Industrial User Permits
I. Significant Industrial User
Significant Industrial Users (SIUs) are defined as:
- All Industrial Users (IUs) subject to categorical pretreatment standards set forth at 40 CFR Chapter I, Subchapter N, parts 405 – 471.
- Any other industrial user that: discharges an average of 25,000 gallons per day of process wastewater (excluding sanitary and 'dilute wastewater', as defined at 40 CFR 403.6 e(1)(i) under 'FD'); contributes a process wastestream which makes up 5 percent or more of average dry weather hydraulic or organic capacity of the POTW treatment plant; or is determined to have reasonable potential for adversely affecting the POTW's operation or for violating any pretreatment standard or requirement.
SIU New User Pre-Discharge Requirements
Federal law requires that industrial users proposing to discharge wastewater to the sewer system from operations subject to categorical pretreatment standards must submit a completed Significant Industrial User Discharge Permit Application (PDF) and a completed Baseline Monitoring Report no less than ninety (90) days prior to the proposed date of initial discharge. Where categorical pretreatment standards include a Total Toxic Organic (TTO) chemical discharge limit, a completed Toxic and Prohibited Organic Chemical Management Plan must also be submitted.
Upon receipt of the application, new dischargers are scheduled to attend a pretreatment conference where operations to be performed and proposed pretreatment technology will be reviewed.
SIU Permit Requirements
- Standard Conditions (PDF)
- Discharge Prohibitions (PDF)
- Local Limits (PDF)
Related Links and Documents
- 40 CFR 136 (EPA Approved Methods for Industrial Wastewater Analysis)
- 40 CFR 400-424
- 40 CFR 425-471
- Appendix A – Definitions (PDF)
- Signatory Authority Confirm or Delegate (PDF)
- Signatory Requirements (PDF)
- Pre-Discharge Letter (PDF)
- Baseline Monitoring Report (PDF)
- Toxic and Prohibited Organic Chemical Management Plan (PDF)