PERMIT RATIONALE FOR REISSUANCE 
International Paper Company, Vicksburg Mill
Warren County
Redwood, Mississippi
Water NPDES Permit No. MS0000191
September 4, 2025

I.	FACILITY INFORMATION

Facility Name:  	International Paper Company, Vicksburg Mill
Facility Address:  	3737 Highway 3 North 
	Redwood, MS  39156    
Redwood, 
Permit No.:  		MS0000191
SIC Code:  		2631
Permit Writer:  	Rajeev Gupta
EPD Branch:  		Water II  

II.	NATURE OF BUSINESS

International Paper Company, Vicksburg Mill (IP) is an integrated pulp and paper mill that manufactures unbleached linerboard and paperboard from the kraft pulping and Fourdrinier paper making process.   
  
According to the permit application, the facility averages 1,496 air dry tons per day of unbleached kraft linerboard product and 175 dry tons per day of paperboard.    

III.	EFFLUENT AND RECEIVING STREAM FLOW DATA

The facility has one outfall which they have applied to be permitted for.  The effluent from Outfall 001 consists of process and non-process wastewater from the production of unbleached kraft linerboard and paperboard.  The average flow from Outfall 001 as reported in the application is 15.82 MGD.  The operations which contribute to discharge from this outfall include the following:

Wastewater Description	Wastewater Flows	
Paper mill	5,694 gpm = 8.199 MGD	
Pulp mill, caustic plant, and wood yard	662 gpm = 1.241 MGD	
Power plant	962 gpm = 1.414 MGD  	
Foul condensate	552 gpm = 1.464 MGD  	
Ash dewatering	680 gpm = 0.979 MGD	
Contact storm water	500 gpm = 0.720 MGD	
Raw water clarifier	355 gpm = 0.511 MGD	
Landfill leachate  	200 gpm = 0.288 MGD  	

Outfall 001 discharges into the Yazoo River in the Yazoo River Basin.  The Yazoo River’s designated use is Fish and Wildlife and has a 7Q10 flow of 750 MGD. 

IV.	TOTAL MAXIMUM DAILY LOAD (TMDL) AND 303(d) ISSUES

The Yazoo River at this location does not appear on the 2024 State of Mississippi 303(d) List of Impaired waterbodies.  This permit complies with the following applicable TMDLs:

•	Fecal Coliform TMDL for the Yazoo River Yazoo River Basin Carroll, Holmes, Leflore and Warren Counties, Mississippi (Final Report June 2003; ID# 903063013)
•	Total Maximum Daily Loads for The Legacy Pesticides DDT and Toxaphene in The Yazoo River Basin (Final Report November 2005; ID# 905110401)
•	Total Maximum Daily Load Yazoo River Basin Delta Region for Impairment Due to Sediment (Final Report April 2008; ID# 908041702)
•	Total Maximum Daily Load Total Nitrogen and Total Phosphorus For Selected Large Rivers in the Delta Yazoo River Basin (Final Report June 2008; ID# 908063054)

V.	TYPE OF WASTEWATER TREATMENT
	
The Main Process Sewer collects wastewater from each process area including the Pulp Mill, Paper Mill, Power Plant, Caustic, Woodyard and Crude Tall Oil Plant, Ash Dewater Basin, Raw Water Clarifier Slowdown, Landfill Leachate, and Contact Stormwater.  Process wastewater conveyances include constructed channels and sewers as well as an earthen ditch system.  Foul Condensate is collected and pumped directly to the ASB.  Wastewater that is collected in the Main Process Sewer is first treated with carbon dioxide to the adjust the pH, if necessary, and then discharged into a large primary settling basin (Pond #1) by way of the earthen ditch.  Primary settling and flow equalization occur in Pond #1.  Pond #1 has a retention time of approximately 6 hours before being discharged in the ASB.

The ASB receives the wastewater from Pond #1 and the Foul Condensate from the Pulp Mill digesters and Power Plant evaporators.  This unit is equipped with surface aerators.  In addition to aeration, a defoaming agent and nutrient can be supplied from tanks sited near the basin to aid in treatment.  The combined wastewater is then discharged into the Annex for additional aeration.  The ASB and Annex have a retention time of approximately 3 days.  

