Backyard Desalination

[wezzy]

I am looking at buying a property on the banks of the Logan River just south of Brisbane. The Logan River at this location is slightly tidal and I was wondering if there is some method of treating the water to make it useable in the garden - e.g desalination. I have seen some small desalination units that would produce about 600-1000 litres per day of potable water. These units are start around $10,000. I was thinking perhaps that at certain times of the tidal movement the water may be fresher and require less treatment i.e. as the water runs out at low tide (although the height of the river does not change at my location).

[milifestyle]

I have heard of several techniques over the years, I even have my own design i may get onto paper one day. The downside of all the techniques is they all require a substantial amount of energy (heat) or constant filtration replacement.

Here's a couple of links you may find useful...

http://www.saltfree.com.au/desalination.html

http://www.consumerwaterpurificationsys ... niques.htm (http://www.consumerwaterpurificationsystems.com/techniques.htm)

[Michaelangelica]

I am looking at buying a property on the banks of the Logan River just south of Brisbane. The Logan River at this location is slightly tidal and I was wondering if there is some method of treating the water to make it useable in the garden - e.g desalination. I have seen some small desalination units that would produce about 600-1000 litres per day of potable water. These units are start around $10,000. I was thinking perhaps that at certain times of the tidal movement the water may be fresher and require less treatment i.e. as the water runs out at low tide (although the height of the river does not change at my location).
Snap.
An interest of mine too.
You will find lots of references to it in previous posts on the forum.
There is one low tech. design in the saving the Murry Darling thread. it looks like a nursery-hot-house/Polly tunnel.

If you search the web you will find even simpler systems going back to Ancient Greece.

I have often wondered why domestic swimming-pool-chlorinatiors aren't more widely used to desalinate.

[ecodharmamark]

G'day Wezzy

Welcome to the PRI Forum.


I am looking at buying a property on the banks of the Logan River just south of Brisbane. The Logan River at this location is slightly tidal and I was wondering if there is some method of treating the water to make it useable in the garden - e.g desalination. I have seen some small desalination units that would produce about 600-1000 litres per day of potable water. These units are start around $10,000. I was thinking perhaps that at certain times of the tidal movement the water may be fresher and require less treatment i.e. as the water runs out at low tide (although the height of the river does not change at my location).

Gee, I don't know much about desal plants, except for the really big ones, and especially this one (see: http://www.dpi.vic.gov.au/DSE/nrenpl.ns ... DA007FAB8B (http://www.dpi.vic.gov.au/DSE/nrenpl.nsf/LinkView/5249619A2A213442CA2573BE007EEAA992FBC7C133A6F520CA 2572DA007FAB8B)). But what I do know (from my studies of the one that I previously provided the link to) is this; desal plants rate extremely high in terms of energy consumption. Even if economy of scale is anything to go by, your proposed backjob jobby is still going to cost an awful lot in terms of energy demand.

Um, in terms of the salt content of the Logan River (and in particular where you are proposing to buy), you might want to check these sites:

Water Resources - QLD
http://www.anra.gov.au/topics/water/qua ... river.html (http://www.anra.gov.au/topics/water/quality/qld/basin-loganalbert-river.html)

EPA (Environment Protection Authorty) - QLD
https://www.epa.qld.gov.au/environmenta ... index.html (https://www.epa.qld.gov.au/environmental_management/water/water_quality_monitoring/projects/water_quality_monitoring_programs/logannerang_water_quality_monitoring_program/index.html)

While you are checking maps, you may want to have a look at this one:

Flood Map - Brisbane City Council QLD
http://www.brisbane.qld.gov.au/BCC:BASE::pc=PC_5909

Have you read this Courier-Mail newspaper report?

New overland flow flood maps for Brisbane
http://www.news.com.au/story/0,27574,26 ... 02,00.html (http://www.news.com.au/story/0,27574,26280939-3102,00.html)

Or read the State and/or Federal Government reports on Climate Change impacts?

Climate Change Risk to Australia's Coasts
http://www.climatechange.gov.au/publica ... oasts.aspx (http://www.climatechange.gov.au/publications/coastline/climate-change-risks-to-australias-coasts.aspx)

Climate Change in Queensland: What the Science is Telling Us
http://www.climatechange.qld.gov.au/__d ... rt_WEB.pdf (http://www.climatechange.qld.gov.au/__data/assets/pdf_file/0014/22262/ClimateScienceReport_WEB.pdf)

Just a few thoughts that spring to mind.

Good luck with finding out about the saline stuff. Let us know how you get on.

