Current through Register Vol. 56, No. 24, December 18, 2024
(a)
Water quality based effluent limitations shall control all pollutants or
pollutant parameters (either conventional, nonconventional, or toxic
pollutants, including whole effluent toxicity) which are or may be discharged
at a level which will cause, have the reasonable potential to cause, or
contribute to an excursion above the Surface Water Quality Standards.
(b) When determining whether a discharge
causes, has the reasonable potential to cause, or contributes to an instream
excursion above any Surface Water Quality Standard the Department shall
evaluate and consider existing controls on point and nonpoint sources of
pollution, the variability of the pollutant or pollutant parameter in the
effluent, the sensitivity of the test species to toxicity testing (when
evaluating whole effluent toxicity), and, where appropriate, the available
dilution of the effluent in the receiving water.
(c) The dilution of the effluent in the
receiving water shall be determined in accordance with
N.J.A.C.
7:9B-1.5(h).
(d) A separate determination of reasonable
potential shall be made for each pollutant or pollutant parameter of interest
(either conventional, nonconventional, or toxic pollutants, including acute and
chronic whole effluent toxicity) that is or may be discharged from the
facility. These determinations shall be based on a WLA or site specific
allocation.
(e) The discharge shall
be determined to cause an excursion above the Surface Water Quality Standards
if the maximum reported effluent concentration, considering the criteria
averaging period, for the pollutant of interest is greater than the WLA or the
site specific allocation for that pollutant.
(f) The discharge shall be determined to
contribute to an excursion above the Surface Water Quality Standards if the
maximum reported effluent concentration, considering the criteria averaging
period, for the pollutant of interest when considered collectively with other
discharges to the receiving water is greater than the WLA determined for that
pollutant.
(g) The discharge shall
be determined to have the reasonable potential to cause an excursion above the
Surface Water Quality Standards if the maximum projected effluent concentration
is greater than the WLA or site specific allocation determined for that
discharge for that pollutant or pollutant parameter. The maximum projected
effluent concentration shall be calculated in accordance with the USEPA TSD, as
amended and/or supplemented, unless the permittee demonstrates for a given
pollutant of interest that none of the methods in the TSD are applicable and
that an alternative statistical method more accurately estimates the maximum
projected effluent concentration.
(h) Where an effluent concentration is
directly caused by a documented facility upset, or other unusual event which
has been identified and appropriately remedied by the permittee, data collected
during the period of upset may be eliminated when making a determination of
reasonable potential. Data no longer representative of effluent quality because
of process modification or pollution prevention activities undertaken shall not
be used when making a determination of reasonable potential.
(k) When the Department determines that a
discharge does not cause, have reasonable potential to cause, or contribute to
an excursion above the water quality standards for a specific pollutant or
pollutant parameter; or that data are insufficient to make such a
determination:
1. Except as specified in
(k)1i through iii below, water quality based effluent limitations shall not be
required for that pollutant or pollutant parameter.
i. Where the discharge is in compliance with
an existing water quality based effluent limitation and the permittee provides
treatment for the limited pollutant or pollutant parameter, the reissued permit
shall include a water quality based effluent limitation for the affected
pollutant or pollutant parameter unless the permittee demonstrates to the
satisfaction of the Department that a water quality based limitation is no
longer required and that the existing effluent quality is anticipated to be
maintained.
ii. When the Department
determines in accordance with (k)1i above that a water quality based effluent
limitation is not required for the reissued permit, the fact sheet for the
reissued permit shall include a summary of effluent data for the pollutant or
pollutant parameter, a justification for eliminating the effluent limitation,
and a determination that eliminating the effluent limitation is not anticipated
to cause or contribute to an exceedance of the surface water quality
standards.
iii. When the Department
determines in accordance with (k)1i above that a water quality based effluent
limitation is not required for the reissued permit, the discharge permit shall
be reopened and modified to include water quality based effluent limitations if
the effluent quality changes so as to cause, contribute, or have the reasonable
potential to cause or contribute to an excursion above the Surface Water
Quality Standards.
iv. The
Department shall consider the following factors when making a determination
regarding reasonable potential for discharges with existing water quality based
effluent limitations:
(1) The permit
compliance history for the facility, including the compliance history for the
specific pollutant or pollutant parameter and any permit conditions related to
the pollutant or pollutant parameter;
(2) The reliability of the treatment process;
and
(3) The ratio between the
permitted or actual effluent flow and the base flow of the receiving
water;
2.
