The composition of trash found in urban stormwater runoff was analysed following its collection by a trash rack and two floating booms in Sydney, Australia. Basically garden refuse, plastic and paper products were the main components of the trash collected. The effectiveness of trash interception devices was examined using results of field trials. For various flow velocities, widths of channel or river, storm-related loads and cleansing frequency the choice of trash racks or booms can be made.
Testing of a range of trash rack designs was performed in the laboratory with the principal aim of preventing rack blockages. Whilst both spacing between bars and the angle of inclination of the rack were related to self cleansing, ultimate blockage could not be prevented for the configuration tested. Either the racks should be designed to allow for overtopping when blocked or booms be used, despite their lesser efficiency.