PERMIT RATIONALE FOR REISSUANCE
Twin Rivers Paper Company LLC
Holmes County
Pickens, Mississippi
Water NPDES Permit No. MS0000795
January 25, 2019  

I.	FACILITY INFORMATION

Facility Name:  	Twin Rivers Paper Company LLC
Facility Address:  	196 Burrows Drive 
	Pickens, MS  39146    

Permit No.:  		MS0000795
SIC Code:  		2621
Permit Writer:  	Carter Cress  
EPD Branch:  		Water II  

II.	NATURE OF BUSINESS

This facility is a paper mill that manufactures lightweight specialty tissue paper.  

III.	EFFLUENT AND RECEIVING STREAM FLOW DATA

Outfall No.	Outfall Description	Facility Maximum Discharge Flow	Receiving Stream	Outfall Location	
		Receiving Stream Designated Use			
		Receiving Stream Basin			
		Receiving Stream 7Q10 Flow			
001	1.	Process Wastewater 
2.	Seal Water
3.	Non-contact Cooling Water  
4.	Boiler Blowdown   	1.31 MGD  	Big Black River	Latitude: 
32º 53' 24.25''
Longitude: 
89º 57' 36.60''	
	1.		Fish and Wildlife  			
	1.		Big Black River Basin  			
		51 cfs = 33 MGD  			

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

The receiving stream, Big Black River, is listed on the Mississippi 2016 Section 303(d) List of Impaired Water Bodies.  However, the 303(d) issues do not apply for this facility’s wastewater discharge because the sections of the Big Black River that are listed as impaired are located in Webster, Choctaw, Yazoo, Madison, Hinds, and Warren Counties.  The affected portions of the Big Black River are listed for biological impairment and pH.  

A TMDL for low pH was established on March 23, 2001 for the lower Big Black River that resides in Madison and Yazoo Counties.  As stated in the conclusion on page 22 of the TMDL report: the TMDL will not impact existing or future NPDES Permits as long as the effluent meets water quality standards for pH.

V.	TYPE OF WASTEWATER TREATMENT

The wastewater effluent passes through a Dissolved Air Flotation (DAF) unit, filtration system, and a cooling tower prior to being discharged.  

VI.	EPA APPLICABLE CATEGORICAL GUIDELINES

40 CFR Part 430 – The Pulp, Paper, and Paperboard Point Source Category.  

VII.	PERTINENT DATA FROM APPLICATION FORM NPDES 2C    

Parameter	Maximum Daily Value	
Flow	1.31 MGD	
Biochemical Oxygen Demand (BOD)	475.7 lb/day	
Chemical Oxygen Demand (COD)	43.2 mg/L	
Total Organic Carbon (TOC)	11.8 mg/L  	
Total Suspended Solids (TSS)	605.9 lb/day  	
Ammonia 	17.49 lb/day	
Nitrogen 	24.3 lb/day	
Phosphorus	5.7 lb/day  	
Cadmium	< 0.00045 lb/day	
Copper	0.15 lb/day  	
Lead	0.0093 lb/day  	
Chlorine	0.59 mg/L  	
Winter Temperature	26.67 ºC = 80.01 ºF  	
Summer Temperature	32.06 ºC = 89.71 ºF	
Minimum pH	7.8 SU	
Maximum pH	8.5 SU  	

VIII. 	WATER QUALITY LIMITATIONS BASED ON WASTELOAD ALLOCATION (WLA) 

Parameter	Average Value  	
Flow	1.205 MGD*  	
Carbonaceous Biochemical Oxygen Demand (CBOD5)	55 mg/L  	
Ammonia Nitrogen  	3 mg/L  	
Dissolved Oxygen	6 mg/L (minimum)	
E. coli Bacteria  	126 col./100 mL  	
Chlorine	0.352 mg/L	
Nitrogen 	Report	
Phosphorus	Report	
pH	6 – 9 SU  	

*WLA modeling was run with 0.905 MGD as process wastewater and 0.3 MGD used as dilution.  These values were originally obtained from the permit application.    

IX.	CATEGORICAL GUIDELINE LIMITATIONS CALCULATIONS
40 CFR Part 430 – The Pulp, Paper, and Paperboard Point Source Category; specifically, Subpart J – Secondary Fiber Non-Deink Subcategory: 40 CFR 430.102 (BPT)

BPT effluent limitations for secondary fiber non-deink facilities where tissue from wastepaper is produced without deinking:
Pollutant or pollutant property	Kg/kkg (or pounds per 1,000 lb) of
product	
	Continuous dischargers	
	Maximum for any 1 day	Average of daily values for 30 consecutive days	
BOD5	13.7	7.1	
TSS	17.05	9.2	
pH	(1)	(1)	
1Within the range of 5.0 to 9.0 at all times.
3.05 tons per day average daily production rate; obtained from application Form NPDES 2C.     
Daily Maximum LOAD:
BOD5:	(13.7 lb/1000 lb)*(3.05 ton/day)*(2000 lb/ton) = 83.6 lb/day   
TSS:	(17.05 lb/1000 lb)*(3.05 ton/day)*(2000 lb/ton) = 104 lb/day
pH:	5.0 – 9.0 SU    
Monthly Average LOAD:
BOD5:	(7.1 lb/1000 lb)*(3.05 ton/day)*(2000 lb/ton) = 43.3 lb/day   
TSS:	(9.2 lb/1000 lb)*(3.05 ton/day)*(2000 lb/ton) = 56.1 lb/day
pH:	5.0 – 9.0 SU    

NOTE: 40 CFR 430.104 (BAT) does not apply for this facility because it has certified to the permit-issuing authority in the past that chlorophenolic-containing biocides are not used.  

