PERMIT RATIONALE FOR REISSUANCE
Jackson POTW, Savanna Street
Hinds County
Jackson, Mississippi
Water NPDES No. MS0024295
March 7, 2017

CLASSIFICATION

Municipal Major

DESCRIPTION OF WASTEWATER

Domestic / Municipal Wastewater

DESCRIPTION OF WASTEWATER TREATMENT  

Wastewater is collected and treated by means of an activated sludge mechanical treatment plant followed by either Chlorine or UV disinfection. See attachment No. 1 for flow diagram.

RECEIVING WATERS

Pearl River. See attachment No. 2 for discharge location map. The receiving is classified as Fish and Wildlife, and is in the Pearl River Basin. This discharge is listed in the TMDLs for pH and Nutrients. The permit complies with the conditions of pH TMDL because the effluent is required to comply with water quality criteria before discharging. Total Nitrogen and Total Phosphorus limitations are included in the permit to comply with the nutrient TMDL. 

The instream wastewater concentration (IWC) 7Q10   at the point of discharge is determined by the following calculation:

Qw = Design flow of the wastewater treatment facility = 46 MGD or 71.21 cfs
Qr =  Receiving stream 7Q10 = 227 cfs
IWC = (Qw/ (Qw + Qr)) * 100 =  (71.21/ 71.21 + 227) =  23.88%

APPLICABLE GUIDELINES 

Mississippi Wastewater Regulations (11 Mississippi Admin code, part 6, Chapter 1), State of Mississippi Water Quality (11 Mississippi Admin code, part 6, Chapter 1), Wasteload Allocation (WLA), Total Maximum Daily Load (TMDL)

SUMMARY OF LIMITATIONS –

	Proposed Limitations

	Parameter						Value				Basis
	Flow (May – Oct)					46 MGD (Monthly Avg)			Design
	Flow (Nov – Apr)					60 MGD (Monthly Avg)			Design
	CBOD5 (May – Oct)					7 mg/l (Monthly Avg.)			WLA
	CBOD5 (Nov – Apr) 					20 mg/l (Monthly Avg.)			WLA
	CBOD5 (Percent Removal)			85% Minimum				Technology
	TSS						30 mg/l (Monthly Avg.)			Technology
	TSS (Percent Removal)				85% Minimum				Technology
	NH3-N (May – Oct)					2 mg/l (Monthly Avg.)			WLA
	NH3-N (Nov – Apr) 					3.3 mg/l (Monthly Avg.)			WLA
	Dissolved Oxygen					> 6.0 mg/l (Monthly Avg.)			WLA
	Fecal Coliform						200 # col/ 100 ml (Monthly Avg.)		11 MS code part 6
	pH						6.0 – 9.0 SU				TMDL
	Chlorine, Total Residual				0.046 mg/l (Monthly Avg.)			TMDL
	Total Nitrogen Effluent				Report lbs/day (Monthly Avg.)		TMDL
	Total Nitrogen Net Effluent			6031 lbs/day (Monthly Avg.)		TMDL
	Total Nitrogen Influent				Report lbs/day (Monthly Avg.)		TMDL
	Total Phosphorus Effluent			Report lbs/day (Monthly Avg.)		TMDL
	Total Phosphorus Net Effluent			 1297 lbs/day (Monthly Avg.)		TMDL
	Total Phosphorus Influent			Report lbs/day (Monthly Avg.)		TMDL
	Pimephale promelas					23.88% Minimum				11 MS code part 6
	Ceriodaphnia dubia	23.88% Minimum				11 MS code part 6

The minimum and maximum values for Dissolved Oxygen in aeration unit and 30-Minute Sludge Settleability in aeration unit must be reported.

The TMDL requires this Savanna Street facility to meet with Total Nitrogen 5220.9 lbs/day and Total Phosphorus 1131.7 lbs/day. The TMDL also gives opportunity for TP load to be adjusted in combination and divided between the three (3) Jackson facilities (Trahon/Big Creek, Savannah Street and OB Curtis) for a total of 1297 lbs/day. These effluent values are combined together to meet the TMDL combined load in the Jackson POTW, Savanna Street permit.

The Total Nitrogen load can also be adjusted in combination and divided between the three (3) Jackson facilities (Trahon/Big Creek, Savannah Street and OB Curtis) for a total of 6031 lbs/day. 
 
CBOD5, NH3-N and DO limits are based on the Wasteload Allocation and the STREAM model, which accounts for oxygen depletion in the receiving stream. The toxicity limit for NH3-N was determined by choosing more stringent of the modeled limit and the toxicity limit given in the Wasteload Allocation, to meet Water Quality Based Effluent Limitations ( WQBELs).

A reopener clause has been added to the permit which states that the NPDES MS0024295, shall be reopened and modified, or alternately revoked and reissued, accordingly to reflect any additional, or otherwise updated limitations, and any additional monitoring determined to be necessary to be consistent with the findings of any additional stream monitoring performed as a requirement of the approval of the 2015 Pearl River Nutrient TMDL of which this facility is a part.

The permit requires internal monitoring before the combination of the wastestreams from the activated sludge treatment plant (Outfall 101) and the stormwater lagoons (Outfall 201). The permit states that an effluent discharge by Outfall 201 will be considered a bypass of the wastewater treatment system, and is subject to the conditions of bypassing. The internal outfalls are used for monitoring purposes only.

