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NC DEQ »   About »   Divisions »   Water Resources »   Water Quality Permitting »   Municipal: NPDES, Pretreatment and Collection System »   Pretreatment »   Headworks Analysis

Headworks Analysis

The Headworks Analysis (HWA) calculates the flow and pollutant treatment capacity of a wastewater treatment plant (WWTP). It incorporate the WWTP design criteria as well as environmental criteria to protect the receiving stream (NC Water Quality Standards or NPDES limits), the WWTP biomass (inhibition criteria), and the sludge disposal site (40 CFR 503 land application or incineration standards).

The Allocation Table compares the flow and pollutant loads permitted to the WWTP's significant industrial users (SIUs) to the allowable WWTP influent loads from the HWA to ensure the WWTP will not be overloaded.

HWA Training Materials

  • HWA Workshop Slides.  These slides (Tab 2 of the workshop materials) include detailed discussions on calculations, definitions, references, decision making and explanations.

    • Individual Workshop Materials: Tabs 1, 3A, 3B, 3C, 3D, Calculator

Spreadsheets for the HWA

  • Headworks Analysis Spreadsheet with linked Allocation Table and Headworks Addendum for Sludge Loading (HASL) Worksheet (February 2008)
  • Calculator (April 2017)
  • Separate Allocation Table (not linked to the HWA Spreadsheet)
  • Generic Data Summary Spreadsheet
  • Removal Rate Spreadsheet
  • Uncontrollable Mass Balance Spreadsheet

Guidance Documents for HWA

  • HWA Design Memos (February 2007, December 2007 and December 2008)
  • What items to submit with your POTW's HWA (February 2009)
  • February 2009 HWA Numbers
  • Removal Rate Determination Guidance (2004)
  • Headworks Addendum for Sludge Loading (HASL) (2004 modifications)
  • Sludge conversion formulas
  • Typical Problems with HWA

Organics HWA and Related Guidance Documents

  • Organics Headworks Analysis Spreadsheet
  • Organics Headworks Analysis Guidance

Pharmaceutical HWA and Related Guidance Documents

  • Pharmaceutical Organics Headworks Analysis Spreadsheet
  • Pharmaceutical OHWA Guidance

Pretreatment

  • Categorical User Information
  • Comprehensive Guide
  • Headworks Analysis
  • Industrial Waste Survey
  • Other Downloads
  • Mercury Guidance
  • Annual Report Guidance
  • Permit Writing Guidance
  • Training

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https://deq.nc.gov/about/divisions/water-resources/water-resources-permit-guidance/pretreatment-guide/headworks-analysis