The Underground Environmentalists

Nigel Plumb is a director of David Plumb & Co, a specialist in fuel storage tank cleaning and the decommissioning of service stations and other commercial, industrial and military refuelling sites. Here he looks at some of the special problems involved with reclaiming land that has been previously used for petrol and diesel storage.

The problems for most demolition companies end at ground level, or at least at the foundations and services, but when your speciality is service station decommissioning, you have to dig a whole lot deeper than that.

The aim of decommissioning is to leave the site ready to redevelop for anything from a new petrol station to houses or a shop. This means that no contamination whatsoever can be left in the ground.

To ensure this, before we even go near the site, we bring in an environmental consultancy to establish as much of its history as possible. Often a site will have been developed several times over its lifetime, with new tanks and lines being added without the old ones being removed.

Current and disused utilities will also crisscross the site and, often, the plans for these do not exist. So, before even making a dent in the ground, it is essential to look for those ‘unknown’ hazards with specialist scanning equipment.

This is where we often hit another problem. Ever since the Government decided to levy an increasingly heavy landfill tax, fly tipping is on the increase. By definition, disused forecourts are quiet, open flat land that is easily accessible to vehicles – in other words, the ideal place to fly tip. We recently completed a job at Erith, in Kent, where there were head high mounds of rubbish.

So before we can even get started, we often have to move lorry loads of soil, rubble, timber and the odd kitchen sink off the site to an official landfill site. The only way to avoid this is to strongly secure the site the minute it closes to the public.

The initial part of the decommissioning process is similar to most other demolitions; we make sure all the utilities are disconnected and we knock down the surface buildings. It is only when the site has been levelled that the problems really start, as you cannot see what you are dealing with until you start digging.

The first holes we make in the ground are a series of test bore holes, so our environmental consultants can test for possible areas of contamination.

article continues