Friday, October 31, 2008

A controversial week in water

It has been a controversial week with at least four very negative articles about the safety of recycled water appearing in newspapers across the country.

Wednesday’s focus was Prof Patrick Troy from ANU, quoted in a high profile story in The Australian stating that “it will not be possible to remove all biologically active waste molecules from the system”.

On the same day, Narelle Towie, the science writer for News Corporation’s Perth.Now website, was quoting water experts from Perth and Melbourne calling for potable water recycling as a sustainable measure to address water shortages in those cities.

On Thursday, The Australian had a second story ready to go featuring ANU microbiologist Prof Peter Collignon. Prof Collignon had apparently told the Australian that the “Namibian capital of Windhoek, located in a desert, had the only comparable system” to that proposed for South East Queensland. I’m not sure by what criteria Peter is comparing water treatment or water recycling systems. I’d have said Windhoek was one of the least comparable schemes. This news article is particularly worth reading for the interesting comments left by readers (except for the guy trying to flog his ‘water from air’ technology…there’s always one!).

Fears were somewhat allayed for a while today after Queensland Premier Anna Bligh confirmed “absolutely that she would drink recycled sewage in Queensland's tap water”… presumably not her own words!

But the week was concluded with The West Australian’s story “Recycled sewage can’t be made safe”. The story focused on Prof Collignon’s concerns, translated for a West Australian audience: “Just say it went wrong one day in 365, what do you do when you have all that (contaminated) water in your aquifer?”

The West Australian stated that Prof Collignon’s “views were backed by Don Bursill, head of the Federal Government’s National Health and Medical Research Council water quality advisory committee, who said even if the technology worked, human error, which accounted for some 80 per cent of water-quality incidents, could not be ruled out”.

Well at least we’re all talking about recycled water. Oh... except for us here in Sydney where we apparently have more pressing issues to discus. Can’t wait to see what the weekend brings!


Anonymous said...

It is a shame that these academics make such claims without first fully iunderstanding the proposal. Perhaps they are trying to get noticed so that their applicaton for research funds has an improvement of being granted.

I was always of the understanding that sensible academics methodically researched a topic and came to a full understanding before opening their mouths. Seems I was mistaken.

Although the concerns raised this week in the papers by the academics, a quick phone call to their colleagues in Qld actually running the show, or a visit to the sites and an explaination of the framework PRW is being formulated in would in my mind have answered much of the questions and allayed thier concerns.

To me, it weems that they would rather be part of the problem then part of the solution, and stir the pot to get their name in the press. I can only trust that the students that they teach at the universities are giving them a hard time asking some direct questions.

Anonymous said...

Thanks Stuart for the "low down" on pressing issues from Sydney. More in The Australian today: "Support wavers for use of recycled sewage water",25197,24584275-5013404,00.html

Stuart Khan said...

Thanks Anonymous, here's the same link with a hyper-.

Mark said...

You say that Windhoek is "one of the least comparable schemes", but didn't elaborate.

I can think of why you would say this ...

1. Namibia only use their system in times of severe water shortages (not all the time)

2. They have handled the public relations a lot better.

3. They exhausted all other alternatives, whereas we haven't yet realised that there is huge amounts of urban runoff flowing into the bay.

Are there others?

Stuart Khan said...

Hi Mark (nice to hear from you!),

I was thinking more about the fact that the water treatment processes are very different in Windhoek and that there is no real environmental buffer before the water is re-distributed to consumers. That is, the Windhoek scheme does not have an equivalent of Lake Wivenhoe. Because of this, the Windhoek scheme is generally recognised as being the only direct potable water recycling scheme in the world.

I think the Upper Occoquan scheme in Virginia USA is more obviously comparable to the SEQ scheme. However, I acknowledge that that scheme also has quite a different treatment process to SEQ (no reverse osmosis and no advanced oxidation).

I guess the fact is that there are no two identical water supply systems anywhere in the world.

Mark said...

I should disclose that as a purely scientific experiment I've had sampled some Windhoek lager and suffered no ill effects.

I may not have the latest info, but I read that Windhoek has a multi-barrier system that is not wildly different to the SEQ project ... activated carbon instead of RO. Otherwise they both would seem to have UF and Oxidation (ozone instead of UV). It sounds like they use the latest European technology from Veolia as well. Correct me if I'm wrong, even though its in Africa it doesn't sound like they have skimped on technology. The other thing of cause is that the Namibians have been at this for a long time and I wouldn't at all assume that our system is better or smarter than theirs - in fact the opposite.

