force report were:

• Negative economic (including environmental) outcomes for society.
• Negative environmental outcomes from 2009 to the end of scheme life.
• Negative financial outcomes for the scheme(s) in that it/they recover between 16% and 21% of commercial requirements. The water costs of between $841 per Megalitre (ML) and $1079/ML are well above the $150 /ML price offered.
• Social advantages in employment and population for the receiving areas.
• Hydrological feasibility – but requires management particularly in some specific areas.
• A shortfall where project revenues do not cover operating costs. Revenues recover approximately 22 – 28% of lower bound costs being operating costs and including the cost of capital, without capital recovery. Under agreements reached at CoAG between all states and territories, new water infrastructure projects are required to at least receive revenues at or above the lower bound cost before they can be considered as being eligible for a Government Community Service Obligation payment.



Interestingly, Nuwater participated in the recent Toowoomba City indirect potable recycling debate. As their Spring 2006 newsletter states:

“Most significantly, the Toowoomba water referendum delivered a stunning victory to common sense. As members and sponsors would know, NUWater - through CEO John McVeigh - played an active role in the campaign, urging a No vote to adding 25% recycled sewerage to Toowoomba’s drinking water.”

The Nuwater Winter 2006 newsletter had previously introduced a Nuwater proposal thus:

"So why is NUWater opposed to Toowoomba Water Futures? Put simply, there is a better option - a broader, regional approach which is a true win-win for all. It involves a clean water swap between Oakey Creek Groundwater licence holders, drawing on the vast artesian reserves below the Norwin district, and treated Wetalla water" [Wetalla being the Toowoomba sewage treatment plant].

In other words, a pipeline from Toowoomba would carry recycled water to the Norwin district for irrigators, while a second pipeline from the Norwin district would carry ground water to Toowoomba for potable use.

Shortly before the Toowoomba recycled water poll, a private consultancy - Parsons Brinckerhoff - was engaged to review the various options being proposed to address the city’s water woes. The consultants costed this water swap at around $200 million, which practically ruled the approach out as a viable option.

Nuwater has since revised its proposal and has now offered to simply lease 5000 megalitres a year of water to Toowoomba, at a cost of $40 million (their claim). No supply of recycled water to the irrigators seems to be included in the current proposal. This is strange since it is the complete reverse of the concept that Nuwater was set up and funded to lobby for.

The idea of a small group of Norwin Irrigators leasing water to a thirsty city of more than 90,000 people is somewhat fascinating to say the least. However, it seems that Nuwater have well earned their lobbying fees. The residents of Toowoomba voted against the indirect potable recycling scheme (with Nuwater claiming some credit) and the Norwin proposal remains widely touted as a popular solution for the city.

According to the Nuwater website, ex-Toowoomba City Councilor and State National Party candidate, Lyle Shelton is a member of the Nuwater committee. In fact, Nuwater seem to have broad QLD National Party support with leader Lawrence Springborg also having touted their proposal as a reason for Toowoomba to vote against indirect potable recycling.

Having now celebrated the “No” vote in Toowoomba, it must soon be time for Nuwater to publicly provide a little detail on their proposal. Surely the residents of Toowoomba are keen to find out the conditions of the deal that many seem so keen to enter into?

Water trading is set to become a very important and controversial issue in Australia over the coming decade. Are the Norwin irrigators and the residents of Toowoomba about to set a precedent for the rest of the country?

Investment tip: Buy shares in companies holding large irrigation licenses in close proximity to large desperately thirsty cities.

Monday, September 25, 2006

Planned potable proposals provide pristine perspective

The controversy surrounding recent planned potable recycling proposals seems to have had one very positive outcome. Australians are finally beginning to recognise the realities of the water cycle outside of high school science classes.

Until recently, ignorance about such realities seemed to have been almost actively encouraged. I suppose it made sense. Why would water authorities want to unnecessarily raise awareness of practices that might prove controversial? But with communities now under pressure to consider planned potable recycling schemes, a more realistic understanding of the water cycle has become pertinent.

Serious discussion of potable recycling began in Sydney around two years ago when we were publicly debating alternatives to the proposed seawater desalination plant. In October 2005, the Sydney Morning Herald published an article describing how treated effluent from both Goulburn and Lithgow supplement supplies stored in Warragamba Dam.

