Full Retention, Forecourt And Bypass Separators: Which One, If Any? // Octane
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Full Retention, Forecourt and Bypass Separators: Which One, If Any?

Date: 15/02/2018

Full Retention, Forecourt and Bypass Separators

In a previous article I wrote about fuel and oil separator maintenance. This time, I thought it would be a good idea to talk to you about the different types of fuel and oil separators, to give you a better understanding of which one would best suits your needs. Or if you need one at all.

Fuel and oil separators used to be known as interceptors or petrol interceptors. These were normally made up of a 3-chambered tank, which filtered contaminants into different chambers.

Now they’re far simpler and more effective. The most common separators you’ll come across now are single pot with coalescent filters.

But first, I want to talk to you about the role separators play in maintaining your refuelling site.


Kingspan Klargester Fuel Oil Separators


Fuel and oil separators are designed to manage runoffs or spills. This might be from large amounts of rainfall or accidental spillage during a fuel delivery, or possibly from maintenance work. Whatever the cause, the separator will protect your local environment from pollutants.

This will also minimise the risk of a large fine from the Environment Agency, and protect your reputation.

Most surface water drains will either discharge to a watercourse, or a soakaway, which may go indirectly through an underground watercourse. So, you really want to know that your wastewater management system is the right one for the job.

In modern industry and business there are so many products that can easily contaminate your drainage systems or waterways. And the penalties for unlawful discharge into waterways are severe.

fuel leak river pollution

These might include unlimited fines and/or imprisonment up to 5 years, as well as you having to paying for the cost of the clean-up.

Let’s have a closer look at each of the systems in turn, so that you to decide which best fits your situation. First, what are some questions you might ask.

·       What are you using the area for?

·       What’s the level of risk for flooding or spillage from contaminants?

·       How many vehicles, if any, will use the area, and for what purpose?

·       Are fuel oils delivered to the site? (e.g. retail forecourt).

·       Do you have a very low risk of oil contamination? (e.g. roof water).

Full Retention Separator

The full retention separator is designed to treat the full flow that might be delivered by a drainage system. You would use it where there’s a medium to high risk of contamination caused by spillage or flooding. You're talking about 65mm/hr of rainfall, which is pretty heavy.

full retention cutaway separator

High-risk areas where you might need a full retention separator could be a car park with a large number of cars. It might also be a fuel distribution depot, vehicle maintenance or industrial workshop, or a scrap metal or recycling yards.

And when you need to protect a nearby waterway, or an area that’s environmentally fragile, an oil alarm system will give you added peace of mind.

Forecourt Separator

Forecourt separators are used to capture hydrocarbon pollutants. This would include petroleum and oil, which are then prevented from entering the drainage system. This might be a petrol filling forecourt, a refuelling station, a car breakers yard or scrap metal yard.

forecourt separator cutaway

The forecourt separator system includes an automatic closure device. What that does is to ensure oil can’t escape the separator should you have a major spillage. In such an event, you would need to empty the separator as soon as possible.

The forecourt separator can also hold up to 7600 litres of pollutant. That means that should a fuel delivery tanker accidently spill its load on the petrol forecourt, the forecourt separator will contain the whole load.

Bypass Separator

You would use a bypass separator when the area has an acceptable or low risk of contamination. Then you wouldn’t need to provide full treatment to the drain off. It can cope with water flow generated by rainfall up to 6.5mm/hr.

bypass separator cutaway

You would install a bypass separator where you have areas which are used for short term parking, or maybe roadways or commercial areas that only get light contamination.

For you to decide on the type and size of full retention, forecourt or bypass separator you need, what other information do you want to consider?

As well as the standard features on all of the systems, they’re also fitted with an oil spillage alarm, and this is calibrated by a qualified engineer. And don't forget that with all of the systems you’ll need to get permission from both your Local Service Provider and relevant Environmental Agency.

Prevention & Maintenance requirements

So, you know which fuel and oil separator you need. You also understand the need to take action to protect the environment and comply with the law, and you can see how it can benefit you. Well the good news is that in 2013 the Environment Agency released a new regulatory framework that looked closely at pollution prevention guidelines.

Let's consider some of the highlights of a typical prevention plan.

Make a drain plan



It’s a good idea to make a plan of your drains which can be done via a CCTV Drain Survey.  This will not only make it easier for you to use them correctly, but also to carry out maintenance. And if you have a spill or pollution incident, you’ll have the ability to deal with it in the best possible way. 

Use the right drain

You will need to check with the water company that you’re using the correct drain to discharge into. You’ll need their permission to drain into either the foul water or clean water (rainwater) system. They may be a combined system, so make sure you check that, as it may affect what separator system you use.

Check your drains

Once you have installed your system, be sure to make regular checks on your drains for blockages or leaks. And make sure you're diligent in clearing or repairing any problems that may arise.

Mark your manhole covers

You will need to paint your manhole covers according to their use.

You can indicate the flow direction by painting an arrow on the manhole cover. Also mark another arrow on the ground so that when you remove the cover it can be placed back in the correct position.

So for your own peace of mind, and as legislation gets tougher on pollution, it’s important that you choose the right fuel and oil separator to install. Not only that, you don’t want anything to disrupt your business, and thus eat into your hard-earned profits.

Kingspan Klargester Fuel Oil Separators

Octane are a Kingspan Klargester Accredited Installer and sell and install the different types of fuel and oil separators discussed above.

If you have anymore questions which aren’t covered in this post or need other assistance, give us a call on 0113 2012 460. We’re here to help.