A container for receiving and holding effluent water containing oil/grease to be removed has sectional covers. A main sectional cover supports a partially immersed rotatable disk; a drive on the main sectional cover rotates the disk; a trough on the main sectional cover straddles the disk; and a blade on the trough scrapes a side of the disk, to direct oil and grease from the disk along the scraper blade along the trough for collection in a storage container. Efficiencies of construction of the sectional covers, disk and a sensor probe are disclosed.