By July this year, it was the Queensland State Government themselves that began to promote the common occurrence of “unplanned” potable reuse in that state. The minister in charge of water resources provided the following information to The Australian:

Fernvale, Esk, Lowood, Toogoolawah, Gatton and Laidley pump recycled sewage into the Mt Crosby Weir system, which supplies drinking water for Brisbane, Ipswich, Logan and Beenleigh residents. Dalby and Chinchilla drink Toowoomba's treated sewage, put back into the Condamine River, while Caloundra and Maroochy shires drink Maleny's treated wastewater from the Baroon Pocket Dam. Maryborough drinks from Gympie, Kingaroy drinks its own, Goondiwindi drinks from Inglewood and Beaudesert residents take theirs from Kooralbin.

This week, the (Melbourne) Herald Sun reports that treated effluent is discharged into one of the Yarra River's tributary creeks upstream of the point where river water is pumped into the Sugarloaf reservoir. The Victorian State Government seems keen to talk it down. However, I think that doing so is a disservice to some parched Australian towns and cities. Surely its time that we all just bit the bullet and focused on raising awareness.

If we want communities to identify the fact that potable recycling is absolutely normal, then we really do need to cooperate and encourage an open-eyed understanding of urban water cycles.

Whadda you reckon?

Sunday, September 17, 2006

Recycled water for electricity production

The vast majority of electricity produced in Australia is generated by burning coal. This process uses large volumes of water, much of which is converted to steam (and subsequently lost to the atmosphere). For example, Delta Electricity in NSW report the use of around 1 Megalitre of water for each gigawatt-hour of electricity produced. Given the large volumes of water required in a single location, power production seems like an ideal use for recycled water.

In fact, Australia is a world pioneer of using recycled water for power stations. Pacific Power’s Eraring Power Station supplies around 25 % of the electricity requirements to NSW and has been using recycled water for a decade now.

Eraring Station is located in the Hunter Valley close to the Dora Creek Sewage Treatment Plant. In the mid 1990s a 15-year agreement was signed to enable Eraring to access more than five megalitres of effluent from Dora Creek STP each day. This water is transferred directly to a water reclamation plant at the station where it undergoes further treatment by microfiltration and reverse osmosis.

Access to recycled water provides a sure source for Eraring Power Station. Furthermore, it helps protect the sensitive aquatic environment of Lake Macquarie, which would otherwise be further impacted by treated effluent.

In the last couple of years, Western Australia, Queensland and now Victoria have identified similar opportunities. In these cases, the primary motivation has been to free-up potable water supplies, which are currently used for power production.

Recycled water efforts around Perth have largely focused on an industrial precinct called Kwinana, about 40 km south of Perth. At Kwinana, a centralised water recycling plant supplies 17 megalitres per day to a diverse range of industries, including power production by Western Power.

Shortly before the recent Queensland state election, Premier Beattie announced plans to build a pipeline from Luggage Point sewage treatment plant to Tarong and Swanbank power stations, which are major suppliers of electricity to Brisbane.

In just the last few weeks, Victorian Government plans have been revealed to allocate large volumes of recycled water from Melbourne for use by power plants in the Latrobe Valley, 100 kilometers west. This plan would add more than 20 per cent to Melbourne’s total water supply, significantly increasing security during extended dry periods. It would be a massive water recycling scheme and is estimated to come at a cost of $1-2 billion dollars.

In addition to potable water savings, the Victorian Government plan has plenty of potential environmental benefits to recommend it. Importantly, it would drastically reduce water discharged by ocean outfall at Gunnamatta, southeast of Melbourne. Furthermore, the reduction of freshwater use by the Latrobe Valley power stations would significantly boost flows in the Gippsland rivers (and subsequently add to drinking water supplies for Melbourne).

The primary opposition to the proposal, appears to have been expressed by Victorian National Party leader, Peter Ryan who was quoted this week as saying "The Nationals' view is that Melbourne already receives enough of Gippsland's fresh water and has to learn to live within its water means".

What do you reckon?

Tuesday, August 29, 2006

Taronga Zoo

Sydney Harbour has copped a fair battering from human activities throughout the last two centuries. Recent revelations about the extent of dioxin contamination are a sad reflection of the careless way in which we have used and abused the harbour as a dump for disposal of a wide range of wastewaters. Contaminated sources have included considerable industrial discharges, municipal wastewaters and urban stormwater.

A decade ago, the cocktail discharged to Sydney Harbour included one more unusual source of contaminants. Elephants, tigers, camels and giraffes contributed to wastewater discharged from Taronga Zoo on Bradley's Head.

Between 1989 and 1992, Mosman Council’s water quality monitoring showed high faecal coliform counts at beaches adjacent to the zoo. At that time, water from the animal enclosure wash downs and all stormwater was being discharged directly into the harbour causing concerns for public health, beach closures and complaints from local residents.