40 CFR Part 430 – The Pulp, Paper, and Paperboard Point Source Category; specifically, Subpart K – Fine and Lightweight Papers from Purchased Pulp Subcategory: 40 CFR 430.112 (BPT)

BPT effluent limitations for non-integrated mills where lightweight papers are produced from purchased pulp:
Pollutant or pollutant property	Kg/kkg (or pounds per 1,000 lb) of
product	
	Continuous dischargers	
	Maximum for any 1 day	Average of daily values for 30 consecutive days	
BOD5	24.1	13.2	
TSS	21.6	      10.6	
pH	(1)	(1)	
1Within the range of 5.0 to 9.0 at all times.
1.02 tons per day average daily production rate; obtained from application Form NPDES 2C.     
Daily Maximum LOAD:
BOD5:	(24.1 lb/1000 lb)*(1.02 ton/day)*(2000 lb/ton) = 49.2 lb/day   
TSS:	(21.6 lb/1000 lb)*(1.02 ton/day)*(2000 lb/ton) = 44.1 lb/day
pH:	5.0 – 9.0 SU    
Monthly Average LOAD:
BOD5:	(13.2 lb/1000 lb)*(1.02 ton/day)*(2000 lb/ton) = 26.9 lb/day   
TSS:	(10.6 lb/1000 lb)*(1.02 ton/day)*(2000 lb/ton) = 21.6 lb/day
pH:	5.0 – 9.0 SU    

NOTE: 40 CFR 430.114 (BAT) does not apply for this facility because it has certified to the permit-issuing authority in the past that chlorophenolic-containing biocides are not used.  

40 CFR Part 430 – The Pulp, Paper, and Paperboard Point Source Category; specifically, Subpart L – Tissue, Filter, Non-woven, and Paperboard from Purchased Pulp Subcategory: 40 CFR 430.122 (BPT)
BPT effluent limitations for non-integrated mills where tissue papers are produced from purchased pulp:
Pollutant or pollutant property	Kg/kkg (or pounds per 1,000 lb) of
product	
	Continuous dischargers	
	Maximum for any 1 day	Average of daily values for 30 consecutive days	
BOD5	11.4	6.25	
TSS	10.25	5.0	
pH	(1)	(1)	
1Within the range of 5.0 to 9.0 at all times.
80.0 tons per day average daily production rate; obtained from application Form NPDES 2C.     
Daily Maximum LOAD:
BOD5:	(11.4 lb/1000 lb)*(80.0 ton/day)*(2000 lb/ton) = 1824 lb/day   
TSS:	(10.25 lb/1000 lb)*(80.0 ton/day)*(2000 lb/ton) = 1640 lb/day
pH:	5.0 – 9.0 SU    
Monthly Average LOAD:
BOD5:	(6.25 lb/1000 lb)*(80.0 ton/day)*(2000 lb/ton) = 1000 lb/day   
TSS:	(5.0 lb/1000 lb)*(80.0 ton/day)*(2000 lb/ton) = 800 lb/day
pH:	5.0 – 9.0 SU    

NOTE: 40 CFR 430.124 (BAT) does not apply for this facility because it has certified to the permit-issuing authority in the past that chlorophenolic-containing biocides are not used.  

TOTAL Categorical Limitation LOADS from all applicable Subparts	
Pollutant	Daily Maximum (lb/day)	Monthly Average (lb/day)	
BOD5	83.6 + 49.2 + 1824 = 1957 	43.3 + 26.9 + 1000 = 1070	
TSS	104 + 44.1 + 1640 = 1788	56.1 + 21.6 + 800 = 878    	
pH	5.0 – 9.0 SU	

X.	CHEMICAL TRANSLATOR CALCULATIONS

The dissolved fraction may be calculated from site specific Total Suspended Solids (TSS) data and partitioning coefficients listed in the Technical Guidance Manual for Performing Wasteload Allocations.  Book II: Streams and Rivers.  Chapter 3 (EPA 440/4-84-022).  The Linear Partition Coefficient is calculated using the following formula:

Kp = Kpo * TSSa

Where:	Kp = 	Linear Partition Coefficient
	Kpo = 	Regression Coefficient (from table)
	TSS =	Total Suspended Solids Concentration (site specific 15th percentile)
	a = 	Exponent Constant (from table)

The Dissolved Fraction is then calculated as follows:

C/CT = 1/(1 + (Kp * TSS * 10-6))

Where: C/CT = Dissolved Fraction of metal

The permit limits are then calculated as follows:

Permit Limit = Screening Value/C/CT

During the permit issuing process in the past, the facility had failed the toxicity screening for total recoverable copper, total recoverable lead, and total recoverable cadmium and had requested during phone conversations that permit limitations for these metals be established using the Linear Partition Coefficient approach.

The facility collected 38 samples for TSS during the 2009 calendar year.  Using Excel software, the site specific 15th percentile was calculated as being 2 mg/L.   

