In an unventilated sand trap, sand and other particles collect as the flow speed of the wastewater is reduced, and can then be siphoned off the bottom. Flammable oil and fat remain in the basin. In a ventilated sand trap, air is blown into the basin from below, causing matter to sink and collect on the bottom.
What is the purpose of a sand trap?
A sand trap provides for the quick removal of settleable (sand) particles from the water, in order to prevent damage to mechanical components in the water treatment plant. A sand trap is usually carried out as a concrete gutter, where the waste water flows through while sand particles settle.