Very cheap emergency water filtration

[allen-1]

I've got a lifestraw in my GHB and a larger filtration unit in my stocks, but this is about as cheap and simple as it gets:

http://bluecollarprepping.blogspot.com/2015/09/water-filtration-with-stick.html

 

[teaser452]

That is pretty cool! I'm going to have to experiment with this. This will be a great science project for the kids!

 

[bigblue]

Cool? That is GENIUS! Much rep inbound.

 

[Boghog1]

I'll have to try this, I think I already have the tube at home and several white pines

 

[ToddDubya]

If you tried to use that like a Lifestraw your eyeballs would get pulled into your brain. Looks cool for a "fill and forget" type of system, though (4L per day).

 

[Boghog1]

If you tried to use that like a Lifestraw your eyeballs would get pulled into your brain. Looks cool for a "fill and forget" type of system, though (4L per day).

Figured I could adapt it to a 5 gallon bucket and see what it actually produces, I should get NH Andy to Photo Document it

 

[bigblue]

Couldn't you set that up with a funnel and use it as a drip filter?

 

[ToddDubya]

I wonder how long the filter is good for.

 

[allen-1]

Couldn't you set that up with a funnel and use it as a drip filter?

I'm thinking funnel into hose thru wood into clean catch container just to see how it works.

Worth playing around with to keep in back of mind. A single drip isn't going to do much, but a number of these could easily be created if circumstances warranted.

 

[bigblue]

I'm thinking funnel into hose thru wood into clean catch container just to see how it works.

Worth playing around with to keep in back of mind. A single drip isn't going to do much, but a number of these could easily be created if circumstances warranted.

That's what I was thinking.

 

[robjax]

this looks interesting. I shall have to try this.

 

[sharona]

Very cool thanks for posting this

 

[enbloc]

.

 

[Boghog1]

Would love to try this with a PPM meter before and after.

Do you know anyone?

 

[bigblue]

Would love to try this with a PPM meter before and after.

You don't trust MIT?

 

[enbloc]

.

 

[bigblue]

I don't think Romney had much to do with writing this paper.

 

[enbloc]

.

 

[bigblue]

Play on words. MIT:Romney

...

 

[Cmaro21]

They say you want to keep the wood wet so why not just leave it in the bucket?

Drill several holes in the bottom, 1/8" smaller than the diameter of the surgical hose.
Pull several of these wood filter setups through the holes so they are tight and don't leak.
Place on top of another 5 gallon bucket with lid cutout to allow hose drips.
You could even put a spigot on the bottom bucket.
With 7 of these you would be doing 7.4 gallons a day, only do 5 lines and you are doing ~ 5 gallons in 24 hours.

Think this

with a something like this to the lid inbetween

reps inbound to op - thanks for sharing that link.

 

[bigblue]

They say you want to keep the wood wet so why not just leave it in the bucket?

Drill several holes in the bottom, 1/8" smaller than the diameter of the surgical hose.
Pull several of these wood filter setups through the holes so they are tight and don't leak.
Place on top of another 5 gallon bucket with lid cutout to allow hose drips.
You could even put a spigot on the bottom bucket.
With 7 of these you would be doing 7.4 gallons a day, only do 5 lines and you are doing ~ 5 gallons in 24 hours.

Think this

with a something like this to the lid inbetween

reps inbound to op - thanks for sharing that link.

Like you wrote, as long as it doesn't leak so I would think changing filters would be a challenge with that setup. Otherwise, I like the concept.

 

[allen-1]

They say you want to keep the wood wet so why not just leave it in the bucket?

Drill several holes in the bottom, 1/8" smaller than the diameter of the surgical hose.
Pull several of these wood filter setups through the holes so they are tight and don't leak.
Place on top of another 5 gallon bucket with lid cutout to allow hose drips.
You could even put a spigot on the bottom bucket.
With 7 of these you would be doing 7.4 gallons a day, only do 5 lines and you are doing ~ 5 gallons in 24 hours.

Think this

with a something like this to the lid inbetween

reps inbound to op - thanks for sharing that link.

Industrializing...

I was just kind of thinking along the lines of I've got a life straw, (actually a couple), I've got a filtration unit - but this is cool, and I have hose, I have hose clamps, in an emergency I've got another way to filter water.

The brain trust here is fascinating.

 

[Cmaro21]

Would love to try this with a PPM meter before and after.

"Filtration of Bacteria from Water

Finally, we investigated the ability of the xylem filter to remove bacteria from water. As a model bacterium, we used fluorescently labeled and inactivated Escherichia coli bacteria that are cylindrical in shape with a diameter of ~1 µm. Use of fluorescently labeled bacteria enabled easy enumeration of their concentrations, and also allowed us to track the location in the xylem filter where they were trapped. Since filtration is dominated by size-exclusion at this length scale, we do not expect modification with the dye to significantly affect filtration characteristics. Filtration using three different xylem filters showed nearly complete rejection of the bacteria (Figure 4a). Using a hemacytometer to count the bacteria, we estimate that the rejection was at least 99.9%." - http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0089934

I wonder how long the filter is good for.

