Public Notice Draft
Date:  9/21/2022

Second Draft
Date:  9/08/2022

	PERMIT RATIONALE FOR REISSUANCE
Mississippi Power Company, Plant Victor J Daniel
Water NPDES No. MS0024511
Thomas Kelly, Water I Branch
September 21, 2022

I.	FACILITY INFORMATION

Facility Address:  13201 Highway 63 North, Moss Point, MS  39562-6489
Facility County:  Jackson
EPA ID:  110040875666
SIC:  4911

II.	NATURE OF BUSINESS

Mississippi Power Company, Plant Victor J Daniel is a steam electric power generation facility that operates two coal-fired simple-cycle generating units (Units 1 & 2) and two natural-gas fired combined-cycle generating units (Units 3 & 4) with a total capacity of 2,142 MW. The cooling water intake structure (CWIS) for the Jackson County Port Authority Black Creek Cooling Facility (BCCF) is located in the Pascagoula River at Cumbest Bluff. This facility is classified as an NPDES minor source. 

III.	MODIFICATION TO THE FACILITY

The renewal permit includes modifications associated with the elimination of the facility’s sanitary waste water and the ash sluice (wet) system including the ash transport waste water. The wet sluice system which previously utilized a bottom ash pond is currently being converted to an Industrial Waste Water Pond (IWWP). Because the ash transport water was eliminated, the corresponding categorical limitations (EGLs) of 40 CFR 423.12(b)(4) were removed from Outfall 008. Since low volume wastes, coal pile runoff, and combustion residual leachate combine in the IWWP for treatment prior to discharge, the corresponding EGLs and the combined wastestreams formula were used to determine the alternative discharge limitations for Outfall 008. Since low volume wastes are now regulated by the alternative discharge limitations, the limitations on Outfall 608 have been removed. Also, the elimination of sanitary waste water resulted in the elimination of internal Outfall 208. 

IV.	EFFLUENT AND RECEIVING STREAM FLOW DATA

External Outfalls:

Outfall 001: Effluent discharge consisting of re-circulated cooling water. The effluent discharges to the BCCF and has a maximum monthly flow of 571.20 MGD.  Cooling water discharged from this outfall flows to the BCCF and is re-circulated back to the cooling system.
Outfall 007: Effluent discharge consisting of cooling tower blowdown from Units 3 and 4. The effluent discharges to the BCCF and has a maximum 30-day flow of 2.391 MGD.

Outfall 008:  Effluent discharge from the Industrial Waste Water Pond (IWWP). This discharge is a combination coal pile runoff, combustion residual leachate, storm water, and low volume wastes. The proposed discharge limitations are determined using the categorical limitations for coal pile runoff, low volume wastes, combustion residual leachate, and the combined waste streams formula (see Section IX). The IWWP discharges to the BCCF and has a maximum 30-day flow of 8.305 MGD.

Outfall 009:  Emergency overflow discharge from the Coal Pile Runoff Pond to Detention Pond B and thence to Gray Bayou. Detention Pond B is a facility storm water pond that is permitted via their Industrial Storm Water General Permit coverage No. MSR000395. Under normal operations, the coal pile runoff discharges into the IWWP. The last observed emergency overflow of 13.732 MGD occurred as a result of Hurricane Isaac in 2012.

Internal Outfalls:

Outfall 208 (Removed):   This outfall previously consisted of treated sanitary wastewater. The sanitary wastewater treatment system has been removed, and all sanitary waste water from the plant site is currently sent to the Jackson County Utility Authority (POTW). The facility has requested removal of the outfall from the permit.

Outfall 408:  Effluent consisting of chemical metal cleaning wastes. The effluent discharge has a maximum monthly flow of 0.179 MGD and discharges to the BCCF via external outfall 008.

Outfall 608 (Removed): Effluent consisting of low-volume waste water. This effluent discharge has a maximum daily flow of 0.01 MGD and discharges from an internal wastewater basin to the BCCF via external Outfall 008. Utilizing the combined wastestreams formula, the combined equivalent limit was placed on Outfall 008. As a result, the internal monitoring requirements for this outfall have been removed from the permit. 

Mississippi Power Company, Plant Victor Daniel has four (4) external outfalls and one (1) internal Outfall.  External Outfalls 001, 007, and 008 discharge into the BCCF (Non State and Non Federal Waters), and Outfall 009 is an emergency overflow of the coal pile runoff into Storm Water Detention Pond B. Coal pile runoff and low volume wastes are recycled to the IWWP for reuse. Because wastewater from internal Outfall 408 and the IWWP discharge both utilize the same discharge pipe on route to the BCCF, the permittee shall not discharge from Outfall 408 while the IWWP is discharging.

V.	303(d) and TMDL ISSUES

None.

VI.	TYPE OF WASTEWATER TREATMENT:

Outfall 001 - Disinfection
Outfall 007 - Cooling, Disinfection, Dechlorination
Outfall 008 - Flocculation and Sedimentation
Outfall 408 - Sedimentation
Outfall 009 - Sedimentation

VII.	EPA APPLICABLE CATEGORICAL GUIDELINES

40 CFR Part 423 - Steam Electric Power Generation Point Source Category; Sections 423.12 (BPT- Best Practicable Control Technology Currently Available) and 423.13 (BAT- Best Available Technology Economically Available).  

