Numerical modeling of fluid-structure interaction between sewage water flow and bar screen to improve the screening process

A self-cleaning bar screen is often used in the first filtration level of a wastewater treatment plant to screen out solid debris from sewage water. The screening process of the bar screen was numerically investigated using the arbitrary Lagrangian-Eulerian method to model the fluid-structure interaction between the sewage water and bar screen. The bar screen design is improved by installing a rotating subscreen under the bar screen to prevent solid waste from passing through. The effects of bar screen on the water flow were examined using hydrodynamic properties. The structural properties were estimated to observe the effects of water flow on the parts of the bar screen. Various inlet flow rates and positions of subscreen and rake were used to examine their effects on velocity, pressure coefficient, structural deformation and von Mises stress. The screening process decreased with the increase in sewage flow rates. The water flow significantly affected the bar screen when the subscreen and rake are not in contact.