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Australia's future water needs

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Started 1 year ago by Diver
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Diver
Member

This week, the Water Services Association of Australia released a report that estimates the annual demand for water would increase by 1 trillion litres if Australia's population reached 31 million by 2056.

PM Julia Gillard has stated her personal opposition to a "big Australia" and has rejected the previous claim by former PM Kevin Rudd that Australia's population was set to hit 36 million by 2050.

The A.B.S. population clock http://www.abs.gov.au/ausstats/abs@.nsf/94713ad445ff1425ca25682000192af2/1647509ef7e25faaca2568a900154b63?OpenDocument shows that Australia's population is projected to reach 22,390,961 at 4.20 pm., Canberra time, on 18/07/2010. This is now.

Australia's population growth is 2% p.a.; twice the world average and about 8 times the Western average. Simple arithmetic shows that at this rate, we will reach 36 million by 2035 and 50 million by 2050.

We can only increase water supply by additional harvesting, recycling or making it in energy hungry desalination plants. Water is also heavy and pumping water long distances demands high energy. However, there are considerable savings to be made from new technology such as washing machines that use just one cup (8 oz) of water, better urban harvesting techniques and improved legislation.

New houses must be energy efficient but are they environmentally friendly? New houses with trendy black rooves and driveways plus minimal permeable outdoor surface areas give off heat signatures akin to a desert. These urban deserts are influencing our rainfall patterns through the Urban Heat Island Effect and cement manufacture is a major contributor to man made greenhouse gas emissions.

There are many easy to implement strategies to help safeguard future water demands without expensive engineering solutions but the time to act is now.

https://www.wsaa.asn.au/Media/Press%20Releases/20100713%20WSAA%20Occasional%20Paper%20on%20population%20media%20release%20RY.pdf

http://www.theage.com.au/environment/water-issues/demand-for-water-set-to-soar-20100715-10c1z.html

Posted Sunday 18 Jul 2010 @ 6:21:20 am from IP #
Catopsilia
Member

When I planned my house, 12 years ago, I was motivated to collect rain-water from my roof. It seemed silly to let it run "to waste", eroding the soil as it went.
Collecting my own rain-water is much more expensive than subscibing to an urban water system, but I have happily used my thirty-thousand litres for all household needs.
However, I suspect that I am, in my own small way, part of the reason the Murray-Darling basin rivers are drying up. I am sure that these reduced river flows are more from increased water use in the catchments than from changes in the climate.
My detention of water in rain-water tanks is just like on-farm water storages. Farmers have become very skilled at preventing run-off. So they should, but it is now clear that there is not nearly so much water to share out as was supposed.
Our local reservoirs have stubbornly stayed at low levels despite some quite wet years: Lake Keepit at 27% and Split Rock at 2.7%. The historic over-commitment of the available water is obvious.

Posted Sunday 18 Jul 2010 @ 2:01:09 pm from IP #
dymonite69
Member

Are we running out of water because of how much we have or how we use it.

http://permaculture.org.au/2005/02/01/use-of-permaculture-under-salinity-and-drought-conditions/

http://earthship.com/water

Isn't it interesting that of the potable water used in a household only a small fraction is used for drinking or cooking. And up to half of it can be used for recreational purposes or gardening.

Posted Sunday 18 Jul 2010 @ 3:38:21 pm from IP #
dymonite69
Member

A city is one big rainwater catchment surface - yet we just dump it back into the ocean.

Posted Sunday 18 Jul 2010 @ 3:42:21 pm from IP #
rockabye
Member

Quite right. It is the same for water as it is for energy.

It's not what we use that is the problem, it is what we waste.

Posted Sunday 18 Jul 2010 @ 7:33:34 pm from IP #
matas
Member

I think water companies, like Sydney Water, should give us a bit more incentive to collect our own water in tanks, by increasing the cost per kilolitre ($1.87), and lowering the fixed connection fee ($101.52 per year).
I am planning to get water tanks, even though it's probably not "economically rational".
I wouldn't even be suprised, if the electricity used to pump water from a tank, is nearly as expensive, as buying it from Sydney Water.
Not to mention the hassle and maintenace and wear of the pump.
No doubt the pump will have to be replaced periodically.
$1.87 just seems too low.

Posted Sunday 18 Jul 2010 @ 11:59:10 pm from IP #
gully
Member

Yes and instead of treating it before dumping it out, we're gonna pull it back in and boil it to remove the salt. Talk about taking the low road.

Matas: You're right, there is zero incentive except those rebates which are a one-off.

