DISCLAIMER

The full text of certain NPDES permits and the associated fact sheets has been made available to 

provide online access to this public information. EPA is making permits and fact sheets available 

electronically to provide convenient access for interested public parties and as a reference for 

permit writers. The ownership of these documents lies with the permitting authority, typically a 

State with an authorized NPDES program. 

While EPA makes every effort to ensure that this web site remains current and contains the final 

version of the active permit, we cannot guarantee it is so. For example, there may be some delay 

in posting modifications made after a permit is issued. Also note that not all active permits are 

currently available electronically. Only permits and fact sheets for which the full text has been 

provided to Headquarters by the permitting authority may be made available. Headquarters has 

requested the full text only for permits as they are issued or reissued, beginning November 1, 

2002. 

Please contact the appropriate permitting authority (either a State or EPA Regional office) prior to 

acting on this information to ensure you have the most up-to-date permit and/or fact sheet. EPA 

recognizes the official version of a permit or fact sheet to be the version designated as such and 

appropriately stored by the respective permitting authority. 

The documents are gathered from all permitting authorities, and all documents thus obtained are 

made available electronically, with no screening for completeness or quality. Thus, availability 

on the website does not constitute endorsement by EPA. 
FACT SHEET 

AND 

PERMIT RATIONALE 

Rationale 

Page 1 of 44 

Permit No. SC0001333 

Voridian August 23, 2004 

NPDES Permit No. SC0001333 

Permitting Engineer: Melanie Kastler 

Facility Rating: Major (EPA review required) 

Minor (EPA review may be required; see below) 

Permit application included in Appendix A. 

Facility Address: P.O. Box 1782, Columbia SC 29202 (see map, Appendix E) 

County: Calhoun 

Watershed: Basin 02 (Saluda-Edisto River Basin) 

Issuance (New) Reissuance Modification 

If this application is for a new facility or expansion of an existing facility, an 

antidegradation review may be required per the requirements of R.61-68.D. 

Facility Description (include SIC code): This facility manufactures organic 

intermediates and plastic material, and compounds and extrudes specialty plastics. 

SIC Codes are 2865, 2821 and 3087. 

Does this permit contain more than one outfall, including internal outfalls? Yes 

Outfalls will be listed in Section III of this rationale with a general description of the 

discharge, treatment system, stream flows and other pertinent information about each 

outfall. 

→Is any discharge subject to any of the Primary Industry Categories identified in 

R.61-9.122, Appendix A as listed at right? Yes (If yes, EPA review required.) 

Indicate category(ies) applicable and Regulations governing the discharge: OCPSF, 40 CFR 410 

Auto and other laundries 

Coal mining 

Coil coating 

Copper forming 

Electrical and electronic components 

Electroplating 

Explosives manufacturing 

Foundries 

Gum and wood chemicals 

Inorganic chemicals manufacturing 

Iron and steel manufacturing 

Leather tanning and finishing 

Mechanical products manufacturing 

Nonferrous metal manufacturing 

Ore mining 

Paint and ink formulation 

Pesticides 

Petroleum refining 

Photographic equipment and supplies 

Plastics processing 

Printing and publishing 

Rubber processing 

Soap and detergent manufacturing 

Textile Mills 

Timber Products Processing 

Primary Industry Categories 

Adhesives and sealants 

Aluminum forming 

Battery manufacturing 

Organic chemicals manufacturing 

Pharmaceutical preparations 

Plastic and synthetic materials manufacturing 

Porcelain enameling 

Pulp and paper mills 

Steam electric power plants 

Receiving Water: Internal Outfalls: 01A, 01B (proposed), 01D, 01E, 01F, 01G and Outfall 001- Congaree River 

Receiving Water Classification (see R.61-69 for water classifications): Fresh Water 

→Does any discharge(s) have the potential to affect waters in another state? No (If yes, EPA review required.) 

Is any discharge to Impaired Waters?: Yes 

If Yes, list the monitoring station number and parameter(s) causing impairment: Based on DHEC’s assessment of ambient 

monitoring data, C-074 is impaired for copper and fecal coliform, C-007 is impaired for mercury and copper and Lake Marion 

is impaired for phosphorus at SC-008. 

→Average Discharge Flow from outfall with largest average flow: (Qd) (MGD): 92.31 (from permit application; including 

increase in production) (EPA review required for any average discharge exceeding 0.5 MGD) 

→Is this permit for a Federal facility with a daily average flow greater than 0.05 MGD (from all sources)? No (If yes, EPA 

review required.) 

Data from Discharge Monitoring Reports (DMRs) and NPDES permit application (including all subsequent data presented) 

from 1/31/00-1/31/04 has been used to evaluate permit limitations. 
Rationale 

Page 2 of 44 

Permit No. SC0001333 

I. GENERAL INFORMATION 

A. The effluent from this facility may be subject to the requirements of any of the following regulations: R.61-9.125, 129, 

133, and 403; 40 CFR Part 136; Subchapter N (40 CFR Parts 400 through 402 and 404 through 471); R.61-9.503, 

R.61-9.504 and R.61-9.505. 

B. Authority: This permit is written in accordance with applicable laws and regulations including, but not limited to, 

Regulation 61-9, Regulation 61-68, Pollution Control Act and Clean Water Act. 

C. Under R.61-9.124.8 (Fact Sheet), a fact sheet shall be prepared for every draft permit for a major NPDES facility or 

activity, for every Class I sludge management facility, for every NPDES draft permit that incorporates a variance or 

requires an explanation under section 124.56(b), and for every draft permit which the Department finds is the subject of 

wide-spread public interest or raises major issues. 

D. The conclusions noted in the Rationale establish proposed effluent limitations and permit requirements addressed in 

R.61-9.122.43 (Establishing Permit Conditions), R.61-9.122.44 (Establishing Limitations, Standards and other permit 

conditions) and other appropriate sections of R.61-9. 

II. RATIONALE GUIDANCE PROCEDURES 

A. The receiving waterbody 7Q10, annual average flow or other critical flow condition at the discharge point, and 7Q10, 

annual average flow, or other critical flow condition at the boundary of the source water protection area above a 

proposed or existing drinking water intake (if applicable) are determined by the SCDHEC’s Wasteload Allocation 

Section. The 7Q10, Annual Average Flow or other critical flow conditions are based on information published or 

verified by the USGS, an estimate extrapolation from published or verified USGS data or from data provided by the 

permittee. These flows may be adjusted by the Wasteload Allocation Section to account for existing water 

withdrawals that impact the flow. The 7Q10 (or 30Q5 if provided by the applicant), annual average flow at the 

discharge point, or other critical flow condition or 7Q10 (or 30Q5 if provided by the applicant), annual average flow 

or other critical flow condition at the boundary of the SWP area for a proposed or existing drinking water intake will 

be used to determine dilution factors, as appropriate, in accordance with R.61-68.C.4.a & 4.b for aquatic life, human 

health, and organoleptic effects respectively. 

B. Water and organism consumption and drinking water MCL data will be evaluated as human health values when 

calculating dilution factors. “The Department may, after Notice of Intent included in a notice of a proposed NPDES 

permit in accordance with Regulation 61-9.124.10, determine that drinking water MCLs or W/O shall not apply to 

discharges to those waterbodies where there is: no potential to affect an existing or proposed drinking water source 

and no state-approved source water protection area.” For permitting purposes, a proposed drinking water source is 

one for which a complete permit application, including plans and specifications for the intake, is on file with the 

Department at the time of consideration of an NPDES permit application for a discharge that will affect or has the 

potential to affect the drinking water source.” See R.61-68.E.12.c(5). The Department defines the source water 

protection (SWP) area to be the primary SWP area delineated by the Source-Water Assessment and Protection 

(SWAP) Program initiated by the EPA and required by the states to identify SWP areas to protect drinking water 

sources. Using the procedure described in the document entitled, “Determination of the Primary and Secondary 

Source-Water Protection Areas for Selected Surface-Water Public-Supply Systems in South Carolina, 1999,” USGS 

Water Resource Investigations Report 00-4097, the primary SWP area for a drinking water intake is the area which 

encompasses all 14-digit Hydrologic Unit Code (HUC) basins that adjoin streams, tributaries, and reservoirs between 

an intake and the upstream 10-percent exceedance, 24-hour travel distance (TOT10). The entire basin above a drinking 

water intake has been designated as the SWP area where the drainage area is equal to or less than one HUC basin or is 

estimated to have less than 24-hours of instream travel time between the intake and the HUC basin in the headwaters 

of the drainage basin. 
Rationale 

Page 3 of 44 

Permit No. SC0001333 

C. Application of numeric criteria to protect human health: If separate numeric criteria are given for organism 

consumption, water and organism consumption (W/O), and drinking water Maximum Contaminant Levels (MCLs), 

they shall be applied as appropriate. The most stringent of the criteria shall be applied to protect the existing and 

classified uses of the waters of the State. See R.61-68.E.12.b(1). 

D. Numeric criteria have been established in R.61-68 based on organoleptic data (prevention of undesirable taste and 

odor). For those substances which have aquatic life and/or human health numeric criteria and organoleptic 

numeric criteria, the most stringent of the three shall be used for derivation of permit effluent limitations. See 

R.61-68.E.11. 

E. Sampling Frequency: Samples and measurements taken for the purpose of monitoring shall be representative of 

the monitored activity. Monitoring results must be conducted according to test procedures approved under 40 

CFR Part 136, unless other test procedures have been specified in the permit (R.61-9.122.41). Typically 

requirements to report monitoring results shall be established on a case-by-case basis with a frequency dependent 

on the nature and effect of the discharge but in no case less than once a year (R.61-9.122.44) 

F. Compliance Schedules: 

1. A person issued an NPDES permit by the Department who is not in compliance with applicable effluent standards 

and limitations or other requirements contained therein at the time the permit is issued, shall be required to achieve 

compliance within a period of time as set forth by the Department, with effluent standards and limitations, with water 

quality standards, or with specific requirements or conditions set by the Department. The Department shall require 

compliance with terms and conditions of the permit in the shortest reasonable period of time as determined thereby or 

within a time schedule for compliance which shall be specified in the issued permit. 

2. If a time schedule for compliance specified in an NPDES permit which is established by the Department, exceeds 

nine (9) months, the time schedule shall provide for interim dates of achievement for compliance with certain 

applicable terms and conditions of the permit. (R.61-9.122.47) 

G. Procedure for establishing effluent limitations: 

1. Effluent limits (mass and concentration) for Five day Biochemical Oxygen Demand (BOD5), Ultimate Oxygen 

Demand (UOD), Dissolved Oxygen (DO), Total Ammonia Nitrogen (as N), and Nutrients are established by the 

Wasteload Allocation (WLA) Section, with consideration given to technology-based limitations. 

a. Five day Biochemical Oxygen Demand BOD5, Ultimate Oxygen Demand UOD, Dissolved Oxygen DO: 

Effluent limits for conventional oxygen demanding constituents (BOD5, UOD and DO) are established to 

protect in-stream water quality and uses, while utilizing a portion of the assimilative capacity of the receiving 

water. The ability of a water body to assimilate oxygen-demanding substances is a function of its physical 

and chemical characteristics above and below the discharge point. Various mathematical techniques, called 

models, have been developed to estimate this capacity. The Department follows the procedures as outlined in 

the “State/EPA Region IV Agreement on the Development of Wasteload Allocations/Total Maximum Daily 

Loads and NPDES Permit Limitations” dated October 30, 1991 (as updated) for determining the assimilative 

capacity of a given water body. Mathematical models such as QUAL2E and QUAL2E-UNCAS are used in 

accordance with “Enhanced Stream Water Quality Models QUAL2E and QUAL2E-UNCAS: Documentation 

and Users Manual” (EPA/600/3-87/007; dated May 1987) as updated. BOD5 and UOD values determined 

from modeling results will be used in permitting as monthly average derived limits (Cwla). Daily maximum 

derived limits will typically be determined by multiplying the monthly average value by two. 

For facilities subject to effluent guidelines limitations or other technology-based limitations, BOD5 will also 

be evaluated in accordance with the applicable industrial categorical guidelines. These parameters will be 

identified in Part III of this rationale when they are applicable to the permit. 
Rationale 

Page 4 of 44 

Permit No. SC0001333 

b. Total Ammonia Nitrogen (as N): 

Ammonia limitations based on oxygen demand will be determined from modeling information as described 

above. These values will be used as monthly average derived limits and a daily maximum will typically be 

determined by multiplying the monthly average derived limit by two. These values will be compared with the 

ammonia water quality criteria for protection of aquatic life from Regulation 61-68, Attachment 3 and any 

categorical limitations. The more stringent of the limitations will be imposed. Calculations for aquatic life 

criteria and other wasteload recommendations will be shown later in Part III of this rationale when ammonia 

is a pollutant of concern. 

c. Discharges of Nutrients: 

In order to protect and maintain lakes and other waters of the State, consideration is given to the control of 

nutrients reaching the waters of the State. Therefore, in accordance with regulation R.61-68.E.9, the 

Department controls the nutrients as prescribed below. Nutrient limitations will be determined from the best 

available information and/or modeling performed by the Wasteload Allocation Section to meet these water 

quality standards. 

i. Discharges of nutrients from all sources, including point and nonpoint, to waters of the State shall be 

prohibited or limited if the discharge would result in or if the waters experience growths of microscopic 

or macroscopic vegetation such that the water quality standards would be violated or the existing or 

classified uses of the waters would be impaired. Loading of nutrients shall be addressed on an individual 

basis as necessary to ensure compliance with the narrative and numeric criteria. 

ii. Numeric nutrient criteria for lakes are based on an ecoregional approach which takes into account the 

geographic location of the lakes within the State and are listed below. These numeric criteria are 

applicable to lakes of 40 acres or more. Lakes of less than 40 acres will continue to be protected by the 

narrative criteria. 

