Im thinking the liquid is from the cooling tower.
I wonder if maybe this bldg. had a large water storage tank on the top floor for fire prevention. I know in some cities there are areas that water supplies are quite limited for fire protection and they mandate a large tank at our new the top of the bldg. to be used as a source of water for sprinklers. I seen some of those tanks get pretty grungy which may explain why the water was running black.Any ideas on what the liquid spewing out at the top is? It starts out clear and turns to black.