Kp, Kpo, and a for total recoverable copper, total recoverable lead, and total recoverable cadmium are as follows:

Total Recoverable Copper:
	Kp = 	621137
	Kpo =	1.04 * 106
	a = 	-0.7436
C/CT = 0.446

Total Recoverable Cadmium:
	Kp = 	1826776
	Kpo =	4 * 106
	a = 	-1.1307
C/CT = 0.214

Total Recoverable Lead:
	Kp = 	1608178
	Kpo =	2.8 * 106
	a = 	-0.8
C/CT = 0.237

Parameter			Acute Screening Value	Chronic Screening Value
Total Recoverable Cadmium	     	0.001 mg/L			0.00015 mg/L 	
Total Recoverable Lead		0.03 mg/L			0.00118 mg/L
Total Recoverable Copper		0.007 mg/L			0.005 mg/L

Total Recoverable Cadmium, Acute = 	0.001 mg/L/0.214 = 		0.0047 mg/L
Total Recoverable Cadmium, Chronic = 	0.00015 mg/L/0.214 = 	0.0007 mg/L

Total Recoverable Lead, Acute = 		0.03 mg/L/0.237 = 		0.127 mg/L
Total Recoverable Lead, Chronic = 		0.00118 mg/L/0.237 = 	0.005 mg/L

Total Recoverable Copper, Acute = 		0.007 mg/L/0.446 = 		0.016 mg/L
Total Recoverable Copper, Chronic = 	0.005 mg/L/0.446 = 		0.011 mg/L

XI.	WATER QUALITY CALCULATIONS

Outfall 001 

Water Quality Evaluation for discharge to the Big Black River

QW	=	maximum 30-day average wastewater flow; obtained from permit application
Q7/10	=	receiving stream lowest 7-day average flow in a 10-year period
Qr 	=	receiving stream flow; mean annual flow at Pickens for Big Black River   
Qfacility 	=	Expected long-term average flow as reported in the application 
IWC 	=	Instream Wastewater Concentration
XW	=	historical effluent data
XWa 	=	permit limits from previous permit or from effluent guidelines
Xt	=	the calculated instream concentration based on historical effluent data 
Xta	=	the calculated instream concentration based on existing permit limits or the              	calculated limit based on current effluent guidelines

QW = 0.998 MGD = 1.0 MGD 
Q7/10 = 51 cfs = 33 MGD  
Qr = 1815 cfs = 1171.5 MGD 
Qfacility = 1.205 MGD  
IWC (Chronic) = 3.125 %
IWC (Acute) = 3.73 %
IWC (Mean Annual Flow) = [Qfacility / (Qfacility + Qr)] * 100 = [1.205 MGD/(1.205 MGD + 1171.5 MGD)] * 100 = 0.10 %

The facility requested a regulatory mixing zone of 10 meters downstream of the diffuser for compliance with the acute limitations.  According to the COREMIX analysis performed, this corresponded to a dilution of 25.8:1 or an IWC of 3.73 %.  The facility requested a regulatory mixing zone of 100 meters downstream of the diffuser for compliance with chronic limitations. COREMIX calculated a dilution of 31:1 or an IWC of 3.125 % at this distance.

Parameter			Acute Screening Value		Chronic Screening Value
Copper	*			0.016 mg/L				0.011 mg/L
Cadmium*			0.0047 mg/L				0.0007 mg/L
Lead*				0.127 mg/L				0.005 mg/L

* Please see Chemical Translator Calculations above for derivation of acute and chronic screening values for these metals.

PROPOSED METALLIC PERMIT LIMITS: 

Total Recoverable Copper, Acute = 		0.016 mg/L/0.0373 = 		0.428 mg/L 
Total Recoverable Copper, Chronic = 	0.011 mg/L/0.03125 =		0.35 mg/L

Total Recoverable Cadmium, Acute = 	0.0047 mg/L/0.0373 = 	0.126 mg/L
Total Recoverable Cadmium, Chronic = 	0.0007 mg/L/0.03125 = 	0.022 mg/L

Total Recoverable Lead, Acute = 		0.127 mg/L/0.0373 = 		3.40 mg/L
Total Recoverable Lead, Chronic = 		0.005 mg/L/0.03125 = 	0.16 mg/L

Parameter	Daily Maximum (mg/L)	Monthly Average (mg/L)	
Copper	0.428	0.35	
Cadmium	0.126	0.022	
Lead 	3.40	0.16	

XII.	TOXICITY SCREENING  

Total Aluminum

XW = 0.58 mg/L * 10 = 5.80 mg/L (No. of Samples < 12)
Xt (Chronic) = 5.80 * 0.03125 = 0.18 mg/L
Xt (Acute) = 5.80 * 0.0373 = 0.216 mg/L
Xt (Human Health) = (1.0 MGD * 5.80 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.0049 mg/L 

XWa = No Data Available
Xta (Chronic) = No Data Available
Xta (Acute) = No Data Available
Xta (Human Health) = No Data Available

AWQC = 0.750 mg/L
CWQC = 0.340 mg/L
HHWQC = No Data Available
Total Cadmium

Facility Monthly Average cadmium concentration discharge values using 12 months of recently-available DMR data (mg/L): 

04/17	05/17	06/17	07/17	08/17	09/17	10/17	11/17	12/17	01/18	02/18	03/18	
NODI=B1	NODI=B	NODI=B	0.000045	NODI=B	NODI=B	0.000045	0.000045	0.000045	0.000045	0.000045	0.000048	

1 NODI=B is an EPA indicator code that means “below detect limit/no detect.”  

XW = long-term average concentration value = 0.000027 mg/L  
Xt (Chronic) = 0.000027 * 0.03125 = 0.00000084 mg/L
Xt (Human Health) = (1.0 MGD * 0.000027 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.000000023 mg/L 

Facility Daily Maximum cadmium concentration discharge values using 12 months of recently-available DMR data (mg/L): 

04/17	05/17	06/17	07/17	08/17	09/17	10/17	11/17	12/17	01/18	02/18	03/18	
NODI=B1	NODI=B	NODI=B	0.000045	NODI=B	NODI=B	0.000045	0.000045	0.000045	0.000045	0.000045	0.000048	