Posted Monday 19 Jul 2010 @ 12:52:09 am from IP #
termite
Member

Of course it's too cheap - just like fossil-fuelled power. There isn't enough incentive to economise, or we would see financial advisors put it high on the list of goals to stay within a budget.
On a recent housing blog, one contributor said their local water supplier deemed that if a dwelling used "less that 150 litres" (/day), that it was unoccupied. Such cynical expectation of high water usage is sadly typical in some parts of society.

Of course, traditionally, freely-available potable water has been one of the big-ticket goals of a prosperous society. This may well have led governments to give the perception that our dams were big enough "for all our current and future needs". I don't know if they ever said that in so many words, but I know that, during this drought, many have whinged about Sydney's and Brisbane's water storages being inadequate and that governments had failed to build enough dams to guarantee plentiful water.
We should never allow justification of such self-serving arguments. Conspicuous consumption/waste should always be seen as antisocial, as it used to be before the excesses of the 1980s. To blame governments (to the extent that we do) is, in effect, to blame ourselves. We need to be responsible for our votes - even for answers in opinion polls, since these are given so much weight lately! Sorry if I'm getting too political, but ultimately we won't get better government until we show that we will vote for one that does what is necessary, not just popular in the short term.

Actually, I remember my parents spoke of councils requiring people to remove water tanks when Warragamba Dam was first filled. Apparently the tanks were considered unsightly.

On the issue of pumps, I wonder if anyone has designed a windmill (like the old Southern Cross types) that compresses air, to be used as a pump to push water out of a tank, instead of using electricity.

Posted Monday 19 Jul 2010 @ 1:12:24 am from IP #
matas
Member

Yes, I have often thought a windmill would be nice for pumping tank water.
This website shows how it can be done (from a 5000l tank, 10 metres uphill to a 1000l header tank)

http://www.thebackshed.com/Windmill/articles/SouthernCross.asp

Though I think, you would probably have to be a real enthusiast to get it all working.

Posted Monday 19 Jul 2010 @ 2:27:39 am from IP #
termite
Member

Hmmm... that requires two tanks and extra space/height. Very nostalgic, though.

What about something that compresses air in a small reservoir as part of the tank outlet (with a valve to relieve excess pressure), storing enough pressure to push water out at a given pressure for a defined period of time. The power could cut in only when the compressed air pressure drops below a comfortable threshold. Surely it could work like those pressure washers, but at a lower rate.

Posted Monday 19 Jul 2010 @ 2:59:27 am from IP #
munter
Member

The energy requirements of small scale rainwater systems have been investigated and reported in an interesting paper produced through the UTS here in Sydney. My sketchy memory of the contents of the paper was that local pumping resulted in energy usage of anywhere between 0.8 to 2 kwhrs/1000 L delivered. this compared poorly with mains water which had an energy component of a bit under 0.5 kwhr/kl. This is my memory and may not be exact.
Anyway - there is clearly a long way to go on the residential energy efficiency fron and indeed, if you used 2kwhrs/kl you could be paying $0.70 just in energy costs for the water (assuming TOU peak period consumption).

Posted Monday 19 Jul 2010 @ 3:25:49 am from IP #
Diver
Member

You can buy pumps fitted with pressure tanks; the larger the better. Pumps connected to toilets have high start up energy demands but low duration run time. I posted the following on another thread as a means of filling a cistern from a header tank with little use of a pump:

Buy two Fluidmaster 400UK063 cistern float valves and the same number of gravity feed flaps 242LP071 to replace the present float valve(s).
Connect the mains pressure hose to one float valve and a hose connected from a rainwater tank to the other. Turn the mains off at the wall.
The tank needs to supply head pressure to the cistern and 1 metre is recommended. In most instances, a lesser head will still work. Fluidmaster is the only product I know of that has a gravity flap valve option.

CunningPlansDept also offered the following as a means of topping up the header tank once it reached near empty:

The switching you need is common in industry for emptying sumps. You need a non-spring-return switch with a long arm (talk to a friendly electrician or maybe Jaycar/Dick Smith) and a ball float on a long rod. The rod runs through a fixed guide (to stop if twisting) and a hole in the switch arm. As the ball floats up the rod slides through the switch until a nut/striker on the rod pushes the switch up, same on the way down.
If you have a pressurised supply system, the same can work with a quarter turn valve instead of an electrical switch.

Munter- The info on pump electricity use is something I have been wanting for some time. Very interesting. If you could confirm the figures, that would be great.