From the Annex, wastewater then flows through the polishing pond (Pond #2) for final treatment and settling.  Pond #2 is equipped with partitions and baffle curtains to increase the retention time and allow biologic activity to polish the wastewater prior to discharge through Outfall 001 into the Yazoo River.  Pond #2 has a retention time of approximately 5.5 days.

VI.	
EPA APPLICABLE CATEGORICAL GUIDELINES AND LIMITATION CALCULATIONS

40 CFR Part 430 – The Pulp, Paper, and Paperboard Point Source Category; specifically, Subpart C – Unbleached Kraft Subcategory: 40 CFR 430.32 (BPT) and 40 CFR 430.34(BAT); Subpart J – Secondary Fiber Non-Deink Subcategory: 40 CFR 430.102 (BPT) and 40 CFR 430.104 (BAT) 

	Section 316(b) of the Clean Water Act for existing power generating facilities and existing manufacturing and industrial facilities that are designed to withdraw more than 2 MGD of water from waters of the United States and use at least 25 % of the water they withdraw exclusively for cooling purposes does not apply to this facility because the cooling water is reused for other processes; it is not exclusively used for cooling.  

VII.	NPDES FORM 2C APPLICATION DATA  

A.  OUTFALL 001 (In terms of concentration)

Maximum		Maximum 		Long	     		
Daily			30 Day			Term			No. of 
Parameter		Value			Value			Average Value	Samp.
BOD			248 mg/L		---			55 mg/L		711
COD			1,670 mg/L		---			438 mg/L		1596
TOC			59.1 mg/L		---			---			1
TSS			231 mg/L		---			79 mg/L		713
Ammonia		15.6 mg/L		---			2.92 mg/L		109
Flow			37.2 MGD		23.46 MGD		15.82 MGD		1598
Temp. (Winter)	29.1 deg C		---			17.0 deg C		868
Temp. (Summer)	34.4 deg C		---			27.1 deg C		730
pH (max)		8.9 s.u.			---			7.8 s.u.	       	    	1598
Fecal Colifom		18 mpn/100 ml	---			---			1
Total Phosphorus 	4.20 mg/L		---			1.15			61
(as P)
Total Organic 
Nitrogen (as N)	32.6 mg/L		---			5.34 mg/L		61
Total Aluminum	1.45 mg/L		---			---			1
Total Iron		0.810 mg/L		---			---			1
Total Arsenic		0.000905 mg/L	---			---			1
Total Cadmium	0.000310 mg/L	---			---			1
Total Chromium	0.00264 mg/L		---			---			1
Total Copper		0.00431 mg/L		---			---			1
Total Mercury		3.56 ng/L		---			---			5
Total Nickel		0.00457 mg/L		---			---			1
Total Silver		0.000101 mg/L							1
Total Zinc		0.0414 mg/L		---			---			1
Pentachlorophenol	<62.5 ppb		---			---			1
Trichlorophenol	<62.5 ppb		---			---			1
	
OUTFALL 001 (In terms of Mass)

Maximum		Maximum 		Long	     		
Daily			30 Day			Term			No. of 
Parameter		Value			Value			Average Value	Samp.
BOD			34,900 #/day		---			6,650 #/day		711
COD			177,000 #/day		---			55,700 #/day		1596
TOC			8,920 #/day		---			---			1
TSS			41,800 #/day		---			9,600 #/day		713
Ammonia		2,260 #/day		---			421 #/day		109
Total Phosphorus 	396 #/day		---			159 #/day 		61
(as P)
Total Organic 
Nitrogen (as N)	3050 #/day		---			722 #/day		61
Total Aluminum	219 #/day		---			---			1
Total Iron		122 #/day		---			---			1
Total Arsenic		0.136 #/day		---			---			1
Total Cadmium	0.0468  #/day		---			---			1
Total Chromium	0.398 #/day		---			---			1
Total Copper		0.650 #/day		---			---			1
Total Mercury		0.000537 #/day	---			---			5
Total Nickel		0.689 #/day		---			---			1
Total Silver		0.152 #/day		---			---			1
Total Zinc		6.25 #/day		---			---			1