But the situation was dramatically improved in 1996 with the implementation of a modern water recycling scheme. At a cost of $2.2 million, the scheme was developed with the assistance of Sydney Water, The NSW Department of Health and Clean Up Australia. It now treats between 100 and 650 kilolitres of water onsite each day.


Wastewater at Taronga Zoo consists primarily of stormwater, hose washings from animal enclosures and moat fillings. The first flush runoff and wastewater from enclosure wash downs and moats are now directed through the water recycling plant.

At the plant, the water flows through a screen and grit removal chamber for the removal of large solids. Next it undergoes a biological aeration treatment process to degrade dissolved organic chemicals. Biological treatment is succeeded with a hollow-fibre microfiltration membrane process. In addition to suspended particulates, the microfiltration process is effective for the removal of many bacteria and viruses. Ultraviolet disinfection is then used to inactivate remaining pathogens.

The recycled water is redistributed around the zoo via a separate reticulation system comprising two and a half kilometres of PVC pipe. The water is then reused for lawn and garden irrigation, animal exhibit hose down, moat filling as well as toilet and urinal flushing within the zoo.

A decade on, the water recycling scheme has proved its worth in achieving its original aim of reducing and improving discharged water quality into Sydney Harbour. An additional benefit has been a considerable reduction of use of Sydney’s dwindling fresh potable water supplies. This reduction has led to water bill savings for the zoo of around $70,000 per year.

Taronga Zoo’s water recycling scheme is a relatively simple, but highly effective innovation, providing a great precedent for zoos and other animal-housing operations throughout the world. I'd be keen to hear of any similar good opportunities that you can think of.

Tuesday, August 15, 2006

Lessons from Toowoomba

It is now more than a fortnight since the City of Toowoomba voted ‘no’ to an indirect potable water recycling proposal. The outcome of the poll will have been cause for concern for other towns and cities currently considering similar proposals.

However, having watched the Toowoomba debate closely (if from a distance) and communicated with a number of prominent ‘yes’ and ‘no’ campaigners, I have arrived very firmly at one conclusion: Overwhelmingly, the people of Toowoomba did not reject the concept of potable water recycling, they rejected the process being used to introduce it. The concept may have been workable, but the process deeply flawed.

Accordingly, I present some lessons from Toowoomba, which community leaders in Australia may like to closely consider.

1. Involve the community early

If potable water recycling is subject to serious consideration, now is the time to say so. Planning first and informing later is a doomed strategy. Planning that is perceived to have been undertaken in secret breeds suspicion and contempt. Preparing an application to fund a potable recycling scheme prior to properly involving the community is offensive and sets the scene for confrontation. It sends the message that decisions have been made and that the role of the community is to accept them.

Communities have a valuable role to play in planning, and public officials should recognise and capitalise on this. Your community is home to a diverse collection of combined experience, technical knowledge and skills. Not only are they capable of constructively contributing to debate and decision-making, they have a right to do so.

2. Keep outside interests at bay

The purpose of a local water management strategy is to address local problems and it requires local decisions. The community that is most directly affected has the most to gain or lose by any strategy. Perceptions of outside influences driving the agenda will naturally lead to resentment.

The suggestion that a local plan may provide a case study, a demonstration, or worse –a pioneering experiment for the benefit of other communities is inappropriate and unconstructive. If you must be a pioneer of something, make it community involvement in decision-making.

The water industry has an essential contribution to make in water management. However, conflicts of interest (real or perceived) are too easily created. A private company or organisation with a financial interest in the outcome of a consultation process is probably a poor choice for facilitator. Accepting offers from out-of-town environmental groups to come in and tell people how to vote is a similarly crummy decision.

3. Give serious consideration to all options

Real choice is not about ‘yes’ or ‘no’. Real choice involves putting all options on the table for fair consideration. Potable water recycling has many attributes to recommend it, but it makes little sense when considered in isolation. Therefore, it is essential for potable recycling proposals to be judged by detailed comparison to alternative strategies.

Other strategies requiring equal consideration include water conservation, increased utilisation of natural resources, dam construction, non-potable recycling strategies, water trading, ‘do nothing’, and applying limits to population growth. A triple-bottom-line evaluation process will allow transparent consideration of environmental, social and economic costs and benefits. If potable water recycling can not stand up against these alternatives, it is simply not the optimum strategy.

4. Inform, don’t coerce

Potable recycling is an issue that most communities have not had reason to seriously consider until very recently. Therefore, reliable information is required for them to make an informed decision. It is the responsibility of community leaders to provide this information and there are many effective means of doing so. It is essential for this information to be balanced and to stick closely to the facts. It should avoid making unreasonable predictions about how dire things may become if a strategy is not adopted.

