Biosand filters in schools: can they be restarted after abandonment over the long holidays?

Biosand filters are an established point-of-use water treatment technology for household use. However, their need for daily operation makes them challenging to implement in school settings where long holidays may mean the filter remains dormant for several months. This study investigated whether school filters could be restarted without reinstallation after having remained dormant during the Honduran winter break. Two months before the start of the winter break, eight filters were operated and tested in schools near Trojes, Honduras. They were left dormant for at least two months over the school holidays, then restarted and operated for two weeks before the onset of testing. All eight test filters performed acceptably (median E.coli concentrations in filtered water of <1 cfu/100mL) after having been restarted.