PERMIT RATIONALE FOR REISSUANCE
Calgon Carbon Corporation
Hancock County
Bay St. Louis, Mississippi
Water NPDES No. MS0046515
October 2025

I.	FACILITY INFORMATION

Facility Name:  Calgon Carbon Corporation (CCC)
Facility Address: 13121 Webre Road 
Bay St. Louis, MS  39520    
Pittsburgh, 
Permit No.:  MS0046515
SIC:  2819 (Industrial Inorganic Chemicals, Not Elsewhere Classified)
Permit Writer:  Samar Patel
EPD Branch:  Water I Branch

II.	NATURE OF BUSINESS

Calgon manufactures activated carbon from coal and coal tar pitch and impregnation of activated carbon.  The coal and pitch are mixed, ground into powder then compressed into briquettes.  The briquettes are crushed into granular form.  The granular material is fed into bakers then sent to a multiple hearth furnace where the carbon surface is activated. The facility also manufactures Cooperite and other products.

III.	EFFLUENT AND RECEIVING STREAM FLOW DATA

Outfall 001 – The process wastewater generated from F-line and G-line operations are identical in nature, which consists of steam condensate, scrubber blowdowns, non-contact cooling water, filter backwash, boiler blowdowns, process area washdown, water softening brine, cooling tower blowdowns, and storm water runoff from the process areas. Discharges from the F-line sump and from the G-line sump are joined below grade into a common buried pipe and flow through approximately 3 miles of underground pipeline and is discharged through a diffuser into Mulatto Bayou.  

Mulatto Bayou is a tributary of the Pearl River with a Mississippi water body classification of Fish & Wildlife.  The bayou is estuarine in nature.  

The discharge point, end of pipe, is located approximately 9 to 14 feet below the water surface of Mulatto Bayou.  A dilution ratio of one part effluent to six parts receiving water body has been used due to the absence of a site specific dilution ratio per 11 Miss. Admin. Code Pt. 6, R.1.2.6.D - Wastewater Regulations for National Pollutant Discharge Elimination System (NPDES) Permits, Underground Injection Control (UIC) Permits, State Permits, Water Quality Based Effluent Limitations and Water Quality Certification (Hereafter referred to as the Mississippi Wastewater Regulations).
	
Outfall 001:    Maximum Daily Flow = 0.754 MGD
		Long-Term Average = 0.441 MGD
IV.	303(d) ISSUES

	There are no 303(d) issues.

V.	TYPE OF WASTEWATER TREATMENT:

Outfall 001 – Neutralization, Oxidation, Flocculation, fine filtration, Flotation, and sludge dewatering, 

VI.	EPA APPLICABLE CATEGORICAL GUIDELINES

None.

VII.	DATA FROM APPLICATION FORM 2C
	
Pollutant/Parameter	Maximum Daily Value	Average	# Analysis	
BOD	<20 mg/L	--	1	
COD	13.98 mg/L	--	1	
TOC	1.31 mg/L	--	1	
TSS	44 mg/L	7.20 mg/L	25	
Ammonia (as N)	9.27 mg/L	2.17 mg/L	25	
Temperature  winter
                      summer	51.5oC
65.9 oC	48.9oC
58.7oC	2
2	
pH	8.9 s.u.	6.1 s.u. (min)	25	
Fluoride	3.50 mg/L	--	1	
Nitrate-Nitrite (as N)	0.99 mg/L	--	1	
Oil and Grease	ND	ND	25	
Total Phosphorus (as P)	0.442 mg/L	--	1	
Sulfite (as SO3)	54 mg/L	18.80 mg/L	25	
Aluminum	0.571 mg/L	--	1	
Boron	0.458 mg/L	--	1	
Total Iron	0.181 mg/L	--	1	
Total Magnesium	0.012 mg/L	--	1	
Total Molybdenum	0.014 mg/L	--	1	
Total Titanium	0.007 mg/L	--	1	
Total Antimony	0.009 mg/L	--	1	
Total Arsenic	0.031 mg/L	--	1	
Total Lead	0.010 mg/L	--	1	
Total Selenium	0.067 mg/L	--	1	
Total Thallium	0.002 mg/L	--	1	
Total Zinc	<0.05 mg/L	--	1	
	1ND = Non-Detech
	*Based on DMRs data from April 2022 through April 2024 and renewal application received 
                  on September 6, 2024. 

VIII.   WATER QUALITY LIMITATIONS BASED ON WASTELOAD ALLOCATION 

	Not Applicable

IX.	CATEGORICAL GUIDELINE LIMITATIONS CALCULATIONS

Not Applicable

X.	TOXICITY SCREENING

See Attachment  A.