VIII.	DATA FROM APPLICATION FORM (2C)

	Maximum Daily Value	
Parameter	Outfall 001	Outfall 007	Outfall 008	
BOD	6.0 mg/L	9.0 mg/L	<3.0 mg/L	
COD	36 mg/L	94.0 mg/L	20 mg/L	
TOC	10.2 mg/L	29.8 mg/L	5.67 mg/L	
TSS	6.3 mg/L	238 mg/L	173.15 mg/L	
Ammonia (as N)	<0.21 mg/L	<0.21 mg/L	0.30 mg/L	
Flow	571.4 MGD	4.236 MGD	14.2 MGD	
Temperature (winter)	15°C1	35.2 °C	15 °C	
Temperature (summer)	37.4 °C	39.4 °C	32.7 °C	
pH	8.34 SU	8.91 SU	9.19 SU	
Chlorine, Total Residual	<0.02 mg/L	0.04 mg/L	<0.02 mg/L	
Fecal Coliform	136 col/100 mL	112 col/100 mL	28 col/100 mL	
Nitrogen, Total Organic	<0.1 mg/L	0.672 mg/L	<0.1 mg/L	
Oil & Grease	<5.2 mg/L	<5.0 mg/L	22.5 mg/L	
Sulfate	17.1 mg/L	60.5 mg/L	104 mg/L	
Aluminum, Total	0.119 mg/L	0.16 mg/L	2.21 mg/L	
Barium, Total	0.04 mg/L	0.14 mg/L	0.240 mg/L	
Boron	0.51 mg/L	2.20 mg/L	1.67 mg/L	
Iron, Total	0.25 mg/L	0.461 mg/L	0.18 mg/L	
Magnesium, Total	1.66 mg/L	6.83 mg/L	3.03 mg/L	
Molybdenum	0.006 mg/L	0.020 mg/L	0.03 mg/L	
Manganese, Total	0.03 mg/L	0.090 mg/L	0.01 mg/L	
Arsenic, Total	<0.002 mg/L	0.0003 mg/L	0.004 mg/L	
Chromium, Total	<0.001 mg/L	0.001 mg/L	0.035 mg/L	
Copper, Total	0.005 mg/L	0.014 mg/L	0.006 mg/L	

	Maximum Daily Value	
Parameter	Outfall 001	Outfall 007	Outfall 008	
Mercury, Total	0.9 ng/L	2.33 ng/L	1.16 ng/L	
Nickel, Total	0.002 mg/L	0.035 mg/L	<0.001 mg/L	
Selenium, Total	<0.002 mg/L	<0.001 mg/L	0.002 mg/L	
Zinc, Total	0.01 mg/L	0.008 mg/L	<0.01 mg/L	
Hexachloroethane	2.3 ug/L	<2.0 ug/L	<2.0 ug/L	
Nitrobenzene	3.0 ug/L	<2.0 ug/L	<2.0 ug/L	

	Maximum Daily Value	
Parameter	Outfall 408	Outfall 009	
BOD	3 mg/L	*	
COD	25 mg/L	*	
TOC	5.01 mg/L	*	
TSS	2.3 mg/L	*	
Ammonia (as N)	<0.21 mg/L	*	
Flow	0.179 MGD	*	
Temperature (winter)	15°C1	*	
Temperature (summer)	33.1 °C	*	
pH	8.69 SU	*	
Chlorine, Total Residual	< 0.02 mg/L	*	
Color	40 c.u.	*	
Fecal Coliform	128 col/100 mL	*	
Sulfate	< 5.0 mg/L	*	
Aluminum, Total	0.11 mg/L	*	
Barium, Total	0.04 mg/L	*	
Boron	0.04 mg/L	*	
Iron, Total	0.113 mg/L	*	
Magnesium, Total	1.23 mg/L	*	
Molybdenum, Total	0.040 mg/L	*	
Manganese, Total	0.006 mg/L	*	
Chromium, Total	<0.001 mg/L	*	
Copper, Total	0.011 mg/L	*	
Mercury, Total	1.67 ng/L	*	
Nickel, Total	<0.001 mg/L	*	
Zinc, Total	0.01 mg/L	*	
Bis (2-ethylhexyl) phthalate	<3.0 ug/L	*	
(1)These values were estimated since winter temperature values were not available.

*Effluent characterization is not available because there has not been a discharge since 2012 as a result of Hurricane Isaac.
Many of the parameters listed above were reported at a concentration greater than the appropriate minimum quantification level (MQL). All other parameters listed on the Form 2C application are not shown due to one of the following reasons: (1) testing was not required, (2) the parameters were believed absent, (3) the reported concentrations were non-detect or less than the appropriate MQL for each parameter tested.

VIII. 	WATER QUALITY LIMITATIONS BASED ON WASTELOAD ALLOCATION 

A wasteload allocation was not requested since the outfalls do not discharge to State Waters or Waters of the United States (WOUS).

