After a very informative conversation with Jim, the author of several of the comments on this blog, it has become obvious that some additions to the websites and this blog are in order. First, where and how to get the sand needed to put together a small slow sand filter.
Links to sand suppliers:
Under “A variety of applications”, this website says they have sand that will work for “water filtration and purification”. I have not checked this one out closely yet. . . . . :
the Cemex company
Standard Sand and Silica company in Florida
Lane mountain sand company in Washington state
Red Flint sand company in Wisconsin
target sand company in Canada and USA
A subsidiary of the QUIKRETE® Companies
Unimin (this link is to the company’s locations page) A local supplier here in Seattle is Salmon Bay Sand and Gravel.
Manufacturers Mineral Company in Renton, WA (no website found) they have a .25 mm effective size sand called “TB Sand”.
1215 Monster Rd SW
Renton, WA 98057
(425) 228-2120
These suppliers may not sell directly to individuals, so it will be necessary to find a local sand and gravel company or hardware store to order the sand for you. The large hardware stores may be able to order it for you if you have the supplier’s name and the product description. Alternatively, one could dig sand from a riverbed, (taking extreme care to avoid destroying ecosystems), wash it, sterilize it, dry it and then run it through sieve to size it appropriately.
If you live in a place where there is lots of sand readily available, this may be the best option. . . however it will be extremely time consuming, one would have to purchase the proper sieve devices which would likely be super expensive. I have already tried using un sized sand directly from the ground. It works but not very well. In an emergency situation, sifting sand through a makeshift sieve would probably work and would be able to provide safe water, but it would not be ideal.
Can “play sand” be used for a slow sand filter? Yes, but it is difficult to wash and contains lots of silt and furthermore the sizes of the grains vary widely. As a result the filter will plug up very quickly. Can mason’s sand be used? Maybe, depending on what is in it. Again, the effective size and uniformity coefficient may not be suitable for filtration purposes. What about sand from the beach? Probably not, unless the sand is washed and sterilized which would likely cost WAY more than just buying filter sand. If the “beach” is next to salt water, then the sand would be nearly impossible to clean. If the “beach” is contaminated then the sand would also be contaminated. If the “beach” is on fresh water and contamination is minimum, then the sand may be usable, but be aware that there may be horrific contamination from anywhere. The sand would need to be washed, and then heated to very high temps to be safe.
Much more info later as I get time. . . . .
Thank you sir! This is very useful information. –jim
I have two questions please:
1) How much sand is 18″ of .35mm sand in a 58 gallon barrel, i.e, what quantity should I order?
2) The same on 12″ of .25mm sand in the same barrel?
Thanks!
Jim
Let’s see, I’m trying to remember how much sand I put in filter 2 and 3. . . . Let me look into this further. I’ll get back on here when I have some useful info.
The flow meters look good, Jim. I would use the one that starts at .8 L/minute. I’m going to order one and hook it up. I think it will save hours of time fooling around with jars, and jugs and trying to measure flow that way. For the price they are asking it seems like a very good deal. Thank you for the info.
Are you using the flow meter yet?
Thank you for reminding me, Jim. Not using the flow meter yet. I’ve got one on order, but it will be a while until it arrives.
We had a major plumbing failure here and had to dig up all our drain pipes – a real huge horrific muddy mess. Will finish up today. When I get the meter hooked up I’ll post the info here so others can see what happens to the flow rate over time.
Any tips on where I might be able to purchase (in Indiana) the .25mm & .35mm sands and gravel I need to build one of these. I have looked all over in my area (central Indiana) and when I ask people/businesses in the area for these kinds of sands they usually have very little useful info to provide and seem pretty clueless. Any ideas on what companies or kinds of companies I should contact in my area and what to ask for? I am collecting already I just need to get the sand filter built. Thanks for all the info you provide here.
Darrin;
See if you can find a local landscape company or hardware store that will order sand for you from Red Flint. They will probably want prepayment. Check with Red Flint first and talk with the sales person. I spoke with them several years ago, and they were willing to ship me some sand, however I found a supplier here in Seattle.
