Forrest

Your elucidation on de-sal methods is very welcome.

My suspicions on the proposed desal plant by the Victorian government is that it is just a further step in privatising (therefore profiteering) a public and ecological necessity - humans aren't the only life forms in need of safe water.

If desalination could be achieved using secondary heat from a variety of industrial processes and I believe it is as you say, the result would be distilled water - yes or no?

If yes, could this water be added to natural resources for it to revitalised with the minerals required for consumption - the "shandying" effect as Csteele posited for recycled effluent?

Are you concerned as I am, that nothing substantial will be done towards sustainable living until a way to profit in the short term rather than the long term is found?

At the foundation of my concern is the following excerpt from 10 Myths about Sustainability (http://www.sciam.com/article.cfm?id=top-10-myths-about-sustainability):

"Myth 5: Sustainability is too expensive.
If there is an 800-pound gorilla in the room of sustainability, this myth is it. That’s because, as Gabriel observes, “there’s a grain of truth to it.” But only a grain. “It’s only true in the short term in certain circumstances,” Cortese says, “but certainly not in the long term.” The truth lies in the fact that if you already have an unsustainable system in place—a factory or a transportation system, for example, or a furnace in your house, an incandescent lightbulb in your lamp or a Hummer in your driveway—you have to spend some money up front to switch to a more sustainable technology."

Hey Fracteelle,

I think to take the pragmatic point of view one needs to ask the question would you prefer to see recycling of water at half the energy use but utilising ‘brown’ energy or desal with all of the energy being sourced from green credits? This is what we are faced with in Victoria.

If the government sticks to its promises (a big if I know) the desal plant will mean an extra 1500ML a year for a river I am fighting for down here and it will cause a big boost in green energy investment in the state.

In our area the government, Shell and the water authority have come to an agreement to recycle water from a sewerage treatment plant in the northern suburbs to be used by the refinery thus freeing up drinking water. All good stuff but without a solid commitment to use green energy credits I would rather see the desal option instead.

What to do with the hyper saline water? I had been lobbying for a plant in our area. The position was between a salt works and a sewerage farm. For the salt works to take an amount would have been ideal for them as it would have enabled them to dramatically shorten production times. The left over could then have been shandied up with the sewerage outfall water to make it closer to the salinity of the ocean. Fresh water discharged inappropriately into the marine environment can also have quite damaging effects.

To give you an ideal of the salinity levels predicted from the Wonthaggi plant, if it where all dumped into Port Phillip Bay (which takes a year to turnover all the water it holds) instead of the ocean it would be the equivalent to two weeks extra sunlight on the bay.

I am more concerned with the chemicals it discharges rather than the salinity of the water and the membrane waste issue still needs to be resolved satisfactorily.

For those who have not already made Google their friend, a paper, "Large scale Solar Desalination using Multi Effect Humidification", by Dr Alan Williams, is the top listing of a google search using the terms 'reduced pressure desalination'. Here is the link:
http://www.globalwarmingsolutions.co.uk/large_scale_solar_desalination_using_multi_effect_humidification.htm

Now, of course, I had effectively already given this link earlier in this thread, in this post to which I again link, see: http://forum.onlineopinion.com.au/thread.asp?article=5616#74547 Reading the next 12 posts in the OLO thread may give a fuller idea of the potential significance of reduced-pressure distillation as it was envisaged as applying in the then (2006) SE Queensland context of possibly RUNNING RIGHT OUT of reticulable water.

It is the very real prospect of future literal run-outs of dam water supplies (or indeed extra dam sites) that is the inherent weakness involved in opting for the recycling of effluent water, rather than that of seawater desalination, as a pathway to maintainance of adequate urban water supply in Australia. It is not just the claimed prospect of intensified drought conditions, but the ongoing immigration population boosting of these very urban centres that are already experiencing water supply problems, that increases the likelihood of such total run-outs being experienced.

There is another dimension to the use of waste heat in effecting the reduced-pressure distillation of seawater. That is in the production of concentrated brine as a corollary of distillation. This brine, piped to good solar pond locations, is not so much a disposal problem as a valuable resource. For a look at how this may have been made to work in SE Queensland, and for future renewable-based energy supply in Australia generally, see: http://forum.onlineopinion.com.au/thread.asp?discussion=495#9790

Forget about this quibble over such water being 'distilled'. Of course it is. So, effectively, by the pathway of evaporation and condensation, is rain! A red herring if ever there was one.

There does exist a non-proprietary way forward!

Many thanks Csteele & Forrest. I have much homework to do until now I have relied upon a very basic knowledge set and my own abilities for analysis.

Until I research further, what I am gleaning from your posts is that we can achieve sustainable management of water. I just want to be sure that it will achieved in a holistic sense rather than completely privatised. For example, I have complete confidence that we will solve the problems of chemically laden membrane waste.

I tend to the philosophy that essential services require government regulation. And I am worried that 'green' credits will wind up being used by the more greedy as another 'ponzi' scheme.

Hey Fractelle,

Could I commend to you the writings from Maude Barlow, a Canadian activist who was recently made a UN special advisor on water.

She also has grave and valid concerns about the privatisation of water. We were lucky enough through the efforts of one of our group to enlist her support when she was out for the Melbourne Writers Festival. Maude was kind enough to come on a tour of our river and the resultant public statements from her were a great help in securing increased environmental flows this summer.

We did agree to disagree on her assessment of desalination projects but in nearly everything else I feel Maude’s warnings about the privatisation of this essential resource are timely and not overstated.

However it is still my understanding that the plant will revert to public ownership after a period of time.
See http://www.ourwater.vic.gov.au/__data/assets/pdf_file/0015/474/Fast-Facts---Merged-September-2008.pdf

Other links for interest,

http://www.theage.com.au/environment/renewable-energy-for-northsouth-pipe-20080726-3lfa.html

http://www.theage.com.au/environment/cost-to-offset-desal-plants-carbon-footprint-hits-42m-20080615-2qzw.html

http://www.smh.com.au/news/environment/wind-farm-vow-to-power-desalination/2008/05/13/1210444436869.html

http://www.abc.net.au/news/stories/2008/06/26/2286353.htm

Happy researching. I will be doing the same with Forrest's contribution.

Thank you Csteele

It is raining steadily in the Dandenong Ranges - something of a novel event. I will be able to conduct my research to a rare symphony; the base notes drumming of rain on my iron roof, fluting trickles of water down drain pipes and the breath of the forest in open embrace to the thunder gods.