Because of govemment mandated industry pretreatment longer detention times for waste water due to construction of regions treatment plants recent air quality regulations, and other factors, concrete structures in waste water treatment plants are exposed to more severe exposure conditions now than in the past. Protective coating systems which had performed successfully for many years no longer protide adequate protection. The result is frequent coating failure and rapid concrete degradation. This paper discusses the more aggressive service conditions today and the changes which have promoted them. The paper will give examples and then present suggested material selection criteria to be used in the future by engineers and operators to ensure successful long term corrosion protection of concrete structures in municipal Waste Water Treatment Systems.
Keywords: Headspace, H2S (hydrogen sulfide), SRB (Sulfate Reducing Bacteria), SOB (Sulfir Oxidizing Bacteria), Sulfide (S), permeation, and domestic waste water.