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Bund survey reveals many bunds in poor state

The EPA requires IPC licence holders to have their bunds tested at regular intervals. A recent survey of these bund test results suggests that the nation's bunds are in a poor state and that a large proportion of bunds fail the required water retention test.

These findings are of concern to site operators on a number of levels.

Firstly, it would indicate that the facilities for the protection of groundwater from pollution are not to the standard required. Any leak from a tank within the bund would pollute the ground and groundwater. Not only does this put drinking water supplies at risk, but it has serious cost implications as the site clean-up costs can be significant and may not be covered by insurance.
Secondly, poor bunding is often identified by EPA site inspections. This not only can result in corrective action being imposed to repair bunds, but may also result in the EPA requiring assessments of ground or groundwater contamination to be carried out. If such an assessment identifies contamination, then the remediation costs can be significant.
Thirdly, retesting of bunds is an added expense and - depending on the test protocol used - can seriously disrupt production.

It is, therefore, important that bunds are maintained to the necessary standards so that they do not become an issue when the EPA carries out site inspections.

A poorly maintained bund will draw attention and may result in corrective actions - as mentioned earlier.

In addition, properly maintained bunds will pass a water retention test at the first time of asking - thereby saving time, money and minimising any disruption to production.

Based on their own bund testing results - and a review of other tests held on file by the EPA - Environmental Efficiency has produced a guide to help site operators identify and correct the common faults with bunds. This guide is available free of charge from Environmental Efficiency. Following these guidelines will ensure that bunds will not be an issue during EPA inspections. In addition, they are much more likely to pass the water retention test first time.

From the survey, over 50% of the bunds tested, failed the water retention test. The main causes of failure were cracks in the wall (30% of failures) and cracks in the base (27% of failures). Other causes of failure included poor construction techniques and poor sealing around pipes.

Many of the reports on file identified poor construction techniques and poor design -

Many bunds had filling pipes and nozzles located outside the bund, leading to contamination of the ground from drips and leaks from poor hose connections.
Many bunds had drain holes deliberately placed in the bund.
A large number of bunds were constructed using an existing wall of a building as the back wall of the bund. Most of these bunds failed water retention tests as the joint between the building wall and the bund sidewall moves under water pressure.
A number of bunds were undersized and required either the walls to be raised or the tanks contents to be restricted.
Tanks were located against bund walls, thereby making inspection and repair difficult.

Cracks in walls

To avoid repeat bund test fees, it is suggested that site operators make a simple assessment of the fitness of their bunds prior to testing. These check are detailed in the 'Good bunding guidelines' produced by Environmental Efficiency. The simplest check is to see if the bund is holding rainwater. Look in the bund after a wet spell. If there is no rainwater, there is most likely to be a leak.

Secondly, walk round the bund. Are there damp patches on the walls or at the base? Typical examples are shown below. This could indicate defects that would result in a failed water retention test.

Damp patches on bund walls

Thirdly, check to see if there are any drain holes in the bunds. Many bunds have intentional gaps at the base to let out rainwater (which entirely defeats the purpose of the bund). These should be sealed up with waterproof cement.

Due to the high failure rate of bunds tested under the requirements of EPA IPC licences, Environmental Efficiency now issues a 'Good bunding guidelines' free of charge to site operators. This allows environmental managers to ensure that their bunds will meet the requirements of the EPA and achieve a higher pass rate than would otherwise be the case. For a free copy, please email the author [email protected]

Environmental Efficiency has been conducting bund tests for many years in Ireland for both IPC and non-IPC licensed sites. These include testing for sites with a single bund to large pharmachem sites with up to 200 bunds. For a confidential discussion on bunds, bund testing and alternatives to bunds, Environmental Efficiency would be happy to discuss these aspects further.

Causes of bund failure

The survey data used in this article is based on a random survey of bund reports held on file at EPA offices during 2004 and 2005.

This article does not purport to reflect the views of the EPA, nor offer a legal interpretation of the EPA Act or other statutory requirements.

The author, Bob Sutcliffe, is the Technical Director of Environmental Efficiency and is a Chartered Engineer and a Chartered Member of the Institutes of Wastes Management. Feedback on this article is welcomed and should be addressed to [email protected]

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