My concern with future water demands is that high cost engineering solutions will be enacted as opposed to full utilisation of current cost effective measures. By way of example, Adelaide is proceeding with a $1.9 billion desalination plant that will see three story high pumping stations located in parks and major disruption to homes and business despite little more than 50% of homes equipped with tanks, under utilised recycled water, small dams overflowing during major rain events, stormwater discharging to the sea, lack of rainwater storage infrastructure on industrial sites etc. etc. etc. Unfortunately, those who have financially committed to making a difference will still pay for the indifference of others.

Posted Monday 19 Jul 2010 @ 4:32:08 am from IP #
munter
Member

It seems my memory isn't a good reference!!

http://www.isf.uts.edu.au/publications/retamal2009climatechange.pdf

There are many figures quoted in this short article (which isn't the one I was referring to previously but is written by the same author so presumably are related).

In this article they suggest 2.7kwhr/kl for small scale rainwater systems and anywhere from 0.5 to 1.8 for large scale utilities (heavily dependent on the geography and source).

Posted Monday 19 Jul 2010 @ 4:52:18 am from IP #
munter
Member

There is also some interesting info on page 5-4 of this KBR report. It puts rainwater tank supplied water at about 3 kwhr/kl. Desal comes in a fair bit higher while a local dam (Traveston) appears much, much lower. The major infrastructure options are obviously highly dependent on the specifics of the project whereas small scale systems are probably all relatively similar.

http://www.qwc.qld.gov.au/myfiles/uploads/SEQWS/supporting%20docs/Energy%20consumption%20discussion%20paper.pdf

D'oh - it appears that this paper also references Gardener 2006 (as per the previous paper) so its no wonder they come up with a similar figure...

Posted Monday 19 Jul 2010 @ 4:58:44 am from IP #
Diver
Member

Thanks Munter. Good paper.

I have heard that the start up energy demand for many pumps can be around 3 times higher than normal use but have not seen a study as yet. The start up demand is obviously a factor during short run cycles such as when filling a cistern and I think pumps should be rated accordingly.

Posted Monday 19 Jul 2010 @ 5:38:17 am from IP #
Diver
Member

Hi Munter.

I posted before seeing your last post and link. Good paper with information about pump start up energy demands which states x4 normal operational load.

Of particular interest was the 'trickle pump' inefficiencies. I have never been a fan of these as I think it is best to simply switch over to mains. The figure for Brisbane showing trickle systems pumping 2.3 times more water than the amount harvested is a real eye opener!

Posted Monday 19 Jul 2010 @ 6:44:45 am from IP #
matas
Member

Yes thanks Munter, for those studies, very interesting.

And thanks Diver the header tank setup description.

A header tank system seems to me, to have several advantages -
1/ No need for a complex expensive electronic pressure switch, instead a simple float switch (in the header tank).
2/ Pump is not turning on and off continuously, saving running cost.
3/ Pump could run once a day, in off peak time, (TOU meter) saving electricity cost.
4/ Pump could be low power and slower (just enough to get to the header tank), further saving electricity (I guess ?)
5/ Leaves open the possibility of later adding supplementary pumping, with something like a windmill.

Disadvantages
1/ Extra cost of a header tank and piping
2/ Need a high site, for the header tank.
3/ Taps only have gravity feed pressure.

Just wondering, does anyone successfully use a header tank system, with their rainwater tank, for household use ?

Posted Monday 19 Jul 2010 @ 9:52:06 am from IP #
Diver
Member

I use my main tank which is very close to the cistern but there are a couple of months of the year that I switch over to mains and reserve my water storage for the garden and vehicle washing. To view the float valve and pressure seal, go to:

http://www.haron.com.au/fluidmaster_products.html

If you try to buy the gravity seal, you need to quote the part number and have it ordered in as it is not listed in the parts catalogue. As you will see on the web link, there is also a low pressure seal. This will not work; you need 242LP071 very low pressure seal for gravity fed cisterns. You only need one as the other float valve will connect to mains water. I advise my customers to print out the web page and take it with them as counter staff can be hard to convince but I am considering carrying a few spares in stock.

I have thought about a separate header tank but for my situation, it is not worth considering.

I generally take out a brick and push a very small hole through the plaster wall. If I have taken out the correct brick (the hard part), I enlarge then line up the hole in the plaster with the brick and drill a hole through the brick. The rest, including replacing the brick after feeding through the hose, is easy and you will save a lot of money.

This method qualifies for the 'plumb tank to toilet' rebate but you may need the plumber to connect the flexible hose to the cistern so he can sign off on it.

