Hell no - your water filter is in the mail.

One of the limitations of this type of communication is simultaneously speaking to someone you know understands your POV and providing information for people who are less well informed.

I don't think you were doubting my intelligence at all - I have people like Yabby for that.

The more I read on this subject, the more I
realise that this is a problem that we all
will have to face sooner or later. Water
shortage is something that simply won't go
away so the sooner we look at all the
options available to us, the better.

I agree with examinator - it is a matter of
perception. Of our getting our minds around
the 'poo' question. But as Fractelle has
also pointed out - we need to make a start,
and not just talk about what we're 'going' to do.
We need to act by examining all the possibilities
open to us.

There was a good overview of the whole treatment process for recycling sewage water on Catalyst this evening. It really doesn’t sound too bad.

However, that is by no means my main point of interest in this subject.

Pelican wrote on 9 March;

“Shouldn't we be more concerned with why we have let Australia's population grow to a point where we have to start talking about recycling sewage?”

This is MUCH more important than debating the recycling of sewage water versus desalination, mining groundwater, building new dams, raising the cost of water, rationing, etc.

The craziest thing in the world is happening right now. This is the fact that many people are putting a great deal of thought and energy into debating these things, while failing to even question our national and state policies of continued rapid endless population growth!!

This is whacky beyond belief. How can it even be possible that so many intelligent and highly concerned people are thinking in such a lopsided manner about this issue?

Can’t they see that recycled sewage WILL be necessary even if we develop other forms of water provision and conservation first, if the population is just going to continue to grow, or that it if we get recycled sewage in the near future, it won’t alleviate the stress on our water supplies if population growth continues, and other measures will be needed as well.

Pushing for a cap on the size of our national population and state and regional populations, especially where water is an issue, is vastly more important than debating recycled sewage, or than having or not having this increase in supply, or imposition placed upon us…whichever way you might view it.

Just a note about desalination, which I actually support. There is a problem with boron ions which are too small to be effectively removed easily. This is often why you hear the term double reverse osmosis. Boron ions from memory are 6 times more prevalent in sea water. It has quite insidious effect on the male reproductive system. This makes the idea of shandying it attractive.

The energy question is important. From my research recycling to Class A uses about 2/3 the energy of desal while Class C is about 1/3, roughly speaking.

In my area they are planning another aquifer raid. The interesting stat is that the pressure required for desal is equivalent to a water column about 270mts high to move water against the osmotic gradient. The aquifer in question will be moving water from 650mts down. It is not that hard to do the math. The water sector in Australia is currently in the top 20 of greenhouse gas generators and that is likely to increase.

The good thing about desal in no government in Australia to my knowledge has put one in or is planning to do so without sourcing close to 100% green energy credits to run it. The WA one is probably the most suss with the Emu Downs wind farm supposedly offsetting its energy use but MW for MW it doesn't stack up. Still recycling and aquifer extraction are under far less pressure, if any, to do the same.

The synergy between renewable energy and water harvesting is only just being exploited. Also membrane technology advances such as nanotechnology and aquaporins promise far less energy requirements than is currently the case.

As for drinking treated sewerage I still see not unjustified opposition to direct potable (drinking) reuse however there is far better support for indirect potable reuse i.e. shandying it in a dam or letting nature ‘massage’ it by sending it down 40 or 50 kilometres of river before extracting it. This may well prove to be a lifesaver for rivers suffering through a water stressed future.

Csteele

I fully concur with adding recycled water to dams for "letting nature ‘massage’ it. And as an aid to our depleted river systems.

However, I remain concerned with desal plants, not only for the expense and energy in running them (can this really be offset by the purchase of 'green' credits?), but the issue you raised with effective cleansing of sea water, what happens to the ultimate waste product? It is far too concentrated to dump in the marine environment. While we could obtain salt from the waste I posit that the process would produce more salt than we could effectively use. And we are still left with a toxic residue requiring effective disposal.

I guess I am a 'desal' sceptic.

Oh this thread is becoming fun! And educational.

Fractelle, in her post of Thursday 12 March 2009 at 12:07:03 PM, says:

"I try to check for vested interests in any claim ...".

If only this was the first step taken by all participants in general environmental and public utilities discussions. So much of the (generally undocumented) claim and counter-claim could then be seen for what it really is: pre-'privatisation' scaremongering, followed by 'solution-offerring' propaganda from pollies or pollie-wannabees.

Let's take the general topic of 'desalination', and apply this test.

In most cases the water to be desalinated is seawater, for it is the relatively large-scale augmentation of reticulated urban water supply that is the object of such excercises, and only seawater is an inexhaustively abundant enough source for that requirement. The 'customers' are those already connected water-rate-paying urban residents and businesses that constitute a (large) TAX base: not discretionary spenders that may withhold from purchasing, but persons and businesses that MUST pay for the 'privilege' of connection to the utility.

There are two major pathways to desalination of seawater: reverse osmosis, a process generally intimately related to proprietary membrane technology, and involving continued re-purchase of expendables; and distillation, involving non-proprietary technology and no expensive expendable components of the system.

The pollie propaganda machine misses no opportunity to emphasise that the distillation pathway is 'energy intensive', and therefore environmentally unfriendly. The pollie-wannabee propaganda machine misses no opportunity to decry desalination in general, including RO, as being environmentally damaging, all the time pushing for RO-type reprocessing of effluent water. Why? Could it be that RO is not really competitive in the long term with distillation with respect to desalination, but by stressing the buzzword 'recycling' with respect to effluent management, an opportunity to insert 'privatised' proprietary technology into servicing a captive market is not passed up.

There's no shortage of energy for distillation. We have much of it already in coal-fired power station waste heat, but that's by no means the only source.

Reduced-pressure distillation!