Another thought (but a lot of extra work) is order some stainless steel wire mesh, and sift your own sand. The “play sand” available at Lowe’s is sterilized and washed so it would be easy to sift out some .25 mm effective size sand with 2 mesh sizes – one to pass .25 and larger, then the next one to hold back .15 and larger. The stuff is real inexpensive – something like 3.25 a bag. They (supposedly) take out a lot of the silica dust so the stuff is safe for play sand.
I would love to make this filter, but after searching the web for 2 hours and clicking on all of those links on this page I still can not find any sand in North Texas Dallas Area that comes remotely close to .25 or .35mm. I was hoping you would have some idea about how to find it.
Thanks Michelle
Thank you for asking about the sand, Michelle. You can try Lowe’s or Home Depot. Go to their customer service counter where the “contractors” get their supplies. Ask them if they will order sand for you. (Here, in Washington state they have told me they would be happy to do that.) Unimin, or RedFlint are two manufacturers that have the sand you need. Just give them a call and get the product information and stock numbers; then go to Lowes or Home Depot (or your local hardware store) and ask them to order the sand for you. When you call the manufacturers, have the technical info so you can speak their language.
You should ask them for .15 mm effective size sand, with a uniformity coefficient of less than 2.
If they don’t have .15 mm effective sand, then anything between .25 and .15 will work as long as it is of uniform size (in other words has a uniformity coefficient of less than 2). RedFlint specializes in water filtration sand. Also, you might try talking to your local water utility to see if you can determine where they get the filter sand they use in the public water supply filter systems. There might be a local supplier that just is not listed in the normal retail store rosters.
That was how I found the supplier here that has .25 mm sand. They supply well drillers and county utility districts.
The Unimin sand that is .15 mm effective size and has printed on the end of the bag: 4010/1.4/.15 (#50). The 4010 means: 10 percent retained on 40 mesh or coarser, the 1.4 means: surface profile as abrasive (MILS), and the #50 can either refer to 50 mesh as the “size” or could refer to the Unimin number something like #50 sand.
Sand manufacturers:
http://www.optaminerals.com/Water-Filtration/FilPro-Filtration-Sand-and-Filtration-Gravel.html
http://www.unimin.com/unimin-locations.cfm
http://www.redflint.com/filter_sand.htm
http://www.ussilica.com/locations/kosse-tx
http://www.ussilica.com/products/whole-grain-silica
As a last resort, you can sift your own sand. Most home improvement stores have a product called “play sand”, which comes in 50 pound bags and is really inexpensive ( here it runs about 3.50 a bag). It is washed and sterilized so children won’t be harmed by dust or pathogens. This makes it ideal for water filters with one caveat: it is not of uniform size. You will need to sift it so the size of grains are more uniform in size. “Wire cloth” can be used to sift sand if the sand is dry. Ideally you want between 60 mesh and 40 mesh sizes. Since 60 mesh is smaller than 40 mesh, you want the sand sizes between 60 mesh and 40 mesh, in other words the grains larger than 60 mesh and smaller than 40 mesh. So, on the first run through with the 60 mesh you want the sand that is larger – the grains that won’t fit through the mesh, so discard the stuff that goes through the finer mesh – it will be like very very fine almost powder, and save the sand that does not go through the finer mesh, then put that through the coarser 40 mesh cloth screen and save the sand that does go through that one the stuff that does not go through will be larger than 40 mesh really larger and that’s the stuff you don’t want. Also, most important, when you sift the sand wear a dust mask. Usually, when these filters are put together in third world countries, this is exactly the way they get the sand to use in them, by sifting it themselves.
Sieves (wire cloth) sources:
http://www.grainger.com/Grainger/Wire-Cloth-3AKF5?cm_sp=EN-_-L2-_-TopSellers&cm_vc=FFTS
http://www.grainger.com/Grainger/wire-cloth-sieves/wire-cloth/raw-materials/ecatalog/N-c26?Ndr=basedimid10071&ef_id=AOdP2QuWZyUAAAAB%3A20120613215222%3As&sst=subset
Thank you so much! Very helpful.. now I am going to hunt for the sieve. 🙂