Filtering milky water

[Matthew / BPL]

Any idea why a creek would be white? I’ve seen green water (algae) and brown (muddy) but not whitish. I was walking along a creek yesterday that looked like a 1:10 mixture of milk in water. Not white scummy foam.

[Bob Moulder]

Probably clay.

[Roger Caffin]

It could be white clay. If it was Nepal, it would be glacier dust – ground rock, very common.

Or it could be a burst cow.

Cheers

 

[Jeffs Eleven]

Volcanoes around?  Oregon has ‘milky’ water and its volcanic silt or something.

Burst cow took me a minute.

[Matthew / BPL]

OMG ROGER

Actually the trail had fine white sand on it in places. It refracted light in a sparkly manner so I’m guessing silica. I think I’ll pour my water through a bandana before clogging my filter…

[Mark V.]

I’ve seen milky water after a heavy thunder stom with a lot of hail. This was at about 7,000 feet where most of the time the water is very clear. I think it was a lot of silt running down stream, but I don’t know for sure.

[Matthew / BPL]

The area had been hit with a heavy thunderstorm just a couple hours before. I’ll be on the same trail next weekend. I’m curious to see if it looks any different.

[Jerry Adams]

glacier silt water is pretty milky

filtering with bandana won’t help – too fine

put the water in a container and let the silt settle for a few hours, or over night.  Be careful not to accidentally stir up the water and undo your settling.

or try to find a tributary or side channel that isn’t so silty

[Ralph Burgess]

If it’s too fine to settle immediately, use alum (aluminum sulfate) from the supermarket (it’s a pickling and baking ingredient).    A very tiny pinch, shake thoroughly for it to dissolve and homogenize, and the fine particles will flocculate and settle out much more quickly, usually in under an hour.   Platypus 70oz bottles are good for this, because of their tall profile you can easily decant off the clear water without disturbing the silt on the bottom.

[David Thomas]

+1 on the alum.  It’s how your sewer treatment plant makes things settle out of the water in tens of minutes instead of many, many hours.

I’ve ordered 15 pounds of alum off of Amazon (for a “little” pond we built on our 13 acres).  If you want a sample sent to you in mail, PM me a snail-mail address.

[Matthew / BPL]

David, thanks for the offer but that sounds like a really good way to get the Secret Service over to my house and then they might find the tiny Baggie of baby powder in my first aid kit right next to the ampule of Tincture of Benzoin.

ive heard of people using alum in the chocolate milk water of the Colorado River in the Grand Canyon. This wasn’t nearly as gritty. I’ll be there with a bunch of scout next weekend and it will be interesting to see how a Sawyer filter does with the water. I’m not too worried about it.

[Steve K]

What are you expected to do with the alum once it has done its duty? Surely not dump it out…?

[David Thomas]

Just drink the water.  With a bit of residual alum in it (much will have settled to the bottom with the flocculated sediment.  It’s in the food aisle of the grocery store next to the cream of tartar, baking powder and baking soda and is called for in various foods like milk cake and especially in pickling recipes.  It will make the water slightly acidic, but very slightly in the amounts used to settle drinking water –  a pinch in a gallon.

We’ve had whole threads on this, often around Colorado River water use, but you want a container that you can smoothly decant the clear water off the top without disturbing the sediments at the bottom.  At best, you’ll get 3/4 of the volume of water poured off before the bottom sediments start to get kicked up, so a larger-than-normal container is helpful.  On a rafting trip, the standard water container is the ubiquitous stacking 5-gallon bucket – $4 at Home Depot in orange and a bit less at Walmart (in blue or white).

[Ben H.]

What are you expected to do with the alum once it has done its duty? Surely not dump it out…?

If you have ever cleaned your dishes while backpacking, use the same procedures to dump out the sediment water.  Dumping in a cathole would probably be best.  A little pinch of Alum isn’t any less LNT than rinsing out your hot cocoa mug.

 

[Ralph Burgess]

You use an almost unbelievably tiny amount of alum.   I’ve tried titrating down with water that’s essentially liquid orange mud, and you need no more than a few grains in a liter of water, maybe 1/8 teaspoon or something.   It dissolves completely, is harmless and tasteless.   It is important to shake very thoroughly to dissolve and homogenize.   That’s why I favor multiple 2L platypus bottles rather than an open bucket for settling.    The triple-charged Al+++ ions somehow deal with the repulsive electrostatic charge on the surface of the silt grains and allow them to flocculate.

SInce you need so little anyway for these purposes, it’s probably better to use food grade (it’s a pickling & baking ingredient, you’ll find it in well-stocked supermarkets) than bulk.

So you obviously drink most of it, ane there’s a trace amount dissolved in the sediment-laden dregs that you dump — but it’s totally harmless to both your body and the environment in such minute quantities.

[Author]

Posts