1. for the Blue Ridge Mountains ecoregion of the State, total phosphorus shall not exceed 0.02 mg/l, 

chlorophyll a shall not exceed 10 ug/l, and total nitrogen shall not exceed 0.35 mg/l 

2. for the Piedmont and Southeastern Plains ecoregions of the State, total phosphorus shall not exceed 

0.06 mg/l, chlorophyll a shall not exceed 40 ug/l, and total nitrogen shall not exceed 1.50 mg/l 

3. for the Middle Atlantic Coastal Plains ecoregion of the State, total phosphorus shall not exceed 0.09 

mg/l, chlorophyll a shall not exceed 40 ug/l, and total nitrogen shall not exceed 1.50 mg/l. 

iii. In evaluating the effects of nutrients upon the quality of lakes and other waters of the State, the 

Department may consider, but not be limited to, such factors as the hydrology and morphometry of the 

waterbody, the existing and projected trophic state, characteristics of the loadings, and other control 

mechanisms in order to protect the existing and classified uses of the waters. 

iv. The Department shall take appropriate action, to include, but not limited to: establishing numeric effluent 

limitations in permits, establishing Total Maximum Daily Loads, establishing waste load allocations, and 

establishing load allocations for nutrients to ensure that the lakes attain and maintain the above narrative 

and numeric criteria and other applicable water quality standards. 

v. The criteria specific to lakes shall be applicable to all portions of the lake. For this purpose, the 

Department shall define the applicable area to be that area covered when measured at full pool elevation. 
Rationale 

Page 5 of 44 

Permit No. SC0001333 

2. Effluent concentration limits (Cefflim) for parameters other than the parameters listed inG.1.aabove are established using the following procedures: 

Q7Q10 7Q10 or other critical flow condition of the receiving water at the discharge point in mgd. (may 

require adjustment for withdrawals) 

AAFd Average Annual Flow (AAF) or other critical flow condition of the receiving water at the discharge 

point in mgd. (may require adjustment for withdrawals) 

Q7Q10i 7Q10 or other critical flow condition of the receiving water at the SWP Area boundary in mgd. 

AAFi Average Annual Flow (AAF) of the receiving water at the SWP Area boundary in mgd. 

Qd Long term average discharge flow in mgd. 

a. Determine dilution factors: 

The following information is to be used (where applicable) for establishing effluent concentration limits: 

DF1: Dilution factor based on 7Q10 or other critical flow condition of the receiving water at the 

discharge point (Q7Q10). This dilution factor is used to determine the derived limits for protection 

of the following aquatic life and human health concerns for the reasons indicated: 

i. Aquatic Life (see R.61-68.C.4.a(1)). Protection of aquatic life on a short-term basis is 

needed at the point where aquatic organisms become exposed to the discharge. 

ii. Human Health – Organism Consumption for parameters identified as non-carcinogens per 

R.61-68.C.4.b(1). Protection for human health on a short-term basis for consumption of 

aquatic organisms is needed at the point the aquatic organisms become exposed to the 

discharge. 

⎛ Q Qd ⎞

⎟

⎟

7Q10 + ⎜

⎜

⎝

DF1 = Qd ⎠

DF2: Dilution factor, at the discharge point, based on the Average Annual Flow of the receiving water 

at the discharge point (AAFd). This dilution factor is used to determine the derived limits for 

protection of the following human health and organoleptic concerns for the reasons indicated: 

i. Human Health – Organism Consumption for parameters identified as carcinogens per R.61-

68.C.4.b(1). Protection for human health on a long-term basis to prevent cancer due to 

consumption of aquatic organisms is needed at the point the aquatic organisms become 

exposed to the discharge where it enters the receiving water. 

ii. Organoleptic effects per R.61-68.C.4.b(1). Protection for taste and odor issues related to the 

discharge is needed at the point where the discharge enters the receiving water. 

⎛ ⎞

⎟

⎟

AAFd + Qd ⎜

⎜

⎝

DF2 = Qd ⎠

DF3: Dilution factor based on the 7Q10 or other critical flow condition at the source water protection 

area boundary for protection of a proposed or existing water intake downstream of the discharge 

(Q7Q10i). This dilution factor is used to determine the derived limits for protection of the 

following human health concerns for the reasons indicated: 
Rationale 

Page 6 of 44 

Permit No. SC0001333 

i. Human Health – Water and Organism Consumption for parameters identified as noncarcinogens per R.61-68.C.4.b(1) and E.12.c(5) to protect for short-term health effects when 

the discharge is above any drinking water intake. Protection of human health relative to 

drinking the water from the waterbody and consuming aquatic organisms from the same 

waterbody is provided by this criterion, but drinking the water withdrawn from the 

waterbody may require a potentially higher level of protection in terms of applicable dilution 

than consumption of organisms. In addition, to satisfy the requirements of R.61-68.C.10(a), 

the Department has determined that dilution at the boundary of the Source Water Protection 

area will protect the drinking water intake to meet this requirement. 

For discharges affecting the primary SWP area, dilution will be determined using the largest 

TOT10 flow along the SWP area boundary upstream of the drinking water intake of concern. 

If multiple drinking water intakes are present below the discharge, the SWP area of the 

intake closest to the discharge will be protected. If the entire basin is designated as the SWP 

area, the boundary will be the TOT10 at the beginning of the basin, even if it is outside the 

State boundaries (e.g. North Carolina). 

ii. Human Health - Drinking Water Maximum Contaminant Level (MCL) for parameters 

identified as non-carcinogens per R.61-68.C.4.b(1) and E.12.c(5) to protect for short-term 

health effects when the discharge is above any drinking water intake. Protection of human 

health relative to drinking the water from the waterbody after conventional treatment per 

R.61-68.G.8 and 10 is provided by this criterion. In addition, to satisfy the requirements of 

R.61-68.C.10(a), the Department has determined that dilution at the boundary of the Source 

Water Protection area will protect the drinking water intake to meet this requirement. 

For discharges affecting the primary SWP area, dilution will be determined using the largest 

TOT10 flow along the SWP area boundary upstream of the drinking water intake of concern. 

If multiple drinking water intakes are present below the discharge, the SWP area of the 

intake closest to the discharge will be protected. If the entire basin is designated as the SWP 

area, the boundary will be the TOT10 at the beginning of the basin, even if it is outside the 

State boundaries (e.g. North Carolina). 

⎛ Q Qd ⎞

⎟

⎟ 7Q10i + ⎜

⎜

⎝

DF3 = Qd ⎠

DF4: Dilution factor based on the Average Annual Flow at the source water protection area boundary 

for protection of a proposed or existing water intake downstream of the discharge (AAFi ) 

This dilution factor is used to determine the derived limits for protection of the following human 

health concerns for the reasons indicated: 

i. Human Health–Water and Organism Consumption for parameters identified as carcinogens 

per R.61-68.C.4.b(1) and E.12.c(5) to protect for long-term health effects due to cancer when 

the discharge is above any drinking water intake. Protection of human health relative to 

drinking the water from the waterbody and consuming aquatic organisms from the same 

waterbody is provided by this criterion, but drinking the water withdrawn from the 

waterbody may require a potentially higher level of protection in terms of applicable dilution 

than consumption of organisms. In addition, to satisfy the requirements of R.61-68.C.10(a), 

the Department has determined that dilution at the boundary of the Source Water Protection 

area will protect the drinking water intake to meet this requirement. 
Rationale 

Page 7 of 44 

Permit No. SC0001333 

For discharges affecting the primary SWP area, dilution will be determined using the largest 

TOT10 flow along the SWP area boundary upstream of the drinking water intake of concern. 

If multiple drinking water intakes are present below the discharge, the SWP area of the 

intake closest to the discharge will be protected. If the entire basin is designated as the SWP 

area, the boundary will be the TOT10 at the beginning of the basin, even if it is outside the 

State boundaries (e.g. North Carolina). 

ii. Human Health - Drinking Water Maximum Contaminant Level (MCL) for parameters 

identified as carcinogens per R.61-68.C.4.b(1) and E.12.c(5) to protect for long-term health 

effects due to cancer when the discharge is above any drinking water intake. Protection of 

human health relative to drinking the water from the waterbody and consuming aquatic 

organisms from the same waterbody is provided by this criterion, but drinking the water 

withdrawn from the waterbody may require a potentially higher level of protection in terms 

of applicable dilution than consumption of organisms. In addition, to satisfy the 

requirements of R.61-68.C.10(a), the Department has determined that dilution at the 

boundary of the Source Water Protection area will protect the drinking water intake to meet 

this requirement. 

For discharges affecting the primary SWP area, dilution will be determined using the largest 

TOT10 flow along the SWP area boundary upstream of the drinking water intake of concern. 

If multiple drinking water intakes are present below the discharge, the SWP area of the 

intake closest to the discharge will be protected. If the entire basin is designated as the SWP 

area, the boundary will be the TOT10 at the beginning of the basin, even if it is outside the 

State boundaries (e.g. North Carolina). 

⎛ AAFi + Qd ⎞

⎟

⎟ DF4 ⎜

⎜

⎝

= Qd ⎠

b. Determine monthly average derived limits using the following procedures: 

WQSal Freshwater Standard (based on an established criteria or other published data per R.61-68) for 

protection of Aquatic Life; may be a CCC or CMC as defined below 

WQSorg Standard (based on an established criteria or other published data per R.61-68), for protection of 

Human Health – Organism Consumption 

WQSwo Standard (based on an established criteria or other published data per R.61-68), for protection of 

Human Health – Water & Organism Consumption. Applicable only if any portion of the mixing 

zone for this discharge is in a state-approved source water protection area for a proposed or 

existing water intake downstream of the wastewater treatment plant discharge point. 

WQSmcl Standard (based on an established criteria or other published data per R.61-68), for Drinking 

Water MCL (Maximum Contaminant Level). Applicable only if any portion of the mixing zone 

for this discharge is in a state-approved source water protection area for a proposed or existing 

water intake downstream of the wastewater treatment plant discharge point. 

WQSol: Standard (based on an established criteria or other published data per R.61-68), based on 

Organoleptic Data. 

Caqlife Concentration limit derived from aquatic life data 

CHH Concentration limit derived from human health data as determined from organism (Corg), 

water/organism (Cwo)and MCL (Cmcl) data 

Col Concentration limit derived from organoleptic data 
Rationale 

Page 8 of 44 

Permit No. SC0001333 

Cb Background concentration of the concerned parameter in mg/l determined from ambient 

monitoring data or data provided by applicant. The 90th percentile of ambient monitoring data 

for aquatic life protection for the parameters identified in the Appendix (Water Quality Numeric 

Criteria) to Regulation 61-68 from the last 3 years, or whatever is available if less than 3 years, 

will typically be used per the procedures used for 303(d) listing. The median value of ambient 

monitoring data for human health protection for the parameters identified in the Appendix (Water 

Quality Numeric Criteria) to Regulation 61-68 from the last 3 years, or whatever is available if 

less than 3 years, will typically be used per the procedures used for 303(d) listing. The 

background concentration is assumed to be zero (0) in the absence of actual data based on 

Departmental guidance and EPA recommendation. 

i. Determine the derived limit for protection of Aquatic Life (Caqlife) 

1. The following guidelines apply to determining aquatic life limits: 

a. Typically, the Criterion Maximum Concentration (CMC) is applied as a daily maximum 

derived limit and the Criterion Continuous Concentration (CCC) is applied as a monthly 

average derived limit, after consideration of dilution and background concentrations. 

Exceptions exist based on EPA criteria and are indicated for specific parameters. The CMC 

and CCC for specific metals will be adjusted using the procedures in 60 FR 22229, “Water 

Quality Standards; Establishment of Numeric Criteria for Priority Toxic Pollutants; States’ 

Compliance-Revision of Metals Criteria,” May 4, 1995 and the “Technical Guidance on 

Interpretation and Implementation of Aquatic Life Metals Criteria,” Oct. 1, 1993 and applied 

as a daily maximum and monthly average, respectively, after consideration of dilution and 

background concentrations. 

b. If only a CMC exists for a particular parameter, a daily maximum derived permit limit only 

(no monthly average) will be set using that value, after consideration of dilution and 

background concentrations. If only a CCC is given, it will be used as a monthly average 

derived limit and the daily maximum derived limit will be two (2) times the value obtained 

for the monthly average based on a simplified statistical procedure for determining permit 

limits recommended in Section 5.4.2 of the US EPA’s “Technical Support Document for 

Water Quality-based Toxics Control”, EPA/505/2-90-001, March 1991 (hereafter known as 

the TSD) considering an assumed coefficient of variation (CV) of 0.6 and 95th percentile 

occurrence probability. 

c. If only an acute toxicity effect concentration for a number of species for a particular 

pollutant is given as a LC50, the lowest concentration should be divided by an acute-tochronic ratio (ACR) of 10 and a sensitivity factor of 3.3, for an acceptable instream 

concentration in order to protect against chronic toxicity effects (from R.61-68.E.14.a(1)). 

Other acute toxicity data will be handled similarly. The value obtained from this calculation 

will be used as a monthly average derived limit after consideration of dilution and 

background concentrations. The daily maximum will be two (2) times the value obtained for 

the monthly average based on a simplified statistical procedure for determining permit limits 

recommended in Section 5.4.2 of the TSD considering an assumed coefficient of variation 

(CV) of 0.6 and 95th percentile occurrence probability. 
Rationale 

Page 9 of 44 

Permit No. SC0001333 

d. If a chronic toxicity effect concentration for a number of species for a particular pollutant is 

given as a no observed effect concentration (NOEC), the lowest concentration should be 

divided by a sensitivity factor of 3.3 in order to protect against chronic toxicity to the most 

sensitive species (from R.61-68.E.14.a(2)). Other chronic toxicity data will be handled 

similarly. The value obtained from this calculation will be used as a monthly average derived 

limit after consideration of dilution and background concentrations. The daily maximum 

will be two (2) times the value obtained for the monthly average based on a simplified 

statistical procedure for determining permit limits recommended in Section 5.4.2 of the TSD 

considering an assumed coefficient of variation (CV) of 0.6 and 95th percentile occurrence 

probability. 

e. If both acute and chronic data are available for a particular pollutant, monthly average 

derived limit will be calculated as in c and d above for each acute and chronic, respectively. 

The more stringent of the monthly average derived limits will be the monthly average 

derived limit used after consideration of dilution and background concentrations. The daily 

maximum will be two (2) times the value obtained for the monthly average based on a 

simplified statistical procedure for determining permit limits recommended in Section 5.4.2 

of the TSD considering an assumed coefficient of variation (CV) of 0.6 and 95th percentile 

occurrence probability. 

2. Consider the background concentration (Cb) of the parameter of concern. If the background 

concentration is equal to or greater than the applicable standard (WQS, as defined above) for the 

parameter of concern, then the derived concentration limit (Caqlife) for that parameter and for the 

protection of that standard, is established equal to the standard (WQS). An exception exists 

where the naturally occurring instream concentration for a substance is higher than the derived 

permit effluent limitation. In those situations, the Department may establish permit effluent 

limitations (Cefflim) at a level higher than the derived limit, but no higher than the natural 

background concentration. In such cases, the Department may require biological instream 

monitoring and/or whole effluent toxicity (WET) testing (See R.61-68.E.12.c.2). i.e. 

