Pretreatment

Pretreatment Training

Categorical User Information Permit Writing Guidance 

The Federal and State Pretreatment Program gives regulatory authority for EPA, states, and municipal governments to control the discharge of industrial wastewater into municipal Wastewater Treatment Plants (WWTPs) or Publicly Owned Treatment Works (POTWs).   The objectives of the Pretreatment Program are to prevent pass-through, interference, or other adverse impacts to the POTW, its workers or the environment; to promote the beneficial reuse of biosolids, and to assure that all categorical pretreatment standards are met. DWR is the approval authority in this process, acting as compliance judgement and enforcement for failure to implement pretreatment programs that uphold state and federal regulatory standards. Pretreatment guidelines originate in Part IV of the NPDES Permit, as the POTW is the control authority, using Sewer Use Ordinances and Industrial User Permits as control mechanisms to maintain the pretreatment program objectives. Federal and Local limits exist to uphold the standards of the Clean Water Act. 

There are over 100 Active Pretreatment Programs in North Carolina, with more than 200 local POTW pretreatment coordinators and consultants. This fluxes with the state's pretreatment needs to reflect the current industrial picture, new programs are added and dropped as needed.

Significant Industrial Users (SIUs) are monitored using the pretreatment program. To be considered an SIU, the industry must:

 (A) Discharges an average of 25,000 gallons per day or more of process wastewater to the POTW excluding sanitary, noncontact cooling, and boiler blowdown wastewater;

(B) Contributes process wastewater that makes up five percent or more of the NPDES or nondischarge permitted flow limit or organic capacity of the POTW treatment plant. In this context, organic capacity refers to BOD, TSS, and ammonia;

(C) Is subject to categorical standards under 40 CFR 403.6 and 40 CFR Chapter I, Subpart N; 

(D) is designated as such by the control authority on the basis that the industrial user has a reasonable potential for adversely affecting the POTW's operation (including contributing to violations of the limitation and requirements of the NPDES or non-discharge permit or limiting the POTW's sludge disposal options) or for violating any pretreatment standard or requirement.

Please see 15A NCAC 02H .0903 (b)(30) for more information.

State Pretreatment Regulations

 The Rules are final and effective as of July 1, 2019.

• Pretreatment Rules:  15A NCAC 02H .0900

Q/A Silver Information: 

• PQL Q/A Silver Letter 

• Comp Guide Update for PQLs

DWR’s Pretreatment Staff received a set of questions related to the “March 2022 Silver Letter,” which contained general PQL Guidance. The Q/A letter contains detailed responses provided by DWR staff. The Division recommends that all pretreatment professionals review this STMP/LTMP/HWA development information. 

If you have any further questions that are not addressed in these documents, please contact the Pretreatment staff listed at the bottom of this webpage. 

PQL Letter

The North Carolina Pretreatment Consortium (NC-PC) has expressed the need for consistent minimum sampling limits that could be met by all State labs and provide the most appropriate data. In cooperation with NC-PC the Division has collaborated to provide a Practical Quantitation Limit (PQL) guidance letter. The Division believes that meeting the PQLs outlined in this letter will be achievable by most if not all labs across the State. The PQL letter provides a sampling sensitivity floor for common pollutants. The Division recognizes that some unique situations will require deviation from the guidelines presented in this document, for such cases we require that the program reach out to the Division and discuss possible changes. 

PQL Guidance Document

Sewer Use Ordinance (SUO) 

This Model SUO includes many revisions to address the 2011 revisions to NCAC 15A 02H .0900 - Local Pretreatment Programs.  

• Model Pretreatment SUO
• NC SUO Checklist
• Summary of SUO Comments
• Example Attorney's Statement

Federal Regulations

• General Pretreatment regulations: 40 CFR 403
• Categorical Pretreatment Regulations: 40 CFRs 400-471
• EPA Effluent Guidelines
  • EPA Dental Effluent Guidelines
  • Dental Amalgam Rule Guidance - 40 CFR 441
• EPA's NPDES Pretreatment Streamlining Rule Fact Sheets
• EPA CWA Analytical Methods for Per- and Polyfluorinated Alkyl PFAS Guidance
• NCDEQ Water Quality PFAS
  • NCDEQ Pretreatment PFAS forms and Guidance
• See the Other Downloads Webpage for more information 

Pretreatment Staff in Municipal Permitting Unit