I have a project that has a lift st

[Sam_imported]

I have a project that has a lift station that services a single family dwelling foundation perimeter drain tile; the roof gravity flows to the city storm sewer. The lift station is experiencing a "scale" buildup on the pump and within the pump line but does not appear to be building up on the inside of the lift station concrete chamber. The "scale" looks like iron oxide but with a weak crystalline structure with the size about what would be retained on a #40 sieve. The last time the pump was replaced both the pump chamber and the sump were pumped out with a sucker truck (vacuum truck). The general soil conditions consist of sedimentary materials. I have designed several dozen lift stations in the area and have not encountered this material before. Any thoughts?

 

[Ron]

You need some basic chemistry on the water. Sounds like an iron-carbonate reaction/precipitate. Likely needs an occasional acid shock treatment similar to a swimming pool.