IX.	COMBINED WASTESTREAMS CALCULATIONS

Coal pile runoff, low volume wastes, and combustion residual leachate combine in the industrial waste water pond (IWWP) for treatment and discharge via Outfall 008. These waste streams have EGLs that can be found in 40 CFR Parts 423.12(b)(3), (9), and (11). The combined wastestreams formula is used to determine the alternative limits after dilution.

CT -	The alternative concentration limit for the combined waste streams.

Ci -	 The categorical standard concentration limit for a pollutant in the regulated waste stream i.
Fi -	The average daily flow (at least a 30-day average) for waste stream i. Waste streams include both regulated (regulated by ELGs) and for unregulated waste streams (wastes not covered by ELGs).

FD -	The average daily flow (at least a 30-day average) from the following all dilute waste streams (e.g. once-through cooling, storm water, demineralizer backwash, non-contact cooling water not covered by and ELG, and sanitary wastewater not covered by an ELG.)

FT - The average daily flow (at least a 30-day average) of all contributing flows.

N -   The total number of regulated streams.

1The ~30 mg/L average limitation was determined by dividing the 50 mg/L maximum EGL by 1.5 and is based on technical judgment (TJ).

X.	TOXICITY SCREENING

Mississippi Power Company, Plant Victor Daniel has 4 external outfalls.  Outfalls 001, 007, and 008 discharge into the BCCF (Non State and Non Federal Waters). Since none of these outfalls discharge into State or Federal waters, a toxicity screen was not performed. Outfall 009 is an emergency overflow of the coal pile runoff pond into Storm Water Detention Basin B and thence to Gray Bayou. Under normal operations, the coal pile runoff pond discharges into the industrial waste water pond (IWWP) for reuse. However, during emergency situations, the coal pile runoff pond will overflow into Detention Basin B. Because the last observed emergency overflow occurred as a result of Hurricane Isaac in 2012, there is no effluent characteristics data available for Outfall 009. Therefore, a toxicity screen was not performed for this outfall.

XI.	PROPOSED FINAL LIMITATIONS 

1.	Average Permit Limitations:   mass (conc.)

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Monitoring Frequency	Sample Type	DMR Reporting Frequency	[1]Basis	
001	Flow (MGD)	--	--	Report	Report	Continuously	Instantaneous Sampling	Annually	PPL, TJ	
001	Chlorine, total residual	--	--	Report	Report	Weekly	Grab Sampling	Annually	PPL, TJ	
001	Chlorination Duration	--	--	Report	Report	Daily	Grab Sampling	Annually	PPL, TJ	
208	Chlorine, total residual	--	--	Report	Removed	Twice/quarter	Grab Sampling	Quarterly	Waste stream eliminated	
208	Flow (MGD)	--	--	Report	Removed	Twice/quarter	Instantaneous Sampling	Quarterly	Waste stream eliminated	
208	BOD5	--	--	Report	Removed	Twice/quarter	8-hr Composite	Quarterly	Waste stream eliminated	
208	Fecal Coliform	--	--	Report	Removed	Semiannually	Grab Sampling	Annually	Waste stream eliminated	
408	Copper, TR	(1.0)	--	Report (1.0)	Report (1.0)	Weekly	Grab Sampling	Monthly	PPL, Cat.	
408	Flow (MGD)	--	--	Report	Report	Continuously	Totalizer	Monthly	PPL, TJ	
408	Iron, TR	(1.0)	--	Report (1.0)	Report (1.0)	Weekly	Grab Sampling	Monthly	PPL, Cat.	
608	Flow (MGD)	--	--	--	Alternative limits were placed on Outfall 008 using the CWF[3]	Continuously	Pump Log	Monthly	TJ, CWF	
608	TSS	(30)	--	Report (30)		Weekly	Grab Sampling	Monthly	TJ, CWF	
608	Oil and grease	 (15)	--	Report (15)		Weekly	Grab Sampling	Monthly	TJ, CWF	
608	pH (min)	6.0 SU	--	6.0 SU		Weekly	Weekly	Monthly	TJ, CWF	
007	Chlorination Duration	--	--	Report	Report	Daily When Discharging	Pump Log	Monthly	PPL, TJ	
007	Chlorine, FA	(0.20)	--	Report (0.20)	Report (0.20)	Daily When Discharging	8 Grab Samples	Monthly	PPL, Cat. 423.	
007	Flow (MGD)	--	--	Report	Report	Daily When Discharging	Totalizer	Monthly	PPL, TJ	
007	pH (min)	6.0 SU	--	6.0 SU	6.0 SU	Weekly	Grab Sampling	Monthly	PPL, Cat.	
007	Chromium, TR	(0.20)	--	(0.20)	(0.20)	Annually	Grab Sampling	Annually	PPL, Cat.	
007	Zinc, TR	(1.0)	--	Report (1.0)	Report (1.0)	Annually	Grab Sampling	Annually	PPL, Cat.	