VIII. 	PROPOSED PERMIT LIMITATIONS 

	Average Permit Limitations

Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation (PPL)	Proposed Permit Limitation	Basis1	
NH3-N	-----	2,755 lb/day
15 mg/L	2,755 lb/day
19 mg/L	2,755 lb/day
19 mg/L	MSWQS	
BOD5	9357.6 lb/day	8,815 lb/day 	8,815 lb/day	8,815 lb/day
	TJ/MSWQS  
	
TSS  	19562 lb/day	Report	18,925 lb/day
	18,925 lb/day
	TJ	
Pentachlorophenol	----	0.22 mg/L	----	—	Categorical	
pH (minimum)	6.0 SU	6.0 SU	6.0 SU	6.0 SU	CAT/MSWQS	
4TN	N/A	4,154 lb/day	4154 lbs/day	4,154 lb/day	MSWQS	
4TP  	N/A	517 lb/day	517 lbs/day	517 lb/day	MSWQS	

	Maximum Permit Limitations

Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation (PPL)	Proposed Permit Limitation	Basis1	
NH3-N	-----	-----	4133 lbs/day
28 mg/L	4,133 lb/day
28 mg/L	TJ	
BOD5	18750 lb/day	-----	17,442 lb/day
	17,442 lb/day	TJ	
TSS	39124 lb/day
	-----	37,850 lb/day	37,850 lb/day	TJ	
Pentachlorophenol 	2.0395 lb/day
	0.287 mg/L	1.83 lb/day
0.015 mg/L	---	CAT
	
Trichlorophenol 	1.691 lb/day
	0.066 mg/L	1.67 lb/day
0.014 mg/L	---	CAT
	
pH(maximum)	9.0 SU	9.0 SU	9.0 SU	9.0 SU	CAT/MSWQS	
4TN	-----	-----	6,231 lb/day	6,231 lb/day	TJ	
4TP  	-----	-----	776 lb/day	776 lb/day	TJ	

1TJ = Technical Judgment; CAT = Categorical Limitation; MSWQS = State of Mississippi Water Quality Criteria 

Flow

Flow shall be measured continuously using a continuous recorder.  

pH

The pH limitations are based on the categorical limitations and the State of Mississippi Water Quality Criteria.  pH shall be monitored twice per week with a grab sample of the effluent.  

Total Suspended Solids (TSS)

The TSS limitations are based on technical judgement and the existing limitations found in the permit.  TSS shall be monitored twice per week with a grab sample of the effluent.  

BOD5

The average BOD5 limitation is based on technical judgement and the limitation found in the existing permit. As part of the permitting for the existing permit, Internation Paper submitted a modeling study in which they requested to reduce the CBOD5  limit to 8,815 lbs/day. The facility submitted the study as part of a request to remove dissolved oxygen from the permit.  Modeling has been performed using the existing limitation to ensure the limit is still protective of water quality.  The maximum limitation is based on the existing permit limitation and was calculated using the the 99th percentile daily maximum permit limit for normal distribution formula found on page E-4 of EPA’s Technical Support Document For Water Quality-based Toxics Control, EPA/505/2-90-001, March 1991.  BOD5 shall be monitored twice per week with a grab sample of effluent.  

Total Nitrogen and Total Phosphorus

The average limits for TN and TP are based on existing permit limitations and the Wasteload Allocation (WLA) received from MDEQ’s Modeling and TMDL Branch on August 18, 2025.  These limits comply with the 2008 Total Nitrogen and Total Phosphorus TMDL for selected large rivers in the Delta.  The maximum limitations are based on the average limitations times a multiplication factor of 1.5.  Both pollutants shall be monitored monthly with a grab sample of the effluent.  

Pentachlorophenol and Trichlorophenol 

Limitations for these parameters are required to be addressed as per the categorical regulations. In the categorical regulations, it is stated that, in lieu of monitoring for these parameters, the permittee may certify to the permitting authority that it is not using these compounds as biocides. The permittee has provided correspondence in which they certify that they are not using chlorophenolic containing biocides. Furthermore, the testing for these parameters revealed them to be non-detect in the effluent as reported in the permit application.  As such, International Paper will not be required to monitor for these parameters as part of the permit.

