Thread: Alternatives to desalinisation

My first thought was "I'm sure Israel has figured something out", turns out they've developed a system to pull drinkable water out of the air Watergen | Water from Air

Here's a combined shower water limiter and timer device

Shower Timers, Save Water, Eco Water Solutions

The Watergen solution appears to operate like a de-humidifier, cooling the air to dewpoint and would be dependent on RH. With its additional filtration, it seems to be aimed more at providing drinking water volumes (2.5 litres/day for adults) rather than the volumes needed for showering i.e. 9 litres/min for 3 minutes using a water limiter = 27 litres/person but could be as high as 70 litres/person for a 3 minute shower with out a limiter.
Pete

You might think about sinking a bore. Maybe ask around the district to learn more about others who might have done the same. Even if the water is not potable, it could be used for other purposes.

My neighbour near Oberon has one which yields sterile pure water.

mick

A few months ago, my dad (who lives on a decent farm) asked me the same question.

He is on the sea, brackish inlet, but little rainfall. Place use to be a vineyard 100 years ago, but no more due to salinity.


When he asked, there happened to be a parched primary school that had installed a Water-from-Air systems as posted above. Different brand though. The things were enough to supply water to the kiddos plus excess for the schools needs. It ran on solar.

I did the maths and he could fill the two 10k litre storage tanks in only a couple of weeks. They could also be run from solar as independent units - no mains electricity.

They were tested in Israel and Palestine and supplied buildings with water.

I'll find the article.


The other way we worked out was a desal unit that pumped (via solar pump) water to a parabolic evaporator. This thing could really thunder out the volume! The unit itself was pretty big... about 15 metres long and involved a solar tracker, pump and some other bits.

Overall the idea is dead simple - brackish water in one end, run via a pipe in which a long curved surface focused the sun on the pipe, it boiled the hell out of the water. Steam out one end (which is condensed and collected) and the concentrate is flowed back to the sea.

As he was a little inland in needed a pump to get the clear H2O back to him, but that didn't seem too arduous.



edit - similar to this Long-weekend read: PV pulls water from thin air – pv magazine Australia


edit 2 - this is the parabolic thing, or at least the design/idea is the same.... seems quite easy to build and very low tech Solar Desalination Could be a Game Changer for California Farms – National Geographic Society Newsroom

WaterFX-parabolic-mirrors-768x510.jpg

The first thing that I would be finding out would be how your farmer neighbours are sourcing the water you use now, and how difficult/expensive it would be to replicate that process at a scale to meet your needs. If they are getting potable bore water close enough to you to gravity feed to you, there is a good chance that you should be able to access it as well from within your boundaries, though you would have the initial cost of license/permits, plumbing and pumps to consider, plus ongoing electricity costs etc to run the system.

The solar distillation concept appears interesting, but when you look at the picture in blown up form, the white thing in the background on the RHS is a very large LPG or similar cylinder and the small figure in front of the cylinder appears to be an adult. Based on that, the actual solar distillation system appears to be in the vicinity of 100m long and 15m or so high, so appears to be a very expensive option. Of course you still need a water source, a lot of plumbing and pumps to make it work as well.

Desal is viable on a small scale for 8-10 people, but becomes more difficult when you need to cater for more people on an ongoing basis. Beyond the initial cost to set up, you have to pump a huge amount of water and only get to keep a small amount, the rest being used to flush the membranes etc. You also need to be able source your raw water from somewhere that has significant flow and mixing, otherwise the flush water increases the concentration of material to removed by the desal unit, leading to increased electricity costs and shorter lifetimes for the membranes.

Originally Posted by Glider

You might think about sinking a bore. Maybe ask around the district to learn more about others who might have done the same. Even if the water is not potable, it could be used for other purposes.

My neighbour near Oberon has one which yields sterile pure water.

mick

bore I would love to, but the buildings are 100Meters away from high tide, so the underground water would need a lot of treatment.

We can cater from 10 - 150 people in one camp group, add to that equation, dippy teenagers from big cities who have no idea about water savings.

The neighbours tank that we use is end of the run from the mains water take off valve & water meter that is 6 Kms away. the proposed new owner is quoted as saying ' they can install their own meter and pipe at same connection. We are both end of the road literally.

We have a family group of 20 in at present, the ave reading from meter is 1200 L/day that is gravity fed from the farm storage tank. Add to that ?? litres of water from our storage tanks (combination of rain & mains pumped water?

There is always a large young peoples camp over Easter. My plan is to have our 2 storage tanks full and then after camp record average daily use plus what it takes to refill both tanks and divide that by number of people camping, remembering that young teenagers are the worst offenders but it will give us a ball park figure to work on/around.

Originally Posted by Tonyz

bore I would love to, but the buildings are 100Meters away from high tide, so the underground water would need a lot of treatment.

The bore water would not necessarily be contaminated by the sea as you would be drawing from an aquifer which could be quite deep. You need to contact the relative authority to find out if there is a suitable source of water under your site.

Originally Posted by Bohdan

The bore water would not necessarily be contaminated by the sea as you would be drawing from an aquifer which could be quite deep. You need to contact the relative authority to find out if there is a suitable source of water under your site.

would that be local council, SA Water, Dept of Environment all of which Id prefer to shy away from. Not that we are doing or plan to do anything illegal but the more sticky beak nobs there are involved the more fingers in the pie, so to speak.

part related ....15 years ago a family visited our camp, he was in management with MFS metropolitan Fire service
The question was asked why we didnt have a fire water tank?
For our needs completely useless, if we had a fire the nearest CFS fire truck is 15 minutes drive awat let alone waiting for the crew to arrive.
Pressure was put on us and finally our insurance provider that this should be done to these specifications.

So for the past 12-13 years we have a 180000litre fire tank with connection to a MFS fire truck only. (the nearest is 40 minutes away) CFS cannot hook up to it and are not prepared to start arguing with MFS.

and you wonder why we hate the thought of sitting around a table having a discussion.

I know a similar caravan park situation on the ocean and they use a bore for general water and showers etc. The water has a very high mineral content and is hard on the plumbing fittings and tapware but is still suitable for use
Rainwater is connected to the kitchen sink only

Apply for a government assistance grant (there are many) and put the mains water line in, much better option in the long term, and zero maintenance.

Is there an opportunity of putting up a windmill for power generation?

I have a mate in Cairns who manufactures and supplies desal plants, from small portable units to large industrial plants.
If interested send me a PM.