Grease separators

In businesses which produce wastewater containing fat or grease, grease separators must be installed in accordance with EN 1825 and DIN 4040-100 in order to prevent damage to sewer pipes and wastewater treatment facilities. They reduce incidents of blocked drains from kitchen, improve the performance of septic tanks, prevent contamination of small sewage treatment plants.


Traps and separators allow fats and grease to naturally (principle of gravity) separate out from water.


ROTO grease separators are made from environmentally friendly material (PE) and are suitable for faecal and clean water storage. They are very durable, lightweight and resistant against various chemical substances used in kitchens.


  • produced by a European manufacturer
  • in accordance with standard BS EN 1825-1
  • made from durable, hard polyethylene (LLDPE)
  • has a long lifetime
  • 100% recyclable
  • are waterproof
  • quick and easy installation (light weight, no need for a crane (when placing in a pit), panelling, no need for masons, concrete mixers, etc.).
  • easy maintenance
  • low operating costs
  • competitive prices

Determinate the size

Size of grease trap is determined by number of meals or the maximum possible flow of contaminated water, type of pollution, effluent temperature and detergent use.

Size can calculated by the formula:

NG = Qs * fd * ft * fr * fm

Qs – the amount of waste water in l/s
fd – density of grease (if it is greater or lesser than 0.94 g/cm3
ft – temperature factor (if higher than 50 °C, is increased)
fr – detergents factor
fm – increased grease factor

Oil separators

Light liquid separators according to EN 858 and DIN 1999-10. Oil separators are installed on surface water drainage systems to protect receiving waters from pollution by oil, which may be present due to minor leaks from vehicles.

Separator classes

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

Class II
Designed to achieve a concentration of less than 100mg/l oil under standard test conditions and are suitable for dealing with discharges where a lower quality requirement applies.

With bypass
Bypass separators fully treat all flows generated by rainfall rates of up to 6.5mm/hr. (99% of all rainfall events). These separators are used on parking area 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 occurring at the same time is small.

Selection of the appropriate trap

Roto oil separator must be used in combination with the mud separator and sample shaft. Therefore the entire chain consists of: mud separator – oil separator – 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 (Table I)
Fd = density factor for the suitable light fluid (Table I)