Current through August 26, 2024
Modifications to limitations specified in s.
NR 210.05(1) to
(3) may be approved as follows:
(1) INDUSTRIAL WASTES. For publicly owned
treatment facilities receiving effluent from certain categories of industries,
the applicable effluent limitations for BOD5 and SS as set forth in s.
NR 210.05(1) may be modified. The
limitations for BOD 5 and SS in s.
NR 210.05(1) may be adjusted upwards
provided that:
(a) The discharge of such
pollutants attributable to the industrial category will not be greater than
that allowed by applicable effluent limitations if such industrial category
were to discharge directly into the waters of the state; and
(b) The flow or loading of such pollutants
introduced by the industrial category exceeds 10% of the design flow or loading
of the publicly owned treatment works. When such an adjustment is made, the
limitations for BOD5 or SS in s.
NR 210.05(1) shall be adjusted
proportionally.
(2)
AERATED LAGOONS AND STABILIZATION PONDS. A variance for SS may be made in cases
where aerated lagoons or waste stabilization ponds are the principal treatment
processes. The SS limitation may be raised to a maximum of 60 mg/l for a 30-day
average. This variance is not applicable to polishing or holding ponds which
are preceded by other biological or physical/chemical treatment processes.
Note: See s.
NR 110.24 for design requirements of aerated lagoons and
stabilization ponds.
(3)
pH. The effluent pH limitations may be adjusted on a case-by-case basis if the
permittee or the owner can demonstrate that the limits need to be adjusted
based on the following:
(a) Inorganic
chemicals are not added as part of the treatment process; and
(b) In the case of a publicly owned treatment
works, contributions from industrial sources do not cause the pH of the
effluent to be less than 6.0 or greater than 9.0.
(4) CBOD5. Upon
request by the permittee, the parameter CBOD5 may be substituted for the
parameter BOD5, provided the following conditions are met:
(a) For treatment facilities with BOD5
limitations specified in s.
NR 210.05(1) (a), (2) (a), or
(3) (a), the permittee shall provide paired
sampling of the effluent for BOD5 and CBOD 5 for the months of January and
July. The sample frequency shall be at the same frequency as required by the
permit for BOD5 sampling. Additional sampling for nitrogen compounds (NH3-N,
NO3-N) or other sampling may also be required on a case-by-case
basis.
(b) For treatment facilities
with BOD5 limitations established in accordance with those specified in s.
NR 210.05(1) (e), (2) (g), or
(3) (f), the permittee shall provide paired
sampling of the effluent for BOD5, CBOD5, NH3-N and NO3-N. At the end of the
BOD5 test, an analysis of that BOD5 sample for NO3-N shall also be conducted.
1. This sampling shall be provided for the
months of January, February, July, and August at a frequency of 3 times weekly
for facilities with a design flowover 0.5 MGD and for those facilities which
discharge to trout waters or may impact trout waters.
2. This sampling shall be provided for the
months of January and July at a sample frequency as required by the permit for
BOD5 sampling, with a maximum of 3 times weekly for facilities with a design
flow less than 0.5 MGD.
(5) TREATMENT EQUIVALENT TO SECONDARY
TREATMENT.
(a) Facilities eligible for
treatment equivalent to secondary treatment as defined in s.
NR 210.03(6) shall provide the following
minimum level of effluent quality in terms of the parameters BOD5, SS, and pH.
All requirements for the specified parameters in subd. 1., 2. or 3. shall be
achieved except where provided for in sub. (2) or par. (b), (c), or (d).
1. The following effluent limits for BOD5
apply:
a. The 30-day average may not exceed 45
mg/l.
b. The 7-day average may not
exceed 65 mg/l.
c. The 30-day
average percent removal may not be less than 65%.
2. The following effluent limits for SS
apply: except where SS values have been adjusted in accordance with s. NR 210.07(2):
a. The 30-day average may not
exceed 45 mg/l.
b. The 7-day
average may not exceed 65 mg/l.
c.
The 30-day average percent removal may not be less than 65%.
3. The requirements of s.
NR 210.05(1)
(c) shall be met.
(b) Except as limited by par. (d) and subject
to EPA approval, the department may after notice and opportunity for public
comment, adjust the minimum levels of effluent quality set forth in par. (a) 1.
a., b., 2. a. and b. for trickling filter facilities and in par. (a) 1. a. and
b. for waste stabilization pond facilities to conform to the BOD5 and SS
effluent concentrations consistently achievable through proper operation and
maintenance by the median (50th percentile) facility in a representative sample
of facilities within a state or appropriate contiguous geographical area that
meet the definition of facilities eligible for treatment equivalent to
secondary treatment.
(c) Where
data are available to establish CBOD5 limitations for a treatment works subject
to this subsection, the department may substitute the parameter CBOD5 for the
parameter BOD5 in pars. (a) and (b), on a case-by-case basis.
1. The levels of CBOD5 effluent may not be
less stringent than the following:
a. The
30-day average may not exceed 40 mg/l.
b. The 7-day average may not exceed 60
mg/l.
c. The 30-day average percent
removal may not be less than 65%.
2. To apply for the CBOD5 variance, the
permittee shall provide the data outlined in sub. (4).
(d) Any permit adjustment made pursuant to
this section may not be any less stringent than the limitation required
pursuant to sub. (5) (a). The department shall require more stringent
limitations when adjusting permits if:
1. For
existing facilities the permitting authority determines that the 30-day average
and 7-day average BOD5 and SS effluent values that could be achievable through
proper operation and maintenance of the treatment works, based on an analysis
of the past performance of the treatment works, would enable the treatment
works to achieve more stringent limitations, or
2. For new facilities, the department
determines that the 30-day average and 7-day average BOD5 and SS effluent
values that could be achievable through proper operation and maintenance of the
treatment works, considering the design capability of the treatment process and
geographical and climatic conditions, would enable the treatment works to
achieve more stringent limitations.
(6) COMBINED SEWERS. Treatment works which
have a combined sewer system may not be capable of meeting the percentage
removal requirements established in sub. (5) (a) 1. c. and 2. c. or in s.
NR 210.05(1) (a) 3. and (b)
3. during wet weather where the treatment
works receive flows from combined sewers. For each treatment works, the
decision shall 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.
