In our second research meeting of the year on Thursday 21st October, we made sand filters from a combination of sand and gravel. The two groups then tested their filters with dirty water and both groups produced relatively clean water but at different flow rates.

The purpose of this workshop was to give a practical demonstration of the workings of sand filters and to get us them thinking about the proportions of material that should be used. At the next research project meeting we'll be focusing on the theory behind biosand filters and possible ways of improving them.