If Cb is not based on naturally occurring concentrations and 

C b ≥ WQS 

Then 

Caqlife = WQS . 

If Cb is based on naturally occurring concentrations and 

C b ≥ WQS 

Then 

C aqlife < C eff lim ≤ C b . 

Otherwise, the limits are established as described in Item 3 or 4 below. 
Rationale 

Page 10 of 44 

Permit No. SC0001333 

3. For the parameters listed in Table A below, Regulation R.61-68 Section E.12 provides for the use 

of the EPA Office of Water Policy and "Technical Guidance on Interpretation and 

Implementation of Aquatic Life Metals Criteria", October 1, 1993. A subsequent revision 

published in the Federal Register (60 FR 22229) on May 4, 1995 updated the data in the original 

report. See R.61-68 Attachment 1 “Conversion Factors for Dissolved Metals” and Attachment 2 

“Parameter for Calculating Freshwater Dissolved Metals Criteria that are Hardness-Dependent”. 

The following equations and constants will be used to calculate aquatic life metals limits based 

on the Federal Register data. The water quality standard for these metals (CCC or CMC) will 

also be adjusted using this approach in accordance with Regulation 61-68.E.12.d(3) for 

evaluation of ambient water quality. 

TSSe Effluent Total Suspended Solids (TSS) concentration in mg/l from actual or proposed 

monthly average permit limits. 

TSSb Background or in-stream Total Suspended Solids (TSS) concentration. The background 

TSS is assumed to be 1 mg/l in the absence of actual instream data based on the 5th 

percentile of ambient TSS data on South Carolina waterbodies from 1993-2000. 

TSSavg Average in-stream (mixed) TSS concentration. 

CF Conversion factor considered most relevant in fresh water for aquatic life as defined by 

EPA in dissolved metals documents for each listed metal 

H Hardness in mg/l of CaCO3. Per R.61-68.E.12.a(3), the CMC and CCC are based on a 

hardness of 25 mg/l if the ambient hardness is less than 25 mg/l. Concentrations of 

hardness less than 400 mg/l may be based on the actual mixed stream hardness if it is 

greater than 25 mg/l and less than 400 mg/l and 400 mg/l if the ambient hardness is 

greater than 400 mg/l. The background hardness is assumed to be 25 mg/l in the absence 

of actual stream data. Mixed stream hardness may be determined using effluent 

hardness and actual stream hardness. 

Kpo Metal-specific equilibrium constant 

a Metal-specific constant 

Kp Linear partition coefficient 

Kpb Linear partition coefficient for use in the derivation of an adjusted water quality standard 

Cd Dissolved phase metal concentration 

Ct Total metal concentration 

S a constant to represent the CCC or CMC 

The following table lists the values for the constants, the CCC and CMC, and the recommended 

values of the conversion factors (CF). 

 Table A 

Parameter kpo a CMC CFCMC CCC CFCCC 

(μg/l) (μg/l) 

Arsenic 0.48 x 106 -0.7286 340 100 150 100 

Cadmium 4.00 x 106 -1.1307 0.95* 100* 0.83* 96.7* 

Chromium+3 3.36 x 106 -0.9304 580* 31.6 28* 86 

Chromium+6 3.36 x 106 -0.9304 16 98.2 11 96.2 

Copper 1.04 x 106 -0.7436 3.8* 96 2.9* 96 

Lead 0.31 x 106 -0.1856 14* 99.3* 0.54* 99.3* 

Mercury 2.91 x 106 -1.1356 1.6 85 0.91 85 

Nickel 0.49 x 106 -0.5719 150* 99.8 16* 99.7 

Zinc 1.25 x 106 -0.7038 37* 97.8 37* 98.6 
Rationale 

Page 11 of 44 

Permit No. SC0001333 

* The equations for calculating the CCC, CMC, and conversion factors are given in the Appendix 

to Regulation 61-68 and Attachments 1and 2 for each parameter. The values given for the CMC 

and CCC and CF in the table are based on 25 milligrams/liter (mg/l) hardness (as expressed as 

CaCO3). 

From Technical Guidance Manual for Performing Waste Load Allocations Book II, Rivers and 

Streams, EPA/440/484/022: 

S = CMC or CCC 

Cd = S ×CF

To determine the adjusted water quality standard (WQSal), use S and the equation for Cd above 

and the following equations: 

K = K a ( TSS ) p× b b po 

) − 1 K 10 6 }

To determine the effluent limit (Caqlife) , use S and the equation for Cd above and the following 

equations: 

WQSal = C d ×{ + ( pb ×TSSb ×

(Q 

Q 

×TSSb ( Q ×TSS ) + ) d e 7Q10 TSSavg = Qd + 7Q10 

K K a ( TSSavg = × ) p po 

) − {1 10 6 }

Once Ct has been calculated, it is multiplied by DF1 and background concentrations are 

accounted for to obtain the monthly average derived limit (Caqlife): 

(K C t = C d × + p×TSSavg ×

⎪

⎨

⎧

C ⎪

⎬ Q ⎫ ⎛ 7Q10 ⎜

⎜

⎞

⎟

⎟ Caqlife = (Ct × DF1 ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭

4. For all other parameters not included in paragraph 3, Table A, monthly average derived limits 

(Caqlife) for aquatic life protection are calculated as follows: 

⎪

⎨

⎧

C ⎪

⎬ Q ⎫ 7Q10 ⎛

⎜

⎜

⎞

⎟

⎟ Caqlife = (DF1 ×WQSal ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭

ii. Determine derived limit for protection of Human Health 

1. The following guidelines apply to determining human health limits: 
Rationale 

Page 12 of 44 

Permit No. SC0001333 

a. The human health criterion given by Regulation 61-68 will be applied as a monthly average 

derived limit after consideration of dilution and background concentrations (CHH-avg). 

Exceptions exist based on EPA criteria and are indicated for specific parameters. No limits 

on human health based on water and organism consumption or drinking water MCLs will be 

imposed if there is no potential to affect a drinking water intake or source water protection 

area (i.e., if there is no intake downstream of the discharge). 

b. The daily maximum permit limit will be determined from the monthly average value from (a) 

above and a multiplier (M) determined using a statistical procedure recommended in Section 

5.5 using average = 95th percentile from Table 5-3 in the TSD. The permitted or proposed 

number of samples per month (n) is used with the coefficient of variation (CV) to determine 

M. CV is assumed to be 0.6 as a default value if information is not known. 

( Z σ − 5. 0 σ2 m )

M = e 

( Zaσ n − 5. 0 σ 2 ) n e 

where: 

2 ⎞

σ

2 = ln⎜

⎜

⎛ CV 

+1⎟

⎟ n

σ

⎝ n ⎠

2 2 = ln(CV +1)

Std. Deviation

CV = coefficient of variation of the effluent concentration = 

Mean 

n = the number of effluent samples per month (where frequency is less than 

1/month, n =1) 

zm = the percentile exceedance probability for the daily maximum permit limit 

(=2.326 for 99th percentile basis) 

za = the percentile exceedance probability for the monthly average permit limit 

(=1.645 for 95th percentile basis) 

CHH-max = M * CHH-avg 

2. Consider the background concentration (Cb) of the parameter of concern. If the background 

concentration is equal to or greater than the applicable standard (WQS, as defined above) for the 

parameter of concern, then the derived concentration limit (CHHe) for that parameter and for the 

protection of that standard, is established equal to the standard (WQS). An exception exists 

where the naturally occurring instream concentration for a substance is higher than the derived 

permit effluent limitation. In those situations, the Department may establish permit effluent 

limitations (Cefflim) at a level higher than the derived limit, but no higher than the natural 

background concentration. In such cases, the Department may require biological instream 

monitoring and/or whole effluent toxicity (WET) testing (See R.61-68.E.12.c.3). 

If Cb is not based on naturally occurring concentrations and 

C b ≥ WQS 

Then 

CHH = WQS . 

If Cb is based on naturally occurring concentrations and 

C b ≥ WQS 
Rationale 

Page 13 of 44 

Permit No. SC0001333 

Then 

C HH < C eff lim ≤ C . b 

Otherwise, the limits are established as described in Items 3-6 below. 

3. Human Health – Organism Consumption (Corg). 

a. For Carcinogens 

The Monthly Average is calculated as follows: 

⎪

⎬

⎫

C

⎪

⎨

⎧ ⎛

⎜

⎜

⎞

⎟

⎟

AAFd Corg = (DF2 ×WQSorg ) − b ×

Qd ⎪⎭ ⎪⎩ ⎝ ⎠

b. For Non-carcinogens 

The Monthly Average is calculated as follows: 

⎪

⎨

⎧

C ⎪

⎬ Q ⎫ 7Q10 ⎛

⎜

⎜

⎞

⎟

⎟ Corg = (DF1 ×WQSorg ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭

4. Human Health – Water and Organism Consumption (Cwo) 

a. For Carcinogens 

The Monthly Average is calculated as follows: 

⎪

⎨

⎧

C ⎪

⎬ ⎛ ⎫ ⎜

⎜

⎞

⎟

⎟

AAFi Cwo = (DF4 ×WQSwo ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭

b. For Non-carcinogens 

The Monthly Average is calculated as follows: 

⎪

⎨

⎧

C ⎪

⎬ Q ⎫ 7Q10i ⎛

⎜

⎜

⎞

⎟

⎟ Cwo = (DF3 ×WQSwo ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭

5. Human Health – Drinking Water Maximum Contaminant Level (MCL) (Cmcl). 

a. For Carcinogens 

The Monthly Average is calculated as follows: 

⎪

⎨

⎧

C ⎪

⎬ ⎛ ⎫ ⎜

⎜

⎞

⎟

⎟

AAFi 

Qd 

Cmcl = (DF4 ×WQSmcl ) − b × ⎪⎩ ⎪ ⎝ ⎠⎭

b. For Non-carcinogens 

The Monthly Average is calculated as follows: 

⎪

⎨

⎧

C Q7Q10i ⎪

⎬ ⎛ ⎫ ⎜

⎜

⎞

⎟

⎟ Cmcl = (DF3 ×WQSmcl ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭
Rationale 

Page 14 of 44 

Permit No. SC0001333 

6. Organoleptic criteria (Col). 

The Monthly Average is calculated as follows: 

C

⎪

⎨

⎧ ⎪

⎬ ⎛ ⎫ ⎜

⎜

⎞

⎟

⎟

AAFd Col = (DF2 ×WQSol ) − b × ⎪⎩ Qd ⎪ ⎝ ⎠⎭

c. Determine most stringent of applicable data using the monthly average derived limits determined or 

calculated above: 

Cefflim = minimum of (Caqlife, Corg, Cwo, Cmcl, Col, Cwla) 

Note: If a CMC is present for the parameter of concern, the daily maximum derived limit obtained from 

that calculation must also be considered under reasonable potential. 

d. Determine whether the discharge causes, has the reasonable potential to cause or contributes to a water 

quality violation. 

Regulation 61-9.122.44(d)(1)(i) states: “Limitations must control all pollutants or pollutant parameters 

(either conventional, nonconventional, or toxic pollutants) which the Department determines are or may 

be discharged at a level which will cause, have the reasonable potential to cause, or contribute to an 

excursion above any State water quality standard, including State narrative criteria for water quality.” 

When determining whether a discharge causes, has the reasonable potential to cause or contributes to an 

instream excursion, the Department will use procedures which account for controls on point and nonpoint 

sources of pollution, the variability of the pollutant in the effluent, the sensitivity of the species to toxicity 

testing (when evaluating whole effluent toxicity), and, where appropriate, the dilution of the effluent in 

the receiving water (R.61-9.122.44(d)(1)(ii)). 

Based on the above statements, there are three scenarios when limitations are required, as follows: 

i. When data provided by the permit applicant indicates values greater than the proposed limitation 

derived above, that discharge will cause an excursion above a narrative or numeric water quality 

criterion. 

ii. A discharge will be determined to contribute to an excursion of a water quality criterion when the 

waterbody is impaired (e.g., on the 303(d) list) for the parameter of concern and that parameter is also 

being discharged at levels above the water quality criterion. 

iii. Reasonable potential to cause a water quality violation is determined using the following information: 

Chapter 3 of the TSD provides information for determining the need for permit limits based on the 

regulatory statements above. A statistical procedure is also presented in Chapter 3 for use in 

determining reasonable potential from effluent data. Other statistical methods may be used as well to 

evaluate data sets. “National Guidance for the Permitting, Monitoring, and Enforcement of Water 

Quality-Based Effluent Limitations Set Below Analytical Detection/Quantitation Level” draft dated 

March 22, 1994, offers recommendations on how to interpret data below detection capabilities to 

make a reasonable potential analysis. 

All pollutants given in a wasteload allocation or an effluent limitation guideline will be limited in the 

permit. 
Rationale 

Page 15 of 44 

Permit No. SC0001333 

When effluent data consists of non-quantifiable/non-detectable values or when no effluent data is 

available, other factors and information are considered to determine reasonable potential. In 

situations where a pollutant is known to be present in the wastestream (due to production data or 

other information), we know it is being discharged and has the potential to impact even though it may 

not be quantifiable. The fact that it is present will be enough information to say reasonable potential 

exists for that pollutant. Therefore, a reasonable potential decision is based on various data and 

information, and not just non-quantifiable/non-detectable data. Consideration is given to existing 

data, dilution in the waterbody, type of receiving water, designated use, type of industry/wastestream, 

ambient data, history of compliance, and history of toxic impact. If any source of information 

indicates reasonable potential to cause, or contribute to an exceedance of the water quality standard, a 

water quality limit will be developed. 

Note: The result of the following calculations may indicate that reasonable potential does not 

exist. However, as stated above, other information may “override” this numerical 

determination to justify the need for a limit. 

1. The procedure for determining reasonable potential from actual effluent data is explained in Box 

3-2 on page 53 of the TSD. Multiplying factors are determined from Table 3-2 at a 95% 

confidence level and 95% probability in Section 3.3.2. The following describes the procedures 

used for determining reasonable potential for chemical-specific parameters and WET, under 

certain circumstances. More information on determining reasonable potential for WET is given 

in Item 2 below. 

Step 1: Data Analysis: The statistical calculations involved in the “Reasonable Potential” analysis 

require discrete numerical data. The following describes how the effluent data will be used 

in determining reasonable potential. 

