BioSand Water Filtration: <a href="http://www.google.com/search?hl=en&source=hp&q=how+to+make+a+biosand+water+filter&aq=3m&oq=%22biosand+water&aqi=g2g-m2" rel="nofollow" target="_blank">http://www.google.com/search?hl=en&source=hp&q=how+to+make+a+biosand+water+filter&aq=3m&oq=%22biosand+water&aqi=g2g-m2</a>