On Dec. 5, 2002, the U.S. Environmental Protection Agency (EPA) authorized Arizona to implement its Arizona Pollutant Discharge Elimination System (AZPDES) program. AZPDES is the state program to carry out the National Pollutant Discharge Elimination System (NPDES), a federal regulatory program to control discharges of pollutants to surface waters of the United States. Arizona is one of 45 other states with this authority.

Pretreatment is an integral component of the federal NPDES permit program to protect the "waters of the U.S." Pretreatment is any biological, chemical, or physical treatment process applied to an industrial wastewater stream before it is mingled with sanitary wastewater and/or released into a sanitary sewer collection system for ultimate treatment at a centralized, (publicly-owned or privately-owned) treatment works (CTW).

Pretreatment protects:

• infrastructure investment (i.e., treatment plant and collection system pipes, pumps, valves and other appurtenances) from physical damage (i.e., corrosion from low pH,); protects the
• operation & maintenance (O&M) workers health and safety; and protects the
• centralized treatment plant operation process from upset, interference, and/or pass-through
• quality of the biosolids/sewage sludge produced by the centralized treatment works to meet the standards for beneficial reuse

For more information

AZPDES Index · Overview of the AZPDES Process · Individual Permits · General Permits · Stormwater · Pretreatment Program · Biosolids Sewage/Sludge · Forms & Guidance · FAQs · Other Programs