Ammonia (as N)

The Ammonia limits proposed are based on existing permit conditions.  As part of the permitting for the existing permit, Internation Paper submitted a modeling study in which they requested to reduce the average Ammonia (as N) concentration limit from 25 mg/L to 15 mg/L.  The flow used to perform the study was 22.02 MGD.  The facility submitted the study as part of a request to remove dissolved oxygen from the permit.   Modeling was performed which indicated 2,755 lbs/day to be protective of water quality.  The maximum limit was derived based on 2,755 lbs/day times a multiplication factor of 1.5.  The concentration limits are based on the long term average flow provided in the last application 14.57 MGD with an additional 20% for fluctuation. A flow of 17.5 MGD was then utilized.  Modeling has been performed which indicates the average limitation is still protective of water quality.  Ammonia (as N) shall be monitored twice per month with a grab sample of the effluent.  

Other Conditions 

As part of the existing permit, the facility is required to perform Whole Effluent Toxicity (WET) tests. Specifically, the facility is required to perform Chronic Bioassays.  The facility is currently subject to an Inhibition Concentration 25 (IC25) limit of 2.4% for the Chronic Bioassay.  A limit of 3.0 % is being set based on the current IWC as per the State of Mississippi Wastewater regulations.    

ATTACHMENT A

	CATEGORICAL GUIDELINES SAMPLE CALCULATIONS

ATTACHMENT A
	
	Categorical Guideline Sample Calculations

OUTFALL 001

The following table is extracted from 40 CFR Part 430.32 (Unbleached Kraft Facilities)
     
Avg.				Max. 
Parameter		(lbs/ 1000 lbs of gross production) 

BOD5			2.8				5.6
TSS			6.0				12.0
pH				6.0-9.0 s.u.

1,496 tons/per day Production Rate  

Avg.				Max.
Parameter			     (lbs/day)

BOD5			8377.6				16755.2
TSS			17952				35904

The following table is extracted from 40 CFR Part 430.34 (Unbleached Kraft Facilities)

Parameter					Maximum Limitations

lbs/1000 lbs		mg/L
Pentachlorophenol				0.00058		(0.011)(12.6)/y
Trichlorophenol				0.00053		(0.010)(12.6)/y

Concentration limitations are only applicable to non-continuous dischargers and are therefore not applicable.

Maximum Limitations

Parameter					lbs/day		mg/L
Pentachlorophenol				1.735		----
Trichlorophenol				1.586		----

OUTFALL 001

The following table is extracted from 40 CFR Part 430.102 (Corrugating Medium Finish Subdivision)

Avg.				Max. 
Parameter		(lbs/ 1000 lbs of gross production) 

BOD5			2.8				5.7
TSS			4.6				9.2
pH				6.0-9.0 s.u.

175 tons/per day Production Rate  

Avg.				Max.
Parameter			     (lbs/day)

BOD5			980				1995
TSS			1610				3220

The following table is extracted from 40 CFR Part 430.104 (Paperboard from Wastepaper is produced)

Parameter					Maximum Limitations

lbs/1000 lbs		mg/L
Pentachlorophenol				0.00087		(0.029)(7.2)/y
Trichlorophenol				0.00030		(0.010)(7.2)/y

Concentration limitations are only applicable to non-continuous dischargers and are therefore not applicable.

Maximum Limitations

Parameter					lbs/day		mg/L
Pentachlorophenol				0.3045		----
Trichlorophenol				0.105		----

TOTAL CATEGORICAL LIMITATIONS CALCULATIONS

BOD5 (Avg.) = 8377.6 + 980 = 9357.6 #/day
BOD5 (Max) = 16755.2 + 1995 = 18750.2 #/day

TSS (Avg.) =17952 +1610 = 19562 #/day 
TSS (Max) =35904 + 3220 = 39124 #/day

Pentachlorophenol (Max) = 1.735+0.3045 = 2.0395 #/day
Trichlorophenol (Max) =  1.586+0.105 = 1.691 #/day

