Underground fuel storage tanks are found in many industrial and commercial premises, including petrol filling stations and factories. When these premises close down, the land is often used for another purpose. This necessitates the safe removal of the tanks, as the ground where they are located is considered to be contaminated land.
According to the guidance issued by the Department for Environment, Food & Rural Affairs and Environment Agency, a risk assessment is required to find out what hazards exist on previously developed land. Contaminated land needs to be remediated. This means preventing or cleaning up contamination. The selected method of remediation will depend on a number of factors, including the nature of the contamination, where the site is, how big it is and how easy it is access.
Why Do Tanks Have to Be Decommissioned?
Working on underground tanks and associated pipework is potentially hazardous. The tank could contain flammable gases, liquids and vapours which present a risk of explosion.
Tar-like deposits can accumulate in the tank, and flushing with water does not always remove them. When these deposits mix with air and sunlight under normal temperatures, they are potentially explosive.
One option is to remove the tank from the ground. An alternative is to decommission the tank in situ by removing its residual contents, purging vapours and filling with inert material.
The Process of Underground Tank Decommissioning
Making underground fuel tanks safe is a specialised service, and you should seek the help of tank decommissioning services to do the job safely and quickly.
When decommissioning experts such as http://www.ashremediation.co.uk/tank-decommissioning/ arrive on site, they will choose the most appropriate method for the particular contamination.
For most tanks, the preferred approach is to fill them with RG22 non-toxic resin foam. This method is both cost-effective and environmentally friendly.
The advantage of using the foam is that the tank does not need a full clean or de-gas. Once any remaining fuel has been pumped out, the foam can be applied through the tank lid.
It is preferable to concrete because it does not leave any hollow voids, and this is very useful for larger tanks in particular. The foam removes the risk of explosion by absorbing flammable hydrocarbons.
As the foam is light (much lighter than concrete), it is easy to remove the tanks at a later date if required.