The effect of pause time on water quality: new research out
Research published by the University of North Carolina has confirmed the importance of residence time of water in a filter. Regarding the daily amount of water put through the filter, they found that microbial reductions were greater with a greater residence time within the filter, especially for water retained in the filter bed overnight. The researchers showed this through taking samples of filtered water at various stages when the filter was re-started after pause time – a significant drop in filtrate quality was noted after the pore volume threshold had been filtered. This showed that water that had been sitting in the filter during pause time had a much better quality, and this seems to be largely due to the increased contact time for biological and chemical processes in the sand. More information here.