Actual analytical results should be used whenever possible. Results less than detection and 

quantification should be used as follows: 

a. If the permittee reports results below the practical quantitation limit (PQL) (as defined 

by the permit), then the reported “less than PQL” value for a given sample is generally 

assumed to be zero. 

b. If the permittee uses a detection/quantification level that is greater than the PQL, then 

the reported “less than” value for a given sample is generally assumed to be a discrete 

value equal to the detection/quantification level used by the permittee. 

c. If the reported data consists of both discrete and non-discrete values and/or the data is 

reported using varying detection/quantification levels, then, generally, a combination of 

the above two approaches is used, or the data is evaluated in a manner that is most 

appropriate for that data set. 

Note: For information on the acceptable analytical methods and PQLs please refer to 

NPDES permit application attachment titled “Practical Quantitation Limits (PQL) 

and Approved Test Methods.” 
Rationale 

Page 16 of 44 

Permit No. SC0001333 

Step 2: Using data from the permit application, other data supplied by the applicant and/or Discharge 

Monitoring Report (DMR) data, determine the total number of observations (n) for a 

particular set of effluent data and determine the highest value (Cmax) from that data set. For 

the monthly average comparison, the data set will include monthly average results and n will 

be the number of months in which they sampled in the time period being evaluated. When 

there is also a daily maximum comparison, the data set will include daily maximum results 

and n will be the total number of samples in the time period being evaluated. Individual 

results may not necessarily be used in the calculation. 

Step 3: Determine the coefficient of variation (CV) for the data set. For a data set where n>10, the 

CV is calculated as standard deviation divided by mean for the data set being evaluated. For 

data set where n<10, the CV is estimated to equal 0.6. For less than 10 items of data, the 

uncertainty in the CV is too large to calculate a standard deviation or mean with sufficient 

confidence. 

CV = 6.0 for n < 10 

σ CV = for n > 10 

μ

where: σ = Standard Deviation of the samples 

μ = Mean of the samples 

Step 4: Determine the appropriate multiplying factor (MF) from either Table 3-2 or using the 

formulae in Section 3.3.2 of the TSD. 

a. Determine the percentile represented by the highest concentration in the sample data. 

1/ n p = (1− Confidence Level ) n 

where: pn = Percentile represented by the highest concentration in the data 

n = number of samples 

Confidence Level = 0.95 i.e. 95% 

b. Determine the multiplying factor (MF), which is the relationship between the 

percentile described above (Cp) and the selected upper bound of the lognormal 

effluent distribution, which in this case will be the 95th percentile (C95). 

MF = C95 = e( Z95σ + 5.0 σ2 ) 

(Z pσ + 5.0 σ2

C )

p e 

where: Z95 is the standardized Z-score for the 95th percentile of the standardized normal 

distribution = 1.645 

Zp is the standardized Z-score for the p

th percentile of the standardized normal 

distribution.(determined in (b) above) 

Note: The values of Z-scores are listed in tables for the normal distribution. If using 

Microsoft® Excel, this can be calculated using the NORMSINV function. 

2 2 σ = ln(CV +1)

σ = ln(CV 2 +1)
Rationale 

Page 17 of 44 

Permit No. SC0001333 

Step 5: Multiply the highest value from the data set (Cmax) by the multiplying factor (MF) 

determined in Step 4 to obtain the maximum receiving water concentration (RWC). 

RWC = C max × MF

Step 6: RWC ≤ Derived monthly average limit (Cefflim) implies that a reasonable potential does not 

exist. 

RWC > Derived monthly average limit (Cefflim) implies that a reasonable potential exists. 

Note: If a CMC is available for a given parameter, the daily maximum value will be used in 

addition to the monthly average for a determination of reasonable potential. 

2. Reasonable potential for WET will be determined from numerical data using one of the following 

procedures: 

a. When the effluent data is given as LC50 and/or NOEC values: 

Step 1: Convert the given LC50 and NOEC values to toxic units, TUa for acute data and TUc for 

chronic data, respectively, using the following formulae: 

100 TU a = LC50 

100 TU c = NOEC 

Step 2: Using DMR data or other data provided by the applicant, determine the total number of 

observations (n) for a particular set of effluent data and determine the highest value (TUa, 

max or TUc, max) from that data set. 

Step 3: Determine the coefficient of variation (CV) for the data set. For a data set where n>10, 

the CV is calculated as standard deviation divided by mean. For data set where n<10, 

the CV is estimated to equal 0.6. For less than 10 items of data, the uncertainty in the 

CV is too large to calculate a standard deviation or mean with sufficient confidence. 

Step 4: Determine the appropriate multiplying factor (MF) from either Table 3-2 or using the 

formulae in Section 3.3.2. (see iii.1, Step 4 above). 

Step 5: Multiply the highest value of TUa, max or TUc, max from the data set by the multiplying 

factor (MF) determined in Step 4 and the dilution at the edge of the mixing zone (the test 

concentration obtained from mixing zone modeling or demonstration) to obtain the 

maximum receiving water concentration (RWC) 

 RWC for Acute Toxicity = [TUa, max * MF * conc. at MZ boundary]

 RWC for Chronic Toxicity = [TUc, max * MF * conc. at MZ boundary] 

Step 6: RWC for Acute Toxicity ≤ 0.3TUa implies that a reasonable potential does not exist 

 RWC for Acute Toxicity > 0.3TUa implies that a reasonable potential exists 

RWC for Chronic Toxicity ≤ 1.0TUc implies that a reasonable potential does not exist 

RWC for Chronic Toxicity >1.0TUc implies that a reasonable potential exists 
Rationale 

Page 18 of 44 

Permit No. SC0001333 

b. When pass/fail effluent data only is available and all tests have passed, the Department may 

be able to determine reasonable potential in a manner similar to Item 1 above assuming the 

test concentration of interest is greater than or equal to the concentration at which the 

permittee has tested. If the permittee has not tested at or above the test concentration of 

interest, the Department cannot say that reasonable potential does not exist, unless perhaps, 

circumstances related to the discharge have changed. If any failures exist in the data set that 

cannot be removed, reasonable potential may be determined to exist. 

c. Where WET results are given as percent effect, the procedures in Item 1, Steps 1-6 above are 

followed. In the case of WET in these circumstances, Clim will be 25% for the monthly 

average and 40% for the maximum since these are the limits for WET testing as a percent 

effect preferred by the Department. 

e. Determine permit limits based on water quality data 

i. When the discharge is determined to cause or have the reasonable potential to cause a water quality 

violation for a particular parameter, except WET, limits are needed. Limits are typically based on the 

monthly average values calculated from G.2.c above. However, daily maximum values may be 

evaluated under reasonable potential under certain circumstances. If reasonable potential exists for 

either average or maximum derived limits, limits on both are needed per Regulation 61-9.122.45(d). 

1. If the monthly average from G.2.c is based on a wasteload allocation for oxygen-demanding 

pollutants and nutrients and 

a. no CMC exists, the water quality limits are 

monthly average = Cwla

daily maximum = 2 x Cwla 

b. a CMC exists (for ammonia), the water quality limits are 

monthly average = Cwla 

and the daily maximum is the most stringent of 

daily maximum = 2 x Cwla 

or 

daily maximum = Caqlife-dm using CMC as WQS in G.2.b.i.3 or 4 

2. If the monthly average from G.2.c is based on aquatic life data given as a CCC, if the discharge 

causes, has the reasonable potential to cause or contributes to a water quality violation based on 

the monthly average and a CMC also exists for the parameter, the water quality limits are 

monthly average = Caqlife-ma using CCC as WQS in G.2.b.i.3 or 4 

daily maximum = Caqlife-dm using CMC as WQS in G.2.b.i.3 or 4 

3. If the monthly average from G.2.c is based on aquatic life data given as a CCC and if the 

discharge does not cause, have the reasonable potential to cause or contribute to a water quality 

violation for that monthly average, but a CMC also exists for the parameter and the discharge 

causes, has the reasonable potential to cause or contributes to a water quality violation based on 

that daily maximum, the water quality limits are 

monthly average = Caqlife-ma using CCC as WQS in G.2.b.i.3 or 4 

daily maximum = Caqlife-dm using CMC as WQS in G.2.b.i.3 or 4 
Rationale 

Page 19 of 44 

Permit No. SC0001333 

4. If the monthly average from G.2.c is based on aquatic life data given as a CCC or other acute or 

chronic data and no CMC exists for the parameter, the water quality limits are 

monthly average = Caqlife

daily maximum = 2 x Caqlife

5. If no CMC exists and the monthly average from G.2.c is based on human health (organism, w/o, 

MCL) data, the water quality limits are 

monthly average = CHH 

daily maximum = M x CHH using the calculation for M from G.2.b.ii.1.b 

6. If a CMC exists and the monthly average from G.2.c is based on human health (organism, w/o, 

MCL) data, the water quality limits will be 

monthly average = CHH 

and the daily maximum will be the most stringent of 

daily maximum = M x CHH using the calculation for M from G.2.b.ii.1.b 

or 

daily maximum = Caqlife-dm using CMC as WQS in G.2.b.i.3 or 4 

7. If no CMC exists and the monthly average from G.2.c is based on organoleptic data, the water 

quality limits are 

monthly average = Col 

daily maximum = M x Col using the calculation for M from G.2.b.ii.1.b 

8. If a CMC exists and the monthly average from G.2.c is based on organoleptic data, the water 

quality limits will be 

monthly average = Col 

and the daily maximum will be the most stringent of 

daily maximum = M x Col using the calculation for M from G.2.b.ii.1.b 

or 

daily maximum = Caqlife-dm using CMC as WQS in G.2.b.i.3 or 4 

9. If only a CMC exists, then the water quality limits will be no monthly average and 

daily maximum = Caqlife-dm using CMC as WQS in G.2.b.i.3 or 4 

ii. If the discharge is determined to cause or have the reasonable potential to cause a water quality 

violation for WET, permit limitations will be explained in the rationale for that parameter. 

iii. If the discharge is determined to contribute to an existing water quality violation, monthly average 

and daily maximum limits will be set giving no credit for dilution of the receiving water (end-of-pipe 

limits) based on the criteria in Item 1 above. 
Rationale 

Page 20 of 44 

Permit No. SC0001333 

f. Consider Effluent Limitations Guidelines (ELG or Categorical guidelines) 

The more stringent of the effluent limitations guidelines average and maximum derived limits and water 

quality-derived average and maximum limits determined in e above shall be used as permit limits, unless 

other information indicates more stringent limits are needed as indicated in Section H at the end of this 

section. Categorical limitations based on mass may first be converted to concentration using the long 

term average flow of the discharge for both the monthly average and daily maximum calculations, unless 

the applicable guidelines require use of an alternate flow. 

1. For Effluent guidelines based on production, limits will be calculated as follows: 

ELG lim = ∑(ELGprod )(ELG) where 

ELGlim: the mass limit, in lbs/day, for an applicable pollutant based on the production 

ELGprod: the production rate, in lbs, for the applicable guideline(s), usually based on long term 

average data 

ELG: the effluent guideline limitation, given as a measure of production (e.g. lbs/1000 lbs), for 

an applicable pollutant 

2. For Effluent guidelines based on flow, limits will be calculated as follows: 

( 34.8 

ELGlim :the mass limit, in lbs/day, for an applicable pollutant based on applicable flow 

ELGprod: the long term average flow rate, in MGD, for the applicable guideline(s) 

ELG: the concentration limitation, in mg/l, for an applicable pollutant from the applicable 

guideline(s) 

a. For BOD and TSS limits based on OCPSF Effluent Guidelines with two or more applicable 

subparts in subparts B-H , the limits will be calculated as follows: 

ELG lim = ∑(ELGflow)(ELG) ) where 

⎛

⎜

⎜

subpart production ⎞

⎟

⎟ ELG O = ∑ (ELG lim) where

total OCPSF production ⎝ ⎠

ELGo: the final OCPSF limitation, in lbs/day 

ELGlim: the limitation, in lbs/day, determined from the calculation in item 2 above. 

H. Other considerations 

1. When the derived permit effluent limitation based on aquatic life numeric criteria is below the practical 

quantitation limit for a substance, the derived permit effluent limitation shall include an accompanying 

statement in the permit that the practical quantitation limit using approved analytical methods shall be 

considered as being in compliance with the limit. Appropriate biological monitoring requirements shall be 

incorporated into the permit to determine compliance with appropriate water quality standards. (R.61-

68.E.12.c(2)) 

2. When the derived permit effluent limitation based on human health numeric criteria is below the practical 

quantitation limit for a substance, the derived permit effluent limitation shall include an accompanying statement 

in the permit that the practical quantitation limit using approved analytical methods shall be considered as being in 

compliance with the limit. (R.61-68.E.12.c(3)) 
Rationale 

Page 21 of 44 

Permit No. SC0001333 

3. The effluent concentration limits determined above may not necessarily be the NPDES permit limit. NPDES 

Permit limits are determined after a reasonable potential analysis is conducted using these derived limits and also 

after evaluating other issues (e.g. anti-backsliding, antidegradation). 

4. Mass limitations may be required in certain circumstances. When mass limits are calculated the formula to be 

used is as follows. 

Mass (lb/day) = Flow (mgd) * Concentration (mg/l) * 8.34 

5. Final Limitations will typically be rounded to two (2) significant figures (based on EPA’s policy with its national 

criteria) while considering the PQL for a given parameter. Rounding will be performed using the following 

procedure (as recommended by the DHEC lab): 

a. If the digit of interest is even and the number following it is a five (5), the digit of interest remains the same. 

b. If the digit of interest is odd and the number following it is a five (5), the digit of interest is rounded up. 

c. If the digit of interest is even or odd and the number following it is between 0 and 4, the digit of interest 

remains the same. 

d. If the digit of interest is even or odd and the number following it is between 6 and 9, the digit of interest is 

rounded up. 
Rationale 

Page 22 of 44 

Permit No. SC0001333 

III. PERMIT LIMITATIONS AND MONITORING REQUIREMENTS 

** NOTE: Although all DMR data since 1/1/00 has been reviewed for this permit reissuance, the permittee has indicated that 

the flow schematic they submitted is a best estimate of their expected flows during the next five years (the flow schematic is 

based on 2003 long term averages plus an expected increase in production). An anti-degradation/alternatives analysis has not 

been completed for this increase, therefore the permittee will be held to their existing discharge limits. This production 

increase will contribute and additional 0.038 mgd of process flow (this production falls under the same guidelines as their 

existing PET production). The final Outfall (001) discharges to the Congaree River. All internal outfalls combine at 001 before 

discharging to the river. 

