How much protection is needed for the concrete in a new sewage treatment plant?
The concrete in domestic sewage treatment plants seldom needs any special protection. If there is hydrogen sulfide gas in a stagnant unventilated environment, however, it can become oxidized to form weak sulfuric acid, which will attack concrete. If there is no way to prevent this from occurring it would be desirable to coat the concrete. Sutible coatings for this purpose are vinyl lacquers, epoxies, chlorinated rubber, or phenolics. For floors, epoxies would be best because of their abrasion resistance. In industrial waste treatment plants acid waste may be highly acid. In such circumstances it is common to use acid-proof brick or tile with chemical resistant mortar, thick bituminous coatings, epoxies, or heavy lining sheets of rubber or plastic.