Regulatory Alert: CTDEEP Issues New General Permit for Miscellaneous Wastewater Discharges to Publicly Owned Treatment Works (POTWs)

On September 29, 2020, CTDEEP issued the new General Permit for Discharges from Miscellaneous Industrial Users (MIU GP), to replace the General Permit for Miscellaneous Discharges of Sewer Compatible (MISC) Wastewater, which will expire on October 30, 2020. The new MIU GP will become effective on October 31, 2020 and existing registrants to the MISC permit will have until January 29, 2021 to submit a written notification/certification and/or supporting documents to their applicable receiving POTW(s).

Similar to the current MISC General Permit, the new MIU GP authorizes discharges up to 25,000 gallons per day (gpd) of miscellaneous process and non-process wastewaters to a POTW. Industrial Users who discharge between 1,000 and 25,000 gpd (cumulative) of designated “Group I” process wastewater, greater than 5,000 gpd of “Group II” non-process wastewaters, or any flow of Vehicle Maintenance Wastewaters are required to register for coverage under the MIU GP. 

Registration requirements under the MIU GP have changed significantly. MIU GP registration (notification/certification form) and fees, if applicable, are required to be submitted to the local POTW Authority and not to CTDEEP. Furthermore, authorization under the MIU GP is effective upon submittal of required documents to the POTW and the satisfaction of local POTW requirements.

The terms and conditions of MIU GP and ongoing compliance requirements have not generally changed much from those prescribed by the MISC permit. The most notable exception is the new phosphorus monitoring requirements that would be imposed by several POTWs in the state. In addition, effluent limits set by certain POTWs in the state, for certain discharges, would supersede those of the MIU GP. 

The MIU GP notification required by January 29, 2021 must include detailed discharge information including recent (within 90 days prior to notification) discharge analysis data for subject wastewaters, a certification by a corporate officer of the Industrial User, qualified professional certification and a copy of the existing authorization/registration certificate (for existing MISC permit registrants).