If you are convinced that you have identified the best solution, then say so. Be enthusiastic about it. But do not allow yourself to give the impression that any sensible person should use the same information to arrive at the same conclusions as you. Attempts to coerce polarise communities. It offends those who disagree and will only harden their resolve.

5. Explain relative risk

Risk is a difficult and complex topic, and one which is commonly misunderstood. Effective risk communication is notoriously difficult and blundered attempts can cause unnecessary alarm. No human activity is without risk, including the use of any water supply. Accordingly, demands that risks be proven to be ‘zero’ can never be satisfied.

A more effective communication approach is to explain the relativeness of the risks that we take and accept in everyday life. Compared to risks such as eating in restaurants, crossing roads, or driving a car, health risks associated with consuming well treated recycled water are negligible. Millions of people consume the product of ‘unplanned potable recycling’ in developed countries everyday. Yet, there is no (reliable) observed evidence of negative health impacts (excluding those exposed to poorly treated sewage in developing countries). Advanced water treatment can only be expected to reduce the risks even further. An improved community understanding of these facts will encourage acceptance.

6. Accept dissent

When people are given choice, some make different decisions. It is their right to do so, and community leaders should respect that right. There is no justification for belittling, ridiculing, demonising or ostracising dissenters. There is a sometimes fine line between ‘engaging in constructive debate’ and arguing stubbornly. If you find yourself telling people that ‘if they don’t like it then they can drink bottled water’ or that you ‘would be prepared to go to war on this issue’, then you have probably missed that line. A better approach is to acknowledge that the community as a whole will need to make a decision and that it is inevitable that not every individual will agree with the outcome.

7. Understand and accept the ‘yuck factor’

The ‘yuck factor’ is real, perfectly normal, and has an essential human purpose. It guards us from dangerous exposure to contaminated and unhygienic substances. It is pointless (and incorrect) to suggest that the ‘yuck factor’ is irrational or the result of a lack of intelligence.

Getting over the ‘yuck factor’ for potable recycling is tough for many of us (myself included!). But the important point to make is that advanced-treated water has no relationship to sewage other than its recent history. Water is water and the safety of water is determined entirely by the contaminants that it may contain. Advanced-treated recycled water is unique in terms of its purity and quality control. Understanding this will allow people to logically disassociate clean water from dirty water.

8. Express costs in meaningful terms

Water management is an expensive business. However, most of us are not accustomed to dealing with multimillion dollar costs. Comparing potential water strategies in these terms can seem meaningless, especially when costs are to be shared over large population. Numerous comments left on this blog are along the lines of ‘why do you mention costs? Cost doesn’t matter!’ The fact is that all responsible government decisions will take costs into account and costs will play an important role in defining viability. A strategy that will bankrupt a local government or require rates to rise excessively is unlikely to be viable. A better communication approach is to define costs in terms of those that will need to be met by individual rate-payers. A strategy that is explained to require a small rate-rise will be seen as a legitimate advantage over one that requires a very large rate-rise.

9. Don’t oversell technology

Misrepresenting the capabilities and limitations of proposed technology is a shortcut to undermining your own credibility. However, I suspect that many such misrepresentations are not the result of deviancy, but more of naivety.

Water treatment is a highly competitive business internationally. Like any competitive industry, the private companies involved are not always enthusiastic about promoting the limitations of the technologies that they supply. Nonetheless, it is the responsibility of decision makers to demand accurate information and to make this available to citizens. Lazy simplifications like ‘reverse osmosis removes all molecules except water’ will only get you into trouble. A quick Google-search will show up the inaccuracy of such simplifications and provide the community with a reason to question both your credibility and motives.

10. Always remember the goal

Remember, the goal is not to introduce a planned potable water recycling scheme to your community. The goal is to identify and implement the optimum sustainable water management strategy, whatever it may be.


Any feedback, further lessons or criticism would be appreciated…

Thursday, August 03, 2006

Environmental Estrogens

Queensland opposition leader, Lawrence Springborg, raised the issue of ‘environmental estrogens’ this week. Predictably, various newspapers and blogs were jammed with arguments about whether chemicals in sewage can change the sex of fish and whether they could turn a male human into a female. Seriously, they were. So let’s get a few facts straight.

