Low tech - high volume water distillation

Doesn't seem to be a forum for purely potable water related topics so ill post here.

Any good ideas on low tech large scale water distillation?
Preferably as passive as possible. No interest in burning firewood or dinosaurs.

Our well, while productive, is high in iron and rather hard. Livestock seem ok with it. It is fine for our small orchard, grapes and berries. It will turn concrete red. No biggie, iron is commonly occurring and abundant mineral. Basically I use it on everything except in the greenhouses and the house where we use "domestic tap" water, which is a dole valve delivering one quart per minute 24/7 to our cistern.
I once read somewhere (can't find it) about a 19th century mining camp in Bolivia of several thousand that relied entirely on a scaled up solar still system. Parabolic reflector systems could be of interest, but also seems fiddly and more complex than neccessary.

My first question I think I would have is when we are talking about high volume, what does that actually mean to you? The passive systems that I see usually work slowly by condensation but perhaps if you are located in a warmer climate you would see better results than I do in the Northeast.

A solar distiller like the one below is scalable but relies on sunlight and has a slower distillation rate. I've seen these systems designed with the intent of desalination.

I'm thinking small community sized....maybe three or 4 households.  Maybe 250-300gal/day?... yes that is alot, but the extra could be stored in the cistern for less productive days..  I also would guess rate of production is dependent on multiple factors including temp differentials, seasonal variations in angle of the sun,  brine concentration maybe.  I have seen a capillary system, but it seems it could maybe maybe to have a high amount of maintenance depending on the quality of water being treated.
I would imagine a fair amount of salt build up.  

I have no what this guys rate of production is or what all is in the box. That little bit could be the whole day's production.

I'm inclined to think that (if you haven't already) in a situation like that it may be worth investing in a separate water system for non-potable household uses. Can the well water be used for washing for example? Toilet flushing (if appropriate) is also a big user of water which doesn't need to be potable. That way a smaller scale still system would be adequate for kitchen use, or for more households.

I'm sure you can build one when you understand the how/why they work.  The way this site explains it, you could setup a container of water with a sheet that is lower in the center and a collector under the center.  If that is above an exit pipe then gravity would let that flow out of the clean water container just like your video.  If you need the water to be under pressure to use a solar panel setup could power a pump and be activated when a spicket, or request for water, was opened.

Solar water distilling explained

If this is to be your only (clean) water source then I would use greywater for toilets and irrigation and save all the clean water for washing and consumption.

Instead of distilling it can you just let it settle?  We have very hard water,  It some times comes out of the well blood red.  I fill a 275 gallon container, and let it settle.  Overnight a lot of the iron settles to the bottom,  I can than carefully take water off the top of the tank.  Once the tank is nearly empty I open the bottom valve to dump the remaining water and rust, rinse it out and refill it to let it settle again.

Or you could look at floculants to remove iron from the water.  There are many chemicals sold to municipalities that will pop up first when you search for floculants but with a bit of digging you may be able to find a common household item that will do the job. Alum is used in food and it is a floculant that will clean muddy water, it may help with iron as well.

Ralph Anders wrote:I'm thinking small community sized....maybe three or 4 households.  Maybe 250-300gal/day?... yes that is alot, but the extra could be stored in the cistern for less productive days..  

For distillation, that is an industrial scale operation with a massive energy input. Where would that energy come from?

I trust there are other options that can clean up your water and make it usable.

Ralph Anders wrote:Our well, while productive, is high in iron and rather hard.

Have you talked to well drillers in the area? Sometimes iron problems are caused by iron bacteria, and that can be controlled.

Re distillation: I recall people around here playing with the giant fresnel lenses from discarded projection televisions. Perhaps this could be an energy source for a modest distillation system?

There are some basic numbers that govern the process.
The heat of vaporization, which is the energy required to turn liquid water to vapor at the boiling point, is ~2260kJ/kg. Recall 1Liter =1 kg of water.
I live in AZ, where I get ~1kW/m^2 of sunlight in summer. A kW is a kJ/second. So, for me, if I had a personal still, I could get (during peak sun), 0.44g/s per square meter of collector. If I have 6hrs of peak sun, I can get 9.5L per square meter per day. With a perfect collector. Taking no hits for preheating from ambient.

The above math is why you can survive on solar stills, as many survival handbooks note (and some even know you can drink your own urine). But at a community scale, and dealing with real wind losses of heat and such, it is challenging to deploy them writ large. To my knowledge, reverse osmosis is the preferred tech for large desalination plants.

I do suspect you could find natural means of treating your well water to improve its usability. You might look into ash or clays that could flocculate the iron (iron water is acidic, raising the pH will aid settling), the settling method noted above sounds workable, and there are several conventional methods described here: https://extension.psu.edu/iron-and-manganese-in-private-water-systems. I was pleased to see that hydrogen peroxide is an alternative to chlorine, but still not easy to DIY.

Finally, do you have a way to check whether the iron is from the ground or from the well pipe or casing? My well is super deep (AZ), and down where the water is there is PVC and stainless steel, for better or worse.
Good luck with your water!
Mark

Thanks for all the replies and imput.

Perhaps I should clarify, I am interested in redundancies. For all possibilities. I have a domestic tap. The well delivers. Limited by law to 15 gpm.  I have a regular high power pump, a solar pump down the hole, and one on the shelf. The well contains ferrous iron at 11ppm. It is clear. When exposed to air it oxidizes and precipitates.  We have a 2000 gpd reverse osmosis system preceded by an air injection and twin self flushing catalyzer tanks  but have never used it. It is a contingency plan. It uses consumables and electricity that I'd rather not.  I understand that I could easily build or buy a still and run it on top of a wood stove or fire and get maybe a couple gph. That sounds like a little bit more chopping wood than I'm into.
We have all the energy we need. Fusion energy is free abundant and available to all for a portion of the day.
I'm more interested in people's experience with something similar to the previous examples shown, or inclined flat plate type systems, or possibly vacuum tube parabolic systems, even that's starting to get a little too techy an fiddly for my steez.

I dig the fresnel lenses, melting stuff with them is big fun, problem with those is the constant need to be re-oriented.

Chemical and radiological remediation is the goal.
I want to have the ability to produce as much distilled drinking water for as many family and neighbors when the need arises.


https://www.researchgate.net/publication/295186633_Experimental_study_of_an_inclined_flat_plate-type_solar_water_distillation_system