Facebook commenter asked us what happens to the material that maintenance trucks suck out of the catch basins. This morning we confirmed the practice with a representative of our Sewer System Maintenance & Operations department.
First point of clarification, catch basins (the collection points you often see along the street curb) are maintained and cleaned by your local municipality, not the Regional Sewer District. But common procedures do exist.
Normally, the material pulled out of catch basins is trash, like paper, plastic bottles, and other floating debris. Any water that gets sucked up in that collection process is drained into a sewer, and the debris is taken to a landfill for disposal. But if the material is mostly grit, it can be brought to a treatment plant and processed.