PERMFILE103819

• Permit No: C1980001
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: 3.7 APPENDIX 3.7-D Part 2
• Media Type: D
• Archive: No

Rationale, Page 4
,: Pittsburgh and Midway Coal
PER.~l17 NU2IBER: GO-0032635
C. DISCUSSION
1. Total Suspended Solids - E.P.A, promulgated BAT regulations on
November 26, 19B2, but BCT (Best Conventional Pollutant Control
Technology) is being reserved pending finalization of EPA's BC'f cost
methodology. Therefore, BPT shall apply. The SES limitation is not
applicable pursuant to Section 10.1.3(3) of the State Regulations for
Effluent Limitations, which states that when EPA has effluent
limitations for an industry, the federal limitations shall take
precedence.
2. Total Iron - The WQS for this facility is 1.0 mg l1. Since discharges
will be intermittent and normally due to storm runoff when high
dilution is available, this Limitation is not appropriate.
Therefore, the limit shall be based on federal effluent standards.
The BPT limitations for total iron are identical to those applicable
under BAT. Because federal regulations dictate that BAT will
prevail, BAI' is the basis for the total iron limitation in this
permit.
3. Settleable Solids - The recently promulgated 8AT regulations set
alternate limitations for precipitation events. Where a discharge
occurs due to a precipitation event, TSS and total iron limitations
may not apply at the discretion of the permittee. Evidence of
precipitation will be required for the permittee to claim exemption
from TSS and total iron. Precipitation - caused discharges are
regulated two ways: '
a) For precipitation events less than or equal [o the facility's
10-year, 24-hour event, settleable solids and pk (in addition to
oil and grease) limits nay apply.
b) For precipitation events greater than [he 10-year, 24-hour event,
only pH and oil and grease limitations may appl}~.
Settleable solids monitoring will be required
precipitation-caused discharges regardless of
with monitoring frequencies as .specified in t
necessary because the size of a precipitation
from the settleable solids limitation can not
after the applicable 24-hour period.
of ~1
volur..a (in accordance
he permit). This is
event and/or exemption
be determined until
Pursuant to CFR 434.63(c), the burden of proof is caith the operator.
In order to claim an exC'!pcion from the settleable solids limitation,
docusen[aCion shall be submitted with [he discharLe monitoring report
(D`1R) which indicates that rainfall (or equivalent snowmelc volume)
greater than the 10-year, 24-Dour event has occurred. In the case of
facilities whicft`h:n•c remote multiple ou[fa11s it may 'te undesirable
[o read individual rain Itauges daily during a lengthy storm.
Therefore, the permittee shall have [he option of waiving the
exemption from the settleable solids limitation lregardless of actual
rainfall amount). Compliance with [he settleable solids limit will
be expected unless documentation has been submitted which supports an
exemption.