A 2 stage interceptor, otherwise known as a separator, is a filter system put in place to separate common oils and contaminants from wastewater before it enters the main sewage system. These pollutants are then stored in the interceptor before being periodically removed.
Wastewater enters into the first chamber of the interceptor through an inlet. It passes into the next chamber through a dip pipe, the opening of which is placed towards the base of the chamber. It is placed there to minimise any oils or petrol passing through to the next chamber, as they naturally rise to the top of the water. Any solid sediments will sink to the bottom of each chamber over time.
Where are interceptors needed?
Interceptors are often used in areas that are likely to see a lot of vehicle or machinery use nearby, as this is where many pollutants and oils will often enter the drainage systems. Some examples of areas where interceptors might be found include:
- car parks
- areas where goods vehicles are parked or manoeuvred
- vehicle maintenance areas
- industrial sites where oil is stored or used
- refuelling facilities
How often do interceptors need to be emptied out?
Interceptors need to be inspected by qualified personnel every six months, checking the integrity of the interceptor, the amount of oil and silt that has accumulated, all linked alarms and management systems, as well as any coalescing devices.
It’s recommended that an interceptor is emptied every five years or so, in order for a more thorough general inspection.
Un-separated surface water can damage the environment, polluting rivers, streams, and groundwater. Allowing this un-separated water to enter the environment due to a faulty or poorly-maintained interceptor can lead to prosecution by the Environment Agency.