1 NODI=B is an EPA indicator code that means “below detect limit/no detect.”  

XW = largest daily maximum concentration value = 0.000048 mg/L  
Xt (Acute) = 0.000048 * 0.0373 = 0.0000018 mg/L

XWa = current monthly average permit limit = 0.022 mg/L    
Xta (Chronic) = 0.022 * 0.03125 = 0.00069 mg/L
Xta (Human Health) = (1.0 MGD * 0.022 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.000019 mg/L 

XWa = current daily maximum permit limit = 0.126 mg/L    
Xta (Acute) = 0.126 * 0.0373 = 0.00470 mg/L

AWQC = 0.0010 mg/L
CWQC = 0.00015 mg/L
HHWQC = 0.168 mg/L

Total Lead

Facility Monthly Average lead concentration discharge values using 12 months of recently-available DMR data (mg/L): 

04/17	05/17	06/17	07/17	08/17	09/17	10/17	11/17	12/17	01/18	02/18	03/18	
0.0033	0.0016	0.002	0.002	0.0012	0.0022	0.0012	0.0011	0.002	0.0012	0.0028	0.0016	

XW = long-term average concentration value = 0.0019 mg/L  
Xt (Chronic) = 0.0019 * 0.03125 = 0.000059 mg/L
Xt (Human Health) = (1.0 MGD * 0.0019 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.0000016 mg/L 

Facility Daily Maximum lead concentration discharge values using 12 months of recently-available DMR data (mg/L): 

04/17	05/17	06/17	07/17	08/17	09/17	10/17	11/17	12/17	01/18	02/18	03/18	
0.0033	0.0016	0.003	0.0021	0.0012	0.0026	0.0012	0.0011	0.002	0.0012	0.0028	0.0017	

XW = largest daily maximum concentration value = 0.0033 mg/L  
Xt (Acute) = 0.0033 * 0.0373 = 0.00012 mg/L

XWa = current monthly average permit limit = 0.16 mg/L  
Xta (Chronic) = 0.16 mg/L * 0.03125 = 0.0050 mg/L
Xta (Human Health) = (1.0 MGD * 0.16 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.00014 mg/L 

XWa = current daily maximum permit limit = 3.40 mg/L  
Xta (Acute) = 3.40 * 0.0373 = 0.127 mg/L

AWQC = 0.030 mg/L
CWQC = 0.00118 mg/L
HHWQC = 0.015 mg/L

Total Recoverable Iron

XW = 0.130 mg/L * 10 = 1.30 mg/L (No. of Samples < 12)
Xt (Chronic) = 1.30 * 0.03125 = 0.041 mg/L
Xt (Acute) = 1.30 * 0.0373 = 0.048 mg/L
Xt (Human Health) = (1.0 MGD * 1.30 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.0011 mg/L 

XWa = No Data Available
Xta (Chronic) = No Data Available
Xta (Acute) = No Data Available
Xta (Human Health) = No Data Available

AWQC = No Data Available
CWQC = 1.0 mg/L
HHWQC = No Data Available

Total Mercury (II)

XW = 0.00000159 mg/L * 10 = 0.0000159 mg/L (No. of Samples < 12)
Xt (Chronic) = 0.0000159 * 0.03125 = 0.0000005 mg/L
Xt (Acute) = 0.0000159 * 0.0373 = 0.0000006 mg/L
Xt (Human Health) = (1.0 MGD * 0.0000159 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.00000001 mg/L

XWa = No Data Available
Xta (Chronic) = No Data Available
Xta (Acute) = No Data Available
Xta (Human Health) = No Data Available

AWQC = 0.0021 mg/L (Mercury II)
CWQC = 0.000012 mg/L (Mercury II)
HHWQC = 0.000153 mg/L (Total Mercury)

Total Recoverable Copper

Facility Monthly Average copper concentration discharge values using 12 months of recently-available DMR data (mg/L): 

04/17	05/17	06/17	07/17	08/17	09/17	10/17	11/17	12/17	01/18	02/18	03/18	
0.0033	0.0039	0.008	0.0039	0.2293	0.006	0.0064	0.0044	0.0046	0.0022	0.0024	0.1971	

XW = long-term average concentration value = 0.039 mg/L  
Xt (Chronic) = 0.039 * 0.03125 = 0.0012 mg/L
Xt (Human Health) = (1.0 MGD * 0.039 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.000033 mg/L

Facility Daily Maximum copper concentration discharge values using 12 months of recently-available DMR data (mg/L): 

04/17	05/17	06/17	07/17	08/17	09/17	10/17	11/17	12/17	01/18	02/18	03/18	
0.0068	0.0085	0.017	0.0043	1.1	0.0084	0.013	0.0088	0.0094	0.003	0.0033	0.78	

XW = largest daily maximum concentration value = 1.1 mg/L  
Xt (Acute) = 1.1 * 0.0373 = 0.041 mg/L

XWa = current monthly average permit limit = 0.35 mg/L  
Xta (Chronic) = 0.35 * 0.03125 = 0.011 mg/L
Xta (Human Health) = (1.0 MGD * 0.35 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.00030 mg/L

XWa = current daily maximum permit limit = 0.428 mg/L  
Xta (Acute) = 0.428 * 0.0373 = 0.0160 mg/L

