Desalination demonstration on a Brick wall

This video clip shows the efficiency of "Captive Head Washing System" by moving the wash head slowly across the surface to allow time for fresh water to dissolve salt lying on and in the surface of the brickwork. Bricks and mortar will be washed by a small amount of swirling water and simultaneously sucked away by the vacuum action. Waste water is collected in the tank and this allows to test for salinity of waste water. An average of 1 cycle (which is 3 passes) is recommended. Allow one day break between second and third pass. Each pass will show a dramatic reduction in salt content (especially the first one) as our many lab report have shown. (Refer to previous articles)
“Captive Head Washing System” (BlueVac) is manufactured by Let’s Clean in Sydney, Australia and is available for purchase or hire.

Question from reader:

I have some questions: 1. Could this have been made with a longer handle to reduce the amount of stooping?2. Does it merely wet the bricks or suck the salt away as well?3. Is it worth doing if the source of the salt, which is what I understand efflorescence to be, is not removed as well. It appeared to me, that there was salt in the soil showing above the retsining wall.I am not having a go at the creator of this machine, merely seeking answers. Cheers

Answer: 1. Yes, we have one with a longer handle but only recommended if you cannot reach the object.

2. It sucks the salt away as well. The rubber shroud creates a vacuum chamber and the combination with water creates a water whirl and it will wash and draw out salts to a certain depth, depending on porosity of the substrate. It will not flood the substrate but it will activate salts further in and will draw it nearer to the surface, ready for a second wash and a third wash.

3. Washes (or passes) is called a cycle. Wait one day between pass 2 & 3 to allow salt movement. If the salt load is very high a second cycle is required 2 weeks or a month later. 3. Efflorescence will come off as well is it’s soluble.

Note: You should not look at this wall for other things than the vacuum wash head. We have chosen this object for demonstration because it made a good contrast. It was not an actual job. However, over the last few years we have collected data of salt removal from contractors using this system and from jobs we did. All of them showing massive reduction in salt load.

Tests done by core drill samples (before and after) and/or conductivity of captured waste water.

This system is an alternative to poultice type of desalination methods and achieves results within an hour instead weeks.

If you need some proof of results give us a shout. I don’t know where your location is in the world but we can export to anywhere. For more information you can Google “Captive Head Washing” or contact us on