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Monitoring Frequency	Sample Type	DMR Reporting Frequency	[1]Basis	
008	Flow (MGD)	--		Report	Report	Continuously	Totalizer	Monthly	PPL, TJ	
008	Oil and Grease	(15, 15)		Removed	(9.3)	Weekly	Grab Sampling	Monthly	Cat., CWF[2]	
008	pH (min)	6.0 SU		6.0 SU	6.0 SU	Weekly	Grab Sampling	Monthly	PPL, Cat.	
008	TSS	(30, 30)		Removed	(25.9)	Weekly	Grab Sampling	Monthly	Cat., CWF[2]	
009	Flow (MGD)	--	--	Report	Report	Daily When Discharging	Calculations	Monthly	PPL, TJ	
009	pH (min)	6.0 SU	--	6.0 SU	6.0 SU	Weekly	Grab Sampling	Monthly	PPL, Cat.	
009	TSS	--	--	Report (Report)	Report 
(Report)	Weekly	Grab Sampling	Monthly	PPL, TJ	

2.	Maximum Permit Limitations:   mass (conc.)

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Monitoring Frequency	Sample Type	DMR Reporting Frequency	[1]Basis	
001	Flow (MGD)	--	--	Report	Report	Continuously	Instantaneous Sampling	Annually	PPL, TJ	
001	Chlorine, total residual	--	--	(0.20)	(0.20)	Weekly	Grab Sampling	Annually	PPL, Cat.	
001	Chlorination Duration	--	--	120 minutes	120 minutes	Daily	Grab Sampling	Annually	PPL, Cat. 	
208	Chlorine, total residual	--	--	Report	Removed	Twice/quarter	Grab Sampling	Quarterly	Waste stream eliminated	
208	Flow (MGD)	--	--	Report	Removed	Twice/quarter	Instantaneous Sampling	Quarterly	Waste stream eliminated	
208	BOD5	--	--	Report	Removed	Twice/quarter	8-hr Composite	Quarterly	Waste stream eliminated	
208	Fecal Coliform	--	--	Report	Removed	Semiannually	Grab Sampling	Annually	Waste stream eliminated	
408	Copper, TR	(1.0)	--	Report (1.0)	Report (1.0)	Weekly	Grab Sampling	Monthly	PPL, Cat.	
408	Flow (MGD)	--	--	Report	Report	Continuously	Totalizer	Monthly	PPL, TJ	
408	Iron, TR	(1.0)	--	(1.0)	(1.0)	Weekly	Grab Sampling	Monthly	PPL, Cat.	
408	Specific Conductance	--	--	1000 micromhos/cm	1000
micromhos/ cm	Weekly	Grab Sampling	Monthly	PPL, TJ	

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Monitoring Frequency	Sample Type	DMR Reporting Frequency	[1]Basis	
608	Flow (MGD)	--	--	Report	Alternative limits were placed on Outfall 008 using the CWF[3]	Continuously	Pump Log	Monthly	TJ, CWF	
608	TSS	 (100)	--	Report (100)		Weekly	Grab Sampling	Monthly	TJ, CWF	
608	Oil and grease	(20)	--	Report (20)		Weekly	Grab Sampling	Monthly	TJ, CWF	
608	pH (max)	9.0 SU	--	9.0 SU		Weekly	Weekly	Monthly	TJ, CWF	
007	Chlorination Duration	--	--	120 minutes	120 minutes	Daily When Discharging	Pump Log	Monthly	PPL, TJ	
007	Chlorine, FA	(0.20)	--	Report (0.20)	Report (0.20)	Daily When Discharging	8 Grab Samples	Monthly	PPL, Cat.	
007	Flow (MGD)	--	--	Report	Report	Daily When Discharging	Totalizer	Monthly	PPL, TJ	
007	pH (max)	9.0 SU	--	9.0 SU	9.0 SU	Weekly	Grab Sampling	Monthly	PPL, Cat.	
007	Chromium, TR	(0.20)		(0.20)	(0.20)	Annually	Grab Sampling	Annually	PPL, Cat.	
007	Zinc, TR	(1.0)		(1.0)	(1.0)	Annually	Grab Sampling	Annually	PPL, Cat.	
008	Flow (MGD)	--	--	Report	Report	Continuously	Totalizer	Monthly	PPL, TJ	
008	Oil and grease	(20, 20)	--	(20)	(12.4)	Weekly	Grab Sampling	Monthly	Cat., CWF[2]	
008	pH (max)	9.0 SU	--	9.0 SU	9.0 SU	Weekly	Grab Sampling	Monthly	PPL, Cat.	
008	TSS	(100, 100, 50)	--	(100)	(74.2)	Weekly	Grab Sampling	Monthly	Cat., CWF[2]	
009	Flow (MGD)	--	--	Report	Report	Daily When Discharging	Calculations	Monthly	PPL, TJ	
009	pH (max)	9.0 SU	--	9.0 SU	9.0 SU	Weekly	Grab Sampling	Monthly	PPL, Cat.	
009	TSS	(50)	--	Report (50)	Report (50)	Weekly	Grab Sampling	Monthly	PPL, Cat.	

1Basis: TR = Total Recoverable; FA = Free Available; MSWQS = Mississippi Water Quality Standards; TJ = Technical Judgement; Categorical (Cat.) = 40 CFR 423.12 (BPT) and 40 CFR 423.13 (BAT); CWF = Combined Wastestream Formula; PPL = Previous Permit Limits

2The alternative limits described in Section IX (Combined Wastestream Calculations) utilize the EGLs for low volume wastes, coal pile runoff, and combustion residual leachate. Since these waste streams combine in the IWWP for treatment prior to discharge, the corresponding EGLs and the combined wastestreams formula were used to determine the alternative discharge limitations for Outfall 008.

