Michael Helmersson wrote:Our drinking water filter (biosand filter) is designed to maintain a 1" layer of water above the sand. This is the "bio" layer and it is recommended that, in order to keep the biology in there fed, you add a batch of water every day. I assume that it would be possible to plumb your filter to have the same 1" layer of water on top and that it wouldn't evaporate away in 24 hours.
Michael Helmersson wrote:Would it be possible to use a biofilter like this with a manual cistern pump instead of an electric pump? I'd place the pump somewhere that would encourage frequent short bursts of pumping which could feed a surge tank that regulates the flow and smooths out the ups and downs. Conceivably, there'd be long periods with little or no water transfer, so I wonder if the biological layer would suffer. We use a biosand filter for our drinking water and it seems like the same concept. I like your idea, but I feel the urge to complicate it.