Authors

K. Osei, R.Y.G. Andoh, J. MacKinnon and M.G.Faram

Abstract

Laboratory testing of stormwater separators can overcome many of the technical challenges associated with field testing. With laboratory testing, sediment characteristics and the flow rates at which a device is tested are known and measurable before, during, and after the test. This controlled environment ensures that test programmes can be set up to meet specific objectives, and data can be obtained in a repeatable and timely fashion. However there are differences in laboratory test protocols that can have a significant bearing on test results which, if overlooked, can result in invalid comparisons being made between different systems. This paper looks at two protocols for testing separators in the laboratory, normally referred to as the Direct Test Method and the Indirect Test Method. The test methodologies are described and the similarities and differences shown. Results from tests on a stormwater treatment separator using the two protocols are presented. The results show that for the same sediment gradation and flow rate, a difference of over 20% in measured removal efficiency is possible. They also show that the Direct Test Method produces outputs that are more consistent, conservative and representative of the removal efficiencies expected for stormwater treatment separators.