Can We Use Plants Transpiration to Obtain Drinkable Water?

[Paramecium8]

Some type of device or structure that can collect almost all the water from plants transpiration (For example in a garden) could be used as some type of "Filter" if you water the plants with non drinkable water(from rivers, lakes...).

This method could be used to eliminate all the contaminants and pathogens from the water and still use the plants to generate food?

 

[Acme]

Some type of device or structure that can collect almost all the water from plants transpiration (For example in a garden) could be used as some type of "Filter" if you water the plants with non drinkable water(from rivers, lakes...).

 

This method could be used to eliminate all the contaminants and pathogens from the water and still use the plants to generate food?

Collecting water from plant transpiration in emergency situations is well known. Doing it over a long period is problematic as it would stress the plants. The material and labor required to do the collection on a large scales strikes me as problematic as well.

 

Emergency Water Collection

[Paramecium8]

I was thinking about some type of greenhouse that could collect the water but it is too expensive to make one, using plants with atmospheric water generators could be much easier when there are new technologies, for now atmospheric water generators are too expensive to large scale production

[tantalus]

I was thinking about some type of greenhouse that could collect the water but it is too expensive to make one, using plants with atmospheric water generators could be much easier when there are new technologies, for now atmospheric water generators are too expensive to large scale production

I have heard of design projects in Africa which seek to prevent water escaping greenhouses and trapping and reusing it. Not sure what there energy efficiency would be like, and I can't find reference to them online.

 

Did come across this simple design in Ethiophia

http://www.roots-up.org/#!Design-of-a-Dew-collector-Greenhouse/c1j2v/55082c6a0cf2031a76490f16

 

By raising the temperature in the day (I assume the plants they grow must have very high tolerance to high temperatures) they increase evaporation, which increases humidity, as hot air holds more water, the increasing humidity means even more water vapour is present than at lower temperatures, they then lower the temperature at night by removing the roof, the quick drop in temperature leads to condensation on the film (cool air cant hold all that water vapour so it condenses), and into a water container.

 

Clean, usable for drinking or irrigation. It is not clear to me how much of that collected water came from plant transpiration versus evaporation, and would obviously depend on the amount of plant matter, species etc.

 

Another project using a dessicant in the UAE. Although I have to say I don't understand the process as described in the article

http://www.thenational.ae/uae/environment/20150914/greenhouse-that-could-save-uae-farmers-90-per-cent-on-water-unveiled

Edited January 12, 2016 by tantalus

[Paramecium8]

I have heard of design projects in Africa which seek to prevent water escaping greenhouses and trapping and reusing it. Not sure what there energy efficiency would be like, and I can't find reference to them online.

 

Did come across this simple design in Ethiophia

http://www.roots-up.org/#!Design-of-a-Dew-collector-Greenhouse/c1j2v/55082c6a0cf2031a76490f16

 

By raising the temperature in the day (I assume the plants they grow must have very high tolerance to high temperatures) they increase evaporation, which increases humidity, as hot air holds more water, the increasing humidity means even more water vapour is present than at lower temperatures, they then lower the temperature at night by removing the roof, the quick drop in temperature leads to condensation on the film (cool air cant hold all that water vapour so it condenses), and into a water container.

 

Clean, usable for drinking or irrigation. It is not clear to me how much of that collected water came from plant transpiration versus evaporation, and would obviously depend on the amount of plant matter, species etc.

 

Another project using a dessicant in the UAE. Although I have to say I don't understand the process as described in the article

http://www.thenational.ae/uae/environment/20150914/greenhouse-that-could-save-uae-farmers-90-per-cent-on-water-unveiled

The only problem with first greenhouse apparently is the planting areas, one of them is not enough even to subsistence, the second one looks too complicated and expensive to be implanted in poor countries (Normally the ones that need more water).

[Endy0816]

Researchers have been looking into wood:

 

http://www.technologyreview.com/view/520706/how-to-build-a-plant-xylem-water-filter/

 

 

In the video he found he could speed it up by providing suction. Might be an idea to do so via mechanical means.

Edited January 13, 2016 by Endy0816

[Acme]

Researchers have been looking into wood:

 

http://www.technologyreview.com/view/520706/how-to-build-a-plant-xylem-water-filter/

 

 

In the video he found he could speed it up by providing suction. Might be an idea to do so via mechanical means.

The only mention of suction I saw was at the end where he shows a person trying to suck the water up through the wood filter as one uses a straw. He then comments it is impractical inasmuch as the effort required would make you sweat out more water than you could suck up. While using a mechanical vacuum is feasible, it is no more efficient than increasing pressure on the other side and that can be done by simply using a larger holding container to increase the head.

 

In any case, the filtering with wood has nothing to do with the topic of this thread which is on about capturing the water transpired by plants.

[Endy0816]

I was just thinking in terms of readily available filters made by plants.

 

Mechanical aid would simply improve the speed and avoid expending energy lifting water(depending on the source). There are backpacking filters that function along these lines.

[Acme]

I was just thinking in terms of readily available filters made by plants.

 

Mechanical aid would simply improve the speed and avoid expending energy lifting water(depending on the source). There are backpacking filters that function along these lines.

Acknowledged. Whether one expends energy lifting the water or drawing a vacuum, energy must be expended.

 

On the large scale transpiration filter idea I see another problem, which is the re-introduction of contaminants to the water as it collects on the container and runs down the material before it reaches the collection vessel.

[Externet]

I can see an assumption that plants transpire pure water vapor. What compounds are actually transpired, exactly ?

[Acme]

I can see an assumption that plants transpire pure water vapor. What compounds are actually transpired, exactly ?

By definition, transpiration is the movement of water through the plant and into the atmosphere, so I don't think 'assumption' is fitting here. In 20 minutes of searching I can find no other compounds mentioned as being transpired. Certainly plants produce VOCs, but as I understand it these are not very soluble in water. Even if other compounds exit stomata as a part of transpiration, unless they condense with the water on the collection surface they won't contaminate that water.

 

As I just suggested this is not so for bacteria, viruses, dust, and mold spores to name a few contaminates floating around in the air.

[Daecon]

I had no idea of just how much water plants cycled in this way.

 

While they may transpire pure water, I'd expect the quality of the water being absorbed by the plant's roots may have a detrimental effect on the health of the plant, if that water was tainted by harmful chemicals. (As opposed to, say, sewerage.)

 

It may not be feasible to attempt to clean up certain bodies of water in this way if the plants end up dying first.

Edited January 14, 2016 by Daecon

[Paramecium8]

I had no idea of just how much water plants cycled in this way.

 

While they may transpire pure water, I'd expect the quality of the water being absorbed by the plant's roots may have a detrimental effect on the health of the plant, if that water was tainted by harmful chemicals. (As opposed to, say, sewerage.)

 

It may not be feasible to attempt to clean up certain bodies of water in this way if the plants end up dying first.

The plants can be harmed by some chemicals but they can be used to filter less toxic water(Rivers, lakes...), sewerage still needs special treatment but the most polluted rivers I know still have plants living next to it

[Externet]

This link has resided in my bookmarks for years ----> http://www3.telus.net/farallon/

 

As I have much interest in innovative desalinators. Discussing things with its author, a doubt of its engineering surfaced, related as performance differences being vented or not...