(1) POTW's may revise pollutant discharge limits specified in categorical pretreatment standards to reflect removal of pollutants by the POTW.   Revisions must be made in accordance with the provisions of 40 CFR 403.7.   The department hereby incorporates by reference herein 40 CFR 403.7, which concerns removal credits.   A copy of 40 CFR 403.7 may be obtained from the Department of Environmental Quality, PO Box 200901, Helena, MT 59620-0901.