AWQC = 0.007 mg/L
CWQC = 0.005 mg/L
HHWQC = 1.0 mg/L

Total Recoverable Zinc

Single analysis value provided on most recent permit application = 0.00339 mg/L
XW = 0.00339 mg/L * 10 = 0.0339 mg/L (No. of Samples < 12)
Xt (Chronic) = 0.0339 * 0.03125 = 0.00106 mg/L
Xt (Acute) = 0.0339 * 0.0373 = 0.00126 mg/L
Xt (Human Health) = (1.0 MGD * 0.0339 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.0000289 mg/L

XWa = No Data Available
Xta (Chronic) = No Data Available
Xta (Acute) = No Data Available
Xta (Human Health) = No Data Available

AWQC = 0.065 mg/L
CWQC = 0.065 mg/L
HHWQC = 26 mg/L

Total Recoverable Arsenic

Single analysis value provided on most recent permit application = 0.000278 mg/L
XW = 0.000278 mg/L * 10 = 0.00278 mg/L (No. of Samples < 12)
Xt (Chronic) = 0.00278 * 0.03125 = 0.0000869 mg/L
Xt (Acute) = 0.00278 * 0.0373 = 0.000104 mg/L
Xt (Human Health) = (1.0 MGD * 0.00278 mg/L)/(1.0 MGD + 1171.5 MGD) = 0.00000237 mg/L

XWa = No Data Available
Xta (Chronic) = No Data Available
Xta (Acute) = No Data Available
Xta (Human Health) = No Data Available

AWQC = 0.340 mg/L (Arsenic III)
CWQC = 0.150 mg/L (Arsenic III)
HHWQC = 0.024 mg/L (Total Arsenic)

Toxicity Screening Summary

Acute Screening

Parameter			Xt			AWQC			Pass/Fail
Total Aluminum		0.216 mg/L		0.750 mg/L			Pass
Total Cadmium		0.0000018 mg/L	0.0047 mg/L			Pass
Total Lead			0.00012 mg/L		0.127 mg/L			Pass
Total Iron			0.048 mg/L		No Data Available		N/A
Total Mercury (II)		0.0000006 mg/L	0.0021 mg/L			Pass
Total Copper			0.041 mg/L		0.016 mg/L			Fail
Total Zinc			0.00126 mg/L		0.065 mg/L			Pass
Total Arsenic			0.000104 mg/L	0.340 mg/L			Pass

Parameter			Xta			AWQC			Pass/Fail
Total Aluminum		No Data Available	0.750 mg/L			N/A
Total Cadmium		0.00470 mg/L		0.0047 mg/L			Pass
Total Lead			0.127 mg/L		0.127 mg/L			Pass
Total Iron			No Data Available	No Data Available		N/A
Total Mercury (II)		No Data Available	0.0021 mg/L			N/A
Total Copper			0.0160 mg/L		0.016 mg/L			Pass
Total Zinc			No Data Available	0.065 mg/L			N/A
Total Arsenic			No Data Available	0.340 mg/L			N/A

					Chronic Screening

Parameter			Xt			CWQC			Pass/Fail
Total Aluminum		0.18 mg/L		0.340 mg/L			Pass
Total Cadmium		0.00000084 mg/L	0.0007 mg/L			Pass
Total Lead			0.000059 mg/L	0.005 mg/L			Pass
Total Iron			0.041 mg/L		1.0 mg/L			Pass
Total Mercury (II)		0.0000005 mg/L	0.000012 mg/L		Pass
Total Copper			0.0012 mg/L		0.011 mg/L			Pass
Total Zinc			0.00106 mg/L		0.065 mg/L			Pass
Total Arsenic			0.0000869 mg/L	0.150 mg/L			Pass

Parameter			Xta			CWQC			Pass/Fail
Total Aluminum		No Data Available	0.340 mg/L			N/A
Total Cadmium		0.00069 mg/L		0.0007 mg/L			Pass
Total Lead			0.0050 mg/L		0.005 mg/L			Pass
Total Iron			No Data Available	1.0 mg/L			N/A
Total Mercury (II)		No Data Available	0.000012 mg/L		N/A
Total Copper			0.011 mg/L		0.011 mg/L			Pass
Total Zinc			No Data Available	0.065 mg/L			N/A
Total Arsenic			No Data Available	0.150 mg/L			N/A

Human Health Screening	

Parameter			Xt			HHWQC			Pass/Fail
Total Aluminum		0.0049 mg/L		No Data Available		N/A
Total Cadmium		0.000000023 mg/L	0.168 mg/L			Pass
Total Lead			0.0000016 mg/L	0.015 mg/L			Pass
Total Iron			0.0011 mg/L		No Data Available		N/A
Total Mercury (II)		0.00000001 mg/L	0.000153 mg/L		Pass
Total Copper			0.000033 mg/L	1.0 mg/L			Pass
Total Zinc			0.0000289 mg/L	26 mg/L			Pass
Total Arsenic			0.00000237 mg/L	0.024 mg/L			Pass

Parameter			Xta			HHWQC			Pass/Fail
Total Aluminum		No Data Available	No Data Available		N/A
Total Cadmium		0.000019 mg/L	0.168 mg/L			Pass
Total Lead			0.00014 mg/L		0.015 mg/L			Pass
Total Iron			No Data Available	No Data Available		N/A
Total Mercury (II)		No Data Available	0.000153 mg/L		N/A
Total Copper			0.00030 mg/L		1.0 mg/L			Pass
Total Zinc			No Data Available	26 mg/L			N/A
Total Arsenic			No Data Available	0.024 mg/L			N/A		

The existing permit for the facility contains cadmium, copper, and lead limits.  As can be seen, the facility failed the toxicity screening for acute copper due to an exceedance that occurred in August 2017.  It is expected that cadmium, copper, and lead will continue to be present in the facility’s wastewater.  As a result, based on best technical judgment, the existing limits are being retained for all three pollutants.
 