A one-paragraph biology lesson: Human sexuality is determined by DNA chromosomes. Most of us have two chromosomes, either XX or XY (yes, I know there are other possibilities, but lets keep this simple). You got one of these from your father (an X or a Y) and one from your mother (an X). If you scored XX, you are genetically female. If you scored XY, you are genetically male. No amount of exposure to chemicals (such as hormones) in the environment can change this. You can not change a man to a woman or a woman to a man. Yes, I accept that people may identify as “male” or “female” regardless of chromosomes...I don’t mean to offend anyone...I simply want to deal with this complex topic in a single paragraph…woah…a can of worms that I really didn’t mean to open...Move on!

But fish and reptiles are different to mammals. Changing sex is natural for many species and it is common to do this in response to chemical signals.

Researchers have found that if they paint a turtle's egg with estrogen, the turtle inside can change from male to female. Strangely enough, the same thing can be achieved using industrial chemicals called polychlorinated biphenyls (PCBs). These (artificial) PCBs have some chemical similarities to (natural) estrogen, which causes them to interact with the estrogen-receptors. In other words, the PCBs ‘mimic’ the action of estrogen.

Male frogs’ eggs or embryos exposed in the lab to the widely used pesticide, atrazine, develop ovaries and are infertile. In fact, not only do the males (which normally only have testes) develop ovaries, they develop multiple ovaries, sometimes six or seven. Unlike the PCBs, atrazine does not mimic estrogen. Instead, it enhances the conversion of testosterone to estrogen.

Even mammals can be affected by these chemical ‘endocrine disruptions’ (although they don’t change sex). For example, sheep that graze on clover ingest natural plant estrogens (phytoestrogens) which can make them infertile.

Recently, researchers at the Cincinnati Zoo were trying to work out why some cheetahs were not breeding. It turned out that phytoestrogens in soy-based materials included in their diet was acting as a contraceptive. When the cheetahs were given a diet without soy several quickly gave birth to kittens.

There are lots of compounds that can act like estrogen. From the above examples, we know that they include natural estrogens, industrial compounds, pesticides and natural phytoestrogens (plant estrogens). Many of these compounds can wind up in sewage, so it is no surprise that poorly treated sewage can also have these sorts of effects.

For example, there are reports of fish in the Potomac River (USA) being “feminised” by water-borne pollutants. This was identified by an increase in the production of the protein that is involved in egg-production, by male fish. This protein, called ‘vitellogenin’ is not usually made by male fish unless they are treated with estrogen. It turns out that some detergents in the water are likely to be responsible for tricking male fish into producing vitellogenin. These detergents can be major constituents of municipal sewage. Human estrogens (excreted in urine) and synthetic steroids such as the contraceptive pill can have the same effect.

So what does all of this have to do with recycled water? Well that depends on how we define ‘recycled water’. If we are talking about advanced water treatment (processes such as reverse osmosis, granular activated carbon, advanced oxidation), then the answer is 'absolutely nothing'.

The concentrations of estrogenic substances in advanced treated recycled water are miniscule (or unmeasurable). We know this both by chemical analysis (measuring the concentrations of chemicals) and by estrogenic activity (running assays to measure the effect of any estrogens or estrogen mimics that may be present).

However, if we are talking about conventionally-treated (or poorly-treated) sewage, then yes, discharging poorly-treated sewage into creeks and rivers can be expected to disrupt the sexuality of some species including fish. All the more reason why we should pay better attention to treating water to a higher level than what we generally get away with today.

If you've come this far, leave a comment...tell me what you reckon.

Saturday, July 29, 2006

How to Run a Successful Scare Campaign

It has been well observed that Toowoomba’s (failed) poll will provide many lessons for future planned potable water recycling schemes in Australia. There will be lessons to learn for both pro- and anti- recycling campaigners. I fully intend to investigate the lessons to be learned by both sides.

First up, I hereby offer this handy guide to running future successful scare campaigns. I expect to see it well utilised in other major cities in the coming months.

1. Exploit the “Yuck Factor” for all its worth

You will go into this campaign with a great natural head-start. All humans have a negative instinctive and emotional response to the concept of water being used in close human contact more than once. Unless people have had a good reason to carefully consider the issue and the capabilities of modern water treatment technology, emotional responses will prevail. This will come naturally for most people, but you can encourage this natural “yuck factor” by drawing on all opportunities to link recycled water with human excrement.

2. Agree on a catchy slogan

A catchy slogan is worth more than any fact. You don’t have to think too hard about this one since you can always recycle slogans from overseas. ‘Toilet-to-Tap’ is a tried and tested standard and should not be overlooked. ‘WEEcycled POOrified Sewage Water’ is perhaps less sophisticated, but can be effective for the right demographic and may appeal to children under the age of nine. If you can work terms relating to human excrement into the name of your town or city, then you are truly on a winner.