3Since the EGLs for low volume wastes are included in the alternative limitations on external Outfall 008, the limitations of internal Outfall 608 will be removed from the permit. 

XI.	COMPLIANCE WITH SECTION 316(B) OF THE CLEAN WATER ACT - COOLING WATER INTAKE STRUCTURES

The information summarized below was obtained from the application submittal provided in accordance with 40 CFR122.21(r):

Cooling System Description

Plant Daniel operates a closed-cycle recirculating system (CCRS) consistent with the requirements of 40 CFR 125.94(c)(1).  The CCRS consists of cooling water that is recirculated from Plant Daniel’s cooling towers to the Black Creek Cooling Facility (BCCF). The cooling water intake structure (CWIS) for the BCCF is located in the Pascagoula River at Cumbest Bluff and supplies makeup water to the BCCF to replenish water losses from evaporation, drift, and blowdown. The CWIS and the BCCF are both owned and operated by the Jackson County Port Authority.

The CWIS has an intake flow of 38.88 MGD (DIF) and 2.84 MGD (AIF) with a through-screen intake velocity of 1.4 ft/s for each pump when the pumps are operating at the DIF. Plant Daniel uses 549.94 MGD of non-contact cooling, which represents 1,300% of the DIF.  The percent of cooling water used for non-contact cooling is much greater than the DIF because the facility operates a CCRS. Plant Daniel uses approximately 3.5 MGD as contact cooling water specifically for quench water which represents 9% of the DIF.  Plant Daniel collects all of its water from the BCCF and discharges all of its water back to the BCCF. All the cooling water, process water, sanitary wastewater, gray water, etc. is recycled 100%.  The BCCF is part of the internal cooling water system and is not a Water of the United States (WOUS). Therefore, the Final 316(b) rule applies to the CWIS at the Pascagoula River. 

Source Water Body Description

The source water body for the facility’s cooling water is the Pascagoula River and is located approximately 3.6 miles north of the facility. The Pascagoula River is approximately 80 miles long and approximately 515 feet wide near the Pascagoula River CWIS at Cumbest Bluff. The water depth of the Pascagoula River averages 6.86 feet near the CWIS. The estimated average flow for the Pascagoula River near the CWIS is 8,570 cfs, with a minimum flow of 1,220 cfs, and a maximum flow of more than 103,000 cfs. The Pascagoula River is the north-to-south waterbody west of the facility on Figure 1 (see attachment A), which contains a scaled topographic map of the relevant portions of the Pascagoula River and the Black Creek Cooling Facility.  

Threatened and Endangered Species

The Gulf sturgeon and pearl darter are the only federally-listed species in Jackson County, Mississippi [U.S. Fish and Wildlife Service (USFWS), 2015]. The Gulf sturgeon is listed as endangered while the pearl darter has been a candidate species since 1999 and was listed as threatened on October 20, 2017.

The Gulf sturgeon is a large fish that occurs along the Gulf Coast and has been collected in the Pascagoula and Pearl River watersheds. The Gulf sturgeon is anadromous, meaning that adults spawn in freshwater in the spring and migrate to marine waters to forage in the fall and winter. Juveniles remain in freshwater rivers for the first 2-3 years (Heise et al. 2005). There is no information available that indicates that the Gulf sturgeon would be susceptible to impingement or entrainment at the Pascagoula River CWIS.

The Pearl darter is a small fish that occurs in the Pascagoula River watershed in Mississippi and Louisiana. The pearl darter prefers freshwater rivers and streams with moderate flow and with sand and gravel substrate. The pearl darter is vulnerable to non-point source pollution and changes in river geomorphology due to its localized distribution (Slack et al. 2002). Although the pearl darter is present in the Pascagoula River basin, it is more likely to be present in smaller, more protected, and less developed segments of the Pascagoula River and therefore less likely to be susceptible to impingement or entrainment at the Pascagoula River CWIS.

Plant Daniel has not sought or obtained an incidental take exemption or authorization for the Pascagoula River CWIS from the USFWS or the National Marine Fisheries Service (NMFS). No such exemption or authorization is believed to be necessary due to the lack of federally listed species.

Comments from the US Fish and Wildlife Service (Service)

The Service received the facility’s NPDES Application and 316(b) application submittal, and provided a written response dated February 3, 2022 stating that they do not have any comments or specific concerns regarding the Mississippi Power Company, Plant Victor J Daniels’s NPDES permit application at this time.

316(b) CWIS Site Specific Impingement BTA Determination

MPC intends to comply with the impingement mortality standard at the CWIS through compliance with §125.94(c)(1) by operating the existing CCRS and no once-through cooling for this CWIS. A CCRS as described in 40 CFR 125.94(c)(1) is a pre-approved technology for complying with the impingement mortality standard. The Director has determined that the facility’s CCRS will be considered impingement BTA. EPA also considers that facilities employing a CCRS is deemed in compliance with the impingement mortality standard.