The State of Mississippi has not promulgated a numerical water quality standard for total recoverable aluminum.  However, the State of Mississippi Water Quality Criteria, Section II.10.G(1). requires permit writers to determine numeric criteria for those toxic and human health parameters for which no numeric criteria have been established using available references.  As a result, the Federal standards found in EPA’s “National Recommended Water Quality Criteria” table are used in establishing limitations for this parameter.  There is new Federal aluminum criteria that has to be calculated using pH, hardness, and dissolved organic carbon (DOC).  MDEQ’s Surface Water Division provided the new Federal criteria of 0.340 mg/L chronic and 0.750 mg/L acute using a pH of 7 SU, a hardness of 25 mg/L as CaCO3 and a DOC of 1.5 mg/L because the Big Black River is within Ecoregion 74.  Aluminum was screened using a 10 multiplying factor because there were less than 12 data points and aluminum still passed the toxicity screening.  Therefore, aluminum limits are not being proposed in this draft permit.

XIII.	RECENTLY-AVAILABLE DISCHARGE MONITORING REPORT (DMR) DATA  

LOADS

Parameter 	Current Permit Limit	Year 2016	Year 2017	Year 2018
(through March)	
Largest Average Flow	Report 	0.886 MGD 	1.03 MGD	0.971 MGD	
Largest Maximum Flow	Report 	1.027 MGD	1.1447 MGD	1.21 MGD  	
Smallest Minimum pH	6.0 SU	7.4 SU	7.8 SU	7.6 SU	
Largest Maximum pH	9.0 SU	10.3 SU	9.6 SU	8.1 SU	
Largest Temperature	90 ºF	88 ºF	89.7 ºF	82.4 ºF  	
Largest Average Ammonia	25 lb/day	8.6 lb/day	17 lb/day	1.6 lb/day	
Largest Maximum Ammonia   	37.5 lb/day	9.6 lb/day	20 lb/day	3.3 lb/day	
Largest Average Cadmium	0.18 lb/day	0.001 lb/day	0.000045 lb/day	0.000396 lb/day	
Largest Maximum Cadmium	1.05 lb/day	0.001 lb/day	0.000045 lb/day	0.000396 lb/day	
Largest Average Copper	2.92 lb/day	0.502 lb/day	1.22 lb/day	1.589 lb/day	
Largest Maximum Copper	3.57 lb/day	1.405 lb/day	5.7429 lb/day	6.292 lb/day  	
Largest Average Lead	1.33 lb/day	0.05 lb/day	0.026 lb/day	0.013 lb/day	
Largest Maximum Lead	28.4 lb/day	0.05 lb/day	0.026 lb/day	0.014 lb/day	
Largest Average BOD5	667 lb/day	231.6 lb/day	258.69 lb/day	72.18 lb/day	
Largest Maximum BOD5	1000 lb/day	475.7 lb/day	475.7 lb/day	121.1 lb/day	
Largest Average TSS	550 lb/day	309 lb/day	324.2 lb/day	98.76 lb/day	
Largest Maximum TSS	1100 lb/day	641 lb/day	738.6 lb/day	148.6 lb/day	
Largest Average Nitrogen	Report 	20.3 lb/day	13.2 lb/day	---	
Largest Maximum Nitrogen	Report 	20.4 lb/day	26.4 lb/day	---	
Largest Average Phosphorus	Report	4.22 lb/day	3.6 lb/day	---	
Largest Maximum Phosphorus	Report	4.26 lb/day	7.2 lb/day	---	

CONCENTRATIONS  

Parameter 	Current Permit Limit	Year 2016	Year 2017	Year 2018
(through March)	
Smallest Dissolved Oxygen  	6.0 mg/L	6.9 mg/L	7.2 mg/L	7.3 mg/L	
Largest Average Ammonia	3 mg/L	1.5 mg/L	2.4 mg/L	0.4 mg/L	
Largest Maximum Ammonia   	4.5 mg/L	1.66 mg/L	2.7 mg/L	0.4 mg/L	
Largest Average Cadmium	0.022 mg/L	0.0001 mg/L	0.000045 mg/L	0.000048 mg/L	
Largest Maximum Cadmium	0.126 mg/L	0.0001 mg/L	0.000045 mg/L	0.000048 mg/L	
Largest Average Copper	0.35 mg/L	0.064 mg/L	0.2293 mg/L	0.1971 mg/L	
Largest Maximum Copper	0.428 mg/L	0.17 mg/L	1.1 mg/L	0.78 mg/L	
Largest Average Lead	0.16 mg/L	0.007 mg/L	0.0033 mg/L	0.0028 mg/L	
Largest Maximum Lead	3.40 mg/L	0.007 mg/L	0.0033 mg/L	0.0028 mg/L	
Largest Average BOD5	Report 	35 mg/L	30.5 mg/L	9 mg/L	
Largest Maximum BOD5	Report 	61 mg/L	61 mg/L	15 mg/L	
Largest Average TSS	Report 	49 mg/L	38.25 mg/L	12.25 mg/L	
Largest Maximum TSS	Report 	96 mg/L	82 mg/L	18 mg/L	
Largest Average Nitrogen	Report 	2.95 mg/L	2.8 mg/L	---	
Largest Maximum Nitrogen	Report 	3.06 mg/L	2.8 mg/L	---	
Largest Average Phosphorus	Report	0.614 mg/L	0.76 mg/L	---	
Largest Maximum Phosphorus	Report	0.626 mg/L	0.76 mg/L	---	
XIV.	PROPOSED FINAL LIMITATIONS 

