What is sediment and water/B S & W in cargo calculation?

Sediment and Water (S & W) Also called B S & W: –

A material coexisting with, yet foreign to petroleum liquid, that requires a separate measurement for reasons that include sales accounting. This foreign material includes (either) free water and sediment (FW&S) (dynamic measurement) and/or emulsified or suspended water and sediment (SW&S) – (Static measurement). The quantity of suspended material (SW&S) present is determined by a centrifuge or laboratory testing of a sample of petroleum liquid (See Free Water).