What are oil separators?
Oil separators (previously referred to as interceptors) are installed underground in car parks as part of a drainage system in places such as supermarkets, office blocks, shopping centres, universities, schools, hospitals, council buildings and new housing estates. They are everywhere and the list of their locations is endless.
Oil separators are essential surface water capture devices and in low risk environments they remove sediment and oil from surface water before it is released into the wider environment. When not connected to a foul sewer they serve an important role in protecting water courses from oil contamination. This protection helps maintain marine life bio-diversity and as such separators should not be neglected or ignored. The responsibility and their control is an integral part of a company’s environmental management system.
Classes of oil separator
Separator classes BS EN 858 refers to two ‘classes’ of separator, based on performance under standard test conditions.
- Class 1 separators are designed to achieve a discharge concentration of less than 5 mg/litre of oil under standard test conditions. These separators are required for discharges to surface water drains and the water environment. Many Class 1 separators contain coalescing devices, which draw the oil droplets together and facilitate the separation.
- Class 2 separators are designed to achieve a discharge concentration of less than 100 mg/litre of oil under standard test conditions. They are suitable for dealing with discharges where a lower quality requirement applies where discharge is typically to foul drainage.
Both classes can be produced as ‘full retention’, ‘bypass’ or ‘forecourt’ separators. The oil concentration limits of 5 mg/litre and 100 mg/litre only apply under standard test conditions.