1.	Average Permit Limitations

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Current Permit Limitation	Proposed Permit Limitation	Basis1	
	Load
(lb/day)	Concentration
(mg/L)	Load
(lb/day)	Concentration
(mg/L)  		
001	Flow 	---	---	---	Report MGD  	---	Report MGD	CPL	
	Cadmium	---	0.022 mg/L	0.18	0.022	0.18	0.022	WQS	
	Copper	---	0.35 mg/L	2.92	0.35	2.92	0.35	WQS	
	Lead	---	0.16 mg/L	1.33	0.16	1.33	0.16	WQS	
	Ammonia Nitrogen	---	---	25	3	25	3	CPL	
	BOD5	1070 lb/day	---	667	Report 	553	Report 	WLA	
	Dissolved Oxygen  	---	> 5.0 mg/L 	---	6.0 (minimum)	---	6.0 (minimum)	WLA	
	Total Suspended Solids	878 lb/day	---	550	Report	550	Report 	CPL	
	Chlorine	---	---	---	---	3.54	0.352	WLA	
	Nitrogen 	---	---	Report	Report	Report	Report	WLA	
	Phosphorus 	---	---	Report	Report	Report 	Report	WLA	
	Production	---	---	---	---	Report	---	BTJ  	
	Chronic Ceriodaphnia dubia WET Testing	---	---	---	IC25 > 3.125 % 	---	IC25 > 3.125 %	CPL	
	Chronic Pimephales promelas WET Testing	---	---	---	IC25 > 3.125 %	---	IC25 > 3.125 %	CPL  	
	pH  	5.0 – 9.0 SU	6.0 – 9.0 SU	---	6.0 SU (minimum)	---	6.0 SU (minimum)	WLA	

2.	Maximum Permit Limitations

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Current Permit Limitation	Proposed Permit Limitation	Basis1	
	Load
(lb/day)	Concentration
(mg/L)	Load
(lb/day)	Concentration
(mg/L)  		
001	Flow 	---	---	---	Report MGD  	---	Report MGD	CPL	
	Cadmium	---	0.126 mg/L	1.05	0.126	1.05	0.126	WQS	
	Copper	---	0.428 mg/L	3.57	0.428	3.57	0.428	WQS	
	Lead	---	3.40 mg/L	28.4	3.40	28.4	3.40	WQS	
	Ammonia Nitrogen	---	---	37.5	4.5	37.5	4.5	CPL	
	BOD5	1957 lb/day	---	1000	Report 	830	Report	WLA	
	Total Suspended Solids	1788 lb/day	---	1100	Report	1100	Report 	CPL	
	Chlorine	---	---	---	---	5.31	0.528	WLA	
	Nitrogen 	---	---	Report	Report	Report	Report	WLA	
	Phosphorus 	---	---	Report	Report	Report	Report	WLA	
	Temperature 	---	90 ºF	---	90 ºF  	---	90 ºF	WQS	
	pH  	5.0 – 9.0 SU	6.0 – 9.0 SU	---	9.0 SU 	---	9.0 SU  	WLA	

1 Basis: CPL = Current Permit Limitation; WQS = Water Quality Standard; WLA = Waste Load Allocation; BTJ = Best Technical Judgment.    

The currently-active permit contains conditions requiring chronic Whole Effluent Toxicity (WET) testing to be conducted.  These permit requirements will remain applicable in the proposed permit.  The applicable permit requirements are displayed below:

Condition M-1:	Chronic Bioassay Requirements

The Water Quality Standards of Mississippi require that all waters be free from substances in concentrations or combinations which are harmful to humans, animals, or aquatic life (State of Mississippi, Water Quality Criteria for Intrastate and Coastal Waters, Section II.4., Minimum Conditions Applicable to All Waters, page 3, adopted March 22, 1990).  In accordance with such requirements, the permittee is authorized to discharge from outfall(s) 001 only in accordance with the following conditions:

(1) The permittee shall submit any existing toxicity data for review by the Mississippi Office of Pollution Control within 30 days of the effective date of this permit.

(2) The permittee shall perform 7-day chronic, static renewal, definitive (a control and five effluent concentrations) WET tests in accordance with Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, (EPA/821/R-02/013) or Short-Term Methods for Estimating the Chronic Toxicity of Effluents and
Receiving Waters to Marine and Estuarine Organisms, (EPA/821/R-02/014) or the most recent edition*.  

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]

Condition M-2:	Chronic Bioassay Requirements- continued

(2)(i) Dilution water used for these tests shall consist of reagent grade water, defined as distilled or deionized water that does not contain substances which are toxic to the test organisms.  For freshwater tests, dilution water shall consist of reagent grade chemicals or mineral water combined to make moderately hard dilution water according to Short-Term Methods for
Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms (EPA/821/R-02/013) or most recent edition*.  For estuarine testing, dilution water shall consist of synthetic seawater or hypersaline brine combined to achieve a salinity of 20 parts per thousand according to Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms (EPA/821/R-02/012) or most recent edition*.  These dilution waters will be deemed acceptable if the control organisms in the toxicity tests meet the minimum EPA criteria for chronic tests. 