Cheerio, Marko.

[pebble]

Have you tasted the water when the tide is at different flows eg when it's going out, just before it turns to come in etc? What does it taste like?

[Michaelangelica]

Have you tasted the water when the tide is at different flows eg when it's going out, just before it turns to come in etc? What does it taste like?
BGQ pebble.
You need to know what you are starting with.

It might be worth your while talking to these people in Townsville
http://www.abc.net.au/rural/content/2008/s2575977.htm
If they can do that for calcium, why not salt?

commercial 'off-the-shelf' desalinators are available from boat chandlers, including a hand operated model

[pebble]

Taste the water from different depths too. Doesn't fresh water sit on top of salty water? Not sure if that works where the water is moving alot (don't know how big or fast your river and tides are).

[wezzy]

Thanks everyone - you have given me plenty of homework. As I stood on the bank of the Logan River and saw all that water I thought there must be a way to harvest just a little for my thirsty garden in this hot , hot weather.

I'll keep you informed.

[Michaelangelica]

Thanks everyone - you have given me plenty of homework. As I stood on the bank of the Logan River and saw all that water I thought there must be a way to harvest just a little for my thirsty garden in this hot , hot weather.

I'll keep you informed.
Maybe you could get a government grant?
Stranger things have happened!


Subsidies for private desal plant approved
Thursday, November 12, 2009

LOS ANGELES —The board of the Metropolitan Water District of Southern California (MWD) on November 10 voted to approve about $350 million in subsidies over 25 years for Poseidon Resources’ seawater desalination plant project in Carlsbad, The Los Angeles Times reported November 11.

The subsidies would go to the nine San Diego County districts that have signed on to buy the water, as part of an MWD project to encourage development of new local water sources.
http://www.watertechonline.com/news.asp?N_ID=72933

[Michaelangelica]

Thanks everyone - you have given me plenty of homework. As I stood on the bank of the Logan River and saw all that water I thought there must be a way to harvest just a little for my thirsty garden in this hot , hot weather.

I'll keep you informed.
Maybe you could get a government grant?
Stranger things have happened!


Subsidies for private desal plant approved
Thursday, November 12, 2009

LOS ANGELES —The board of the Metropolitan Water District of Southern California (MWD) on November 10 voted to approve about $350 million in subsidies over 25 years for Poseidon Resources’ seawater desalination plant project in Carlsbad, The Los Angeles Times reported November 11.

The subsidies would go to the nine San Diego County districts that have signed on to buy the water, as part of an MWD project to encourage development of new local water sources.
http://www.watertechonline.com/news.asp?N_ID=72933

Like solar panels you hear of new technological breakthoughs all the time. Yest it seems to take forever for these to filter though
This is the latest buzz with de-sal

Soon, disposable batteries made from salt and paper
By Ani
August 25th, 2009 LONDON - Researchers have developed a new microbial desalination system that can remove 90 per cent of the salt from a seawater-like solution. Microbial desalination could offer big advantages over the methods ... August 7th, 2009 WASHINGTON - An international team of researchers from China and the US has determined that a process that cleans wastewater and generates electricity can also remove 90 percent of salt from brackish water or seawater. ...
Breaking News - http://blog.taragana.com/n/

A New Method for Water Desalination Using Microbial Desalination ...
24 Jul 2009 ... The main desalination technologies currently used are reverse osmosis, ... New membrane systems are also being developed that reduce the need for .... Three- chamber MDCs were inoculated with a mixed bacterial culture ...
pubs.acs.org/doi/abs/10.1021/es901950j

[Michaelangelica]

I just found an interesting site you may wish to explore

http://www.excelwater.com/eng/img_site/our_product/insidedistiller.jpg

How It Works

When your fully automatic Distiller is installed in your furnace or utility room, tapped into the main water line (1) and, Plugged into the normal household current, your Distiller will automatically draw water into the boiling chamber (2), A regulated start / stop float system (3) extends the life of the heating element (4). When the water boils, steam rises, leaving contaminants behind. The vapor then goes into an exclusive double-baffle system (5) and any volatile gases are released through a special built-in vent (6). After the steam passes through a fan-cooled condensing coil (7), the Distilled Water runs through a coconut charcoal filter (8), and finally into the holding tank (9).

