A drainage bund is designed to capture liquids if the primary tank fails or leaks, this prevents contaminants escaping the site and polluting the environment. The bund also captures drips and leaks from pumps and hoses. In addition the bund must provide a safe working platform for staff to access the primary container and perform repairs.
A good drainage bund will be able to retain up to 6 times its own volume of liquid. Bunds should be constructed from a suitable durable material such as concrete or reinforced masonry, depending on site requirements. Prefabricated bund walls which are fixed to an impermeable base can be used if the required dimensions are accurate and a more cost effective solution.
Optimizing Drainage Bunds: Key Components and Maintenance
The construction of the bund should be leak tight, with expansion joints provided for different casts of concrete in the walls, and where pipe penetrations are located. Surfaces should be smooth and crack free with no discontinuities which could allow the migration of liquid.
It is important to include a drain at the low point of a bund wall, with a valve normally kept closed. This should be operated on a schedule, to enable the valve to be opened daily to remove any accumulated rainwater, this will help to identify minor leaks and reduce maintenance costs.