[Code of Federal Regulations]
[Title 40, Volume 21]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR133.103]
[Page 547-548]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 133_SECONDARY TREATMENT REGULATION--Table of Contents
Sec. 133.103 Special considerations.
(a) Combined sewers. Treatment works subject to this part may not
be capable of meeting the percentage removal requirements established
under Sec. Sec. 133.102(a)(3) and 133.102(b)(3), or Sec. Sec.
133.105(a)(3) and 133.105(b)(3) during wet weather where the treatment
works receive flows from combined sewers (i.e., sewers which are
designed to transport both storm water and sanitary sewage). For such
treatment works, the decision must be made on a case-by-case basis as to
whether any attainable percentage removal level can be defined, and if
so, what the level should be.
(b) Industrial wastes. For certain industrial categories, the
discharge to navigable waters of BOD5 and SS permitted under
sections 301(b)(1)(A)(i), (b)(2)(E) or 306 of the Act may be less
stringent than the values given in Sec. Sec. 133.102(a)(1),
133.102(a)(4)(i), 133.102(b)(1), 133.105(a)(1), 133.105(b)(1) and
133.105(e)(1)(i). In cases when wastes would be introduced from such an
industrial category into a publicly owned treatment works, the values
for BOD5 and SS in Sec. Sec. 133.102(a)(1),
133.102(a)(4)(i), 133.102(b)(1), 133.105(a)(1), 133.105(b)(1), and
133.105(e)(1)(i) may be adjusted upwards provided that: (1) The
permitted discharge of such pollutants, attributable to the industrial
category, would not be greater than that which would be permitted under
sections 301(b)(1)(A)(i), 301(b)(2)(E) or 306 of the Act if such
industrial category were to discharge directly into the navigable
waters, and (2) the flow or loading of such pollutants introduced by the
industrial category exceeds 10 percent of the design flow or loading of
the publicly owned treatment works. When such an adjustment is made, the
values for BOD5 or SS in Sec. Sec. 133.102(a)(2),
133.102(a)(4)(ii), Sec. 133.102(b)(2), 133.105(a)(2), 133.105(b)(2),
and 133.105(e)(1)(ii) should be adjusted proportionately.
(c) Waste stabilization ponds. The Regional Administrator, or, if
appropriate, State Director subject to EPA approval, is authorized to
adjust the minimum levels of effluent quality set forth in Sec. 133.105
(b)(1), (b)(2), and (b)(3) for treatment works subject to this part, to
conform to the SS concentrations achievable with waste stabilization
ponds, provided that: (1) Waste stablization ponds are the principal
process used for secondary treatment; and (2) operation and maintenance
data indicate that the SS values specified in Sec. 133.105 (b)(1),
(b)(2), and (b)(3) cannot be achieved. The term ``SS concentrations
achievable with waste stabilization ponds'' means a SS value, determined
by the Regional Administrator, or, if appropriate, State Director
subject to EPA approval, which is equal to the effluent concentration
achieved 90 percent of the time within a State or appropriate contiguous
geographical area by waste stabilization ponds that are achieving the
levels of effluent quality for BOD5 specified in Sec.
133.105(a)(1). [cf. 43 FR 55279].
(d) Less concentrated influent wastewater for separate sewers. The
Regional Administrator or, if appropriate, State Director is authorized
to substitute either a lower percent removal requirement or a mass
loading limit for the percent removal requirements set forth in
Sec. Sec. 133.102(a)(3), 133.102(a)(4)(iii), 133.102(b)(3),
102.105(a)(3), 133.105(b)(3) and 133.105(e)(1)(iii) provided that the
permittee satisfactorily demonstrates that: (1) The treatment works is
consistently meeting, or will consistently meet, its permit effluent
concentration limits but its percent removal requirements cannot be met
due to less concentrated influent wastewater, (2) to meet the percent
removal requirements, the treatment works would have to achieve
significantly more stringent limitations than would otherwise be
required by the concentration-based standards, and (3) the less
concentrated influent wastewater is not the result of excessive I/I. The
determination of whether the less concentrated wastewater is the result
of
[[Page 548]]
excessive I/I will use the definition of excessive I/I in 40 CFR
35.2005(b)(16) plus the additional criterion that inflow is nonexcessive
if the total flow to the POTW (i.e., wastewater plus inflow plus
infiltration) is less than 275 gallons per capita per day.
(e) Less concentrated influent wastewater for combined sewers during
dry weather. The Regional Administrator or, if appropriate, the State
Director is authorized to substitute either a lower percent removal
requirement or a mass loading limit for the percent removal requirements
set forth in Sec. Sec. 133.102(a)(3), 133.102(a)(4)(iii),
133.102(b)(3), 133.105(a)(3), 133.105(b)(3) and 133.105(e)(1)(iii)
provided that the permittee satisfactorily demonstrates that: (1) The
treatment works is consistently meeting, or will consistently meet, its
permit effluent concentration limits, but the percent removal
requirements cannot be met due to less concentrated influent wastewater;
(2) to meet the percent removal requirements, the treatment works would
have to achieve significantly more stringent effluent concentrations
than would otherwise be required by the concentration-based standards;
and (3) the less concentrated influent wastewater does not result from
either excessive infiltration or clear water industrial discharges
during dry weather periods. The determination of whether the less
concentrated wastewater results from excessive infiltration is discussed
in 40 CFR 35.2005(b)(28), plus the additional criterion that either 40
gallons per capita per day (gpcd) or 1500 gallons per inch diameter per
mile of sewer (gpdim) may be used as the threshold value for that
portion of the dry weather base flow attributed to infiltration. If the
less concentrated influent wastewater is the result of clear water
industrial discharges, then the treatment works must control such
discharges pursuant to 40 CFR part 403.
[49 FR 37006, Sept. 20, 1984, as amended at 50 FR 23387, June 3, 1985;
50 FR 36880, Sept. 10, 1985; 54 FR 4228, Jan. 27, 1989]