In the event that the federal government promulgates
a regulation for a given new or existing user in a specific industrial
subcategory that establishes pretreatment standards, revises existing
pretreatment standards or establishes that such a user is exempt from
pretreatment standards, such federal regulations shall immediately
supersede the existing regulations unless the Department of Water
and Sewage determines that the revised standards, if implemented,
would be deleterious to the operation of the wastewater treatment
system.