316(b) CWIS Site Specific Entrainment BTA Determination

The following correlate to subparagraphs of 40 CFR 125.98(f)(2) and are factors the Director must consider in the BTA determination.
Must Consider Factors:

•	Numbers and types of organism entrained, including, specifically, the numbers and species (or lowest taxonomic classification possible) of Federally-listed, threatened and 
endangered species, and designated critical habitat (e.g., prey base).

Plant Daniel is not required to perform an entrainment study because the AIF is less than 125 MGD. All cooling at the facility is accomplished via closed-cycle cooling which minimizes cooling water intakes. This minimized intake flow minimizes the intake of entrainable organisms and meets the requirements of BTA for impingement protection. Based on these results, additional entrainment controls are not warranted for this facility’s cooling water intake.

•	Impact of changes in particulate emissions or other pollutants associated with entrainment technologies.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. There is no need for additional cooling at this time. Therefore, there will be no increase in particulate emissions or other pollutants associated with the installation of entrainment technologies.

•	Land availability inasmuch as it relates to the feasibility of entrainment technology.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. There is no need to add additional impingement or entrainment technologies at this time. Therefore, there will be no increase in particulate emissions or other pollutants associated with the installation of entrainment technologies. There is no need to construct additional impingement or entrainment technologies, so land availability is not relevant to this facility.

•	Remaining useful plant life.

The coal-fired units (Unit 1 and Unit 2) will be fully retired by the end of 2027. The useful life of the gas-fired units is at least 20 years.

•	Quantified and qualitative social benefits and costs of available entrainment technologies when such information on both benefits and costs is of sufficient rigor to make a decision.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. There is no need to add additional impingement or entrainment technologies at this time. Therefore, there will be no increase in particulate emissions or other pollutants associated with the installation of entrainment technologies.

The following correlate to subparagraphs of 40 CFR 125.98(f)(3) and are factors the Director may consider in the BTA determination.

May Consider Factors:

•	Entrainment impacts on the waterbody.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. Plant Daniel is not required to perform an entrainment study because the AIF is less than 125 MGD. All cooling at the facility is accomplished via the CCRS which minimizes cooling water intakes. This minimized intake flow minimizes the intake of entrainable organisms and meets the requirements of BTA for impingement protection. Based on these results, additional entrainment controls are not warranted for this facility’s cooling water intake.

•	Thermal discharge impacts.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. The discharged cooling water is returned to the Black Creek Cooling Facility, which is not a WOUS. The overflow from the Black Creek Cooling Facility has had significant time to reach ambient temperatures. Therefore, there is no thermal discharge impact associated with the Plant Daniel cooling water discharges.

•	Credit for reductions in flow associated with the retirement of units occurring with the ten years preceding October 14, 2014.

No units have been retired at Plant Daniel to date.  No credit for flow reductions is being sought.

•	Impacts on the reliability of energy within the immediate area.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. There is no need to add additional impingement or entrainment technologies at this time. Therefore, there will be no impact to energy reliability resulting from the construction of additional impingement and/or entrainment control devices.

•	Impacts on water consumption.

MPC currently operates a CCRS at Plant Daniel, which EPA has identified as BTA for impingement and effectively as BTA for entrainment. There is no need to add additional impingement or entrainment technologies at this time. Therefore, there will be no impact to water consumption resulting from the construction of additional impingement and/or entrainment control devices.

•	Availability of process water, gray water, wastewater, reclaimed water, or other waters of the appropriate quantity and quality for reuse as cooling water. 

There are insufficient alternate water sources to meet the facility’s cooling requirements. See Section 8.2.1 of the 316(b) Study Report for further information.

MPC currently complies with the impingement mortality standard for the Pascagoula River CWIS through the continued use of a CCRS. The facility design currently provides a 95% reduction in intake flow when comparing the DIF to the baseline intake flow. The reduced flow reduces the impingement potential due to lower intake velocities associated with the lower flow. Entrainment benefits are similarly based on the reduced intake flow over the baseline condition. A reduction of 95% in intake flow rate yields a corresponding 95% reduction in entrainment. The Director considers the facility’s use of the CCRS as entrainment BTA to minimize adverse environmental impacts.

Other Candidate Entrainment Technologies

•	Fine Mesh Traveling Screens - Fine-mesh traveling screens (i.e. screen size less than 2.0 mm) are used to exclude fish eggs and larvae from entrainment. The use of fine mesh traveling screens affects the through-screen velocity because the total through screen area is decreased due to smaller slot sizes. Therefore, it is essential to design the system so that the intake velocity does not negatively affect impingement. These screens are effective, commercially proven, and have no impact on facility reliability and operation. However, fouling by debris is a significant concern on waterbodies like the Pascagoula river, which have a high concentration of suspended sediments and algal/plant material where clogging of the screens is common and screen rotation and backwashing on a routine basis is essential. These screens would be subject to fouling and potentially reduce the open area leading to higher intake velocities and increased risk of impingement. The screens are not considered feasible for impingement at the facility due to the potential for frequent clogging. Furthermore, this technology has not been demonstrated to provide any additional benefit for IM&E reduction compared to the CCRS employed at the facility.