3. Remember, it’s not ‘water’, it’s ‘sewage’ (or sewerage)

Smarmy scientists and politicians may claim that water should be judged by its quality, rather than its history. You should seek to remind them of the well known scientific adage: ‘once sewage, always sewage’. It doesn’t matter how much water (sewage) is purified, it has a tainted past from which it can never be redeemed. Homeopathy is a well-established science in our community and this fact can be conveniently exploited. It means that many people will understand that water has a ‘molecular memory’ and will forever be tarnished by that with which it has previously been in contact.

People who use the term ‘water’ rather than ‘sewage’ are simply trying to sanitise the issue and these propaganda merchants should be quickly exposed.

4. Use suggestive images

A picture is worth a thousand clich├ęs. Invest about 10 seconds on Google Images to find a few good shots of sewage being treated by conventional treatment processes. Useful keywords to try are ‘activated sludge’ or just simply ‘sludge’. Present your images with a caption like “Is This Our Future Water Source?”

An image of a dog drinking from a toilet bowl, or a glass of water placed in the general vicinity of toilet, is worth two thousand clich├ęs. A graphic suggesting a direct connection between a toilet and a bathroom tap is worth three thousand. A pseudo-medical image of a foetus inside a womb is priceless.



5. Refuse to be a lab rat

Insist that your community should not be the ‘lab rats’ for the rest of the country (‘guinea pigs’ is a possible alternative, but may be too cute).

No two towns or cities are identical and this means that no two water management schemes will be identical. Obviously, if no existing scheme is identical to the one planned for your town, then you are being asked to be the subject of a radical and dangerous experiment.

Differences to look for include the precise treatment process (it doesn’t matter if yours is more comprehensive), precise proportions of ‘sewage water’ to be mixed with ‘pristine natural water’, and whether a scheme is generally considered to be ‘planned’ or ‘unplanned’ (remember that ‘unplanned’ is usually safer). If all of these fail (which is highly unlikely), demand details of the likely colour schemes for the plant office.

6. Defend children and future generations

Are children and future generations being consulted? If not, why not? It is your responsibility to assume the role of defender of those ‘without a voice’. Who knows what effects purified water may have on the fragile immune systems of children and unborn foetuses? Tell those monsters and their cronies that they have no right to harm your family!!! How dare these evil-doers even consider harming children!?

7. Be prepared to misrepresent science

It is perfectly honest, ethical and acceptable to intentionally misrepresent science when there is ‘a greater good’ at stake. Effective strategies include quoting facts out of context and careful juxtaposition to suggest a relationship between unrelated facts.

It is well established that raw sewage contains all sorts of nasty chemicals and microbial organisms. Furthermore, conventionally treated sewage processes are not 100 per cent effective at removing trace concentrations of all chemicals. People who drink poorly treated sewage get sick and some die!! This fact can be used to provide conclusive evidence that any recycled water is a deadly cocktail.

Even reports that claim to provide evidence that recycled water can be just as safe as any other source can be misrepresented by careful selection of key quotes. If all else fails, you can always claim that the authors (and peer-reviewers) have misinterpreted the results. “Flawed” is a useful and flexible term that can be applied to prove that you speak the ‘scientific language’ and are therefore a credible authority on any subject.

Remember that if someone else has already expressed an anti-recycling opinion on the internet, then it is thus proved to be indisputably true. Such opinions can be extrapolated to any potential scheme regardless of trivial details such as the treatment processes involved. Pioneers from previous campaigns in California will provide rich pickings. Google is a loyal friend.

8. Point out that you can run but you can’t hide

Buying bottled water will not save people from the peril of recycled water. People will still be exposed in baths and showers. Remember that the skin is porus and all chemicals will be quickly absorbed into the body. All food that is prepared in your city will be highly contaminated with recycled water. This will cause local food-producing industries to be bankrupted with devastating flow-on effects to the local economy. A quiet cup of coffee in town will be rendered an adrenaline-inducing deadly game of Russian roulette.

9. Exploit the broad use of the term “recycled water”

Precedents exist on the internet referring to all sorts of waters as ‘recycled water’. If secondary treated sewage is used to irrigate a timber plantation, then that is ‘recycled water’. A few schemes distribute lower-quality water to houses by ‘purple pipe dual reticulation’ systems. Utilities involved in managing this water publish information regarding how the recycled water should be used. This can be a useful source for quotes such as: “Recycled water is suitable for watering gardens and flushing toilets, but should never be used for drinking, washing or filling swimming pools”. The mere existence of such information provides irrefutable evidence that anybody that suggests drinking recycled water, from any source, has a sinister ulterior motive.

