Any industrial user required to obtain an industrial wastewater discharge permit who was discharging wastewater into the POTW prior to the effective date of this subchapter and who wishes to continue such discharges in the future, shall, within 60 days after said date, apply to the Public Works Superintendent for an industrial wastewater discharge permit in accordance with § 55.028, and shall not cause or allow discharges to the POTW to continue after 90 days of the effective date of this subchapter except in accordance with an industrial wastewater discharge permit issued by the Public Works Superintendent.