DSM Screen Vs Rotary Drum Screen: Key Differences and Performance in Wastewater Treatment Wastewater treatment plants rely on mechanical screening systems to remove solids before biological or chemical processing. Two technologies are commonly compared: the DSM screen (also known as the wedge wire curved screen) and the rotary drum screen. https://www.johnsonwedgewire.com/news/dsm-screen-vs-rotary-drum-screen.html