Concrete for Clarifier for Acid Mine Remediation

[vincentpa]

I am designing a concrete clarifier and treatment tanks for the remediation of a stream with acid mine drainage. I have read the ACI articles 201.2, 318, 350 & 1515. They offer general guidelines but do not offer any specifics as to when I need to provide a protective barrier. I know the concrete will be exposed to a moderate sulfate attack. The acid is sulfuric acid which is highly corrosive to concrete. What is the cut-off for providing a protective barrier for acid attack? I am specifying Type II cement for moderate sulfate exposure, W/C ratio = 0.45, and fly ash ASTM C 618 Class F. Is this enough? Or, do I need a chemically resistant barrier instead? This is the chemical composition of the water that the concrete will be permanently exposed to:
pH = 2.6-4.5
Acidity = 177.8-271.8 mg/l
Fe (total) = 21.9-45.9 mg/l
Al = 12.8-18.2 mg/l
Mn = 1.2-1.5 mg/l
SO4 = 334.2-535 mg/l

 

[Ron]

With the pH you noted and the fact that it is high in sulfuric acid, you need a barrier.

The sulfuric acid will severely attack the concrete, even with type II cement.

 

[JedClampett]

You can line the clarifier (T-Lock) or coat it. But nothing is fool or contractor proof.
I'm guessing someone in the mining business will have some better suggestions.