Page 100 - California Stormwater Workshop Handouts

Industrial General Permit Fact Sheet

The CWA sets forth standards for TBELs based on the type of pollutant or the type
of facility/source involved. The CWA establishes two levels of pollution control for
existing sources. For the first level, existing sources that discharge pollutants
directly to receiving waters were initially subject to effluent limitations based on the
“best practicable control technology currently available” (BPT). (33 U.S.C. §
1314(b)(1)(B).) BPT applies to all pollutants. For the second level, existing sources
that discharge conventional pollutants are subject to effluent limitations based on the
“best conventional pollutant control technology” (BCT). (33 U.S.C. §1314(b)(4)(A);
see also 40 C.F.R. §401.16 (list of conventional pollutants).) Also for the second
level, other existing sources that discharge toxic pollutants or “nonconventional”
pollutants (“nonconventional” pollutants are pollutants that are neither “toxic” nor
“conventional”) are subject to effluent limitations based on “best available technology
economically achievable” (BAT). (33 U.S.C. §1311(b)(2)(A); see also 40 C.F.R.
§401.15 (list of toxic pollutants).) The factors to be considered in establishing the
levels of these control technologies are specified in section 304(b) of the CWA and
in U.S. EPA’s regulations at 40 C.F.R. §125.3.

When establishing ELGs for an industrial category, U.S. EPA evaluates a wide
variety of technical factors to determine BPT, BCT, and BAT. U.S. EPA considers
the specific factors of an industry such as pollutant sources, industrial processes,
and the size and scale of operations. U.S. EPA evaluates the specific treatment,
structural, and operational source control BMPs available to reduce or prevent
pollutants in the discharges. The costs of implementing BMPs to address these
factors are weighed against their effectiveness and ability to protect water quality.
Factors such as industry economic viability, economies of scale, and retrofit costs
are also considered.

To date, U.S. EPA has: (1) not promulgated storm water ELGs for most industrial
categories, (2) not established NELs within all ELGs that have been promulgated,
and (3) exempted certain types of facilities within an industrial category from
complying with established ELGs. The feedlot category (40 Code of Federal
Regulations part 412) provides an example of several of these points. In that
instance, U.S. EPA did not establish numeric effluent limitations but instead: (1)
established a narrative effluent limitation requiring retention of all feedlot-related
runoff from a 25-year, 24-hour storm, and (2) limited application of the ELG to
feedlots with a minimum number of animals. U.S. EPA also recently promulgated
ELGs for the "Construction and Development (C&D)" industry, which included,
among many other limitations, conditional numeric effluent limitations. Though the
NELs in these ELGs were later stayed by U.S. EPA, the ELGs exempted
construction sites of less than 30 acres from complying with the established numeric
effluent limitations.

40 Code of Federal Regulations, Chapter I, Subchapter N (“Subchapter N”), includes
over 40 separate industrial categories where the U.S. EPA has established ELGs for
new and existing industrial wastewater discharges to surface waters, discharges to
publicly owned treatment works (pre-treatment standards), and storm water
discharges to surface waters. Generally, U.S. EPA has focused its efforts on the
development of ELGs for larger industries and those industries with the greatest
potential to pollute. In total, the 40 categories for which ELGs have been

Order 2014-0057-DWQ 16