Laserfiche WebLink
11-1 FUNCTIONAL FEATURES OF PACKED-BED FILTERS 705 <br /> y.�,� r�. <br /> (a) (b) <br /> FIGURE 11-2 <br /> Examples of containers used for packed-bed filters: (a) plywood used to support PVC <br /> liner for buried intermittent sand filter and (b) concrete structure for recirculating sand <br /> filter. <br /> f _ <br /> FIGURE 11-3 <br /> Underdrain system for large packed-bed filters. <br /> I Filtering Medium <br /> Over the,years, a number of different-filtering media have been investigated and <br /> used, including activated carbon, anthracite, bark, garnet, glass, gravel, ilmenite, <br /> lath (bundled), mineral tailings, peat; plastic, plastic foam, shale, and expanded <br /> shale. To date, the most commonly used medium for intermittent Ipacked-bed fil- <br /> ters (IPBF) is sand. Crashed recycled glass has also"proven to be an effective fil- <br /> ter material for IPBFs. Typical filter mediums for recirculating packed-bed filters <br /> I <br />