ATTACHMENT B

	TOXICITY SCREENING PROCEDURE

ATTACHMENT B 

Outfall 001

Water Quality Evaluation for discharge to the Yazoo River

IWC 	=	Instream Wastewater Concentration
QW	=	maximum 30 day average wastewater flow, if available
Qr 	=	receiving stream flow 
Xr	=	receiving stream concentration
XW	=	historical effluent data
XWa 	=	permit limits from previous permit or from effluent guidelines
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

QW =23.46 MGD (Maximum 30 Day Value for Flow as reported in Form 2C Application)
Qr = 1160 cfs = 749.7 MGD (7Q10)
IWC (7Q10) = 3.03%

MDEQ has no ambient in-stream metals data for the Yazoo River.  The background concentration of the pollutants for toxicity screening purposes has been assumed to be 0 mg/L
 
Total Aluminum  
XW (long term average (LTA) as reported in application) = 0.810 mg/L
Xw = 1.45 mg/L* 10 (number of samples < 12) = 14.5 mg/L
Xt = (23.46 MGD*14.5 mg/L)/(23.46 +749.7) = 0.439 mg/L  
AWQC = 1.2 mg/L
CWQC = 0.46 mg/L
HHWQC = No Data Available

Total Iron
XW (long term average (LTA) as reported in application) = 0.810 mg/L
Xw = 0.810 mg/L* 10 (number of samples < 12) = 8.10 mg/L
Xt = (23.46 MGD*8.10 mg/L)/(23.46 +749.7) = 0.245 mg/L  
AWQC = No Data Available
CWQC = 1.0 mg/L
HHWQC = No Data Available

Total Arsenic
XW (long term average (LTA) as reported in application) = 0.000905 mg/L
Xw = 0.000905 mg/L* 10 (number of samples < 12) = 0.00905 mg/L
Xt = (23.46 MGD*0.00905 mg/L)/(23.46 +749.7) = 0.000274 mg/L  
AWQC = 0.340 mg/L
CWQC = 0.150 mg/L
HHWQC = 0.024 mg/L

Total Cadmium
XW (long term average (LTA) as reported in application) = 0.000310 mg/L
Xw = 0.000310 mg/L* 10 (number of samples < 12) = 0.00310 mg/L
Xt = (23.46 MGD*0.00310 mg/L)/(23.46 +749.7) = 0.0000939 mg/L  
AWQC = 0.00103 mg/L
CWQC = 0.00015 mg/L
HHWQC = 0.168 mg/L

Total Chromium
XW (long term average (LTA) as reported in application) = 0.00264 mg/L
Xw = 0.00264 mg/L* 10 (number of samples < 12) = 0.0264 mg/L
Xt = (23.46 MGD*0.0264 mg/L)/(23.46 +749.7) = 0.000799 mg/L  
AWQC = 0.323 mg/L
CWQC = 0.042 mg/L
HHWQC = 140.468 mg/L

Total Copper
XW (long term average (LTA) as reported in application) = 0.00431 mg/L
Xw = 0.00431 mg/L* 10 (number of samples < 12) = 0.0431 mg/L
Xt = (23.46 MGD*0.0431 mg/L)/(23.46 +749.7) = 0.00131 mg/L  
AWQC = 0.007 mg/L
CWQC = 0.005 mg/L
HHWQC = 1.0 mg/L

Total Mercury 
XW (long term average (LTA) as reported in application) = 0.00431 mg/L
Xw = 0.00000356 mg/L* 10 (number of samples < 12) = 0.0000356 mg/L
Xt = (23.46 MGD*0.0000356 mg/L)/(23.46 +749.7) = 0.000001 mg/L  
AWQC = 0.0021 mg/L
CWQC = 0.000012 mg/L
HHWQC = 0.000153 mg/L

Total Nickel
XW (long term average (LTA) as reported in application) = 0.00457 mg/L
Xw = 0.00457 mg/L* 10 (number of samples < 12) = 0.0457 mg/L
Xt = (23.46 MGD*0.0457 mg/L)/(23.46 +749.7) = 0.00138 mg/L  
AWQC = 0.260 mg/L
CWQC = 0.029 mg/L
HHWQC = 4.6 mg/L