XI.	PROPOSED FINAL LIMITATIONS 

1.	Average Permit Limitations

Parameter	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Basis1	Frequency	Sample Type	
Oil and Grease	---	10 mg/L	10 mg/L	ENG/ABS	Once/week	Grab	
pH (minimum)	6.0 s.u.	6.0 s.u.	6.0 s.u.	MSWQC	Once/week	Grab	
Total Suspended Solids (TSS)	---	30 mg/L	30 mg/L	ENG/ABS	Twice/Month	24-hr Composite	

2.	Maximum Permit Limitations

Parameter	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Basis1	Frequency	Sample Type	
Ammonia (as N)	---	---	Report	ENG	Once/Month	Grab	
Oil and Grease	---	15 mg/L	15 mg/L	ENG/ABS	Once/week	Grab	
pH (maximum)	9.0 s.u.	9.0 s.u.	9.0 s.u.	MSWQC	Once/week	Grab	
Total Suspended Solids (TSS)	---	45 mg/L	45 mg/L	ENG/ABS	Twice/Month	24-hr Composite	
Sulfite (as SO3)	---	225 mg/L	225 mg/L	ABS	Once/Month	24-hr Composite	

1 ABS = Anti-backsliding.  If there is a current permit limit which the facility is meeting, it shall remain in the permit as long as the facility has the potential to discharge reasonable amounts.  ENG = engineering judgment.  MSWQS = State of Mississippi Water Quality Criteria for Intrastate, Interstate, and Coastal Waters (referred to hereafter as the State of Mississippi Water Quality Criteria). 

Ammonia
Ammonia (as N) shall be reported.  Monitoring shall be once per month per a grab sample. 

Oil and Grease
Oil and Grease shall be limited to a maximum concentration of 15 mg/L and an average concentration of 10 mg/L.  These limits are based on accepted technology based treatment standards.  Monitoring shall be once per week and collected via a grab sample.

pH
The pH shall be limited to the range of 6.0 – 9.0 standard units per the State of Mississippi Water Quality Criteria.  Monitoring shall be once per week and collected via a grab sample.

Sulfite (as SO3)
Sulfite (as SO3) shall be limited to a maximum of 225 mg/L.  Monitoring shall be once per month and collected via a 24-hour composite sample.

Temperature
The effluent temperature for Calgon is measured prior to exiting the facility’s site; effluent temperature has been reported as high as 150°F.  The effluent travels through approximately 3 miles of underground pipeline thence a diffuser prior to discharging into Mulatto Bayou.  The effluent discharge from Calgon shall not cause the temperature of Mulatto Bayou to exceed 90°F after mixing nor shall the discharge raise the temperatures more than 4°F above natural conditions for temperature during the period of October through May nor more than 1.5°F above natural background temperature during the period of June through September. This condition was included in the Permit issued April 6, 2012. 

To ensure conformance with the State of Mississippi temperature criteria, the permittee shall continue to perform instream temperature monitoring with the frequency of once per quarter upon the effective reissuance date of the permit. The discharge shall not cause the ambient temperature of Mulatto Bayou at a downstream distance of 10 meters to exceed 90°F after mixing during the period of October through May and 16 meters downstream during the period of June through September. Nor shall the discharge raise the instream temperature of the Bayou more than 4°F above natural background temperature at a downstream distance of 10 meters during the period of October through May or more than 1.5°F above natural background temperature at a downstream distance of 16 meters during the period of June through September. A permit condition has been added that require monitoring of Mulatto Bayou instantaneously once per quarter at the following locations: at the point of diffuser discharge, 16 meters downstream of the discharge during the period of June through September, 10 meters downstream of the discharge during the period of October through May and at a point not influenced by the effluent discharge located at least 300 meters upstream of the discharge. The temperature measured upstream of the discharge shall represent the ambient, or background, temperature. This monitoring will ensure that the effluent temperature does not cause an exceedance of the State’s temperature criteria for the receiving stream. The sampling frequency for collecting Bayou temperatures shall be timed evenly to cover the seasonal extremes of the year such as hot-dry (i.e., two samples during the period of June-September) and cold-wet (i.e., two samples during the period of October-May). 

Total Suspended Solids (TSS)
Total suspended solids shall be limited to a maximum concentration of 45 mg/L and an average concentration of 30 mg/L.  These limits are indicative of adequate secondary treatment for TSS.  Monitoring shall be twice per month and collected via a 24-hour composite sample.