INTERNAL OUTFALL 01A 

Information for this outfall based on NPDES Permit Application: 2C dated 3/26/04 

Description of outfall and treatment: This outfall consists of stormwater (13% of the flow), non-contact cooling water 

(81% of the flow) and ancillary non-process water (6% of the flow). There is no treatment for this outfall. 

Flow 

1. Previous permit limits (effective 1/1/00): 

Monthly average: MR mgd 

Daily Maximum: MR mgd

 Sampling Frequency: Daily

 Sample Type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest flow was reported on 4/30/02 as 2.271 mgd. 

4. Actual long-term average flow (from 2003 flow schematic with anticipated future changes): 0.632 MGD 

5. Conclusion: The permittee shall continue to monitor and report flow at this internal outfall. 

Monthly average: MR mgd 

Daily maximum: MR mgd

 Sampling Frequency: Daily

 Sampling Type: Continuous 

pH 

1. Previous Permit Limits (effective 1/1/00): MR standard units the maximum and minimum

 Sampling Frequency: Daily

 Sample type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest and lowest pH were reported on 3/31/02 as 8.3 standard units and 9/30/02 as 5.1 standard units. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: Not applicable to this outfall. 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The permittee shall continue to MR the maximum and minimum pH (in standard units), however the 

monitoring frequency has been reduced to monthly based on the Department’s review of past DMR data. 

 Sampling Frequency: 1/Month 

 Sample type: Grab

Temperature 

1. Previous Permit Limits (effective 1/1/00): 

Monthly average: MR °F 

Daily Maximum: MR °F

 Sampling Frequency: Daily 

Sample type: Grab 
Rationale 

Page 23 of 44 

Permit No. SC0001333 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest temperature was reported on 7/31/02 as 94 °F. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: not applicable 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The permittee shall continue to MR temperature, however the monitoring frequency has been reduced to 

monthly based on the Department’s review of past DMR data. 

Monthly average: MR °F 

Daily Maximum: MR °F

Sampling Frequency: 1/Month 

Sample type: Grab 

Biochemical Oxygen Demand (BOD5) 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: No past DMR data. 

4. Effluent limitations guidelines: The permittee indicated in an e-mail dated 7/26/04 that their non-contact cooling water is 

81% of the flow at this outfall: (0.632 mgd x 0.81 = 0.5119 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 5 mg/l 

Daily Max: 10 mg/l 

Monthly average limit: 0.5119 mgd x 5 mg/l x 8.345 (lbs-L)/(MG-mg) = 21 lbs/day 

Daily maximum limit: 0.5119 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 43 lbs/day 

5. PQL: 2 mg/l 

6. Waste Load Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: None 

8. Conclusion: Although a BOD5 contribution has been determined for this outfall, BOD5 does not need to be monitored at 

this outfall. A net BOD5 limit is established at Outfall 001 

Total Suspended Solids (TSS) 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: No past DMR data. 

4. Water Quality Data: NA 

5. Effluent limitations guidelines: The permittee indicated in an e-mail dated 7/26/04 that their non-contact cooling water is 

81% of the flow at this outfall: (0.632 mgd x 0.81 = 0.5119 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 10 mg/l 

Daily Max: 20 mg/l 

Monthly average limit: 0.5119 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 43 lbs/day 

Daily maximum limit: 0.5119 mgd x 20 mg/l x 8.345 (lbs-L)/(MG-mg) = 85 lbs/day 

6. Other information: None 

7. PQL: 1000 μg/l 

8. Conclusion: Although a TSS contribution has been determined for this outfall, this parameter does not need to be 

monitored at this outfall. A net TSS limit is established at Outfall 001. 
Rationale 

Page 24 of 44 

Permit No. SC0001333 

INTERNAL OUTFALL 01D 

Information for this outfall based on NPDES Permit Application: 2C dated 3/26/04 

Description of outfall and treatment: This outfall consists of stormwater (9.5% of the flow), water filtration effluent 2% of the 

flow), non-contact cooling water (97% of the flow) and ancillary non-process water (0.5% of the flow). There is no treatment 

for this outfall. 

Flow 

1. Previous permit limits (effective 1/1/00): 

Monthly average: MR mgd 

Daily Maximum: MR mgd

 Sampling Frequency: Daily

 Sample Type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest flow was reported on 7/31/02 as 50.971 mgd. 

4. Actual long-term average flow (from 2003 flow schematic with anticipated future changes): 25.586 mgd 

5. Conclusion: The permittee shall continue to monitor and report flow at this internal outfall. 

Monthly average: MR mgd 

Daily maximum: MR mgd 

Sampling Frequency: Daily

 Sampling Type: Continuous 

pH 

1. Previous Permit Limits (effective 1/1/00): MR standard units the maximum and minimum

 Sampling Frequency: Daily

 Sample type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest and lowest pH were reported 10/31/03 as 9.2 standard units and 10/31/01 as 6.8 standard units. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: Not applicable to this discharge. 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The permittee shall continue to MR the maximum and minimum pH (in standard units), however the 

monitoring frequency has been reduced to monthly based on the Department’s review of past DMR data. 

 Sampling Frequency: 1/Month 

 Sample type: Grab

Temperature 

1. Previous Permit Limits (effective 1/1/00): 

Monthly average: MR °F 

Daily Maximum: MR °F

 Sampling Frequency: Daily

 Sample type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest temperature was reported on 7/31/03 as 101°F. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: not applicable 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The permittee shall continue to MR temperature. 

Monthly average: MR °F 

Daily Maximum: MR °F 

Sampling Frequency: Daily 

Sample type: Continuous 
Rationale 

Page 25 of 44 

Permit No. SC0001333 

Biochemical Oxygen Demand (BOD5) 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: No past DMR data. 

4. Effluent limitations guidelines: The permittee indicated in e-mails dated 5/6/04 & 7/26/04 that 97% of the flow at Outfall 

01D is non-contact cooling water (25.586 mgd x 0.97 = 24.8184 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 5 mg/l 

Daily Max: 10 mg/l 

Monthly average limit: 24.8184 mgd x 5 mg/l x 8.345 (lbs-L)/(MG-mg) = 1036 lbs/day 

Daily maximum limit: 24.8184 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 2071 lbs/day 

5. PQL: 2 mg/l 

6. Waste Load Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: None 

8. Conclusion: Although a BOD5 contribution has been determined for this outfall, BOD5 does not need to be monitored at 

this outfall. A net BOD5 limit is established at Outfall 001. 

Total Suspended Solids (TSS) 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: No past DMR data. 

4. Water Quality Data: NA 

5. Effluent Limitation Guidelines: The permittee indicated in e-mails dated 5/6/04 & 7/26/04 that 97% of the flow at Outfall 

01D is non-contact cooling water (25.586 mgd x 0.97 = 24.8184 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 10 mg/l 

Daily Max: 20 mg/l 

Monthly average limit: 24.8184 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 2071 lbs/day 

Daily maximum limit: 24.8184 mgd x 20 mg/l x 8.345 (lbs-L)/(MG-mg) = 4142 lbs/day 

6. Other information: None 

7. PQL: 1000 μg/l 

8. Conclusion: Although a TSS contribution has been determined for this outfall, this parameter does not need to be 

monitored at this outfall. A net TSS limit is established at Outfall 001. 

INTERNAL OUTFALL 01E 

Information for this outfall based on NPDES Permit Application: 2C dated 3/26/04 

Description of outfall and treatment: This outfall consists of stormwater (0.1% of the flow), non-contact cooling water (98.9% 

of the flow), contact cooling water (0.5% of the flow), de-ionized water treatment effluent (0.3% of the flow), groundwater 

withdrawal (<0.1% of the flow), cooling tower blowdown (0.1% of the flow) and ancillary non-process water (0.1% of the 

flow). This discharge is from a cooling basin. The contact cooling water is not subject to categorical guidelines as it only 

comes in contact with molten polymer (inert) and is used to cool the polymer to a solid state. There are no pollutants of 

concern for the contact cooling water, other than temperature. 

Flow 

1. Previous permit limits (effective 1/1/00): 

Monthly average: MR mgd 

Daily Maximum: MR mgd

 Sampling Frequency: Daily

 Sample Type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 
Rationale 

Page 26 of 44 

Permit No. SC0001333 

3. DMR Data: The highest flow was reported on 8/31/03 as 78.199 mgd. 

4. Actual long-term average flow (from 2003 flow schematic with anticipated future changes): 63.423 mgd 

5. Conclusion: The permittee shall continue to monitor and report the flow at this internal outfall. 

Monthly average: MR mgd 

Daily maximum: MR mgd 

Sampling Frequency: Daily

 Sampling Type: Continuous 

Biochemical Oxygen Demand (BOD5) 

1. Previous permit limits (effective 1/1/00): 

Monthly average: MR mg/l 

Daily maximum: MR mg/l

 Sampling frequency: 1/Month 

 Sample type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest BOD5 was reported on 4/30/02 as 7 mg/l. All other DMR data was below 5 mg/l with the majority 

reported as 0 mg/l. 

4. Effluent limitations guidelines: The permittee indicated in e-mails dated 5/6/04 & 7/26/04 that 98.9% of the flow at 

Outfall 01E is non-contact cooling water and that 0.1% of the flow is cooling tower blowdown (63.423 mgd x 0.99 = 

62.7888 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 5 mg/l 

Daily Max: 10 mg/l 

Monthly average limit: 62.7888 mgd x 5 mg/l x 8.345 (lbs-L)/(MG-mg) = 2620 lbs/day 

Daily maximum limit: 62.7888 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 5240 lbs/day 

5. PQL: 2 mg/l 

6. Waste Load Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: None 

8. Conclusion: A net BOD5 limit is established at Outfall 001, therefore there is no need for the permittee to continue to 

monitor BOD5 at this outfall. 

Total Suspended Solids (TSS) 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: No past DMR data. 

4. Water Quality Data: NA 

5. Effluent limitations guidelines: The permittee indicated in e-mails dated 5/6/04 % 7/26/04 that 98.9% of the flow at 

Outfall 01E is non-contact cooling water and that 0.1% of the flow is cooling tower blowdown (63.432 mgd x 0.99 = 

62.7888 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 10 mg/l 

Daily Max: 20 mg/l 

Monthly average limit: 62.7888 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 5240 lbs/day 

Daily maximum limit: 62.7888 mgd x 20 mg/l x 8.345 (lbs-L)/(MG-mg) = 10479 lbs/day 

6. Other information: None 

7. PQL: 1000 μg/l 

8. Conclusion: Although a TSS contribution has been determined for this outfall, this parameter does not need to be 

monitored at this outfall. A net TSS limit is established at Outfall 001. 
Rationale 

Page 27 of 44 

Permit No. SC0001333 

pH 

1. Previous Permit Limits (effective 1/1/00): 6.0-9.0 standard units. 

 Sampling Frequency: Daily

 Sample type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest and lowest pH was reported on 7/31/02 as 10.1 standard units and 7/31/00 as 6 standard units. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: Not applicable to this discharge. 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The pH limits shall be in accordance with the previous permit. 

Range: 6.0-9.0 standard units 

 Sampling Frequency: Daily

 Sample type: Continuous 

Exceeding the limits for pH on this internal outfall is not considered a violation if the permittee can demonstrate that the 

excursion is due to natural biological activity of algae formation. Evidence of this must be submitted with the DMRs and 

must show the variance in day-to-night variation for pH and dissolved oxygen as well as the variance of pH from the 

influent and effluent in the Discharge Lagoon. In order for this condition to apply, the influent pH shall not be less than 6.0 

standard units nor greater than 9.0 standard units. 

*In accordance with 401.17, pH Effluent limitations under continuous monitoring are specified as follows. 

Where a permittee continuously measures the pH of wastewater pursuant to a requirement or option in a National Pollutant 

Discharge Elimination System (NPDES) permit issued pursuant to section 402 of the Act, the permittee shall maintain the 

pH of such wastewater within the range set forth in the applicable effluent limitations guidelines, except excursions from 

the range are permitted subject to the following limitations: 

(a) The total time during which the pH values are outside the required range of pH values shall not exceed 7 hours and 26 

minutes in any calendar month; and 

(b) No individual excursion from the range of pH values shall exceed 60 minutes. 

For purposes of this section, an excursion is an unintentional and temporary incident in which the pH value of 

discharge wastewater exceeds the range set forth in the applicable effluent limitations guidelines. (Secs. 301, 304, 306 

and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 1251 et. 

seq., as amended by the Clean Water Act of 1977, Pub. L. 95-217)) 

Temperature 

1. Previous Permit Limits (effective 1/1/00): 

 Monthly average: 98°F 

 Daily Maximum: 105°F 

 Sampling Frequency: Daily

 Sample type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest temperature was reported on 7/31/02 as 93°F. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: not applicable 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The temperature limits shall be in accordance with the previous permit. 

Monthly average: 98°F 

Daily Maximum: 105 °F 

 Sampling Frequency: Daily

 Sample type: Continuous 
Rationale 

Page 28 of 44 

Permit No. SC0001333 

Oil and grease 

1. Previous Permit Limits (effective 1/1/00): 

Daily Maximum: 5 mg/l

 Sample type: 1/Month 

 Sampling Frequency: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest oil and grease value was reported on 1/31/04 as 9 mg/l. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: Not applicable to this outfall. 

6. Other information: Previous limit due to possible contact with oil & use of oil skimmer in the cooling water basin. 

7. PQL: 5 mg/l 

8. Conclusion: Oil and grease shall be limited in accordance with the pervious permit, as the 9 mg/l DMR data point 

demonstrates that reasonable potential exists to exceed the 5 mg/l limit. MR has been included for monthly average. 

Monthly average: MR mg/l 

Daily Maximum: 5 mg/l

 Sample type: Grab 

Sampling Frequency: 1/Month 

INTERNAL OUTFALL 01F 

Information for this outfall based on NPDES Permit Application: 2C dated 3/26/04 

Description of outfall and treatment: This outfall consists of process and sanitary ww and stormwater. Voridian has a 3.0 mgd 

activated sludge plant with aerobic digestion. Sludge is dewatered and incinerated or land applied onsite (during incinerator 

maintenance/failure only). 