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]

Condition M-3:	Chronic Bioassay Requirements- continued

(2)(ii) If the Mississippi Office of Pollution Control determines the receiving waters are freshwater, the permittee shall conduct a Ceriodaphnia dubia Survival and Reproduction Test, and a Pimephales promelas Larval Survival and Growth Test on serial dilutions of effluent to determine if the discharge from outfall(s) 001 is chronically toxic.  Such testing will determine if the water affects the survival, growth, and reproduction of the test organisms.  Static renewal tests will be conducted on three 24-hour composite samples of effluent.  The first of these composite samples will be used to set up the tests and for the day 1 and day 2 renewals, the second of these composite samples will be used to renew the tests on days 3 and 4, and the third composite sample will be used to renew the tests on days 5 and 6. Not more than 36 hours will elapse between sampling and the first use of any of the composite samples.  The chronic test(s) shall be considered valid only if the acceptability criteria referenced in Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Freshwater Organisms, (EPA/821/R-02/013), or the most recent edition*, are met.  All data shall be statistically analyzed according to the referenced manual. 

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]

Condition M-4:	Chronic Bioassay Requirements- continued

(2)(iii) If the Mississippi Office of Pollution Control determines that the receiving water is estuarine, the permittee shall conduct a Menidia beryllina Larval, Survival, and Growth Test and a Mysidopsis bahia Survival, Growth, and Fecundity Test on serial dilutions of effluent to determine if the discharge from outfall(s) 001 is chronically toxic.  Such testing will
determine if the water affects the survival, growth, and fecundity of the test organisms.  Static renewal tests will be conducted on three 24-hour composite samples of effluent.  The first of these composite samples will be used to set up the tests and for the day 1 and day 2 renewals, the second of these composite samples will be used to renew the tests on days 3 and 4, and the third composite sample will be used to renew the tests on days 5 and 6. Not more than 36 hours will elapse between sampling and the first use of any of the composite samples.  The chronic test(s) shall be considered valid only if the acceptability criteria referenced in Short-Term Methods for Estimating the Chronic Toxicity of Effluents and Receiving Waters to Marine and Estuarine Organisms, (EPA/821/R-02/014) or most recent edition* are met.  All test data shall be statistically analyzed according to the referenced manual. 

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]

Condition M-5:	Chronic Bioassay Requirements- continued

(3) These chronic toxicity tests shall be initiated within 90 days of the date of issuance of the permit to evaluate wastewater toxicity.  Such chronic toxicity tests shall be conducted once per quarter for a period of one year following the effective date of the permit.  After the first year of monitoring, provided the IC25 is greater than or equal to 3.125%, the frequency of monitoring will be reduced to once per six months for the life of the permit. Sampling shall be timed to cover the seasonal extremes of the year (hot-dry and cold-wet). 

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]

Condition M-6:	Chronic Bioassay Requirements- continued

(4) If any one chronic toxicity test indicates the IC25 is less than 3.125%, the provisions in Section 6 below shall apply, and the permittee shall conduct another chronic toxicity test(s) with the organism(s) that failed. This follow-up test must be completed within 30 days following completion of the failed test.  Final chronic toxicity test results shall be in report form as outlined in Methods for Measuring the Acute Toxicity of Effluents to Freshwater and Marine Organisms, Fourth Edition, (EPA 821/R-02/012) or most recent edition*.  The permittee must also submit a completed Mississippi Office of Pollution Control NPDES Whole Effluent Toxicity Testing Report Form. 

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]

Condition M-7:	Chronic Bioassay Requirements- continued

(5) In the event the permittee passes the additional WET test, the permittee shall resume testing in accordance with the testing schedule set forth in the permit.  In the event the permittee fails the second WET test, the permittee shall submit a Toxicity Reduction Evaluation Plan (TREP) within 45 days following completion of the follow-up test in order to reduce the toxicity
of the effluent to safe (note 1) levels (note 2).  The first phase of the TREP will include increased monitoring to characterize the toxicity of the effluent.

(6) If the IC25 of any test is less than 3.125%, then the effluent will be considered unacceptably chronically toxic, and this will constitute a violation of this permit. 

(note 1) Safe levels will be determined by the Mississippi Environmental Permit Board.

(note 2) In large rivers, lakes, and estuaries the permittee must provide a schematic map showing isopleths of waste concentrations.

In addition to the specific conditions of this permit, the permittee shall comply with all applicable conditions of 40 CFR 122.7 and 40 CFR 122.61 (06-03-93).

*Contact the Mississippi Office of Pollution Control Laboratory for information on most recent edition(s) of methods manual.  

[11 Miss. Admin. Code Pt. 6, R. 1.2.6.]
  
XV.	STATEMENT OF BASIS  

	Total production rate will now be required to be reported on an annually-submitted DMR.  

	The semiannual chronic WET testing results will now be required to be reported on an annually-submitted DMR.   
	
	The permit load limits for BOD5 have been decreased as a result of the updated WLA that was received from MDEQ’s modeling and TMDL branch on November 16, 2018.  The daily maximum and monthly average load limits for BOD5 have been decreased from 1000 lb/day to 830 lb/day and 667 lb/day to 553 lb/day, respectively. 
     
    	Permit limits for chlorine have been added to the proposed permit as a result of the updated WLA that was received from MDEQ’s modeling and TMDL branch on November 16, 2018. 

	In addition, the facility submitted a letter that was received on August 10, 2018 that requested increases to its permitted limits for BOD5 and TSS.  The letter indicates that significant operational improvements have been implemented over the past 18 months and that subsequent improvements will continue for the next several years.  The goal of these improvements is to increase the facility’s level of production.   

	However, after receiving the updated WLA from MDEQ’s modeling and TMDL branch on November 16, 2018, the requested increases in permit limits will not be implemented.  The permitted limits for TSS will remain unchanged in accordance with EPA’s anti-backsliding provision.  Rather than increasing, BOD5 permitted load limits have decreased in accordance with the updated WLA.