ATTACHMENT A

TOXICITY SCREENING

The toxicity screening is performed per the procedures in the Mississippi Wastewater Regulations, 11 Miss. Admin. Code Pt. 6, R.1.2.6.D.

Definitions
IWC	=	Instream Wastewater Concentration
Qr 	=	7Q10 of receiving stream (acute and chronic screening)
Qw	=	Maximum 30-day average wastewater flow
Xr	=	Receiving stream concentration; assumed zero in the absence of available data
Xw 	=	Historical effluent data
Xwa 	=	Permit limits from previous permit or from effluent guidelines; if no previous permit limit, the long term average concentration
Xta 	=	The calculated instream concentration based on existing permit limits or 
the calculated limit based on current effluent guidelines
Xt	=	The calculated instream concentration based on historical effluent data 
		from application
AWQC    =      Acute Water Quality Criterion value, as denoted in Table-2 of the
                       State Water Quality Criteria and/or the EPA- National Recommended Water
                       Quality Criteria.			
					
CWQC    =     Chronic water Quality Criterion value, as denoted in Table-2 of the
                       State Water Quality Criteria and/or the EPA- National Recommended Water
                       Quality Criteria.			
					
HHV       =     Human Health Value for consumption of organism, as denoted by 10-6
                       risk factors for carcinogens referenced in Table-2 of the State Water
                      Quality Criteria and/or the EPA- National Recommended Water Quality
                      Criteria.	
		
Calculationsa,b
Qw = 0.565 MGD
Qr = 7Q10 flow of receiving stream
IWC = 100*[Qw/(Qr + Qw))] = 100*[1/(6 + 1)] = 14.29%

Xr = 0
Xt = (Qw * Xw)/(Qr + Qw) = (IWC/100) * Xw
Xta = (Qw * Xwa)/(Qr + Qw) = (IWC/100) * Xwa

Acute Calculations:
Ammonia
Xw = (9.27 mg/L) * (17/14) = 11.26 mg/L
Xt = (0.1429 * 11.26 mg/L) = 1.60 mg/L

Nitrate-Nitrite (as N)c
Xw = (0.99 mg/L) * 10 = 9.9 mg/L
Xt = (0.1429 * 9.9 mg/L) = 1.414 mg/L

Total Ironc
Xw = (0.181 mg/L) * 10 = 1.81 mg/L
Xt = (0.1429 * 1.81 mg/L) = 0.80 mg/L

Total leadc
Xw = (0.010 mg/L) * 10 = 0.10 mg/L
Xt = (0.1429 * 0.10 mg/L) = 0.014 mg/L

Total Seleniumc
Xw = (0.067 mg/L) * 10 = 0.67 mg/L
Xt = (0.1429 * 0.67 mg/L) = 0.096 mg/L

Total Zincc
Xw = (0.05 mg/L) * 10 = 0.5 mg/L
Xt = (0.1429 * 0.5 mg/L) = 0.071 mg/L

Acute Valuesd:
Pollutant	Xw (mg/L)	Xt (mg/L)	Xwa (mg/L)	Xta (mg/L)	AWQC (mg/L)	Pass/Fail	
Ammonia 	11.26e	1.60	---	---	17.33f	Pass	
Nitrate-Nitrite (as N)g	9.9	1.41	---	---	---	---	
Total Irong	1.81	0.80	---	---	---	---	
Total Lead 	0.10	0.014	---	---	0.21	Pass	
Total Selenium	0.67	0.096	---	---	0.29	Pass	
Total Zinc	0.5	0.071	---	---	0.09	Pass	
a Since the receiving stream is estuarine in nature, a dilution factor of one part effluent to six parts receiving water body is assumed.  This dilution factor will be used for the screening of acute and chronic toxicity and human health criteria.
b It is assumed that Xr = 0 for all constituents of concern.
c Maximum concentration reported in Form 2C.  If < 12 samples, multiply by 10.
d Due to the estuary-like nature and high salinity near the mouth of the Pearl River, water quality limits will be calculated based on salt water criteria.
e The AWQC/CWQC available from EPA is for total ammonia; whereas, the value reported in Form 2C is reported as total nitrogen.  Therefore, the reported values have been multiplied by 17/14, the mole ratio of ammonia to nitrogen.
f The AWQC and CWQC were obtained from an EPA spreadsheet (see Attachment B) derived from EPA’s Ambient Water Quality Criteria for Ammonia (Saltwater) – 1989.  Based upon the maximum conditions at the Pearlington sampling station for data collected during September 1999, September 2000, and September 2001, the AWQC and CWQC for a pH of 7.3, salinity of 17.2 ppt, and temperature of 29oC were used.  
g There are no federal or state acute water quality criteria (saltwater) for nitrates or total iron.