Note: This internal outfall is subject to the following effluent guidelines: 

40CFR Part 414 Organic Chemicals, Plastics and Synthetic Fibers 

Subparts D (Thermoplastic Resins): 0.648 mgd– PET Production* 

F (Commodity Organic Chemicals): 0.8 mgd – Intermediates Production 

I (Direct Discharge Point Sources that use End-of-Pipe Biological Treatment) 

* The additional 0.038 mgd PET flow (for the production increase) is not shown when the categorical 

limits are calculated below, as the permittee did not ask for an increase. 

Voridian no longer has a process ww from specialty plastics manufacturing. 

Flow 

1. Previous permit limits (effective 1/1/00): 

Monthly average: MR mgd 

Daily Maximum: MR mgd

 Sampling Frequency: Daily

 Sample Type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest flow was reported on 3/31/03 as 2.388 mgd. 

4. Actual long-term average flow (from 2003 flow schematic with anticipated future changes): 1.727 mgd 

5. Conclusion: The permittee shall continue to monitor and report flow at this internal outfall. 

Monthly average: MR mgd 

Daily maximum: MR mgd

 Sampling Frequency: Daily 

Sampling Type: Continuous 
Rationale 

Page 29 of 44 

Permit No. SC0001333 

Dissolved Oxygen (DO) 

1. Previous Permit Limits (effective 1/1/00): ∃ 1.0 mg/l at all times 

 Sampling frequency: 1/Week 

 Sample type: Grab 

2. NPDES Application: not measured 

3. DMR Data: The lowest DO was reported on 4/30/01 as 2 mg/l. 

4. Water Quality Data: The DO water quality limitation will be assessed for Outfall 001, water quality standards are not 

applicable to this internal outfall. 

5. PQL: Not applicable. 

6. Waste Load Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: None 

8. Conclusion: The DO limitation shall be in accordance with the previous permit. 

1.0 mg/l minimum at all times 

 Sampling frequency: 1/Week 

 Sample type: Grab 

Biochemical Oxygen Demand (BOD5) 

1. Previous permit limits (effective 1/1/00): 

Monthly average: 311 #/d 

Daily maximum: 820 #/d 

 Sampling frequency: 3/Week 

Sample type: 24 Hour Composite 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest BOD5 was reported on 11/30/00 as 704 #/d. 

4. Effluent limitations guidelines & Professional Judgment: 

a. Guidelines for 40CFR Part 414 Subpart D: 

Monthly average: 24 mg/l 

Daily maximum: 64 mg/l

b. Guidelines for 40CFR Part 414 Subpart F: 

Monthly average: 30 mg/l 

Daily maximum: 80 mg/l

c. Sanitary WW: Secondary Treatment Regulations (R.61-9.133.102) 

Monthly average: 30 mg/l 

Daily maximum: 60 mg/l

 Calculations: 

a. Part 414 Subpart D Flow: 0.648 mgd 

Monthly Average = 24 mg/l x 0.648 mgd x 8.345 (# L/mg MG) = 129.78 #/d 

Daily Maximum = 64 mg/l x 0.648 mgd x 8.345 (# L/mg MG) = 346.08 #/d 

b. Part 414 Subpart F Flow: 0.8 mgd 

Monthly Average = 30 mg/l x 0.8 mgd x 8.345 (# L/mg MG) = 200.28 #/d 

Daily Maximum = 80 mg/l x 0.8 mgd x 8.345 (# L/mg MG) = 534.08 #/d 

c. Sanitary Flow: 0.052 mgd 

Monthly Average = 30 mg/l x 0.052 mgd x 8.345 (# L/mg MG) = 13 .02 #/d 

Daily Maximum = 60 mg/l x 0.052 mgd x 8.345 (# L/mg MG) = 26.04 #/d 

Total BOD5 Contributions: 

Monthly Average = 129.78 #/d + 200.28 #/d + 13.02 #/d = 343 #/d 

Daily Maximum = 346.08 #/d + 534.08 #/d + 26.04 #/d = 906 #/d 

5. PQL: 2 mg/l 

6. Waste Load Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: PET and intermediates production increased since the last permit reissuance. 
Rationale 

Page 30 of 44 

Permit No. SC0001333 

8. Conclusion: The BOD5 limits are in accordance with the previous permit (they are more stringent than those calculated 

above). The monitoring frequency has been reduced to weekly due to their compliance history and to be consistent with 

other parameters at this outfall. The permittee shall also report the concentration values. 

Monthly average: 311 #/d, MR mg/l 

Daily maximum: 820 #/d, MR mg/l 

Sampling Frequency: 1/Week 

Sampling Type: 24 Hour Composite 

Total Suspended Solids (TSS) 

1. Previous permit limits (effective 1/1/00): 

Monthly average: 510 #/d 

Daily Maximum: 1605 #/d 

 Sampling frequency: 3/Week 

Sample Type: 24 Hour Composite 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest TSS was reported on 12/31/03 as 1202 #/d. 

4. Water Quality Data: NA 

5. Effluent limitations guidelines & Professional Judgment: 

a. Guidelines for 40CFR Part 414 Subpart D: 

Monthly average: 40 mg/l 

Daily maximum: 130 mg/l 

b. Guidelines for 40CFR Part 414 Subpart F: 

Monthly average: 46 mg/l 

Daily maximum: 149 mg/l 

c. Sanitary WW: Secondary Treatment Regulations (R.61-9.133.102) 

Monthly average: 30 mg/l 

Daily maximum: 60 mg/l

 Calculations: 

a. Part 414 Subpart D Flow: 0.648 mgd 

Monthly Average = 40 mg/l x 0.648 mgd x 8.345 (# L/mg MG) = 216.30 #/d 

Daily Maximum = 130 mg/l x 0.648 mgd x 8.345 (# L/mg MG) = 702.98 #/d 

b. Part 414 Subpart F Flow: 0.8 mgd 

Monthly Average = 46 mg/l x 0.8 mgd x 8.345 (# L/mg MG) = 307.10 #/d 

Daily Maximum = 149 mg/l x 0.8 mgd x 8.345 (# L/mg MG) = 994.72 #/d 

c. Sanitary Flow: 0.052 mgd 

Monthly Average = 30 mg/l x 0.052 mgd x 8.345 (# L/mg MG) = 13 .02 #/d 

Daily Maximum = 60 mg/l x 0.052 mgd x 8.345 (# L/mg MG) = 26.04 #/d 

Total TSS Contributions: 

Monthly Average = 216.30 #/d + 307.10 #/d + 13.02 #/d = 536 #/d 

Daily Maximum = 702.98 #/d + 994.72 #/d + 26.04 #/d = 1724 #/d 

6. Other information: PET and intermediates production increased since the last permit reissuance. 

7. PQL: 1 mg/l 

8. Conclusion: The TSS limits are in accordance with the previous permit (they are more stringent than those calculated 

above). The monitoring frequency has been reduced to weekly due to their compliance history and to be consistent with 

other parameters at this outfall. The permittee shall also report the concentration values. 

Monthly average: 510 #/d, MR mg/l 

Daily maximum: 1605 #/d, MR mg/l 

 Sampling Frequency: 1/Week 

Sample type: 24 Hour Composite 
Rationale 

Page 31 of 44 

Permit No. SC0001333 

pH 

1. Previous Permit Limits (effective 1/1/00): 6.0-9.0 standard units. 

 Sampling Frequency: Daily

 Sample type: Continuous 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest and lowest pH was reported on 4/30/03 as 8.8 standard units and 8/31/02 as 6.4 standard units. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: 6.0-9.0 standard units 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The pH should remain between 6.0 and 9.0 standard units, as in the previous permit. 

 Sampling Frequency: Daily

 Sample type: Continuous 

*In accordance with 401.17, pH Effluent limitations under continuous monitoring are specified as follows. 

Where a permittee continuously measures the pH of wastewater pursuant to a requirement or option in a National 

Pollutant Discharge Elimination System (NPDES) permit issued pursuant to section 402 of the Act, the permittee shall 

maintain the pH of such wastewater within the range set forth in the applicable effluent limitations guidelines, except 

excursions from the range are permitted subject to the following limitations: 

(a) The total time during which the pH values are outside the required range of pH values shall not exceed 7 hours 

and 26 minutes in any calendar month; and 

(b) No individual excursion from the range of pH values shall exceed 60 minutes. 

For purposes of this section, an excursion is an unintentional and temporary incident in which the pH value of 

discharge wastewater exceeds the range set forth in the applicable effluent limitations guidelines. (Secs. 301, 304, 306 

and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 1251 et. 

seq., as amended by the Clean Water Act of 1977, Pub. L. 95-217)) 

of 1972, 33 U.S.C. 1251 et. seq., as amended by the Clean Water Act of 1977, Pub. L. 95-217)) 

Oil and grease 

1. Previous Permit Limits (effective 1/1/00): 

Monthly average: 112 #/d 

Daily Maximum: 169 #/d 

 Sampling frequency: 1/Week 

 Sample Type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest oil and grease value was reported on10/31/03 as 118 mg/l 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: 

a. Standard Guidelines for Oil and Grease: 

Monthly average: 10 mg/l 

Daily maximum: 15 mg/l

Calculations: 

a. Process and Sanitary Flows: 1.5 mgd 

Monthly Average = 10 mg/l x 1.5 mgd x 8.345 (# L/mg MG) = 125.18 #/d = 125 #/d 

Daily Maximum = 15 mg/l x 1.5 mgd x 8.345 (# L/mg MG) = 187.76 #/d = 188 #/d 

6. Other information: None 

7. PQL: 5 mg/l 
Rationale 

Page 32 of 44 

Permit No. SC0001333 

8. Conclusion: Oil and grease will be limited in accordance with the previous permit; they have demonstrated they can meet 

their previous limits. The permittee shall also report the concentration values. 

Monthly average: 112 #/d, MR mg/l 

Daily Maximum: 169 #/d, MR mg/l 

 Sample type: Grab 

 Sampling Frequency: 1/Week

Fecal Coliform 

1. Previous Permit Limits (effective 1/1/00): 

Monthly average: 200/100 ml 

Daily maximum: 400/100 ml (no more than 10% of total samples during a 30 day period shall exceed 400/100 ml) 

 Sample type: Grab 

Sampling Frequency: 1/Week 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest value was 1280/100 ml reported on 4/30/00 (the permittee started up their UV system this month; 

this was the only fecal violation). All other DMR data was below 230/100 ml. 

4. Water Quality Data: Fecal coliform standards in Regulation 61-68.G.10(e) for Class FW are not to exceed 200/100ml 

based on five consecutive samples in a 30 day period and no more than 10% of the samples in the 30 day period shall 

exceed 400/100ml . 

5. Effluent limitation guidelines: not applicable 

6. Wasteload Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: Although Station C-074 is impaired for fecal coliform, the permittee samples weekly and has had only 

one violation during the previous permit duration. If the permittee meets fecal coliform standards at this outfall, limits are 

not needed on Outfall 001, this is the only outfall with sanitary contributions. 

8. PQL: 1/100 ml (Standard Method 9221C, 9221 E or 9221 D) 

9. Conclusion: Fecal coliform, per R.61-68.E.12(c)(9), will be limited to 

Monthly average: 200/100 ml 

Daily maximum: 400/100 ml (no more than 10% of total samples during a 30 day period shall exceed 400/100 ml) 

Sample type: Grab 

Sampling Frequency: 1/Week 

OCPSF: All OCPSF parameters listed under 40 CFR Part 414 Subpart I for end of pipe biological treatment will be evaluated. 

The effluent guideline values will be compared to the governing water quality criterion to obtain the more stringent limit. A 

monitoring waiver has not been requested for any of the parameters so all parameters will be limited with a sample frequency 

of once per year. The mass limits are calculated using the process flow and the concentration limits are based on the guideline 

value for that parameter. See Appendix B for OCPSF limits for this outfall. OCPSF flow is 0.8 + 0.648 mgd = 1.448 mgd. 

INTERNAL OUTFALL 01G 

Information for this outfall based on NPDES Permit Application: 2C dated 3/26/04 

Description of outfall and treatment: This outfall consists of stormwater (11%), non-contact cooling water (85%) and 

ancillary non-process water (4%). This discharge is from an ash settling basin. 

Flow 

1. Previous permit limits (effective 1/1/00): 

Monthly average: MR mgd 

Daily Maximum: MR mgd

 Sampling Frequency: 2/Month 

 Sample Type: Estimate 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest flow was reported on 8/31/03 as 1.208 mgd. 
Rationale 

Page 33 of 44 

Permit No. SC0001333 

4. Actual long-term average flow (from 2003 flow schematic with anticipated future changes): 0.304 MGD 

5. Conclusion: The permittee shall continue to monitor and report flow at this internal outfall. The monitoring frequency has 

been increased to daily (to be included in the total daily flow computed for Outfall 001). 

Monthly average: MR mgd 

Daily maximum: MR mgd

 Sampling Frequency: Daily

Sampling Type: Estimate 

Biochemical Oxygen Demand (BOD5) 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: No past DMR data. 

4. Effluent limitations guidelines: The permittee indicated in e-mails dated 5/6/04 & 7/26/04 that 85% of the flow at Outfall 

01G is non-contact cooling water (0.304 mgd x 0.85 = 0.2584 mgd). 

Professional Judgment for the once-through non-contact cooling water portion of this discharge. 

Monthly Avg: 5 mg/l 

Daily Max: 10 mg/l 

Monthly average limit: 0.2584 mgd x 5 mg/l x 8.345 (lbs-L)/(MG-mg) = 11 lbs/day 

Daily maximum limit: 0.2584 mgd x 10 mg/l x 8.345 (lbs-L)/(MG-mg) = 22 lbs/day 

5. PQL: 2 mg/l 

6. Waste Load Allocation dated (8/14/03): Not applicable to this internal outfall. 

7. Other information: None 

8. Conclusion: Although a BOD5 contribution has been determined for this outfall, BOD5 does not need to be monitored at 

this outfall. A net BOD5 limit is established at Outfall 001. 

Total Suspended Solids (TSS) 

1. Previous permit limits (effective 1/1/00): 

Monthly average: 25 mg/l 

Daily Maximum: 40 mg/l

 Sampling frequency: 1/Month 

 Sample Type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest TSS was reported in 3/31/03 as 23 mg/l 

4. Water Quality Data: NA 

5. Effluent Limitation Guidelines: The previous permits had concentration limits of due to the presence of coal fines in this 

discharge. The permittee indicated in e-mails dated 5/6/04 & 7/26/04 that 85% of the flow at Outfall 01G is non-contact 

cooling water and that 11% of the flow is stormwater. There may be suspended solids in both discharges from this outfall. 

(0.304 mgd x 0.85 + 0.304 mgd x 0.11 = 0.2918 mgd). 

