DAVIES, P.D. and WHEATLEY, A.D., 2012. Pilot plant study of alternative filter media for rapid gravity filtration. Water Science & Technology, 66(12), pp.2779-2784.
Sand has been the main filter media used in rapid gravity filtration since its introduction.
The dominance of sand has been due to its low cost and availability. Extensive experience
has led to sand filters with a dependable and predictable performance. Sand remains the
preferred filter medium but usually with a larger sized anthracite capping to reduce the onset
of head loss. Other approved filter media are now commercially available and this paper
compares sand with recycled glass, Filtralite® and slate at pilot scale. The results have
reaffirmed the basic importance of particle size on head loss and turbidity performance rather
than surface activity or specific surface area. The results did suggest, however, that particle shape
and packing exerted a stronger influence on performance than previously acknowledged. These
could be used to improve the design and the contribution to sustainability made by rapid gravity.
This item is Closed Access.
The authors gratefully acknowledge the financial and technical
support of Severn TrentWater Ltd for providing the pilot plant and allowing this work to be conducted on one of their
operating treatment works.