Wastewater Tank Linings and Coatings

Polyurea Spray-On Linings

Polyurea is one of the primary lining systems used in the wastewater tank linings industry . It is a plural component, spray applied system that cures to touch in 6-8 seconds. It is generally applied 60-80 mils thick in wastewater tanks. This compares to 10-12 mils for epoxy. Since it is a spray on lining, it conforms to poles, pumps and other internal structures. Large diameter pipes, manholes and lift stations are perfect candidates for Polyurea. It is flexible, has over 2,000 psi tensile strength and 300% elongation. It's this elongation factor that makes it so attractive when compared to epoxy and other hard thin film coating systems. Hard thin film coatings tend to crack when subjected to repeated expansion - contraction cycles. Whether applied to steel or concrete, Polyurea expands and contracts with no cracking. Since it cures in seconds and has a 2,000 psi tensile strength it can actually be used to repair holes in tanks as part of the lining system. Anti-microbial additives can decrease the microbial growth on the lining.

The video belows show the lining process from beginning to end.


The primary reason that linings and coatings fail is poor surface preparation. Southeastern Industrial Linings has extensive experience getting projects ready for a lining system. We use the Graco EcoQuip Vapor Blaster that removes rust and corrosion with water and garnet. The blast water has soluble salt neutralizers added to it. Soluble salts can cause coating failure.

Vapor Blasting is sandblasting with water and garnet but it reduces the dust by up to 90%. Garnet is a industrial gemstone that creates a profile virtually free of embedment. It is safe and non toxic with very low free silica levels (generally less than 1%). It is one of the most durable abrasive blast medias available anywhere in the world. It's sharp, angular shape is plenty aggressive enough for tough surface preparation like rusted steel or degraded concrete wastewater tanks. Grinding the rust out of the tower will not achieve surface prep comparable to vapor blasting. Grinding cannot reach into corners and unless the tank is pressure washed with a soluble salts remover the salts could cause a coatings failure.