Large aerated grit chambers feature very long (35m) grit screws in a cast-in-place trough and several grit chamber installations in Canada.
In the first solution grit is drawn to a sump pit where it is intermittently pumped out by grit pumps. Low RPM intermittent operation allows for spiral lifetimes up to ten years. This is a very cost-effective, low energy consumption and low operating cost system for large inflows and high grit loads.
The second Grit chamber was commissioned in 2009 and features long run spirals in cast-in-place troughs. Various liner options are available, in this case Hardox wear bars are utilized. This provides long liner and spiral life given low RPM, submerged and intermittent operation.