One of the barriers that I would have liked to see was one like proposed for Toowoomba - a reservoir where water could quarantined and tested before releasing for consumption. Given that the SEQ scheme doesn't provide such safety, I question whether it makes much difference that it is "indirect" compared with "direct". You would, I think, acknowledge that this "environmental barrier" is by far the most expensive barrier considering the capital cost and cost of pumping and water losses. What has not been adequately explained in this debate is the tangible effect on water quality that can be attributed to this pumping process, and why they chose not to use a local reservoir in Brisbane and avoid risking the quality of the Wivenhoe water.

I'm just getting nervous as March approaches. If it came out of the tap as lager, I'd be all for it, but I don't think it is.

Stuart Khan said...

Hi Mark,

Yes, I was not suggesting that the technology used in Windhoek is any ‘less good’ than that used in SEQ, -only that it is quite different. My comment was that with this and other differences, it seemed strange to single out Windhoek as the ‘only comparable system in the world’.

I agree that the costs to pump the extra water to Wivenhoe (rather than somewhere closer to Brisbane) may be considerable. However, in the case of the capital costs, I would take into account that the pipeline is already running adjacent to Lake Wivenhoe on its way up to Tarong Power Station. The capital costs required for the excess water capacity for the IPR component are unlikely to be any greater than the additional capital costs that would have been required for an additional pipe to transport the water to an alternative reservoir.

I disagree somewhat on the issue of water losses. The amount of evaporation from Lake Wivenhoe is much more a function of surface area than it is of volume. Adding an additional 10% volume to the lake by IPR is likely to have only a very marginal effect on the total surface area of water in the reservoir. Accordingly, the amount of evaporation is unlikely to be significantly changed.

I assume that Lake Wivenhoe was chosen due to the fact that it directly feeds the drinking water treatment plant at Mt Crosby. If you have a suggestion regarding what may have been a hydraulically more sensible reservoir to use, I would be interested to know it.

I agree with you on the lager issue, -if the IPR plants were producing XXXX Gold, I reckon much of the opposition would be quietened. The major problem would be how to keep it icy cold!

Mark said...

Hi Stuart,

On Windhoek, I would have thought it to be a very good example because they have a high proportion of recycled water in the same order as the SEQ project. Singapore for example is a poor example because they have only 1% or so (the bulk from storm-water reclaimation which imho is a far smarter option). Manners was making this point yesterday that none of the touted examples of recycling do what we are proposing.

There is a reasonable-sized reservoir in Tingalpa for instance. Curious to know why this or something like it was not considered. I'm no expert here, and maybe there is a good reason, but surely there would be advantages in keeping the recycled water and the bulk of SEQ's rainwater separate as much as possible.

I wouldn't mind if someone explained how water changes for the better if you pump it a longer distance or mix with rainwater at point A vs at point B. Essentially that seems to be the difference between "indirect" and "direct" reuse.

Stuart Khan said...

Hi Mark,

Yes, I understood Snow's point (eventually) to be that there are no two identical water supply systems in the world and that, similarly, SEQ's water supply system will not be identical to any other in the world. I don't disagree with this.

I had a mild problem with Snow stating that no-one had claimed the $1000 dollars bounty that he/they had posted if someone could identity another city that deliberately uses recycled water for drinking. I claimed it (according to their original criteria) in the comments section of the WaterFutures blog a year or two ago. However, it was never paid. I stated at the time that I would have accepted a copy of a receipt for the payment to a charity, but no.

I'm not familiar with Tingpala. Does the reservoir supply a drinking water plant? Is it reasonably close to the existing infrastructure such as the Bundamba plant or the pipeline up to Tarong power station?

Yes, the difference between what is generally referred to as "indirect" and "direct" potable water recycling is the idea of returning the water to an environmental reservoir where it mixes with other water before being re-extracted for treatment in a drinking water treatment plant prior to distribution to customers. It doesn't necessarily imply that one will provide better quality water than the other.

It is perfectly possible to design an indirect scheme that produces terrible quality water and equally possible to design a direct scheme that produces extremely high quality water. The environmental buffer is seen by many as an additional barrier (since it is well known that residence in a reservoir can be extremely effective for pathogen die-off and chemical degradation, -if needed!). However, I am (personally) fairly confident that the major effect of the environmental buffer in SEQ will be a net decrease in quality as the water mixes with the 'natural' run-off into the reservoir.

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