OIL SEPARATORS

Description

Oil interception technology is used to intercept rainwater or spillages contaminated with oil and to retain the liquid so that separation occurs or can be organised. Most equipment relies upon the oil forming a layer on the water. Emulsified oil can be separated by air flotation and centrifugation.

An interception tank has a sufficiently long retention time for the separation of the contaminated stream to take place. Baffles prevent the oil passing through the tank and the floating oil can be removed by pumps when necessary.

Tilted plate separators employ parallel plate technology to increase the efficiency of oil separation. As the oil-water mix enters the separator, the oil rises and hits the undersides of the tilted plates. The oil droplets coalesce, slide up the plate and collect at the top of the chamber. Suspended solids slide down the plates and collect at the base. The direction of wastewater flow and the plate numbers, length, angle and spacing can all be varied to suit particular applications.

Surface oil contamination of lakes, rivers and the sea can be contained through the use of floating booms. These act as physical barriers to the further spread of oil. To separate the surface oil contamination, mop skimmers can be used. These consist of a long loop of shaggy polypropylene that is continuously recirculated through the contaminated area. The oil adheres preferentially to the polypropylene mop and is squeezed out into a container as the mop passes through rollers driven by a motor.

Application

Interception tanks are used in car parks, airports, garage forecourts, tanker loading bays, motorway junctions, oil tank bunds and culverts, factory yards and vehicle washdown areas. They can be installed above or below ground.Tilted plate separators are used In refineries, power stations, garages and railway workshops. They are able to remove oil droplets greater than 60 µm in diameter. They can reduce contamination to concentrations of less than 20 mg/l. Disc centrifuges are used to separate oil from liquids and slurries, and are described on the centrifuges technology page.

Oil interception and separation equipment can be installed, or retained as stand-by equipment for use in emergencies, such as tank or pipeline leaks or major fires.

Sizing

Interception tanks and tilted plate separators are normally gravity-fed. Mop skimmers are rated at up to 6 kW. They are capable of removing up to 18 tonnes of oil per hour.