The automatic pump shut-off control (10) protects the pump from burning out should the holding tank ever run out of water. Polar Bear Water Distiller boiling tanks are designed with a "V" shaped bottom (11) and are engineered from a very high quality stainless steel (12). Other exclusive innovations include an energy-saving system (13) which allows one-third of the Distilled Water in the holding tank to be drawn out before the unit starts up. This is more energy-efficient than running the distiller for small amounts of water and results in 25% lower operating costs!
http://www.excelwater.com/eng/b2c/our_product_dist.php
you might like to explore the rest of the site
Ultraviolet Purifiers
http://www.excelwater.com/eng/b2c/our_product_tmax.php#
and Chlorinators (used in saltwater pools) might also be worth investigating.

[Origin Water]

wezzy,

We are the sole importers and the agents in Queensland for the new Danfoss Watercube2, this is the website http://www.watercube2.com/

In the past, desalination power consumption was the killer with most water makers needing around 2500 -3000 watts of power when running,
The benefit of these new units is that they produce over 5,000 litres of water and only use 720 watts of power when running, that makes them suitable for using solar panels or a small generator, Danfoss have been producing energy efficient motors for fridges and freezers for decades and have turned there attention to small land based desalinators now,

If you have tariff 33 -(controlled supply) the current costing from AGL this little fella will cost you $0.70 cents per KL (1000 litres), normal tariff 11 has it around $1.10 per KL, That includes the feed pump, media filters and UV filter, We are installing these on canal homes to keep the gardens and swimming pools topped up, saves paying the $2.24 per KL on the gold coast and the $ 1.88 from the Brisbane city council, And gives the end user the choice when to water, when to fill up the pool, when to water the garden

We are currently building a solar panel system, that can be used in remote areas especially in the outback, However it will only produce around 2,000 litres / day, - which is enough to water gardens and provide drinking water

Hope this helps in letting you know what is available out there !!

Cheers
Douglas

[springtide]

Have you considered the low tech thing where you get a large shallow tray of water and build a very low greenhouse over it? - the water evaporates in the greenhouse and condenses on the sides and is collected in gutters - flowing into another tank. i remember building a 1 x 1 metre one in Melbourne and filling a 5 litre ice cream bucket with ease. (5mm evaporation per day - i should have gotten more)
I don't know how much water you need or how much space you have but it is cheap and reliable (on a sunny day).

[springtide]

Just a thought on the salinity - the fresh water may be on the bottom - i know it shouldn't work this way but often the fresh water will not easily mix with the sea water (halocline) and is colder than the ocean water esp in winter and sinks low (thermocline)

[Michaelangelica]

Purifying the sea one drop at a time
Microfluidic channels offer promise of cheap, portable desalination.

by Katharine Sanderson
Nature News


Disaster-struck areas desperate for fresh water could benefit from an ion-repelling device that cleans up contaminated salt water.

Jongyoon Han at the Massachusetts Institute of Technology (MIT) in Cambridge and his colleagues have come up with a device that could be used as a simple, portable water-desalination system run from a battery or on solar power.

Han and his team were investigating the physics behind a phenomenon called ion-concentration polarization. This occurs when a voltage is applied across a membrane, setting up an ion current.
Because only positive ions can pass through the membrane, a mismatch is created across it.
A higher proportion of positive ions amass on one side of the membrane together with the negative ions that were unable to traverse it.

The researchers decided to try to exploit this effect to scrub salts out of water.
Instead of a membrane, however, they used an ion-selective material called Nafion to make a nanojunction.
This connects to a larger, micrometre-sized channel that has sea water flowing through it. When a voltage is turned on across the nanojunction, salts are repelled from the sea water as it flows by, although the sea water doesn't actually touch the nanojunction.
The microchannel splits into two at the junction, with fresh water flowing straight on to be collected while the repelled salty water is pushed away through the second microchannel.
Promising trickle

Han and his co-workers used sea water from http://www.bioedonline.org/news/news.cfm?art=6205
This is basically how cells in plants, and most other things, work.


On Ocean currents



An oceanic 'fast-lane' for climate changeA deep-sea current moves millions of cubic metres of water northward every second.

by Richard A. Love
Nature News

Work in Japan and Australia has revealed that a deep-ocean current is carrying frigid water rapidly northward from Antarctica along the edge of a giant underwater plateau.

Other research teams had previously identified a deep current along the eastern edge of the Kerguelen Plateau, a more than 2,200-kilometre-long rise some 3,000 kilometres south-west of Australia. But estimates of its speed, taken as "snapshots" by instruments deployed from research vessels, had been "all over the place", says Steve Rintoul, a physical oceanographer at the Antarctic Climate and Ecosystem Cooperative Research Centre in Hobart, Australia, and a co-author of the new study1.
more at
http://www.bioedonline.org/news/news.cfm?art=6298