Oil separators > Oil separators

Oil separators

Techneau hydrocarbon separators trap free hydrocarbons with a density of 0.85 (light liquids) in run-off water by means of a density difference. They are based on the difference in density between the elements inside the separator. Light liquids, with a density of 0.85, rise to the surface, while heavy matter, with a density of 1, settles to the bottom of the device.

Standards

Techneau sludge traps meet the requirements of the most stringent European standards for separating hydrocarbons and solid pollutants:
– NF EN 858-1: “Principles of product design, performance and testing, marking and quality control”.
– NF EN 858-2: ‘’Separator systems for light liquids (e.g. oil and petrol‘’.

The operating principle

Coalescence
Turbulent flow encourages the fine droplets of hydrocarbons suspended in the water to come together, increasing their volume and encouraging them to float.

The automatic stopper
Positioned downstream of the light liquid separation chamber, it prevents any accidental discharge of decanted free hydrocarbons into the downstream network. It is fitted with a siphon elbow associated with a float which is calibrated according to the density of the light liquids to be trapped.
It operates as follows: The float sinks in the hydrocarbons, but floats in the water.

Useful volumes

The useful volume of an appliance is its effective water volume (the quantity of water below the outlet water line). Standard NF EN858 is based on the principle of purification performance. However, we recommend that you define effective volumes as follows:

Useful volume of the separator
This can be defined using the following equation: Vsep = 90 x TN Vsep = Useful separator volume in litres TN = Nominal size in l/s

Recommendations

Observation of the correlation between the useful volume of the separator compartment and the purification performance shows that below 90 seconds of passage time, the phenomenon of re-dumping of hydrocarbons increases considerably, especially during Q10 rainfall events.

The volume is no longer large enough to :