Changes

Iron is a naturally occurring element in the earth's crust and tends to leave a reddish-brown residue in water that tastes unpleasant and stains clothing, therefore removal is required. There are a few different ways to remove iron, but generally filtration and biologically-enhanced methods are used and most practiced. Sometimes using multiple filters gives the best results. For instance, installing an [[upflow roughing filter]] before a [[slow sand filter]] increases iron removal to an acceptable level, even with high initial concentrations as high as 42mg/l (like in Uganda).<refname="Uganda study"> [http://www.lboro.ac.uk/garnet/tncironm.html Iron and manganese removal.] Andersson, Hanna and Jenny Johansson. Iron removal from groundwater in Rakai District, Uganda: a minor field study. </ref>

The iron removal filter (IRF) is a cylinder built using ferrocement construction techniques. Inside, from top to bottom order, is a plastic basin full of charcoal, a layer of gravel, and an empty space for sedimentation. The media size is not critical, but if the grains are too fine (less than about 1mm diameter) the filter clogs very quickly.<ref> [http://www.lboro.ac.uk/garnet/tncironm.html Iron and manganese removal.] Andersson, Hanna and Jenny Johansson. Iron removal from groundwater in Rakai District, name="Uganda: a minor field study. </ref"> The water to be treated (in this model the water is assumed to be from a hand pump spout) first passes through the charcoal, aerating it, flows to the empty space at the bottom via a pipe where sedimentation of the precipitated iron takes place, then wells up through the gravel for filtration purposes. The finished water accumulates above the gravel filter, and this elevation enables users to draw it.