Operator terms · Wastewater
What is a bar screen?
A bar screen is a set of parallel bars at the start of a wastewater plant that catches rags, sticks, and large debris before they reach the pumps and treatment steps. It is the first stage of preliminary treatment, protecting the equipment downstream from clogs and damage.
Last reviewed 2026-08-03
The first barrier
Wastewater carries rags, plastics, and debris that would jam pumps and clog tanks. The bar screen catches this material right at the headworks.
What happens to the screenings
The caught material, called screenings, is raked off and disposed of. Grit removal usually follows to take out the heavy sand.
Common questions
- What does a bar screen remove?
- Rags, sticks, and large debris at the head of the plant.
- Why is it first?
- To protect pumps and downstream equipment from clogs and damage.
- What comes after it?
- Grit removal, then the primary and biological steps.