Question of the Week: Comparing CWA Control Technologies: BPT, BCT, BAT, BADCT
Q. If I am subject to National Pollutant Discharge Elimination System (NPDES) permitting requirements under the Clean Water Act, which of the many control technology acronyms am I subject to?
A. Short Answer: Check your permit, do what it says.
Long Answer: The type of water treatment controls you need depend on several factors, including the type of pollutants you discharge, and whether you are a new source or an existing source.
What Pollutants Are You Discharging?
The NPDES establishes effluent limitations for three different categories of pollutants. A detailed list of common pollutants under each category can be found at 40 CFR 122, Appendix D. In broad terms, the three categories are:
- Conventional Pollutants – including biochemical oxygen demand, total suspended solids, fecal coliform, pH, oil, and grease
- Non-conventional Pollutants – including nutrients and phosphorous
- Toxic Pollutants – including organics and metals
New Source or Old?
There are four levels of control technology authorized under the NPDES; from least to most stringent they are:
- BPT – Best practicable control technology currently available
- BAT – Best available control technology economically achievable
- BCT – Best conventional pollutant control technology
- BADCT – Best available demonstrated control technology
BPT is the minimum standard for existing point sources of conventional, toxic, or non-conventional pollutants. If local water quality standards require more treatment, then the permitting authority may require you to install BCT (for conventional pollutants) or BAT (for toxic or non-conventional pollutants).
New point sources are subject to BADCT for all categories of water pollution.
Categorical Standards
In addition to discharge permits and generic control technologies, the EPA has created a set of technology-based effluent guidelines and standards for over 50 industrial categories (called Categorical Standards, or Industry-Specific Standards). These Categorical Standards are codified in 40 CFR Subchapter N (specifically Parts 405 through 471).
If your site falls in one of these industrial categories, then the effluent guidelines and standards in Subchapter N automatically become part of your NPDES permit.
If your site is not included in these industrial categories, then it is up to the permit-issuer to establish a site-specific technology-based limit. While the EPA does not have a strict list of what exact controls fall under each of the four levels, the Agency does have some guidance at http://water.epa.gov/scitech/wastetech/guide/questions_index.cfm to help regulated facilities.
Find a Post
Recent Posts
Compliance Archives
Download Our Latest Whitepaper
Use this guide to spot which tanks and substances are regulated under EPA's Underground Storage Tank program, and which are excluded as of October 2018.
By submitting your phone number, you agree to receive recurring marketing and training text messages. Consent to receive text messages is not required for any purchases. Text STOP at any time to cancel. Message and data rates may apply. View our Terms & Conditions and Privacy Policy.