•	Fine Mesh Wedgewire Screens - Fine-mesh wedgewire screens are stationary screens with a reduced slot size that are intended to exclude smaller fish and shellfish, thereby reducing entrainment.  Similar to the fine-mesh travelling screens, a smaller slot size will require larger screen assembly in order to maintain the desired through-slot velocity. Fouling by debris and clogging by sediments are common and backwashing on a routine basis is essential. Fine-mesh wedgewire screens are effective, commercially proven, and have no impact on facility reliability and operation. However, the configuration of the Pascagoula River makes installing these oversized screens impractical. There is insufficient room in the vicinity of the Pascagoula River CWIS to facilitate the installation of these screens. These screens would be undesirable due to frequent clogging and backwash requirements. Furthermore, this technology has not been demonstrated to provide any additional benefit for IM&E reduction compared to the CCRS employed at the facility.

•	Coarse Mesh Traveling Screens - Coarse-mesh traveling screens (i.e. screen size greater than 2.0 mm), also known as “Ristroph” screens, are modified conventional traveling screens that were developed to reduce impingement mortality by removing fish trapped against the screen and returning them to the surface water with minimal injury. Coarse mesh traveling screens are effective, commercially proven, and have no impact on facility reliability and operation. The BCCF’s internal CWIS, which is not subject to the 316(b) regulations, is currently fit with traveling screens and it is possible to retrofit them to include a fish return. Since these screens are located on the BCCF, which is not a WOUS, such modifications would not provide any benefit to the Pascagoula River. Furthermore, this technology has not been demonstrated to provide any additional benefit for IM&E reduction compared to the CCRS employed at the facility.

•	Louvers/Angled Bar Racks - Louvers/angled bar racks typically consist of a series of vertical slats aligned at a specified angle and provide a change in flow direction and velocity. This change is detected by fish and allows them to avoid the turbulence and swim away. The BCCF’s internal CWIS, which is not subject to the 316(b) regulations, is currently fit with angled bar racks. Since the angled bar racks are located on the BCCF, which is not a WOUS, the racks do not provide any benefit to the Pascagoula River. Furthermore, this technology has not been demonstrated to provide any additional benefit for IM&E reduction compared to the CCRS employed at the facility.

•	Barrier Nets - Barrier nets are used to prevent fish and shellfish from entering the CWIS. They are deployed from the bottom of the water column to the surface around the point of water withdrawal. Mesh size varies depending on the water body, species to be protected, and the CWIS configuration. Most barrier nets are designed to reduce impingement and do not prevent entrainment. This technology is not likely to perform well on the Pascagoula River due to the river velocity, amount of debris within the water column, and river traffic. Furthermore, this technology has not been demonstrated to provide any additional benefit for IM&E reduction compared to the CCRS employed at the facility.

•	Variable Speed Pumps/Variable Frequency Drives - Variable speed pumps and variable frequency drives allow a facility to reduce the volume of water being withdrawn by matching the pump speed to the cooling water needs. A reduced flow will reduce the potential for IM&E to fish and shellfish. A reduced flow will also result in the potential reduction in operation and maintenance costs. Variable speed pumps and variable frequency drives are of limited utility at this facility. The existing intake pumps are matched to the heat load required by the generation units.

•	Season Flow Reductions - Seasonal flow reductions are used to reduce the water withdrawn during fish and shellfish spawning seasons or other biologically important time periods. Seasonal flow reduction can be accomplished by variable frequency drives or by shutting down some portion of the pumping system or facility. Seasonal flow reductions will reduce the potential for IM&E to fish and shellfish. Seasonal flow reductions reduce IM&E through the same process as other flow-reduction technologies and are commercially proven and available. However, the facility operates based on market demand at any time. Therefore, seasonal flow reductions are not a feasible method to reduce IM&E for this facility.

•	Alternative Cooling Water Sources - Alternative cooling water sources other than surface water can be used to reduce the withdrawal of surface water. These sources include groundwater, grey water, or other sources of water. 

The United States Geological Survey’s 2015 Water Use Data for the Nation (2018) is available on the National Water Information System Web (NWISWeb) interface and provides a breakdown of water use types in Jackson County, Mississippi. The USGS reports that the total withdrawal of groundwater from all wells in Jackson County is equal to 21.24 MGD of fresh groundwater and 0 MGD of saline groundwater. Groundwater withdrawals include 14.5 MGD for public water supply, 1.11 MGD for domestic use (i.e. private groundwater wells), and 5.63 MGD for industrial purposes.

When operating Units 1 and 2, the facility requires 542.6 MGD of intake water. If MPC were to switch to groundwater, Jackson County groundwater withdrawals would increase by approximately 2,500 %. An increase of this magnitude would put the cooling water needs of the facility into conflict with public drinking water needs. In addition, unanticipated side effects of such groundwater withdrawals may include saltwater intrusion into freshwater aquifers and subsidence. Replacement of the makeup water from the Pascagoula River CWIS with groundwater would represent a 50.1% increase in industrial water use within Jackson County.
MPC maintains two separate groundwater withdrawal permits including MS-GW-09909 and MS-GW-11575. These permits limit MPC to approximately 1.4 MGD of groundwater withdrawal. This limit on groundwater withdrawal also demonstrates that grey water is an impractical alternative source for cooling water. Even if all 1.4 MGD were to be used as an alternative source of cooling water, the facility would require an additional 541.2 MGD of surface water to meet its cooling requirements. There are no treatment devices to treat black and/or grey water to the quality required for cooling water.

