Soil texture are the medium-sized (0.05 - 0.002 mm) and sink to the bottom of the cylinder after the sand. Clay particles are the smallest (<0.002 mm) and separate out above the silt layer. Measurements are taken using a soil hydrometer. A soil hydrometer measures that relative density of liquids (density of a liquid to the density of water). The hydrometer is lowered into the cylinder containing the soil mixture at different times, forty-five seconds to measure sand content, one and a half hours to measure silt content and between six and twenty-four hours (depending on the protocol used) to measure clay.
Sand filter solid-liquid separation such as settling tanks, self-cleaning screen filters, hydrocyclones and centrifuges. There are several kinds of depth filter, some employing fibrous material and others employing granular materials. Sand bed filters are an example of a granular loose media depth filter. They are usually used to separate small amounts (<10 parts per million or <10 g per cubic metre) of fine solids (<100 micrometres) from aqueous solutions. In addition, they are usually used to purify the fluid rather than capture the solids as a valuable material. Therefore they find most of their uses in liquid effluent (wastewater) treatment. Sand bed