(A) Because the effluent standards in §§ 52.015 and 52.021 are based upon concentrations achievable with conventional treatment technology that is largely unaffected by ordinary levels of contaminants in intake water, they are absolute standards that must be met without subtracting background concentrations.
(B) However, it is not the intent of these regulations to require treatment when only traces of contaminants are added to the background. Compliance with the numerical effluent standards result entirely from influent contamination, evaporation, and/or the incidental addition of traces of materials not utilized or produced in the activity that is the source of the waste.
(Prior Code, § 3.1)