Chronic and Human Health Calculations:

Ammonia
Xwa = (2.17 mg/L) * (17/14) = 2.635 mg/L
Xta = (0.1429 * 2.635 mg/L) = 0.377 mg/L

Nitrate-Nitrite (as N)c
Xw = (0.99 mg/L) * 10 = 9.9 mg/L
Xt = (0.1429 * 9.9 mg/L) = 1.414 mg/L
Total Ironc
Xw = (0.181 mg/L) * 10 = 1.81 mg/L
Xt = (0.1429 * 1.81 mg/L) = 0.80 mg/L

Total leadc
Xw = (0.010 mg/L) * 10 = 0.10 mg/L
Xt = (0.1429 * 0.10 mg/L) = 0.014 mg/L

Total Seleniumc
Xw = (0.067 mg/L) * 10 = 0.67 mg/L
Xt = (0.1429 * 0.67 mg/L) = 0.096 mg/L

Total Zincc
Xw = (0.05 mg/L) * 10 = 0.5 mg/L
Xt = (0.1429 * 0.5 mg/L) = 0.071 mg/L

Chronic and Human Health Valuesd:
Pollutant	Xw (mg/L)	Xt (mg/L)	Xwa (mg/L)	Xta (mg/L)	CWQC (mg/L)	Pass/Fail	HHWQC (mg/L)	Pass/Fail	
Ammonia	---	---	2.635e	0.377	2.60f	Pass	---	---	
Nitrate-Nitrite (as N)g	---	---	9.9	1.414	---	---	10.0	Pass	
Total Irong	---	---	1.81	0.80	---	---	0.3	Pass	
Total Lead 	---	---	0.10	0.014	     0.0081	Pass	---	---	
Total Selenium	---	---	0.67	0.096	    0.071	Pass	4.2	Pass	
Total Zinc	---	---	0.5	0.071	    0.081	Pass	26.0	Pass	
a Since the receiving stream is estuarine in nature, a dilution factor of one part effluent to six parts receiving water body is assumed.  This dilution factor will be used for the screening of acute and chronic toxicity and human health criteria.
b It is assumed that Xr = 0 for all constituents of concern.
c Maximum concentration reported in Form 2C.  If < 12 samples, multiply by 10.
d Due to the estuary-like nature and high salinity near the mouth of the Pearl River, water quality limits will be calculated based on saltwater criteria.
e The AWQC/CWQC available from EPA is for total ammonia; whereas the value reported in Form 2C is reported as total nitrogen.  Therefore, the reported values have been multiplied by 17/14, the mole ratio of ammonia to nitrogen.
f The AWQC and CWQC were obtained from an EPA spreadsheet (see Attachment B) derived from EPA’s Ambient Water Quality Criteria for Ammonia (Saltwater) – 1989.  Based upon the maximum conditions at the Pearlington sampling station for data collected during September 1999, September 2000, and September 2001, the AWQC and CWQC for a pH of 7.3, salinity of 17.2 ppt, and temperature of 29oC were used.  
g There are no federal or state chronic water quality criteria (saltwater) for nitrates or total iron.

ATTACHMENT B

Calculation of seawater fraction of un-ionized ammonia	
   from Hampson (1977).  Un-ionized ammonia criteria for 	
   salt water is from EPA 440/5-88-004.	
		
Based on Lotus File NH3SALT.WK1 Revised 19-Oct-93	
 	 	
INPUT	
		
1. Temperature (deg C):	29.0 	
 		
2. pH:	7.3 	
		
3. Salinity (g/Kg):	17.2 	
 	 	
OUTPUT	
		
1. Pressure (atm; EPA criteria assume 1 atm):	1.0 	
		
2. Molal Ionic Strength (not valid if >0.85):	0.349 	
		
3. pKa8 at 25 deg C (Whitfield model "B"):	9.285 	
		
4. Percent of Total Ammonia Present as Unionized:	1.344%	
		
5. Unionized ammonia criteria (mg un-ionized NH3 per liter)		
     from EPA 440/5-88-004		
      Acute:	0.233 	
      Chronic:	0.035 	
		
6. Total Ammonia Criteria (mg/L as NH3)		
      Acute:	17.33 	
      Chronic:	2.60 	
		
7. Total Ammonia Criteria (mg/L as NH3-N)		
      Acute:	14.25 	
      Chronic:	2.14