Environmental guidance for your business in Northern Ireland & Scotland
A well-maintained oil separator is very effective at removing petrol, diesel and oil from water.
Before you set up your site, decide how you will deal with run-off from car parks, storage areas and vehicle wash down areas. These may contain oil in water runoff.
You may need to channel run-off from your site to more than one method of treatment.
For example, if you use detergent to wash vehicles in a car park or vehicle wash down area the detergent will emulsify any oil in the water and make an oil separator ineffective.
Yard water may not require a separator if suitable sustainable drainage techniques (SUDS) can be used. See PPG 3 for further information.
Make sure that the oil separator is big enough to cope with the volume of water that will pass through it. If the flow of water is too fast, the water will be churned up and the separator may not work properly.
You may need to install a storage tank to regulate the flow of water through your separator.
Oil separators (interceptors) that are not maintained do not work properly. They require regular maintenance to ensure that they work correctly and efficiently.
The separator should be filled to its operating level with clean water when it is first installed and every time it is cleaned out.
Any surface scum or debris that has gathered behind the skimmer should be regularly removed and disposed of.
Oil absorbent pads can be used periodically to remove oil and fuel from the surface of the water within the separator (interceptor).
Do not leave oil absorbent pads on the water surface within the separator during periods of high water flow or for longer than the manufacturer's instructions suggest.
These should be disposed of as hazardous/special waste.
If you are hiring oil separators, contact the plant hire business to establish whether they can undertake their maintenance as part of your hiring agreement.
When planning the layout of your site, consider where the discharge from the oil separator (interceptor) will go and what authorisation you will need for the discharge.
The Northern Ireland Environment Agency has published a short guide to the duty of care responsibilities including advice and information for waste producers, carriers and those accepting, storing and treating waste.
Any person intending to alter the use or management of areas of uncultivated or semi-natural land must obtain prior approval from the Department of Agriculture, Environment and Rural Affairs (DAERA).
Read more on the DAERA website
The NetRegs team at SEPA, in partnership with The Northern Ireland Environment Agency, Natural Resources Wales and a number of industry bodies have produced 9 new GPPs to replace out of date PPGs. More are coming! Check the available topics
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