PERMIT RATIONALE FOR REISSUANCE
Southern Natural Gas Company LLC, Louisville Compressor Station
Water NPDES No. MS0051021
Thomas Kelly, Water I Branch
June 26, 2024

I.	FACILITY INFORMATION

Facility Address:  945 Metts Street, Louisville, MS 39339    
	Facility County: Winston 
EPA ID.:  110001472727
SIC:  4922

II.	NATURE OF BUSINESS

Natural gas compressor station

III.	EFFLUENT AND RECEIVING STREAM FLOW DATA

Effluent from Outfall 001 consists of rainwater and groundwater from the compressor building basement sump. The outfall has a maximum daily flow of 0.0108 MGD and will discharge into an unnamed tributary (7Q10=0) of the Hughes Creek located in the Pearl River Basin. 

IV.	303(d) and TMDL ISSUES

A TMDL (Finalized June 2009) for nutrients, ammonia toxicity, and organic enrichment/low dissolved oxygen has been developed for Hughes Creek (Water Body ID  MS122E1). However, this facility was not among the point sources evaluated in the TMDL. Loading limits were not suggested for this facility. 

V.	TYPE OF WASTEWATER TREATMENT:

Oil/water separator.

VI.	EPA APPLICABLE CATEGORICAL GUIDELINES

None.

VII.	DATA FROM APPLICATION FORM (2C)

Parameter	Maximum Daily Value	
BOD	62 mg/L	
COD	< 20 mg/L	
TOC	2.97 mg/L	
TSS	146 mg/L	
Ammonia (as N)	< 2.50 mg/L	

	Parameter	Maximum Daily Value	
Flow	0.0108 MGD	
Temperature (winter)	17.8 ºC	
Temperature (summer)	17.8 ºC	
pH	7.67 SU	
Oil & Grease	7 mg/L	
Surfactants	<0.100 mg/L	
PCB-1242	<0.000555 mg/L	
PCB-1254	<0.000555 mg/L	
PCB-1221	<0.000555 mg/L	
PCB-1232	<0.000555 mg/L	
PCB-1248	<0.000555 mg/L	
PCB-1260	<0.000555 mg/L	
PCB-1016	<0.000555 mg/L	

VIII. 	WATER QUALITY LIMITATIONS BASED ON WASTELOAD ALLOCATION 

	None.

IX.	CATEGORICAL GUIDELINE LIMITATIONS CALCULATIONS

Not Applicable.

X.	CHEMICAL SPECIFIC SCREENING

Not Applicable

.
XI.	PROPOSED FINAL LIMITATIONS 

1.	Average Permit Limitations: 

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Monitoring Frequency	Sample Type	DMR Reporting Frequency	Basis1	
001	Flow (MGD)	--	--	Report	Report	Monthly 	Instantaneous Sampling	Quarterly	PPL, TJ	
001	TSS	--	--	30 mg/L	30 mg/L	Monthly	Grab Sampling	Quarterly	PPL, TJ	
001	BOD, 5-day	--	--	Report	Report	Monthly	Grab Sampling	Quarterly	PPL, TJ	
001	Oil and Grease	--	--	10 mg/L	10 mg/L	Monthly	Grab Sampling	Quarterly	PPL, TJ	
001	pH	--	6.0 SU	6.0 SU	6.0 SU	Monthly	Grab Sampling	Quarterly	PPL, MSWQC	

2.	Maximum Permit Limitations:  lbs/day (mg/L)

Outfall	Parameter	Categorical Limitation	Water Quality Limitation	Present Permit Limitation	Proposed Permit Limitation	Monitoring Frequency	Sample Type	DMR Reporting Frequency	Basis1	
001	Flow (MGD)	--	--	Report	Report	Monthly	Instantaneous Sampling	Quarterly	PPL, TJ	
001	TSS	--	--	45 mg/L	45 mg/L	Monthly	Grab Sampling	Quarterly	PPL, TJ	
001	BOD, 5-day	--	--	Report	Report	Monthly	Grab Sampling	Quarterly	PPL, TJ	
001	Oil and Grease	--	--	15 mg/L	15 mg/L	Monthly	Grab Sampling	Quarterly	PPL, TJ	
001	pH	--	9.0 SU	9.0 SU	9.0 SU	Monthly 	Grab Sampling	Quarterly	PPL, MSWQC	
1Basis:     PPL= Previous Permit Limit;  TJ = Technical Judgment; MSWQC = 11 Miss. Admin Code Pt. 6. Ch. 2