Are there any schematics for an inexpensive (less than S$5), reusable water filter?

I need a water filter that can be built easily, with minimal skill needed, with easily obtainable materials, cost less than S$5 (Singapore dollars), and must make the water look clean (make the water clear) and odorless whether on the 1st attempt or 100th attempt. Does anybody know how to make one and explain the concept behind it? The concept should be understandable by Secondary 1 students, or Grade 7 students.

mikeasaurus8 years ago
there are many chemical methods which will help, but almost all of the commercial ones use a type of sand filter. You can build the same easily enough, the design can be nothing more elaborate than a sealed bucked of sand with hole in the bottom. It's not the concept that is difficult, but the details that make it work. Sand filters work by trapping particulate matter. However much of that matter is very fine, so fine that it slips through the gaps between the sand particles. Many industrial water filters use flocculation (a method of making impurities in water coagulate) which allows the sand to effectively trap the particles. Chemical components will need to be added. The other end of this is maintenance. Sand filtration required 'back flushing' which will free the particles from the sand and effectively 'clean' the system. With a rudimentary setup this will be difficult to achieve. Be advised. There are other methods for filtration of water, however flow rate (or rate of which water is filtered) may be a consideration. Sand filtration is the way the pros do it, and offers the best results while achieving an acceptable rate of flow through the system. I hope this help!