Periodically I see various plans to make homemade water filters published on the internet. Having studied a little on the subject of water filtration I am extremely skeptical about them being reliable for water purification as many people claim.
Normally these filters are made of pipe or plastic bottles (the larger the better) or something similar with various layers of charcoal, sand and gravel with either cloth or grass to keep the charcoal from washing out of the hole in the bottom. While this sounds good in theory and may remove some bacteria, they are by no means reliable. One of the reason is that water tends to create a channel through the charcoal and thus bypasses most of the filtration effect of the charcoal.
In a pinch would they be better than nothing? The answer is yes. But I am going to offer you a better solution. Now I am sure many of you are familiar with the Sodis method of water purification. Here is a link to a previous post on Sodis an inexpensive method of water purification.
Sodis is a method of using the sun to purify water by placing it in plastic bottles made of PET (recycling number 1) and laying the bottle in the sun for 6 or more hours. This method works and is currently being used in many third world counties.
There are two downsides to this method, first you need to have sun. I don’t know of a solution to this problem other than plan ahead. However, the second problem can be easily handled. That is the water cannot be turbid for Sodis to work.
So my solution is to combine your homemade water filters with Sodis. Your homemade filter may not take out all the bacteria, but it will take out muck that makes the water turbid. By taking out this muck you accomplish two things, Sodis works better and you may have improved the taste of the water by getting rid of that pond water taste.
Sodis works well and plastic bottles are easy to find. Combine homemade water filters with Sodis and you will have good water.