Question

As part of the initial treatment for waste water from an industrial site, you will be running the afluent through a sand filter. The filtering ability of the sand in this filter is roughly proportional to the surface area of the sand enclosed. The grains of fine sand are approximately spheres with an average radius of 50 ?m and are made of silicon dioxide. A solid cube of this material with a volume of 1 m3 has a mass of 2500 kg. You have determined that the total surface area (the total area of all the individual grains) is equal to the surface area of a cube 1.4 meters on an edge. 1) What mass of sand grains needed for your filter?

Answer 1