10. Demand that every possible chemical must be monitored

Pick a large number, double it and quote it as the number of chemicals in existence. The number can be preceded with a ‘greater than’ sign or simply stick a ‘plus’ sign on the end. A figure like 87,000 is more convincing than a round number like 100,000 (which is clearly just an estimation). Ask the water testing authority whether they plan to regularly monitor for every single one. If the laboratory manager is unable to even name every one of these chemicals, this is an obvious blow to their credibility and should be exposed.

Ignore the fact that the vast majority of chemicals come from nature. Focus on words like ‘hormones’, ‘endocrine disrupters’, ‘pharmaceuticals’, ‘illicit drugs’, ‘phthalates’, ‘RU486 abortion pills’, ‘emerging contaminants’, ‘prions’ and ‘carcinogens’. Point out that new drugs are being developed all the time and we don’t even have analytical methods for them yet!!!! (multiple exclamation marks reinforce the scientific validity of any statement. CAPITAL LETTERS HAVE A SIMILAR SIGNIFICANCE!!!!).

Read the book “Our Stolen Future”. It doesn’t mention water recycling, but all facts and theories described in this book were written with planned potable water recycling in mind (read between the lines, dummy!). Those alligators were foolish to unquestioningly accept an advanced recycled water supply from the state of Florida (contamination of the swamp by a DDT spill is a red herring invented by pro-water recycling devil worshipers).


I trust that this handy guide will be useful for budding campaigners. Most importantly, have fun and enjoy the assured media exposure. Once the campaign is over you can settle back to the important task of revealing the lies of climate change.

Note: This post is intended to be satirical. However, yes, it is a venting of some frustration. While Toowoomba has certainly seen the type of scare campaign suggested in this post, I do acknowledge that there were other important (legitimate) issues to be considered as well. Readers are welcome to offer alternative lessons (to both sides), seriously.

Thursday, July 27, 2006

Luggage Point to Wivenhoe (and back again)

Queensland Premier, Peter Beattie, expressed support today for the concept of planned potable water recycling for Brisbane. It would add to an existing plan to take advanced-treated recycled water from Brisbane’s largest sewage treatment plant (Luggage Point) to the city’s largest water storage reservoir (Wivenhoe Dam). As reported in the Courier Mail:

"I am saying in an upfront and transparent way today that it would not be very difficult to build a spur line to put this recycled water into Wivenhoe," Mr Beattie said. "So I want the community to know that. I am saying, however, that we wouldn't do it without some form of mandate from the community and there are a number of options, including the next election."

It must be said that Beattie has such a high margin of popularity, that it behoves him to make a few gutsy decisions. However, as the Mayor of Toowoomba could confirm, supporting planned potable recycling really is a gutsy decision.

Until people have really had the opportunity to consider the facts, our initial reactions to potable recycling are normally those of fear and disgust. Most people are not aware that recycling is the normal job-description for water and that it happens, -in an unplanned way- throughout the world. Some people may never be convinced that dirty water can be effectively and reliably cleaned. Others simply do not want to be convinced. Politicians will, as always, exploit this ignorance (wilful or otherwise) for their own political gain.

Scare campaigns about planned potable water recycling are so easy to run. All you need are a few keywords to Google and a willingness to quote facts out of context. Take, for instance, Dr Oppenheimer’s bomb that was dropped in Toowoomba this week. An anonymously authored ‘freelance’ article, was posted to an anti-potable water recycling blog. The article recycled a few quotes from the internet that were already of out context (and misrepresent the conclusions of the reports that they refer to). However, the anonymous author managed to go one step further in the deception by (not so) clever juxtaposition of information, -tying accurate, but unrelated facts together to suggest some relevance which does not exist.

It is so easy to present information that relates to conventional sewage treatment or low pressure (high porosity) membrane treatment and position it such to suggest that it has some relevance to advanced treatment processes such as those proposed for Toowoomba or used at Luggage Point. It’s been happening in Toowoomba and will certainly happen in Brisbane. Major Brisbane newspapers will publish it because it helps to sell papers on Sundays.

Premier Beattie is obviously well aware that scientific knowledge and understanding firmly support the safety of potable water recycling using advanced treatment technology. The problem that he will face is that many couldn’t care less. Even once the deceptions described above are revealed, some people will continue to argue in favour of the article. For some people, the question has nothing to do with science; -it’s a matter of principle. Planned potable water recycling is apparently “unethical”.

Nonetheless, Premier Beattie should remain optimistic. I am confident that the majority of Australians are perfectly capable of investigating and considering facts in an objective manner. For this reason, I think it is essential for Beattie to dedicate his efforts towards providing the community with access to scientifically-supportable information. Don’t just give us the sales pitch, -give us the facts. Access to accurate information will increase support for planned potable water recycling and will truly allow Beattie to claim a mandate from a well informed community.

