Rockford sd-30 – sediment drain – 105 lbs capacity – 30 gallon capacity – steel a rockford separator is designed for exceptionally high efficiency in retaining a wide variety of insoluble wastes. Maximum water travel with minimized turbulence through the filtering action of its screens prevents evacuation into drainage systems which may cause blocking, stoppages and backups. Sd series is a sediment drain for use in garage or industrial floor drainage requirements.