RoSep Oil Separator


RoSep oil separators are designed for underground fitment and installation into commercial premises like petrol/gas stations, car washes, vehicle workshops and car parks. The RoSep require low maintenance and deliver long lasting performance making them an ideal choice for a commercial business.


Manufactured in accordance with EN 858 and DIN 1999-1, Roto oil separators are made from environmentally friendly material (polyethylene LLDPE). As part of the range, the RoSep has Class 1, Class 2 and can have included a bypass 10% or 20% with the tanks ranging from 2,200 ltr to 50,000 ltr.

Class 1 Spec
Designed to achieve a concentration of less than 5mg/l of oil under standard test conditions, and should be used to remove very small oil droplets. A coalescence filter is installed before the drain to improve the separating effect in the separator. When the water flows though, tiny oil drops combine with larger drops which then leave the coalescence material. With oil separators, a special inlet system has a plug-flow effect which slows the flow down and distributes it in a hydraulically effective way over the separator space. The heavy material sinks to the bottom and is separated out while the light materials rise to the top and are separated there.

Class 2 Spec
These are designed to achieve a concentration of 100mg/l oil under standard test conditions and are suitable for dealing with discharges where a lower quality of requirement applies.

With Bypass 10% or 20%
Bypass separators treat all flows generated by rainfall with rates of up to 6.5mm/hr (99% of all rainfall). These separators are used in parking areas when it is considered an acceptable risk not to provide full treatment for high flows, for example, where the risk of a large spillage and heavy rainfall occur at the same time.

What size of oil separator do I need?

Roto oil separators are used in combination with the mud separator and sample shaft. Therefore the entire chain consists of mud separator, oil separator and sample shaft. In accordance with the norm, the nominal size is given by the formula NS = (Qr + fx * Qs) * fd

  • Ns = Nominal volume in l/s
  • Qr = max flow of rainwater in l/s
  • Qs = max flow of wastewater in l/s
  • fx = Retention factor, depending on the nature of release
  • fd = Density factor for the suitable light fluid


Separators should be provided with a visual and audible oil alarm. This operates when the oil level reaches 90% of the oil storage volume and indicates that the separator needs immediate emptying for it to continue to work efficiently.

Automatic Closure Device
Full retention separators must be provided with an automatic closure device which operates in the event of a sudden surge of a quantity of oil entering the system at too high an accumulation. This device should operate in conjunction with the oil alarm.

Sampling Shaft
Sampling shaft makes it possible to monitor the quality of the water on the outflow.


Manufactured in polyethylene, which is 100% recyclable and ribbed for reinforcement. Roto supply the RoSep rotomoulded tanks in one piece from 2,200 ltr to 25,000 ltr and welded from 30,000 ltr to 50,000 ltr. The tanks have a 400mm to 800mm diameter plastic cover, depending on size, with a seal making them watertight. The inflow and outflow pipes range from 110mm to 400mm depending on size of the tank and can be supplied with adjustable necks for ease of fitment. The Roto tank wall thickness ranges from 8-14mm to give the tank its stiffness.


Roto Water Catalogue

UK Contact

Daniel Smithers
Phone: +44 (0) 7880 603010
Skype: danny.smithers1


Roto Group
Puconci 12, Puconci
9201 Puconci

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