Saturday, July 22, 2006

Seawater desalination

Prior to 2004, desalination was practiced in Australia with just a few very small brackish groundwater schemes. The Premier of NSW had disparagingly referred to desalinated seawater as ‘bottled electricity’, noting the considerable energy requirements for its production. However, serious consideration of large-scale seawater desalination schemes has been accelerating during the last two years.

In July 2004, the Western Australian Government announced that it would construct one of the world’s largest seawater desalination plants to supply Perth with up to 45 gigaliters per year of potable water.

Soon after, the NSW government announced plans to build a desalination plant for Sydney on the Kurnell peninsular. Following community anxiety, the construction of this plant has been postponed. However, planning continues and construction will begin when Sydney’s supplies dip below 30 per cent of capacity. The plant will initially produce 125 megaliters per day, but will be built with the capacity for further expansion to 500 megaliters per day.

Other cities, including the Gold Coast and numerous smaller coastal towns around Australia have also begun investigating the feasibility of seawater desalination as a component of their overall municipal water supply and management.

To achieve best-quality water production, a number of alternative treatment approaches could be considered. However, in 2006 Australia, reverse osmosis membrane treatment is by far the most energy efficient approach for adequately upgrading both conventionally treated wastewater (water recycling) and seawater.

The fundamental principal of reverse osmosis is the employment of semi-permeable membranes to separate a ‘purified’ component of the water from a waste-stream retaining the concentrated salts. This waste stream is commonly referred to as the membrane ‘concentrate’ or ‘brine’. The sound management and disposal of concentrates has become one of the greatest concerns regarding both water recycling and desalination, and is often a key factor determining the overall viability of a project. The issues involved include technical challenges, permitting problems and high costs.


Concentrate from seawater desalination typically comprises half of the original in-take volume and almost all of the dissolved salts. Accordingly, it is typically double the normal concentration of seawater. Most commonly, concentrates are discharged via ocean outfalls, however the double salinity renders concentrate plumes denser than seawater and thus they sink and can be difficult to disperse. The potential impact of concentrate plumes on marine species in Australian environments has yet to be properly assessed.

Much public discussion has taken place regarding the relative energy requirements to treat municipal effluents and seawater to qualities suitable for reuse. Reverse osmosis technology has developed dramatically during the last decade, decreasing both the energy costs and therefore the financial costs of treatment. However, the major source of energy requirement remains the necessity to overcome the osmotic potential difference across the membrane. That is, the difference in salinity between the purified water and the retained brine.

Seawater normally has a salinity of around 35 grams per litre. Municipal effluent is typically only one tenth of this salinity. This means that the osmotic potential is lower for municipal effluent than for seawater (and a higher fraction of the water can be recovered before the brine becomes too concentrated). Therefore, considerably less energy is required to produce a volume of clean water by reverse osmosis of municipal effluent than for than to produce the same volume from seawater.

Logically, seawater is sourced from sea level (or slightly below). However, most drinking water supplies are stored inland and somewhat elevated. This helps in the gravity-assisted distribution to our homes. Therefore, a second significant energy requirement in most circumstances is the need to pump desalinated water long distances and often uphill.

Some opponents of potable water recyling in Toowoomba have left comments on this blog recomending seawater desalination as a solution for that city. One suggestion has been to allow Toowoomba to extract water from Brisbane’s Wivenhoe Dam and replace that water with desalinated seawater. The pumping costs involved with such a scheme (from the ocean, up the Great Dividing Range to Toowoomba), combined with the treatment costs would make this about the most expensive water on earth.

In addition to these obvious ‘engineering’-type limitations, some more obtuse consequences of desalination are also worth considering. One such consequence is the weakening of the message highlighting the importance of water conservation. When a potential water source is envisaged to be as great as the world’s oceans the urgency to implement water-efficient technologies and practices is reduced. Furthermore, cities that come to rely on seawater desalination rather than conservation or recycling, will also rely on ocean outfall infrastructure for the discharge of municipal wastewaters (as well as desalination brines). As these cities harvest ever-increasing volumes of water from the ocean, they must also discharge similarly increasing volumes to the detriment of Australia’s precious marine environment.

But of course, desalination does have one great advantage over municipal recycling…no yuck factor! And yes, I know…no hormones, RU486 abortion pills, prions, or other yet-to-be-invented chemicals. However, properly treated recycled water will not contain these either…

Whadda you reckon?