Pipe Material to Use in a WWTP

[cuels]

My question is regarding the pipe material most commonly used in the construction of wwtp's. I have gone back an forth with the State DWQ and pipe suppliers. The plant will be a small 70,000 gpd plant. I have some 10", 8", and 6" pipe. I am currently specifying epoxy coated steel pipe (sch.40). However, I am finding that it is the most expensive pipe out there. The pipe supplier is recommending 316 stainless steel. He says that he supplies stainless most commonly. However, when I talk to the Division of Water Quality, they say that they don't see it very often. I was going to try and use pvc in a few areas throughout the plant, but the reviewer didn't like it penetrating concrete walls (afraid of differential settlement crushing the pvc pipe). I don't know what the implications would be on using HDPE, but I am not as familiar with how it would work with concrete penetrations, flanges, fittings, etc. Also, I don't know what the most economical material would be to use in this plant. Right now, stainless is about $20.00/ft less than epoxy coated steel. So, I guess my question is, what material do you see(or use) in the construction of wwtp's.

 

[LittleWheels]

Which part of the world are you in?

 

[JedClampett]

The differential settlement issues for PVC can be avoided with proper use of supports. HDPE has huge coefficients of expansion for temperature that sometimes affects design, especially for exposed pipe.
We use a lot of ductile iron (DIP) in WWTP design. Unless the process flow is very aggressive or sticky, I'm not sure lining is even required, but it's available. Cement lining is the most common. For the sizes you're using, it's very standard. Check American Ductile Iron Pipe (

http://www.acipco.com/adip/).

 

[cuels]

I am in Utah.

 

[bimr]

Your post says WWTP and you are in the water treatment forum.

Epoxy coated steel, HDPE, and stainless steel are not commonly used in wastewater treatment plants. Maybe just in specialty areas. Ductile iron (DIP) is commonly used in municipal WWTP applications

The piping that is used will depend on the application, i.e. blower, sludge, pressure relief, activated sludge, sewer, plumbing, etc.

State what your application is and people will give you recommendations.

 

[stanier]

Material of choice in Sydney is ABS by Eurapipe (Tyco) to As 3518.

Spiral wound stainless steel (316L) is used provided you pickle and passivate all the welds.