Re Disadvantages 3/ You still need a pump to supply a tap. If plumbing to a tap some distance from the pump, splice in a length of larger diameter pipe to lower friction loss. For garden watering etc., buy an 18 mm hose to further reduce friction loss and connect it to a short 12 mm garden hose so you can use standard fittings. This can often allow the purchase of a smaller pump.

Posted Monday 19 Jul 2010 @ 1:47:19 pm from IP #
matas
Member

Thanks again Diver
So your main tank outlet is just higher than your toilet cistern ?
And have you plumbed your washing machine ?
I assume you need a pump for that, as short gravity would be insufficient, I guess.

Posted Monday 19 Jul 2010 @ 11:52:26 pm from IP #
Diver
Member

The tank's head has to be higher than the required head in the cistern and the manufacturer recommends a 1 metre static head to supply the cistern. My main tank's base and the house floor are roughly the same level and the cistern's water level is about 80 cm above the floor, if my main tank is half full, it operates ok with less than a 1 metre static feed. I also have 4 tanks and I can transfer water around very easily (mostly by gravity transfer) so my situation is different to most.

I advise that any draw off outlets are fitted a minimum 100 mm above the bottom of the tank but I also advise fitting the tank with a low set drain valve.

I did not plumb the laundry but I do run a hose into the laundry to fill the washing machine. I fit a metal sprinkler (for weight), put clothes over it to prevent spray, then fill it up. I have known about Professor Stephen Burkinshaw from Leeds University and his one cup washing machine for quite some time and anticipate keeping my machine for another 4-5 years until the technology is available in Australia. The first phase entry will be into the United States commercial market through a partnership with Green Earth Cleaning.

Posted Tuesday 20 Jul 2010 @ 2:14:33 am from IP #
dymonite69
Member

Xeros - throw beads in, stains go from clothes to beads.

So what do you do with the beads? Throw them out? Wash them? With how much water?

Posted Tuesday 20 Jul 2010 @ 3:26:03 am from IP #
Diver
Member

Approx 100 average washes, then recycle.

Posted Tuesday 20 Jul 2010 @ 3:30:03 am from IP #
dymonite69
Member

Is quality maintained from the 1st wash to the 100th one?

Posted Tuesday 20 Jul 2010 @ 4:34:11 am from IP #
rockabye
Member

Fred Pearce has an interesting book on water sustainability.

WHEN THE RIVERS RUN DRY by Fred Pearce.

Do you know how much water you use each day - not just the 5 litres you may drink, or the 150 litres you guzzle to cook, wash, and flush the toilet with. It takes around 500 litres of water to grow the wheat to produce a loaf of bread. A staggering 11,000 litres to feed enough cows to make a quarter-pound hamburger. You could take 25 baths in the water it takes to grow the cotton for just one T-shirt.

I guess if you eat just one hamburger you could be accused of being a water waster. Puts it all in perspective.

Posted Tuesday 20 Jul 2010 @ 4:38:24 am from IP #
Diver
Member

One cup washing machine.

http://www.xerosltd.com/

http://www.guardian.co.uk/environment/2010/mar/09/xeros-washing-machine-bills

Dymo- Use time of beads vary with how dirty the washing is. If a beads absorbtion capacity has reached lets say 50%, the absorbtion efficiency does not decrease by the same amount. The total bead load has a large surface area and dirt is absorbed into the bead's core, not clung to the outside surface. If you know anyone who has owned a white nylon shirt, they would know how quickly it became grubby. Many nylon articles are coated with other substances including Teflon as in the case of 'nylon' ropes due to pure nylon being highly hydrophilic.

Domestic release will follow the commercial release and current development programs include a closed loop bead cleaning system. If this was fully developed and included in the final product, it would be sensational. This technology also uses 30% less energy, minimal detergent and makes clothes dryers largely redundant.

City of Salisbury S.A. storm water recycling.

http://news-review-messenger.whereilive.com.au/news/story/un-adviser-backs-salisbury-water-recycling/

Posted Tuesday 20 Jul 2010 @ 5:57:27 am from IP #
matas
Member

Thanks again Diver, for all your rainwater plumbing advice.

Posted Tuesday 20 Jul 2010 @ 8:03:24 am from IP #
Buzzman
Member

I'm sure urban Council's would object, but as I understand it from my own research, a 5-7m head provides approx the equivalent pressure to mains pressure.

So a tank on a stand 5m above the shower rose would provide mains pressure to the shower (and everywhere else). Perhaps a better option for rural dwellers.

