a pond or tank having a false bottom covered with sand and serving to filter river or pond waters.
a layer of sand or gravel in a tank or reservoir through which a liquid is passed so as to purify it Compare bacteria bed
any layer of material through which a liquid is passed so as to filter it
- Filter cake
noun 1. (chem) the solid material accumulated by a filter press
[fil-ter] /ˈfɪl tər/ noun 1. any substance, as cloth, paper, porous porcelain, or a layer of charcoal or sand, through which liquid or gas is passed to remove suspended impurities or to recover solids. 2. any device, as a tank or tube, containing such a substance for filtering. 3. any of various analogous devices, as […]
noun, Photography. 1. a number indicating the increased exposure that a particular film should receive when a photograph is taken using a particular filter.
noun 1. an aquatic animal that feeds on particles or small organisms strained out of water by circulating them through its system: includes most of the stationary feeders, as clams, oysters, barnacles, corals, sea squirts, and sponges. filter feeder An aquatic animal, such as a clam or sponge, that feeds by filtering tiny organisms or […]
- Filter feeding
noun 1. (zoology) a method of feeding occurring in some aquatic animals, such as planktonic invertebrates and whalebone whales, in which minute food particles are filtered from the surrounding water