| + | [[File:HydrodynamicSeparatorsPage smallpic.jpg|thumb|400px|An exampel of what a typical Oil-Grit Seperator (OGS) pretreatment device looks liked (3P Technik UK Ltd, n.d.)<ref>3P Technik UK Ltd. n.d. HYDROSYSTEM1000 SUDS MULTI-PROCESS TREATMENT DEVICE. Stormwater Treatment. Accessed September 23 2022. https://www.3ptechnik.co.uk/stormwater-treatment/hydrosystem_1000/</ref>]] |