Effluent limitations other than water quality based limitations may be required
for the pollutant or pollutant parameter in accordance with
N.J.A.C.
7:14A-13.3; and
3. The Department may determine that
monitoring for specific pollutant or pollutant parameters shall be included in
the permit.
(l) When the Department is
unable to determine for one or more pollutants or pollutant parameters of
interest whether the discharge from a particular facility will cause, have the
reasonable potential to cause, or contribute to an excursion above a Surface
Water Quality Standard, the permit for that facility shall include effluent
monitoring requirements for each pollutant or pollutant parameter where such a
determination cannot be made. The discharge permit shall be reopened and
modified to include water quality based effluent limitations if subsequent
monitoring demonstrates that the discharge causes, contributes, or has the
reasonable potential to cause or contribute to an excursion above the Surface
Water Quality Standards.
(m) For a
facility that discharges any pollutant which is present in the process intake
water, the Department may, on a site specific basis, determine that the
discharge does not cause, have reasonable potential to cause, or contribute to
an excursion above the water quality standards in accordance with the
following:
3. The discharge shall meet the following
conditions:
i. The source for all of the
intake water shall be the receiving water body. Hydrologically connected
waterbodies may be determined to be the same waterbody if the water is
completely mixed within a reasonable distance of the outfall location and if
the chemical characteristics of the waterbodies are essentially identical.
Chemical characteristics may be evaluated on a parameter by parameter basis.
For discharges where the intake water is attributed to more than one source,
this condition may be applied to the proportion of the intake water
attributable to the receiving water or hydrologically connected
waterbody;
ii. The discharge shall
not contribute any additional mass of the pollutant of interest to the process
intake water. This determination shall be based on a statistically rigorous
analysis of intake water and outfall data that is representative of various
operating conditions and influences over time and demonstrates that there is no
significant difference at the 99th percent probability level between the intake
concentrations and loadings and the outfall concentrations and loadings. For a
DTW, this condition shall be deemed to be met if there is no significant
difference at the 99th percent probability level between the intake
concentrations and loadings of the public drinking water supply in the area
served and the effluent concentrations and loadings. Where the source water is
attributed to more than one water supply source, this condition may be applied
to the proportion of the source water attributable to the receiving water or
hydrologically connected waterbody;
iii. The discharger shall not chemically or
physically alter the intake water to cause an adverse impact to the receiving
stream for any pollutant of interest in the process intake water;
iv. The pollutant shall not accumulate at the
outfall location or at the edge of the mixing zone in such a way as to increase
the concentration of the pollutant. The Department may require submission of an
acceptable mixing zone study to satisfy this requirement; and
v. The timing and/or location of the
discharge shall not cause adverse impacts in the receiving waterbody that would
not have occurred if the pollutant had remained in the waterbody.
4. The permit shall include the
necessary monitoring conditions to ensure continuing compliance with the
conditions listed in (m)3 above.
5.
The discharge permit shall be reopened and modified to include water quality
based effluent limitations if subsequent monitoring demonstrates that the
discharge causes, contributes, or has the reasonable potential to cause or
contribute to an excursion above the surface water quality standards at
N.J.A.C. 7:9B.
6. The permit fact
sheet shall include a description of the treatment process and specific reasons
for making the determination that the discharge does not cause, have reasonable
potential to cause or contribute to an excursion above the water quality
standard for the pollutants or pollutant parameters subject to this
subsection.
7. For any pollutant or
pollutant parameter where the conditions listed in (m)3 above cannot be met,
reasonable potential shall be determined in accordance with (d) through (k)
above.
8. For site remediation
projects, reasonable potential shall be determined in accordance with this
subsection only for pollutants not subject to remediation.
