DEEP: Industrial Wastewater

Industrial Wastewater

{image of factory and water} Industry in Connecticut provides manufactured products and services sold in Connecticut and throughout the world. Wastewater generated from industrial activities can contain pollutants such as BOD (biochemical oxygen demand), suspended solids, nutrients, heavy metals, oils and greases, and other toxic organic and inorganic chemicals.  If left untreated, these pollutants can cause serious harm to the environment. 

The Department of Energy and Environmental Protection (DEEP) regulates the discharge of industrial wastewater to the ground water, surface water, and to sewage treatment plants through permitting programs. Discharge limits and requirements for treatment, monitoring and reporting, designed to protect the waters of the state from pollution, are specified in all permits.

Two types of permits are available for industrial wastewater discharges:

  1. Individual permits are issued directly to an applicant and are customized for a company's activities based on flow and the pollutants contained in the discharge.
  2. General permits cover a specific category of discharge and are issued to authorize similar minor activities by one or more applicants.
   (DEEP Permits and Licenses page for Wastewater Discharges)
New!  Proposed Reissuance with Modifications of the General Permit for Miscellaneous Discharges of Sewer Compatible (MISC) Wastewater from Industrial Users (Miscellaneous Industrial User GP)
The proposed Miscellaneous Industrial User GP will continue to authorize discharges of "miscellaneous sewer compatible wastewater" either discharged directly to a Publicly Owned Treatment Works (POTW) or transported there by vehicle.  However, the Industrial User initiating, creating, originating or maintaining the discharge cannot be a Significant Industrial User (as defined in the general permit).  The permit proposes that each POTW will administer the Miscellaneous Industrial User GP for those facilities that discharge to its treatment plant.  The Miscellaneous Industrial User GP will have an effective date of October 31, 2020, and an expiration date of October 30, 2025.  The registration form for the proposed Miscellaneous Industrial User GP will be available on this page in the future.
The current General Permit for Miscellaneous Discharges of Sewer Compatible Wastewater which expires October 30, 2020 is available on the Permits and Licenses webpage. 
Proposed Issuance of the General Permit for the Discharge of Wastewaters from Significant Industrial Users (SIU)  
The proposed Significant Industrial User GP (SIU GP) will authorize discharges from Significant Industrial Users (as defined in the general permit) of metal finishing wastewater, process, or non-process wastewater to a Publicly Owned Treatment Works (POTWs) either via the sanitary sewer or a properly licensed transporter.  The SIU GP will have an effective date of October 31, 2020, and an expiration date of October 30, 2025.  For all registrants, the General Permit Registration Form for the Discharge of Wastewaters from Significant Industrial Users (DEEP-WPED-REG-029) shall be submitted for review and approval.  The registration form and instructions for new discharges under the proposed SIU GP will be available on this page in the future. 
Issuance of the General Permit for the Discharge of Groundwater Remediation Wastewater (Groundwater Remediation GP)

The Groundwater Remediation GP authorizes discharges of wastewaters generated during the process of investigating and remediating groundwater and soil, and other related wastewaters whether discharged to a surface water, groundwater, the collection system of a Publicly Owned Treatment Works (POTW) or hauled to a POTW.

This Groundwater Remediation GP combines and replaces the two recently expired groundwater remediation general permits that authorized discharges to sanitary sewer and surface water.  Many of the operational requirements remain substantively similar to the existing structure.  There are some significant changes to activities authorized, as well as new conditions applicable to surface water discharges.  The following summarizes the major changes:

  1. All discharges will be evaluated for emerging pollutants as defined by USEPA.  Should emerging pollutants be documented as a concern, conditions will be established as part of an approval of registration.
  2. Certification by a Qualified Professional, as defined in the permit, will be required for all discharges that continue for longer than thirty (30) days.
  3. All discharges will be screened for Total Nitrogen and Total Phosphorus.
  4. All discharges lasting longer than 90 days are subject to NetDMR reporting requirements.
  5. Discharges to Impaired Waters will be subject to specific conditions.
  6. The following discharges to surface water, which were previously ineligible for coverage, may now be covered under this general permit by issuance of an Approval of Registration:
    1. The discharge is directed to a receiving water with a water quality classification of AA or is tributary to a drinking water supply, or
    2. The combined discharge flow exceeds 10% of the 7Q10 flow of the receiving stream or % of the impoundment, lake or pond receiving the discharge, or
    3. The discharge uses a stormwater conveyance as part of the treatment system for the reduction of volatile organic compounds.
    4. Discharges may also be authorized to groundwater from specific remediation activities and from maintenance of remediation systems.

Renewal registrations are necessary under the current Groundwater Remediation GP.  The registration form and instructions are available on the DEEP Permits and Licenses webpage.

Issuance of the Comprehensive General Permit for Discharges to Surface Water and Groundwater (Comprehensive GP)
The Comprehensive GP replaces the surface and groundwater discharge portions of the following three general permits that expired March 29, 2018:
General Permit for the Discharge of Water Treatment Wastewater
General Permit for the Discharge of Non-contact Cooling Water and Heat Pump Water
General Permit for the Discharge of Hydrostatic Pressure Testing Wastewater. 
The Comprehensive GP also provides authorization for surface water and groundwater discharges of fire suppression testing wastewater, hydrant flushing wastewater, and boiler blowdown wastewater (to groundwater only when no boiler treatment chemicals are used).
The Comprehensive GP was issued December 14, 2017 with an effective date of March 30, 2018.  Registrations for authorization under the Comprehensive GP for existing discharges must be submitted by June 28, 2018.
The registration form and instructions for the Comprehensive GP are available on the DEEP Permits and Licenses webpage.
A draft of the Comprehensive GP was publicly noticed September 30, 2016.  Below please find:

Learn more about how to comply with your permit.

Related Information

List of DPH Approved In-state Commercial Environmental Laboratories

Prohibition on Acceptance and Treatment of Wastes From Hydraulic Fracturing

Facility and Wastewater Treatment System Modifications Factsheet (in conjunction with
RCSA 22a-430-3(i))

NetDMR Electronic Discharge Monitoring Reporting

Fats, Oils, and Grease (FOG) Model Program

List of Connecticut Permitted Waste Transporters

List of Connecticut Publicly Owned Treatment Works (POTWs) Approved to Accept Transported, Non-domestic Wastewaters

Content Last Updated October 2019