Corrosion Protection for Sewer Wet Well 1

[Trackfiend]

I've helped design an addition to an existing sanitary sewer system that has two separate sewer pumping stations. One pumping station is existing and is being refurbished with new pumps and the other pumping station is new. I am unfamiliar with the proper aspects of corrosion protection (both exterior and interior) for the wet wells and valve vaults. Here are a couple of questions:

1. Is coal-tar epoxy acceptable for interior corrosion protection? I've read a some articles where the industry seems to be leaving this product behind and going forward with HDPE and PVC products.

2. If coal-tar is acceptable, what is a standard thickness and number of coatings (Ex: 9 mils, 2 coatings)? Are there any known specific products that you would recommend (Ex: Kop-Coat)

3. If coal-tar is not acceptable, what would be a preferrable product?

Any and all suggestions would be helpful. There seems to be a lot of products out there and I'm just not that knowledgable on which would be appropriate for my application.

 

[nackra]

http://www.sauereisen.com/

http://www.agruamerica.com/prodsure.htm

http://www.tnemec.com/WaterAndWastewaterProcessing

above are some products that I have specified for variety of sewer manhole and pump station projects. I recommend factory applied liner/coating for new construction.

NASSCO is a good source for rehab of existing facilities:

http://www.nassco.org/

 

[SteveWag]

Coal Tar Epoxy is not PC anymore, probably never was. However, if applied properly it will give very good service for forty or more years. I regularly see both steel and concrete, coated with Koppers 300M, that I was involved with, constructed in 1968. The both are sewage treatment units with both exposed and submerged surfaces. The submerged areas are in very good condition and the exposed steel surfaces are in need of touching-up. Apply in two coats at the mfgrs recommended rate.
Steve

 

[bimr]

I would follow nackra's advice. Coatings such as coal-tar epoxies have a history of poor performance where hydrogen sulfide attack can occur. PVC or HDPE liners are more effective.

Coal tar should only be used for exterior waterproofing. The other lining products are far superior.

http://www.eng-tips.com/viewthread.cfm?qid=258769&page=7

 

[Trackfiend]

Thanks for the input. I've decided to use a coal-tar coating on the exterior and a non-coal epoxy from Sauereisen for the interior coatings.