Wastewater State Resources Locator
Industrial and commercial facilities may generate wastewater that can contain a variety of pollutants (metals, oil/grease, solids, etc.). These wastewaters are regulated by federal, state, and sometimes local government agencies under the federal Clean Water Act (CWA).
In general, the applicable regulations depend on whether your facility discharges directly to a receiving stream/river ("direct discharge") or to a publicly owned treatment works ("indirect discharge"). A general summary is provided below with links to more detailed information and points of contact in Arizona.
Direct discharges (i.e. facilities that discharge wastewaters directly into waters of the U.S.) are regulated in permits that specify limits using Best Practicable Control Technology Currently Available (BPT), Best Available Technology Economically Achievable (BAT), Best Conventional Pollutant Control Technology (BCT), and New Source Performance Standards (NSPS). Direct dischargers must obtain a individual or general permit under Arizona's Pollutant Discharge Elimination System program. The permit sets limits on the amount of pollutants that can be discharged to surface waters. Certain categories of industrial facilities, such as metal finishing, are regulated by national minimum limits have been established by U.S. EPA, which are referred to as Effluent Guidelines. The national limits are used as a baseline. Your permit writer may decide to apply more stringent limits based on factors such as receiving stream quality. When there are no national standards for an industrial category, it is up to the permit writer to establish site-specific technology based limits or determine other appropriate means to control the discharge. In most cases, some form of wastewater treatment (e.g., metal precipitation, pH adjustment, etc.) will be needed to meet permit requirements and discharge standards.
Certain categories of discharges that pose less risk to receiving waters (e.g., non-process cooling water or boiler blowdown) may be covered by a general permit that streamlines the permitting process. General permit rules for attaining coverage vary from state to state, but in general, a facility must complete a notice of intent (NOI) and abide by the conditions of the permit. Links to general permits for Arizona can be found below under Additional Resources.
For more information on direct discharge permits in Arizona, here is a list of state contacts.
Industrial and commercial facilities that discharge wastewater into a sewer system that leads to a municipal treatment plant, also known as Publicly Owned Treatment Works (POTW) are indirect dischargers. The POTW typically is owned by the local municipality or a regional board or sewer authority.
Indirect dischargers must meet national General Pretreatment Regulations (40 CFR 403), categorical pretreatment standards (e.g., metal finishing) if they exist as well as local POTW rules. When a pollutant is not specifically limited by pretreatment standards, it is up to the state or local regulatory agency to develop local limits or to determine other appropriate means to control its discharge.
The General Pretreatment Regulations prohibit:
To meet sewer discharge standards, you may need to install equipment such as an oil/water separator, pH adjustment, settling, and metals precipitation processes to prevent pollutants from being discharged to the sewer. This is referred to as "pretreatment."
- discharging any pollutant, including oil, that may upset or interfere with the sewage treatment processes or pass through the system untreated;
- discharging pollutants (e.g., solvents) that may cause a fire in the sewer system; and
- discharging pollutants such as sludge (e.g., grease, dirt) that may clog the sewer system.
For information on regulations affecting indirect discharges, contact your local POTW. Here is a list of state agency contacts. For additional information, you may also contact your EPA Regional contact for pretreatment.