Monthly Avg: 25 mg/l 

Daily Max: 40 mg/l 

Monthly average limit: 0.2918 mgd x 25 mg/l x 8.345 (lbs-L)/(MG-mg) = 61 lbs/day 

Daily maximum limit: 0.2918 mgd x 40 mg/l x 8.345 (lbs-L)/(MG-mg) = 97 lbs/day 

6. Other information: None 

7. PQL: 1000 μg/l 

8. Conclusion: The TSS limits shall be in accordance with the previous permit, however the permittee shall only sample for 

TSS when operating the coal fired boilers. A net TSS limit is established at Outfall 001. 

Monthly average: 25 mg/l, MR #/d 

Daily Maximum: 40 mg/l, MR #/d 

 Sampling frequency: 1/Month 

 Sample Type: Grab 
Rationale 

Page 34 of 44 

Permit No. SC0001333 

pH 

1. Previous Permit Limits (effective 1/1/00): MR standard units. 

 Sampling Frequency: Daily

 Sample type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest and lowest pH were reported on 7/31/00 as 9.8 standard units and 6/30/01 as 4.6 standard units. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: Not applicable to this outfall. 

6. Other information: None 

7. PQL: Not applicable 

8. Conclusion: The permittee shall continue to MR pH (in standard units), however the monitoring frequency has been 

reduced to monthly to be consistent with other parameters at this outfall. 

 Sampling Frequency: 1/Month 

 Sample type: Grab 

Oil and grease 

1. Previous Permit Limits (effective 1/1/00): 

Monthly average: 10 mg/l 

Daily maximum: 15 mg/l

 Sampling Frequency: 1/Month 

 Sample type: Grab 

2. NPDES Application (2C dated 3/26/04): The 2C application reported parameters for Outfall 001 only. 

3. DMR Data: The highest oil and grease value was reported on 12/31/03 as 6 mg/l. 

4. Water Quality Data: Not applicable to this internal outfall. 

5. Effluent limitation guidelines: Standard Guidelines for Oil and Grease 

Monthly average: 10 mg/l 

Daily maximum: 15 mg/l 

6. Other information: See Appendix G for oil and grease reasonable potential determination. 

7. PQL: 5 mg/l 

8. Conclusion: Reasonable Potential does not exist for this discharge to exceed the standard oil and grease guidelines; the 

receiving water concentrations (RWC = maximum concentration * MF) are less than the previous limits. The oil and 

grease limitations have been removed for this outfall. 

OUTFALL 001 

Information for this outfall based on NPDES Permit Application: 2C dated 3/26/04 

Description of outfall and treatment: Outfall 001 consists of a combination of all internal outfalls. 

Waterbody Data from Wasteload Allocation dated 8/14/03 

Receiving Waterbody: cfs MGD 

7Q10 or other critical flow condition at discharge point (Q7Q10) 1601 1032.903 

Average Annual Flow or other critical flow condition at discharge point (AAFd) 9499 6128.387 

Is the discharge above a drinking water intake? Yes, Intake #S08104, Santee Cooper Regional, Congaree River 

Source Water Protection Waterbody Flow Data cfs MGD 

7Q10or other critical flow condition at source water protection area boundary 

(Q7Q10i) 

2320 1496.77419 

Average Annual Flow or other critical flow condition at source water protection 

area boundary (AAFi) 

14684 9473.54839 
Rationale 

Page 35 of 44 

Permit No. SC0001333 

Dilution Factors (using formulas in Section G.2.a) using the total LTA flow of 91.67 mgd: 

DF1 12.2676 

DF2 67.8527 

DF3, if applicable 17.3279 

DF4, if applicable 104.344 

TSS Values for metals calculations: 

Effluent TSS concentration (TSSe) (mg/l) (based on monthly average value) 8.8 

Background or In-stream TSS concentration (TSSb) (mg/l) (Default is 1 mg/l) 1.0 

Calculated In-stream Average TSS concentration after mixing (TSSavg) (mg/l) 1.721 

Appendix C contains the calculations for the water quality-based permit limitations and reasonable potential 

determinations. 

Flow 

1. Previous permit limits (effective 1/1/00): No previous limits 

2. NPDES Application (2C dated 3/26/04): (No. of flow analyses: 285) 

Long Term Average Value: 89.4 mgd 

Maximum Daily Value: 122.1 mgd 

3. DMR Data: No past DMR data. 

4. Actual long-term average flow (from 2003 DMR): Flow is not currently measured at Outfall 001. The total LTA flow 

used for water quality considerations is 91.67 mgd (a combined flow from all internal outfalls). 

5. Conclusion: Flow will be MR using the sum of the internal outfalls. A study is being required to confirm accurate flow 

measurement per Part II.J.1 of this permit. 

Monthly average: MR mgd 

Daily maximum: MR mgd

 Sampling Frequency: Daily

Sampling Type: Estimate

Dissolved Oxygen (DO) 

1. Previous Permit Limits (effective 1/1/00): No limit 

2. NPDES Application: not measured 

3. DMR Data: No past DMR data. 

4. Water Quality Data: Effluent Limits for D.O. are established in accordance with Reg. 61-68.G.10. For Class Fresh 

Water this value is a daily average not less than 5.0 mg/l with a low of 4.0 mg/l. 

5. PQL: Not applicable. 

6. Waste Load Allocation dated (8/14/03): No limit recommended; model predicted DO > 5.0 mg/l instream. 

7. Other information: None 

8. Conclusion: Dissolved oxygen limits are not needed at this time. 

Biochemical Oxygen Demand (BOD5) 

1. Previous permit limits (effective 1/1/00): 

Monthly average: 4 mg/l net 

Daily maximum: 11mg/l net 

 Sampling frequency: Daily

 Sample type: Calculation 
Rationale 

Page 36 of 44 

Permit No. SC0001333 

2. NPDES Application (2C dated 3/26/04): (# of analyses: 362) 

Long Term Average Value: 0.1 mg/l 

Maximum 30-day value: 0.4 mg/l 

Maximum Daily Value: 5.6 mg/l 

3. DMR Data: The highest BOD5 was reported on 4/30/02 as 14 mg/l (net). 

4. Effluent limitations guidelines/BPJ: summing the individual allowances for each internal outfall: 

Monthly average: 21 + 1036 + 2620 + 311 + 11 = 3999 #/d 

 3999 #/d = 5 mg/l 

91.67 mgd x 8.345 (lbs-L)/(MG-mg) 

Daily maximum: 43 + 2071 + 5240 + 820 + 22 = 8196 #/d 

 8196 #/d = 11 mg/l 

91.67 mgd x 8.345 (lbs-L)/(MG-mg) 

5. PQL: 2 mg/l 

6. Waste Load Allocation dated (8/14/03) 

Monthly Average: 4 mg/l net 

7. Other information: The permittee has had one violation of the daily maximum limits (14 mg/l reported on 4/30/02) during 

the last permit period, but no violations of the monthly average limit. The source of the violation is unknown. 

8. Conclusion: The BOD5 limits remain in accordance with the previous permit and the WLA. The permittee has shown they 

are able to meet these limits. 

Monthly average: 4 mg/l net 

Daily maximum: 11 mg/l net

Sampling Frequency: Daily

Sampling Type: Calculation 

Total Suspended Solids (TSS) 

1. Previous permit limits (effective 1/1/00): 7 Day rolling average limit of 22 mg/l 

Sampling frequency: Daily 

Sample Type: Calculation 

2. NPDES Application (2C dated 3/26/04): (No. of TSS analyses: 363) 

Long Term Average Value: 8.8 mg/l 

Maximum Daily Value: 125.4 mg/l 

3. DMR Data: The highest TSS was reported in 7/31/00 as 12 mg/l (net). 

4. Water Quality Data: NA 

5. Effluent limitations guidelines/BPJ: summing the individual allowances for each internal outfall: 

Daily maximum: 85 + 4142 + 10479 + 1605 + 97 = 16408 #/d 

 16408 #/d = 21 mg/l 

91.67 mgd x 8.345 (lbs-L)/(MG-mg) 

6. Other information: The permittee has not had any TSS violations during the last permit period. 

7. PQL: 1000 μg/l 

8. Conclusion: The TSS limits are in accordance with the calculated limits above. A 7-day rolling average of 21 mg/l will be 

used to account for TSS variations in influent concentration and cooling water residence time. 

 Sampling Frequency: Daily

 Sample type: Calculation 
Rationale 

Page 37 of 44 

Permit No. SC0001333 

pH 

1. Previous Permit Limits (effective 1/1/00): 6.0-9.0 standard units. 

 Sampling Frequency: Daily

 Sample type: Continuous 

2. NPDES Application (2C dated 3/26/04): (No. of pH analyses: 365) 

Minimum: 6.6 standard units. 

Maximum: 9.7 standard units. 

3. DMR Data: The highest and lowest pH was reported on 12/31/03 as 9.7 su and 9/30/03 as 6 su. 

4. Water Quality Data: Effluent Limits for pH are established in accordance with Reg. 61-68.G.10. For Class Fresh Water 

this value is 6.0-8.5 standard units. 

5. Effluent limitation guidelines: 40CFR Part 414 Subparts A, D and F: 6.0-9.0 su 

6. Other information: The permittee has had one pH violation during the last permit period (9.7 su reported on 12/31/03) 

7. PQL: Not applicable 

8.Conclusion: Due to the large stream dilution in comparison to the discharge, a maximum pH of 9.0 su shall be granted. 

This small change should not have any adverse impact on the receiving stream. This pH limits are as follows: 

pH should be between 6.0 and 9.0 standard units 

 Sampling Frequency: Daily

 Sample type: Continuous* 

*In accordance with 401.17, pH Effluent limitations under continuous monitoring are specified as follows. 

Where a permittee continuously measures the pH of wastewater pursuant to a requirement or option in a National 

Pollutant Discharge Elimination System (NPDES) permit issued pursuant to section 402 of the Act, the permittee shall 

maintain the pH of such wastewater within the range set forth in the applicable effluent limitations guidelines, except 

excursions from the range are permitted subject to the following limitations: 

(a) The total time during which the pH values are outside the required range of pH values shall not exceed 7 hours 

and 26 minutes in any calendar month; and 

(b) No individual excursion from the range of pH values shall exceed 60 minutes. 

For purposes of this section, an excursion is an unintentional and temporary incident in which the pH value of 

discharge wastewater exceeds the range set forth in the applicable effluent limitations guidelines. (Secs. 301, 304, 

306 and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. 

1251 et. seq., as amended by the Clean Water Act of 1977, Pub. L. 95-217)) 

Temperature 

1. Previous Permit Limits (effective 1/1/00): 

Monthly average: 98 F 

Daily Maximum: 105 F 

 Sampling Frequency: Daily

 Sample Type: Continuous 

2. NPDES Application (2C dated 3/26/04): (No. of analyses: 92) 

Summer: Average: 28.7 C 

Maximum: 32.8 C 

Winter: Average: 10.6 C 

Maximum: 14.4 C 

3. DMR Data: The highest temperature was reported in 7/31/00 as 94 F 

4. Water Quality Data: Effluent Limits for temperature are established in accordance with Reg. 61-68.E.10.a. For Class 

Fresh Water, “The water temperature of all Freshwaters which are free flowing shall not be increased more than 5o

F 

(2.8o

C) above natural temperature conditions and shall not exceed a maximum of 90oF (32.2oC) as a result of the discharge 

of heated liquids unless a different temperature standard as provided for in C.12 has been established, a mixing zone as 

provided in C.10 has been established, or a Section 316(a) determination under the Federal Clean Water Act has been 

completed.” 
Rationale 

Page 38 of 44 

Permit No. SC0001333 

5. Effluent limitation guidelines: not applicable 

6. Other information: At 7Q10 conditions with an upstream ambient water temperature of 79.34 F (from the WLA Section) 

and a 92.31 MGD discharge at 105 F, a heat balance around the outfall gives: 

Q1 + Q2 = Q3 where Q1 = upstream thermal load 

Q2 = discharge thermal load 

Q3 = downstream thermal load 

The heat transfer can be estimated from the following equation: 

Q = mCpT where Q = heat (Btu/hr) 

m = flowrate (lb/hr) 

Cp = specific heat [Btu/(lb *R)]

T = temperature (R) 

m1 = 7Q10 = 1033 MGD 

Combining and re-arranging the two equations gives: 

T3 = m1(T1 + 460 F) + m2(T2 + 460 F)1 - 460 F 

m1 + m2

 = (1033MGD)(79.34 F + 460 F) + (91.67 MGD)(105 F + 460 F) - 460 F 

(1033 +91.67 MGD) 

= 81.43 F 

7. PQL: Not applicable 

8. Conclusion: Due to the nature of the discharge, temperature shall be limited on this permit. The above equation shows that 

a discharge with a temperature of 105 F will not cause an instream excursion above the daily maximum of 90 °F or violate 

the difference in natural conditions with a change of 5 °F. The temperature limits for this permit shall be: 

Monthly Average: 98 F 

Daily Maximum: 105 F 

Sample Frequency: Daily

Sample Type: Continuous 

Total Phosphorus 

1. Previous Permit Limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): (No. of analyses:1) 

Maximum Daily Value: 0.1 mg/l 

3. DMR Data: No past DMR data. 

4. Water Quality Data: See Section II.G.1.c of this rationale. 

5. Effluent limitation guidelines: not applicable 

6. Wasteload Allocation dated (8/14/03): MR mg/l 

7. Other information: Lake Marion (downstream of this discharge) is impaired for phosphorus (Station SC-008). 

8. PQL: 0.050 mg/l (EPA Method 365.1 - 365.4 or 300) 

9. Conclusion: Since the permittee reported an intake value of 0.1 mg/l (equal to their effluent value) the Department has 

included MR requirements to collect intake and effluent data showing they are not causing or contributing to this 

impairment. The following reopener clause will be included in the permit: 

This permit may be reopened to include additional monitoring and/or limitations or to eliminate monitoring for phosphorus 

based on monitoring results obtained. 

Monthly average: MR mg/l net 

Daily Maximum: MR mg/l net 

Sample type: Calculation 

 Sampling Frequency: 1/Quarter
Rationale 

Page 39 of 44 

Permit No. SC0001333 

Total Copper 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): (No. of analyses:1) 

Maximum Daily Value: 0.010 mg/l 

3. DMR Data: No past DMR data 

4. Water Quality Criterion: see spreadsheet 

5. Other Information: The Congaree River is impaired for Copper (Station C-074). 

6. Does the discharge cause, have the Reasonable Potential to Cause or Contribute: Although the Congaree River is impaired, 

the permittee’s application indicates an intake value of 0.011 mg/l (greater than their effluent value); therefore we will 

include MR requirements for the intake and this outfall to determine if this discharge is causing or contributing to the 

impairment. 

