You are still not providing enough information. The term "waste water" could refer to a lot of different streams in different industries. In our plant, this would most likely refer to streams directed to or processed within our waste water treatment plant. These streams come to mind:
Oily Water Sewer – The composition of this water depends on which unit it is located in. In our cokers and crude units, this is rarely very corrosive. The pump would be made of carbon steel with a 410 SS shaft and non-metallic bushings. If the sump was in our sulfuric acid alkylation unit, it might see concentrated acid or caustic. These sumps must be tested and neutralized before they are transferred to waste water. The pumps are solid Alloy 20.
“Bug Water” – This water is removed from our bio-basins and contains microorganisms used to break down organic solids. This water is extremely corrosive. The pumps are made of duplex stainless steel.
Final Effluent – This is the water that has been fully processed and is ready to discharge into the river. It is fully oxygenated and has neutral PH. The pumps are 316 SS.
I could also imagine the term “waste water” used to refer to sour water (unstripped or stripped, phenolic or non-phenolic), process condensate (boiler feed water contaminated with ammonia), sanitary sewer (grey water or brown water), blow-down from reverse osmosis units (hard water) or maybe even storm water.
Give the temperature you specified, I might be able to shorten my list of potential guesses. But, it would still be a guess.
Johnny Pellin