The IKEA warehouse in Peterborough operates as a distribution centre to the company retail outlets in the local region. The warehouse itself is a significant size and, combined with the hard standing required for the parking and turning of large articulated lorries, generates a significant rainfall catchment. The consequent run off from the warehouse generated during rainfall events requires management and treatment prior to discharge back into the environment. The event based nature of the flow, following precipitation events, meant that some form of balancing was required to handle initial high ‘first flush’ volumes. Run off passing over the hard standing areas picked up hydrocarbons from oil and rubber deposits from the lorries as well as grits. These would be present in higher concentrations within the ‘first flush’ and needed to be removed to acceptable levels prior to discharge. The Environment Agency specified a visual consent with a maximum discharge rate of 16.4 l/sec.