DIY water filter kits allow just about anyone to create potable water from natural, fresh water sources such as ponds and streams. Simple, off-grid water systems using these kits can negate the expense and effort of packing in water and having lots of plastic bottles to recycle or dispose of.
The kits discussed below were designed for, and perfected in, developing-world refugee and missionary situations but are also available here at home. Camping, off-grid living, or simple emergency water back-up for just-in-case situations are excellent applications for these DIY kits.
In 2012, a previous article ran on the MOTHER EARTH NEWS website discussing these filters and a few changes have been made since then that will be addressed here.
It is pretty easy to create a water-filter system using a “two-bucket” or “gravity-drip” configuration. The buckets are stacked one on top of the other with the filter connecting them. The upper bucket contains the contaminated source water and the lower bucket collects the filtered water.
The lower bucket also contains a spigot for dispensing the clean water. The basic setup is shown below. Because buckets are cheap but bulky and expensive to ship, DIY kits usually just contain the filter and spigot components and leave it to the end user to procure buckets locally.
Besides buckets, the components can also be mounted into other types of containers at the user’s preference. The spigot and filter come with washers and wingnuts that create a watertight seal with simple hand tightening. The only tool required to make this assembly is a drill and a couple of drill bits.
One of the big improvements since the first article in 2012 is that we now have U.S. manufacturing for the ceramic filter cartridges, which form the heart of the DIY kit. This has a porous ceramic shell coated with colloidal silver that is used to remove micro-organisms. The pore size ratings on these are on the order of 0.2 to 0.5 microns. We have also improved the media inside the shell by adding resins to the activated carbon so that it will remove a wider array of chemicals.
How long the filters last is a common question. While the biological filter can last for as long as the ceramic shell is intact, the chemical filtration only lasts until the media becomes saturated with contaminants. In typical applications is 8 to 12 months with regular use, and usually they are changed out after a fixed amount of time.
The above diagram shows three stages of filtration that includes a pre-filter sock (included in the DIY kit). There is also a picture of the actual device in action and a picture of the components that make up a US made DIY kit. Another improvement that has been made since 2012 is that U.S.-made filter cartridges that remove fluoride in addition to the other chemicals are also available.
A major parameter of water-filter systems is the flow rate. The amount of water you need per day is variable depending on the group size and what you plan to use the water for (drinking only, drinking and cooking, drinking and cooking and washing up, etc.).
Single-filter-element DIY kits are usually able to provide 12 to 15 gallons per day, but these can be sped up by using a siphon tube, which supplies an additional vacuum pressure on the outlet of the filter that is in addition to the water pressure provided by the upper bucket.
Each DIY kit comes with a 2-foot siphon tube. Using siphon tubes, one can easily double the flow rates of these systems. There are ways to configure systems if even more water is needed, such as larger containers (to increase water pressure), putting filters in parallel (up to 3 ceramic, 4-by-4 dome filters can fit in a 5-gallon bucket), or pressurizing the upper bucket. In short, the DIY kits can be configured to match a wide variety of water needs.
All filters will eventually clog up. Many filter types use a back-flush method to clear them. Instead of back flushing, ceramic filters are cleared by removing the outer surface of clogged pores by lightly scouring them. The shell is thick enough that it can be cleared dozens of times. Using pre-filters can increase the length of time needed between cleanings.
The storage life of the filters before they are put into use is indefinite, and it is also noteworthy that the filters can be used intermittently (for example, on annual camping trips) as long as they are thoroughly dried out between uses.
Another system that was not discussed in our earlier article but is very popular with campers and hikers is the hanging bag. This filter type has ceramic cartridges in it but uses a collapsible bag and long siphon instead of buckets.
The bag filter is filled with water and hung from a tree or other object and the water is directed to other containers as needed by the siphon hose. To stop the water flow, the siphon tube is simply turned up so that the end is higher than the water level in the bag. This bag can be rolled up and is a lot more compact for traveling. Because the sides collapse as the water in the bag drains, they have very good flow rates. It is also very nice, because unlike straws or drinking bottles, the water can be dispensed easily for other needs like cooking and washing.
DIY ceramic water filter kits are an easy way to create potable water from natural water sources. They are a proven technology that has been used in many areas of the world for disaster relief and refugee situations. Ceramic filters are now available from a U.S. manufacturer with improved chemical-removal media. Additional filter kit styles are available as are fluoride-removal filters.
Homespun Environmental is a small business specializing in affordable DIY water filter kits, such as the ones discussed in this article. They also offer individual components for maximum creativity. If you are interested in finding out more about them or how to purchase kits please visit the Homespun Environmental website.
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