"The high flow rates and low cost would certainly help address the issues of maintenance and replacement. For example, 200 filters of 10 cm2 area and 0.5 cm thickness could be packaged into a volume of about 1 L, which will be inexpensive and last a few years even with weekly replacement." ..... "Wetting with ethanol or vacuuming to remove air did not significantly increase the flow rate in the wood samples that exhibited the filtration effect, suggesting that the pit membranes may have a tendency to become clogged during drying. These results are consistent with literature showing that the pit membranes can become irreversibly aspirated against the cell wall, blocking the flow " - cited article

It looks like if you let your filter dry or if it is used up / clogged, your flow will just stop. So when it does, replace your filters

Like you wrote, as long as it doesn't leak so I would think changing filters would be a challenge with that setup. Otherwise, I like the concept.

The cost is pretty much free so just get a second bucket and replace the first. To change the filters as is, just dump the bucket and pull the tubes out. Replace wood, pull back through and fill with water.

On a side note - I read through the paper and it had some good findings. If you think use a larger branch make a faster filter you are wrong. It will actually create a better filter at the cost of flowrate "Larger filter thicknesses further increase the total membrane area, but the additional area of the membrane is positioned in series rather than in parallel and therefore reduces the flow rate, but potentially improves the rejection performance of the filter due to multiple filtration steps as shown in Figure 1a." - cited article

 

[enbloc]

.

 

[Fixxah]

How about Brita systems?

 

[bigblue]

How about Brita systems?

Brita aren't rated for bacteria, just "taste" & heavy metals. Brita filters don't filter anything harmful out of the water and are basically useless.

 

[ToddDubya]

On a side note - I read through the paper and it had some good findings. If you think use a larger branch make a faster filter you are wrong. It will actually create a better filter at the cost of flowrate "Larger filter thicknesses further increase the total membrane area, but the additional area of the membrane is positioned in series rather than in parallel and therefore reduces the flow rate, but potentially improves the rejection performance of the filter due to multiple filtration steps as shown in Figure 1a." - cited article

I don't follow this. I see the series/parallel relationship being that a larger diameter branch gives you more "tubes" in parallel, thus increasing the flow rate. Using a longer branch gives you the same number of "tubes", but it takes longer for the water to get through the "tubes".

My thinking is that the section of branch is akin to a bunch of straws. This must be incorrect based on the quoted article, but I don't get it.

 

[bigblue]

I don't follow this. I see the series/parallel relationship being that a larger diameter branch gives you more "tubes" in parallel, thus increasing the flow rate. Using a longer branch gives you the same number of "tubes", but it takes longer for the water to get through the "tubes".

My thinking is that the section of branch is akin to a bunch of straws. This must be incorrect based on the quoted article, but I don't get it.

The resistance to fluid flow is an important consideration for filtration. Pits can contribute a significant fraction (as much as 30–80%) [7], [8] of the resistance to sap flow, but this is remarkably small considering that pit membrane pore sizes are several orders of magnitude smaller than the tracheid or vessel diameter. The pits and pit membranes form a hierarchical structure where the thin, highly-permeable pit membranes are supported across the microscale pits that are arranged around the circumference of the tracheids (Figure 1a). This arrangement permits the pit membranes to be thin, offering low resistance to fluid flow. Furthermore, the parallel arrangement of tracheids with pits around their circumference provides a high packing density for the pit membranes. For a given tracheid with diameter D and length L, where pit membranes occupy a fraction α of the tracheid wall area, each tracheid effectively contributes a pit membrane area of πDLα/2, where the factor of 2 arises as each membrane is shared by two tracheids. However, the nominal area of the tracheid is only πD2/4, and therefore, the structure effectively amplifies the nominal filter area by a factor of 2α(L/D) (Figure 1f). The images inFigure 1c indicate that typical D ~ 10–15 µm and α ~ 0.2 yield an effective area amplification of ~20 for tracheid lengths of 1–2 mm. Therefore, for a filter made by cutting a slice of thickness ~L of the xylem, the actual membrane area is greater by a large factor due to vertical packing of the pit membranes. Larger filter thicknesses further increase the total membrane area, but the additional area of the membrane is positioned in series rather than in parallel and therefore reduces the flow rate, but potentially improves the rejection performance of the filter due to multiple filtration steps as shown in Figure 1a.

 

[Cmaro21]

I think the holes / pits, are horizontal and stacked. Look at figure c above with the red circles. Wider area means the water has to move more horizontally but therefore receives better filtration.