From petrol stations that are no longer in use to factories, fuel depots and farms, old fuel tanks are a common problem. They don’t necessarily have to be removed – although that is often a preferred option, especially if there are development plans for the site. But they do have to be properly decommissioned.
The process of decommissioning can involve a range of activities. An underground storage tank might need to be closed and removed or a tank might need to be replaced. Similarly, lengths of pipe may also need to be replaced. The Department for Environment, Food & Rural Affairs (DEFRA) says that any underground storage tank that isn’t being used should be decommissioned immediately.
With high levels of hazard and risk, it’s a job for professionals
The tank decommissioning process will result in a tank that is clean, structurally sound and can’t contaminate either groundwater or the environment around it. Although it’s not usually a technically complex process, it can be a dangerous and risky one. The dangers come from the possibilities of gases in the tank that may affect operators and from the possibilities of leaks or spills. There is a a risk of prosecution if you don’t comply with DEFRA’s requirements.
These two factors are the reason that the owner or responsible person who needs to decommission a tank usually employs a professional remediation firm such as http://www.ashremediation.co.uk/tank-decommissioning/ to carry out the work.
Steps in the Decommissioning Process
The process can’t start until a full-scale environmental risk assessment has been completed. Then the steps are as follow.
Sample the groundwater and soil at the site. This has to be done at each stage of the decommissioning process.
“Bottom” the tank. This involves removing any leftover fuel or residue from the pipes and the tank. This is the part that can be dangerous, so strict regulations about working in enclosed spaces apply if the operators have to climb inside the tank at any point.
Ensure that both the tank and the pipes are free of vapour.
Remove and clean the dispensers, separators, tank and pipes.
At this point, the extensive regulations and permits for disposing of the waste begin to apply – another reason that people employ professionals who can deal with the documentation that is such a large part of decommissioning.