Sewer Pipes in the Gowanus Canal?

Does anyone have any idea what exactly these huge pipes are doing floating the Gowanus Canal, moored to a bulkhead like some Mary, Queen of Sewers? It appears that they are closed at either end, which keep them airtight and afloat, but are they for some sort of city project? Perhaps something to do with the EPA's ongoing tests for possible Superfund Designation? Seems like a small amount of pipe to have to find space to store.