You could then have solar PV panel feeding a small 12V pump transferring water stored in on-ground or below ground tanks up to the header tank to a float valve in the tank. Tank size would need to be approx 50L/person/day in capacity.

How about planting three or four fast-growing 8m tall trees, like poplars, or maybe bamboo, and once they're up to height build the tank stand and place the tank in between them. Might be a way around objections.

Posted Thursday 22 Jul 2010 @ 7:07:03 am from IP #
ghostgum
Member

Buzzman, you need a tower 50-70m high.

Mains pressure is 5-7bar. One bar is approximately one atmosphere of pressure. From scuba training, 10m depth of water is one atmosphere. So you need your tower to be 50-70m high.

Your trees will need to be Karri or similar, and the planning phase could last 100 years

Posted Thursday 22 Jul 2010 @ 7:56:48 am from IP #
dymonite69
Member

Securing Adelaide metropolitan water needs is a complex issue. Firstly, we have to face that we live in a dry continent with uncertain rainfall. Secondly, it would be naive to think that we can exert any political influence over the Eastern States through which most of the Murray-Darling flows.

This leaves us to work out an alternative and sustainable system beyond the Murray.

Increasing reservoir capacity sound tempting but one needs rain to catch. The actual capacity of all the reservoirs already exceeds our annual consumption. For every metre we increase the dam height of Mt Bold only gives us two extra days of water. One could increase it 10 metres but that capacity will often not be utilised. When the media talks about 3 billions litres flowing out to see, we must remember that still only represents 6 days of water and a event that happens every 5 years. In effect is one extra day of water per year.

Stormwater reclamation is great but it doesn't provide potable water. To store it on a mass scale would require huge constructed wetlands. Most of the Adelaide geography is not suitable. Salisbury is an exception. The water also needs to dwell in the aquifers for a reasonable period before it is drawn on. If consumption was markedly increased, there is a risk it won't be safe to drink.

It will be always be inevitable that we need to divert some stormwater out to sea. No matter how much storage we have, the occasional rain event will exceed that capacity. The option exists to prevent the city being flooded. If wetlands are too big then they will just dry out and be unable to perform the purification process.

Desal is the only option that provides consistent levels of potable water that does not require any temporary storage.

In the end, whatever we do will require a combination of various options including the possibility we need to have one system for potable water and one for non-potable water. Whatever we do will be expensive. The trouble is that the average tax payer thinks we can all do this for free.

Posted Saturday 24 Jul 2010 @ 10:41:02 am from IP #
Diver
Member

Dymo,
I agree. Adelaide has an unenviable, complex and geographically challenged situation and as you say, a solution will involve a combination of various options. Unfortunately, the desalination option is often seized as a one stop panacea. With Adelaide, its adoption was inevitable, unfortunately it may now take urgency from the need to develop other overdue options due to big dollar projects and small populations not being overly compatible.

The Salisbury stormwater recycling project has attracted national and international praise but unfortunately it seems there is difficulty in finding sufficient customers to fully utilise the end product due to the limited pipe distribution network. The project development is long term and hopefully the research will be utilised elsewhere. The water is also mechanically filtered in addition to biofiltration.

http://news-review-messenger.whereilive.com.au/news/story/un-adviser-backs-salisbury-water-recycling/

http://www.adelaidenow.com.au/news/in-depth/un-advisors-disgust-at-policies/story-e6frebk3-1225748852115

http://www.adelaidenow.com.au/news/in-depth/how-the-driest-state-can-walk-on-water/story-e6frebt3-1111118912938

Sufficient stormwater storage requirements are an impossibility during major rain events as you say. A lot of stormwater flows from the hundreds of thousands of Adelaide homes and commercial buildings not harvesting rainwater to tanks. South Australian homes have the highest percentage of urban water tanks of all the capital cities. Considering Adelaide's climate challenge, has it ever been seriously considered to make them compulsory? I think there is/was a case to answer. New harvesting methods now allow existing tanks to harvest greater annual yields but like other options, they do not provide a total solution and of course the water harvested needs to be fully utilised.

I have also posted a news link regarding the new South Australian Water Sensitive Urban Design regulations that require all new housing estates to recycle all waste water and stormwater by 2013. This should interest all Australians.

http://www.adelaidenow.com.au/news/compulsory-water-recycling-for-new-estates/story-e6freo8c-1225747971787

Posted Saturday 24 Jul 2010 @ 3:42:52 pm from IP #

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