Oil separator SEPKO


The oil and hydrocarbons separator SEPKO is a treatment plant for light liquids (eg oil and petrol) for wastewater running off from paved surfaces such as squares, cars parks, underground garages, etc. or it can be used as part of treatment for industrial wastewater such as those discharged from car washes.
The line of SEPKO separators is engineered for a flow rate from 1.5 up to 30 l/s.


There are many human activities where oil products are used. In practice, it is impossible to avoid oil spills into the watercourses. A modern and effective oil separation technology is required to prevent the pollution of the environment. SEPKO oil/water separators are manufactured of all nominal sizes according to European standard EN 858-1 for water flow rates 1.5 to 150 l/s. As an option, integrated sludge trap may be supplied with the separator — all in one body. SEPKO contains no moving or wearing parts therefore it is very durable and requires little service. The separator is equipped with coalescing technology which has established itself as the most efficient gravitational oil separation material on the market. The coalescing media has also a high degree of resistance to plugging caused by dirt, sludge and biological growth.

Applications of oil/water separators:

  • rainwater run-off from petrol stations, parking areas, road terrain
  • process wastewater from car washes, industrial applications etc


Oily water influent enters into the separator tank under water surface through the inlet pipe (1). Water flows to the first primary settling section (2) where solids particles and bigger oil droplets are removed by gravity. Then water is directed through the coalescing media (3). As water passes horizontally through the pack of coalescing media the oil droplets rise vertically until they contact the material. By contacting the oleophilic surface, the oil particles are captured and they coalesce with other particles becoming larger. As the process continues, bigger oil droplets will be formed and driven upwards by gravity until they reach the water surface. As solid deposits accumulate on the coalescing media they increase in mass and eventually slough off to the bottom of the separator where they accumulate until disposal. This self-cleaning feature significantly reduces the frequency of cleaning of the coalescing media. Clean water after treatment is discharged through outlet pipe (5). SEPKO is equipped with an automatic closure device (4) which is calibrated to float on water and to sink in oil. This floating valve closes water outlet when the amount of accumulated oil on the water surface has reached the maximum level.



A body of SEPKO oil/water separator is manufactured from polyethylene by modern process of rotational moulding. The production method is ensuring the proper raw material composition, machine settings and optimised process parameters. Therefore all finished products are made with the highest quality and consistent accuracy. The automatic production is preventing from failures caused by human factor as well. Polyethylene material used for the production can be easily recycled reducing waste and environmental impact. Tanks made from PE are corrosion-proof, their smooth surfaces are ensuring the simple cleaning during servicing.


Technical Specifications

SEPKO provides a perfect load bearing capacity by keeping low weight of the product. The great stiffness of the separator body is achieved due to the advanced design and special ribbed structure. SEPKO is designed to withstand the heavy ground and groundwater loads without any significant deformations. The main advantage of the rigid body is that SEPKO may be installed in a significant depth from the ground surface without any additional concrete slabs or casings etc. Therefore the time and the cost of installation works of the separator are significantly reduced.

Features of the coalescing material:

  • Special oleophilic (oil attractive) polypropylene providing years of trouble free service.
  • Oil droplet‘s rising distance is reduced to 6 mm. The shorter distance means lesser rise time travelled to coalesce which will result in better removal rates.
  • Coalescing surface (approx. 450 m2/m3) is more than three times larger as other commonly used media.
  • Resistance against plugging by solid particles due to self cleaning design.
  • 99,99+ % removal of free and dispersed oil regardless of micron size.

Gross dimension are shown in table as follow.

Vertical cylindrical
Name [-] [mm] [mm] [mm] [mm] [mm] [kg]
SEPKO 1.5 1.5 160 1300 980 800 770 142
SEPKO 3 3 160 1300 980 800 770 150
SEPKO 6 6 160 1300 1480 1275 1205 200
Horizontal cylindrical
NS DN D A L n A1 A2 W
Name [-] [mm] [mm] [mm] [mm] [mm] [mm] [mm] [kg]
SEPKO 10 10 160 1435 1515 2400 1 1200 1130 280
SEPKO 15 15 200 1690 1830 2500 1 1700 1500 410
SEPKO 20 20 200 1690 1830 3000 1 1700 1500 530
SEPKO 30 30 250 1690 1830 4500 1 1700 1500 730

NOTE: sizes can be changed without notice.
The letters in figures and table have the meanings set out below:

NS – nominal flow (NS)
DN – nominal inlet and outlet diameter
D – diameter (vertical or horizontal)
A – total height (extension excluded)
L – total length (horizontal cylindrical tank)
n – number of manholes
A1 – inlet pipe height
A2 – outlet pipe height
W – weight (manhole excluded)

For further information and tailor made solutions, please contact technical office.

The maintenance of SEPKO oil/water separator is very simple; it does not require much labour and material costs. Main servicing procedures are:

  • extraction and disposal of accumulated oil and sludge by means of vacuum truck,
  • cleaning of the coalescing modules from solids using high pressure cleaner.

The design of the modules allows convenient lifting off the tank and washing out of the 4 sides.

After the proper cleaning 100 % functionality is returned to the oil/water separator.
SEPKO does not contain any replacement filters which should be disposed of as hazardous waste.


Telescopic manhole shaft

A ladder is integrated in the manhole shaft providing the personnel an easy and safe access into the tank where allowed by legislation. Telescopic shaft is designed to adjust the manhole cover flush with the ground surface in the range of 200 mm. The manhole shaft is designed for connection with standard polyethylene or cast iron covers for load
classes from A35 to D400 according to standard EN 124. The manhole shaft is equipped with two special seals. The first seal is located between tank body and manhole shaft, the second seal is between manhole and telescope. The seals ensure that no liquid droplet will penetrate into the tank or from the tank.

Bypass systems.

Bypass systems can be used when it is considered an acceptable risk not to provide full treatment for high flows, e.g. where only small spillages may occur and the risk of spillage is small. The system is dividing the peak rainwater flow in case of heavy rain. Only 1/3rd (in some cases even less) of the average maximum rainfall flow is directed to the oil/water separator, and the excess flow goes via bypass. Considerable investment cuts may be obtained by using bypass system, in comparison with conventional full retention treatment systems. The bypass system allows employing of smaller and more cost-efficient oil/water separators. According to the environmental studies the biggest part of oil and other pollutants is washed off in the beginning of the shower while the complete rainwater flow is treated by the oil/water separator. Therefore, although only a part of the peak flow is being processed, the bypass system is ensuring a very efficient oil removal.



SEPKO separators were successfully testes and approved according to provisions of European standard EN 858-1. The testing of treatment efficiency, i.e. determination of nominal size of the separator, water tightness and stiffness of the tank were performed by the independent authorities.
After treatment with SEPKO the residual hydrocarbon content in water of less than 5 mg/I is achieved. This effluent value is mandatory for oil/water separators of Class I according to the standard EN 858-1. Based on the test results separators were granted with CE mark. Our oil/water separators comply with the standards of Russian Federation as well. Appropriate certificates issued by the Russian authorities are in our possession.
AZU Water is available to develop solutions tailored to the particular needs of the customer.