Outfall 101 (Activated Sludge Treatment Plant)
Parameter				Value			
Flow				Report				

Outfall201 (Stormwater Lagoons)
Parameter				Value			
Flow				Report	
NH3-N				Report
CBOD5				Report
Mercury, Total Recoverable	Report
TSS				Report
pH				Report

WHOLE EFFLEUNT TOXICITY AND CHEMICAL SPECIFIC EVALUATION

WHOLE EFFLEUNT TOXICITY EVALUATION

In accordance to State Regulation 11 Mississippi Admin code part 6, chapter 1 VI.B.2b., a whole effluent toxicity evaluation was performed as part of the renewal application.  The applicant was to have tested in accordance with Short – Term Methods for estimating the Chronic toxicity of Effluents and Receiving Water to Freshwater organisms.  Short – term chronic WET test were performed on Ceriodaphnia dubia (invertebrate) and Pimephale promelas (vertebrate).  The results of the wet tests are as follows:

			March 2016
			Ceriodaphnia dubia		IC25    		100%
			Pimephales promelas		IC25   		>100%

			July 2016
			Ceriodaphnia dubia		IC25   		100%
			Pimephales promelas		IC25   		>100%

			August 2016
			Ceriodaphnia dubia		IC25     		100%
			Pimephales promelas		IC25     		>100%

			January 2017
			Ceriodaphnia dubia		IC25  		100%
			Pimephales promelas		IC25   		>100%

All of the inhibitaion concentrations were greater than the predicted IWC of 23.88%. Based upon the results of the WET testing, chronic bioassay requirements will not be placed within the municipal NPDES permit.

Chemical Specific Analysis

Chemical specific analysis has been performed in accordance with State Regulations 11 Mississippi admin code part 6, chapter 1 V1.B1.  Municipalities shall determine the toxic characteristics of their wastewater by analyzing for the toxic pollutant listed in Table III of appendix D of 40 CFR 122.  The results are tabulated in attachment No. 4.  The reported values are then analyzed and compared to water quality criteria (attachment No. 6) to determine any possible toxic effect to the receiving waters.  A synopsis of these calculations is listed in attachment No. 5.  A column by column description of the calculations in attachment No. 5 is hereby provided:

Column No. 1 – Maximum concentration.  The highest effluent reading of the parameter

Column No. 2 – The maximum concentration mixed with the receiving water IWC.  This     is calculated by the following equation:

{Maximum Concentration (Column 1) * IWC %} / 100

Column No. 3 – Acute allowable – Chemical Specific State Water Quality Criteria                                   
	Column No. 4 – Pass or Fail. If column 2 > column 3 water quality criteria is exceeded                              and failure occurs.

Column No. 5 – Long term average (LTA) of all tests.  The summation of the 12 samples divided by 12.

Column No. 6 – The long term average concentration mixed with the receiving water                                  IWC.  This is calculated by the following equation:

{LTA Concentration (Column 5) * IWC%} / 100

Column No. 7 – Chronic allowable – Chemical Specific State Water Quality Criteria                                   
Column No. 8 – Pass or Fail. If column 6 > column 7 water quality criteria is exceeded                                and failure occurs.

Column No. 9 – Human health determination.  Long term average (Column 5) is mixed                with the mean annual flow IWCMA .  This is calculated by the following                            equation:

{LTA Concentration (Column 5) * IWCMA %} / 100

Column No. 10 – Human health allowable – State Water Quality Criteria   Note: Organisms only column is used if receiving waters are not drinking water supply. 

	Column No. 11 – Pass or Fail.  If column 9 > column 10 water quality criteria is exceeded                        and failure occurs.

Chemical Specific Analysis for Metals and Results

Major municipalities shall determine the toxic characteristics of their wastewater by analyzing for toxic pollutants listed in Table II of Appendix D of 40 CFR 122.  Metal analysis shall be for total recoverable metals.  Municipalities shall submit twelve influent and effluent samples collected.  Chemical specific limits shall be placed in a permittee’s permit if any of the parameters evaluated in the toxic screening procedure indicate the reasonable potential for violation of the appropriate criteria (acute, chronic, and human health).
	
The chemical specific data results submitted did not indicate the reasonable potential for violation of the appropriate criteria in Table III of Appendix D of CFR 122.

Chemical specific analysis for Volatile Organics Compounds, Acid-Extractable Compounds, and Base-Neutral Compounds and Results

The chemical specific data results submitted had no detects for Acid-Extractable Compounds.

The chemical specific data results submitted had no detects for Base-Neutral Compounds.

For Volatile Organics, the facility had an average daily concentration of 0.0077 mg/l for Chloroform. According to the 2006 National Recommended: Water Quality Criteria, the Human Health criteria for Chloroform is 0.470 mg/l, Organisms Only. The average concentration, multiplied by the power of 10 (0.076 mg/l), due to less than 12 samples, does not present a reasonable potential to violate Human Health Criteria.  

For Volatile Organics, the facility had an average daily concentration of 0.0006 7 mg/l for Dichlorobromomethane. According to the 2006 National Recommended: Water Quality Criteria, the Human Health criteria for Dichlorobromomethane is 0.017 mg/l, Organisms Only. The average concentration is multiplied by the power of 10 due to less than 12 samples (0.0067 mg/l), does not present a reasonable potential to violate Human Health Criteria.  

For Volatile Organics, the facility had an average daily concentration of 0.0017 mg/l for Toluene. According to the 2006 National Recommended: Water Quality Criteria, the Human Health criteria for Toluene is 15 mg/l, Organisms Only. The average concentration, multiplied by the power of 10 (0.017 mg/l), due to less than 12 samples, does not present a reasonable potential to violate Human Health Criteria

Attachments
Attachment 1	See Application
Attachment 2	See Application
Attachment 3	Waste Load Application Letter
Attachment 4	Tabulated Metals Results 
Attachment 5 	Synopsis of Metals Results 
Attachment 6 	MS State Water Quality Criteria 

Attachment 3

Attachment 4

Attachment5

Attachment 6