7. Effluent limitations guidelines (ELGs) and professional judgment-based limits: Not applicable to this parameter. 

8. PQL: 0.010 mg/l 

9. Conclusion: The Department has included MR requirements to collect intake and effluent data showing they are not 

causing or contributing to this impairment. The following reopener clause will be included in the permit: 

This permit may be reopened to include additional monitoring and/or limitations or to eliminate monitoring for copper 

based on monitoring results obtained. 

Monthly average: MR mg/l net 

Daily Maximum: MR mg/l net 

 Sample type: Calculation 

Sampling Frequency: 1/Quarter

Mercury 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): (No. of analyses:1) 

Maximum Daily Value: 0.0004 mg/l 

3. DMR Data: No past DMR data 

4. Water Quality Criterion: see spreadsheet 

5. Other Information: The Congaree River is impaired for Mercury (Station C-007). 

6. Does the discharge cause, have the Reasonable Potential to Cause or Contribute: Although the Congaree River is impaired, 

the permittee’s application indicates an intake value of 0.0005 mg/l (greater than their effluent value); therefore we will 

include MR requirements for the intake and this outfall to determine if this discharge is causing or contributing to the 

impairment. 

7. Effluent limitations guidelines (ELGs) and professional judgment-based limits: Not applicable to this parameter. 

8. PQL: 0.0000005 mg/l 

9. Conclusion: The permittee shall monitor and report the intake and effluent for mercury as the Congaree River is impaired 

for mercury. The following reopener clause will be included in the permit: 

This permit may be reopened to include additional monitoring and/or limitations or to eliminate monitoring for mercury 

based on monitoring results obtained. 

Monthly average: MR mg/l net 

Daily Maximum: MR mg/l net 

Sample type: Calculation 

Sampling Frequency: 1/Quarter

Iron 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): (No. of analyses:1) 

Maximum Daily Value: 0.314 mg/l 
Rationale 

Page 40 of 44 

Permit No. SC0001333 

3. DMR Data: No past DMR data 

4. Water Quality Criterion: see spreadsheet 

5. Other Information: The permittee reported an intake value of 0.314 mg/l (intake= effluent concentration). 

6. Does the discharge cause, have the Reasonable Potential to Cause or Contribute: Although the spreadsheet indicates the 

permittee demonstrates reasonable potential, their application indicates an intake value equal to their effluent value. 

7. Effluent limitations guidelines (ELGs) and professional judgment-based limits: Not applicable to this parameter. 

8. PQL: 0.020 mg/l 

9. Conclusion: The permittee is only discharging the concentration of iron present in the background (intake water), 

therefore iron monitoring and/or limits are not needed at this time. 

Aluminum 

1. Previous permit limits (effective 1/1/00): No previous limits. 

2. NPDES Application (2C dated 3/26/04): (No. of analyses:1) 

Maximum Daily Value: 0.198 mg/l 

3. DMR Data: No past DMR data 

4. Water Quality Criterion: see spreadsheet 

5. Other Information: The permittee reported an intake value of 0.352 mg/l (intake > effluent concentration). 

6. Effluent limitations guidelines (ELGs) and professional judgment-based limits: Not applicable to this parameter. 

7. PQL: 0.020 mg/l 

8. Conclusion: Aluminum monitoring and/or limits are not needed at this time as the State had not adopted water quality 

criteria for aluminum and the permittee is discharging less aluminum than is present in the background (intake water). 

Whole Effluent Toxicity (WET) Testing 

1. Previous permit limits (effective 1/1/00): Chronic Multiconcentration Limits at CTC = 27% 

Monthly average: 25% Effect 

Daily Maximum: 40% Effect 

Sample type: 24 Hour Composite 

Sampling Frequency: 1/Month 

The dilution series was 7, 14, 27, 54 and 100%

2. DMR Data: The highest percent effect reported for chronic toxicity was 20% on 9/30/01. 

Date M. Avg D. Max. 

1/31/2000 0 0 

2/29/2000 0 0 

3/31/2000 0 0 

4/30/2000 0 0 

5/31/2000 0 0 

6/30/2000 0 0 

7/31/2000 0 0 

8/31/2000 0 0 

9/30/2000 11 11 

10/31/2000 0 0 

11/30/2000 0 0 

12/31/2000 10 10 

1/31/2001 0 0 

2/28/2001 0 0 

3/31/2001 0 0 

4/30/2001 15 15 

5/31/2001 12 12 

6/30/2001 0 0 

7/31/2001 11 11 
Rationale 

Page 41 of 44 

Permit No. SC0001333 

8/31/2001 6 6 

9/30/2001 20 20 

10/31/2001 6 6 

11/30/2001 0 0 

12/31/2001 6 6 

1/31/2002 0 0 

2/28/2002 0 0 

3/31/2002 0 0 

4/30/2002 5 11 

5/31/2002 0 0 

6/30/2002 10 10 

7/31/2002 6 6 

8/31/2002 0 0 

9/30/2002 6 6 

10/31/2002 0 0 

11/30/2002 10 10 

12/31/2002 0 0 

1/31/2003 7 7 

2/28/2003 0 0 

3/31/2003 0 0 

4/30/2003 18 18 

5/31/2003 7 7 

6/30/2003 12 12 

7/31/2003 11 11 

8/31/2003 0 0 

9/30/2003 0 0 

10/31/2003 0 0 

11/30/2003 0 0 

12/31/2003 12 12 

1/31/2004 0 0 

2/29/2004 0 0 

3/31/2004 0 0 

4/30/2004 0 0 

5/31/2004 0 0 

3. Conclusion: The South Carolina General Assembly passed legislation on June 3, 2004, entitled the South Carolina 

Aquatic Life Protection Act. The Act was signed into law by the Governor and, thus, became effective on June 15, 2004. 

Part (E) of Section 2 of the Act (Section 48-1-87 of the Code of Laws of South Carolina) requires DHEC to establish 

formal data quality objectives and an enhanced laboratory certification program. Because these requirements have not 

been satisfied, DHEC cannot evaluate the results of WET tests nor determine reasonable potential for WET since 

reasonable potential evaluations involve evaluating WET test results. As such, DHEC cannot establish WET testing 

requirements for NPDES permits until such time as the requirements of Part (E) are met. Therefore, this permit contains 

no WET testing requirements and/or limitations. 

Land Application of Sludge: 

Some of the requirements in Consent Agreement 01-041-W have been included in this NPDES for the land application of 

sludge onsite. The permittee uses the land application site as .a backup to the incinerator (they are only allowed to land apply 

during equipment failure or incinerator maintenance). Application of sludge cannot exceed six weeks in durations and not 

more often than three times per year. Groundwater monitoring and sludge monitoring requirements have been included in the 

permit. Voridian accepts sludge from Carolina Eastman Company SC0002321 (if the incinerator is down, this sludge would 

also be land applied). 
Rationale 

Page 42 of 44 

Permit No. SC0001333 

IV. PROCEDURES FOR REACHING A FINAL PERMIT DECISION 

A. Comment Period (R.61-9.124.10 and 11) 

The Department of Health and Environmental Control proposes to issue an NPDES permit to this applicant subject to 

the effluent limitations and special conditions outlined in this document. These determinations are tentative. 

During the public comment period, any interested person may submit written comments on the draft permit to the 

following address: 

SC Dept. of Health and Environmental Control 

Industrial, Agricultural and Storm Water Permitting Division 

Bureau of Water 

2600 Bull Street 

Columbia, South Carolina 29201 

For additional information, interested persons may contact Melanie Kastler at 803-898-4223. 

All written comments received during the period beginning ??? and ending on ??? shall be considered in making the 

final decision and shall be answered as prescribed below. See Public Notice #???. 

Per R.61-9.124.17, the Department is only required to issue a response to comments when a final permit is issued. 

This response shall: 

1.Specify which provisions, if any, of the draft permit have been changed in the final permit decision, and the reasons 

for the change; and 

2.Briefly describe and respond to all significant comments on the draft permit raised during the public comment 

period, or during any hearing. 

The response to comments shall be available to the public. 

B. Public Hearings (R.61-9.124.11 and 12) 

During the public comment period, any interested person may request a public hearing, if no hearing has already been 

scheduled. A request for a public hearing shall be in writing and shall state the nature of the issues proposed to be 

raised in the hearing. 

Determinations and Scheduling. 

1. Within the thirty (30) day comment period or other applicable comment period provided after posting or 

publishing of a public notice, an applicant, any affected state or interstate agency, the Regional Administrator or 

any other interested person or agency may file a petition with the Department for a public hearing on an 

application for a permit. A petition for a public hearing shall indicate the specific reasons why a hearing is 

requested, the existing or proposed discharge identified therein and specifically indicate which portions of the 

application or other permit form or information constitutes necessity for a public hearing. If the Department 

determines that a petition constitutes significant cause or that there is sufficient public interest in an application for 

a public hearing, it may direct the scheduling of a hearing thereon. 
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2. A hearing shall be scheduled not less than four (4) nor more than eight (8) weeks after the Department determines 

the necessity of the hearing in the geographical location of the applicant or, at the discretion of the Department, at 

another appropriate location, and shall be noticed at least thirty (30) days before the hearing. The notice of public 

hearing shall be transmitted to the applicant and shall be published in at least one (1) newspaper of general 

circulation in the geographical area of the existing or proposed discharge identified on the permit application and 

shall be mailed to any person or group upon request therefore. Notice shall be mailed to all persons and 

governmental agencies which received a copy of the notice or the fact sheet for the permit application. 

3. The Department may hold a single public hearing on related groups of permit applications. 

4. The Department may also hold a public hearing at its discretion, whenever, for instance, such a hearing might 

clarify one or more issues involved in the permit decision; 

5. Public notice of the hearing shall be given in accordance with R.61-9.124.10. 

Any person may submit oral or written statements and data concerning the draft permit. Reasonable limits may be set 

upon the time allowed for oral statements, and the submission of statements in writing may be required. The public 

comment period under R.61-9.124.10 shall automatically be extended to the close of any public hearing under this 

section. The hearing officer may also extend the comment period by so stating at the hearing. 

A tape recording or written transcript of the hearing shall be made available to the public. 

C. Obligation to raise issues and provide information during the public comment period. (R.61-9.124.13) 

All persons, including applicants, who believe any condition of a draft permit is inappropriate or that the Department’s 

tentative decision to deny an application, terminate a permit, or prepare a draft permit is inappropriate, must raise all 

reasonably ascertainable issues and submit all reasonably available arguments supporting their position by the close of 

the public comment period (including any public hearing). No issue shall be raised during an appeal by any party that 

was not submitted to the administrative record as part of the preparation and comment on a draft permit, unless good 

cause is shown for the failure to submit it. Any supporting materials which are submitted shall be included in full and 

may not be incorporated by reference, unless they are already part of the administrative record in the same proceeding, 

or consist of State or Federal statutes and regulations, Department and EPA documents of general applicability, or 

other generally available reference materials. Commenters shall make supporting materials not already included in the 

administrative record available. (A comment period longer than 30 days may be necessary to give commenters a 

reasonable opportunity to comply with the requirements of this section. Additional time shall be granted under R.61-

9.124.10 to the extent that a commenter who requests additional time demonstrates the need for such time). 

D. Issuance and Effective Date of the Permit 

1. After the close of the public comment period on a draft permit, the Department shall issue a final permit decision. 

The Department shall notify the applicant and each person who has submitted written comments or requested 

notice of the final permit decision. This notice shall include reference to the procedures for appealing a decision 

on a permit. For the purposes of this section, a final permit decision means a final decision to issue, deny, modify, 

revoke and reissue, or terminate a permit. 

2. A final permit decision shall become effective 30 days after the service of notice of the decision unless: 

(a) A later effective date is specified in the decision; or 

(b) No comments requested a change in the draft permit, in which case the permit shall become effective on the 

effective date shown in the issued permit. 
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3. Issuance or Denial of Permits. An appeal to a final determination of the Department or to a condition of a permit 

issued or the denial of a permit pursuant to the State law and this regulation, shall be in accordance with and 

subject to 48-1-200 of the SC Code. 

4. Unless specific circumstances warrant otherwise, the permit will become effective on the first of the month 

following the 15-day appeal period (see E below) or 30-day time required by D.2 above, whichever is longer if 

no request for adjudicatory hearing is filed. If a request for adjudicatory hearing is filed, the permit will become 

effective on the first of the month following resolution of the appeal. 

E. Adjudicatory Hearings 

Any person may submit a request for an administrative adjudicatory hearing to consider the final permit and its 

conditions. If you wish to request an administrative adjudicatory hearing, you must do so in accordance with 

Regulation 61-72, Volume 25, S.C. Code of Laws, 1976, as amended, and the Rules of the Administrative Law Judge 

(ALJ) Division. The request must be filed with the Clerk of the South Carolina Board of Health and Environmental 

Control, 2600 Bull Street, Columbia, South Carolina 29201, within fifteen (15) days following issuance of the permit. 

Service may be effected by personal delivery or by first class mail, but the request must be received by the Clerk on 

or before the fifteenth day. 

The following information, at a minimum, must be included in the request: 

1. the name of the party or parties requesting the hearing and the issue(s) for which the hearing is requested; 

2. the caption or other information sufficient to identify the permit decision being appealed; and 

3. the relief requested. 

In addition, the Administrative Law Judge Division requires that a person requesting a contested case hearing must file 

a copy of the request and a filing fee in the amount of $250.00 with the Administrative Law Judge Division at the 

following address: 

Clerk, Administrative Law Judge Division 

1205 Pendleton Street, Suite 224 

P.O. Box 11667 

Columbia, SC 29211 

A petition for review of a decision to issue a new permit stays all actions for which the permit is a prerequisite. A 

petition for review of a decision to reissue a permit stays the entire permit; the conditions of the expiring/expired 

permit remain in effect until the appeal is resolved. Any party may petition the ALJ Division to allow all uncontested 

provisions of the permit to be placed into effect. Information pertaining to adjudicatory matters may be obtained by 

contacting the Legal Office of the Department of Health and Environmental Control, 2600 Bull Street, Columbia, 

South Carolina or by calling 803-898-3350.