Total Silver
XW (long term average (LTA) as reported in application) = 0.000101 mg/L
Xw = 0.000101 mg/L* 10 (number of samples < 12) = 0.00101 mg/L
Xt = (23.46 MGD*0.00101 mg/L)/(23.46 +749.7) = 0.00003 mg/L  
AWQC = 0.00098 mg/L
CWQC = No Data Available
HHWQC = 0.1 mg/L

Total Zinc
XW (long term average (LTA) as reported in application) = 0.0414 mg/L
Xw = 0.0414 mg/L* 10 (number of samples < 12) = 0.414 mg/L
Xt = (23.46 MGD*0.414 mg/L)/(23.46 +749.7) = 0.0125 mg/L  
AWQC = 0.065 mg/L
CWQC = 0.065 mg/L
HHWQC = 26 mg/L

	Toxicity Screening Summary
	Acute Screening	
Parameter			Xt			AWQC		Pass/Fail
Total Aluminum		0.439 mg/L		1.20 mg/L		Pass
Total Iron			0.245 mg/L		—			N/A
Total Arsenic			0.000274 mg/L	0.340 mg/L		Pass
Total Cadmium		0.0000939 mg/L	0.00103 mg/L		Pass
Total Chromium		0.000799 mg/L	0.323 mg/L 		Pass
Total Copper			0.00131 mg/L		0.007 mg/L 		Pass
Total Mercury			0.000001 mg/L	0.0021 mg/L		Pass
Total Nickel			0.00138 mg/L		0.260 mg/L 		Pass
Total Silver			0.00003 mg/L		0.00098		Pass
Total Zinc			0.0125 mg/L		0.065 mg/L		Pass

Chronic Screening
Parameter			Xt			CWQC		Pass/Fail
Total Aluminum		0.439 mg/L		0.46 mg/L		Pass
Total Iron			0.245 mg/L		1.0 mg/L		Pass
Total Arsenic			0.000274 mg/L	0.150 mg/L		Pass
Total Cadmium		0.0000939 mg/L	0.00015 mg/L		Pass
Total Chromium		0.000799 mg/L	0.042 mg/L		Pass
Total Copper			0.00131 mg/L		0.005 mg/L		Pass
Total Mercury			0.000001 mg/L	0.000012		Pass
Total Nickel			0.00138 mg/L		0.029 mg/L		Pass
Total Silver			0.00003 mg/L		—			N/A
Total Zinc			0.0125 mg/L		0.065 mg/L		Pass

	Human Health Screening	
Parameter			Xt			HHWQC		Pass/Fail
Total Aluminum		0.439 mg/L		—			N/A
Total Iron			0.245 mg/L		—			N/A
Total Arsenic			0.000274 mg/L	0.024 mg/L		Pass
Total Cadmium		0.0000939 mg/L	0.168 mg/L		Pass
Total Chromium		0.000799 mg/L	140.468 mg/L		Pass
Total Copper			0.00131 mg/L		1.0 mg/L		Pass
Total Mercury			0.000001 mg/L	0.000153 mg/L	Pass
Total Nickel			0.00138 mg/L		4.6 mg/L		Pass
Total Silver			0.00003 mg/L		0.1 mg/L		Pass
Total Zinc			0.0125 mg/L		26 mg/L		Pass

As can be seen above, the facility passed the toxicity screening for all pollutants.

ATTACHMENT C

WASTELOAD ALLOCATION

ATTACHMENT D

WATER QUALITY CALCULATIONS

ATTACHMENT D

	Water Quality Calculations

Maximum 30 day value for flow for Outfall 001 as reported on the Form 2C = 23.46 MGD
7Q10 of the Yazoo River= 749.7 MGD

Instream Waste Concentration(7Q10)  = 3.03 %

Parameter			Acute Screening Value		Chronic Screening Value
Total Pentachlorophenol	      0.0087 mg/L			     0.0067 mg/L 	

Parameter			Human Health Screening Value (Organism Consumption)
Trichlorophenol			0.002 mg/L

Total Pentachlorophenol, Acute	0.0087/0.0303 = 0.287 mg/L
Total Pentachlorophenol, Chronic	0.0067/0.0303	= 0.22 mg/L
    
Trichlorophenol, Acute or Max limit	0.002/0.0303 = 0.066 mg/L