Based on the information provided in the application, the Director has determined that the above candidate technologies are not suitable for this facility and have been rejected. See Section 8.0 of the NPDES application 316(b) study report for 40 CFR 122.21 r(2)-r(8) for more information.

316(b) - Director Requirements (40 CFR 125.98)

•	Visual or Remote Inspections:

The facility must either conduct weekly visual inspections or employ remote monitoring devices during the period the cooling water intake structure is in operation. [40 CFR 125.98(b)(3), 40 CFR 125.96(e)]

•	Reporting Requirements:

The permittee shall submit an annual certification statement signed by the responsible corporate officer indicating whether there have been any substantial modifications of any units that impact the cooling water withdrawals and a summary of those changes. In addition, revisions must be submitted to the information required at 40 CFR 122.21(r) during the next permit application when new information is available. [40 CFR 125.98(b)(4), 40 CFR 125.97(c)]

•	Endangered Species Act:

Nothing in this permit authorizes take for the purpose of a facility’s compliance with the Endangered Species Act. [40 CFR 125.98(b)(1)]

•	Annual Certification Statement and Report:

The annual certification statement is subject to the following:
(1) If the information contained in the previous year's annual certification is still pertinent, you may simply state as such in a letter to the Director and the letter, along with any applicable data submission requirements specified in this section shall constitute the annual certification.
(2) If you have substantially modified operation of any unit at your facility that impacts cooling water withdrawals or operation of your cooling water intake structures, you must provide a summary of those changes in the report. In addition, you must submit revisions to the information required at §122.21(r) of this chapter in your next permit application.
The certification statement shall be signed by the responsible corporate officer as defined in 40 CFR 122.22. [40 CFR 125.98(b)(4), 40 CFR 125.97(c)]
•	Recordkeeping Requirements:

The permittee shall keep records of the following items until the subsequent permit is issued:
(1)	 The permit application, and all submissions that are part of the permit application;
(2)	 All submissions that are part of the permit reporting requirements;
(3)	 Monitoring reports;
(4)	 Annual certification statement and report;
(5)	 Related supporting information and materials

All records supporting the Director's Determination of BTA for Entrainment under 40 CFR 125.98(f) or (g) must be retained until such time as the Director revises the Determination of BTA for Entrainment in the permit. [40 CFR 125.98(b)(4), 40 CFR 125.95(e)]
•	Entrainment BTA Determination:

The entrainment BTA determination is provided on pages 10-16 of this document. [40 CFR 125.98(f)(1) and (2)]

Other Permit Requirements

•	Neither free available chlorine nor total residual chlorine may be discharged from any unit for more than two hours in any one day and not more than one unit in any plant may discharge free available or total residual chlorine at any one time. [40 CFR 423.12(b)(8)]

•	All chlorine related monitoring requirements are applicable only if chlorine is instituted.

•	126 Priority Pollutants Certification

The permittee shall certify, not less than once annually (with the DMR due on January 28th of each year), that chemicals added for cooling tower maintenance, including such chemicals used for corrosion inhibition, do not result in the discharge via cooling tower blowdown of any of the 126 priority pollutants (excluding chromium and zinc) in detectable concentrations. Additionally, once for each product used for cooling tower maintenance (unless subsequent changes in the product formulation occur or, the product is obtained from a different source), compliance shall be demonstrated by submission of certification from the  manufacturer that such product contains no priority pollutants or, if any of the 126 priority pollutants are contained in such product, calculations which show that the addition of such product does not result in the discharge of the individual priority pollutant at concentrations greater than 10 micrograms per liter due to dilution within the cooling system. [40 CFR 423.13(d)(3)]
•	All chlorine related monitoring requirements are applicable only if chlorine is instituted.

•	Submit a Permit Application

Due within one year after permit effective date, the permittee shall submit to the MDEQ Environmental Permits Division a completed EPA Form 2C application containing the results of effluent sampling from the Outfall 008 discharge. The application should contain effluent sampling for all Table A parameters, for the Table B parameters for which testing is required or believed present, and the Table C parameters that are believed present. Based upon the results of the sampling, the permit may be reopened to address limits or requirements deemed necessary to protect water quality.

XII.	STATEMENT OF BASIS: 

It is our judgment that the foregoing limitations represent Technical Judgment (TJ), 11 Miss. Admin. Code Pt.6, Ch.1 and 2 (MSWQS), and the applicable Categorical Guidelines (Cat.). The permit limitations include the categorical limitations for low volume wastes (40 CFR 423.12(b)(3)), cooling tower blowdown (40 CFR 423.13(d)(1)), metal cleaning wastes (40 CFR 423.13(e)), coal pile runoff (40 CFR 423.12 (b)(9)), combustion residual leachate (40 CFR 423.12 (b)(11)), and the pH limitations of 40 CFR 423.12(b)(1).

ATTACHMENT A

FACILITY LOCATION MAP