Pipe Material for Industrial Process Wastewater 1

[RJSH]

What type of pipe material is in common practice to convey industrial process wastewater (acidic = pH 4)? It appears, in spite of being susceptible to the corrosion, carbon steel pipe is still used widely in the industrial wastewater with allowance for scraficing thickness for corrosion (i.e. provide extra thick pipe). Is that true with industrial practice? Can PVC pipe be used in lieu? (Application is outdoor, the pipe is not in continuous service. The pipe will have drain connections to drain the content when not in use and leave the pipe empty. No freeze protection is considered. The area has high temperature upto 100 F during summer and may go down to zero sometime during winter.
Any thoughts and insights will be highly appreciated.

 

[micalbrch]

I would not use carbon steel with this pH value if the pipe was drained and was not in continuous service. A stainless steel pipe will most probably work well. 0 °F is too low a PVC pipe but there are PP pipes available which can withstand this temperature.

 

[RJSH]

You mean, Even if the pipe is drained and not in continuous service, is that right?
Do you have any thoughts aboout Fiberglass Reinforced (FRP) pipe?
I was surprise to see many industries use steel pipe for wastewater application and other corrosive environment.

 

[micalbrch]

No, I meant because the pipe is drained and not in continuous service I would not recommend carbon steel.
Well, I know that FRP pipes are used but I do not how the behave at low temperatures.

 

[RJSH]

What are the concerns when the pipe is drained and not in continuous?
Which pipe material is the best at outdoor application for such wastewater?

 

[micalbrch]

"What are the concerns when the pipe is drained and not in continuous?" Oxygen inside the pipe in combination with the remaining (slightly acidic) fluid. That leads to corrosion.

 

[bimr]

FRP is a good choice and there are many options depending on the flluid properties. Bondstrand makes a gppd product.

 

[RJSH]

Do you guys have any thoughts of FRP for outdoor service? The Pipe will not get a freeze protection. The thought is to drain the pipe after every use, and keep the pipe empty.

 

[bimr]

FRP is great for outdoor service when it is correctly specified. Just put it into the specification.